ADM14

Part and Assembly Modelingwith ANSYS DesignModeler 14

Huei-Huang Lee

Contents 1

ContentsPreface 2

Section A. Sketching 5

Exercise 1. Arm 6

Exercise 1a. Structural Analysis of the Arm 21

Exercise 2. Ratchet Stop 28

Exercise 3. Ratchet Wheel 35

Exercise 4. Cover Plate 44

Section B. Part Modeling 54

Exercise 5. Crank 55

Exercise 6. Geneva Gear Index 64

Exercise 7. Yoke 72

Exercise 8. Support 79

Exercise 8a. Structural Analysis of the Support 88

Exercise 9. Wheel 94

Exercise 10. Pipe 98

Exercise 11. C-Bar Dynamometer 106

Exercise 11a. Deformation of the C-Bar 111

Exercise 12. Threaded Shaft 119

Exercise 13. Lifting Fork 124

Exercise 14. Caster Frame 130

Section C. Assembly Modeling 144

Exercise 15. Threaded Shaft Assembly 145

Exercise 16. Universal Joint 152

Exercise 16a. Dynamic Simulation of the Universal Joint 165

Exercise 17. Clamping Mechanism 176

Exercise 17a. Simulation of the Clamping Mechanism 197

Section D. Concept Modeling 215

Exercise 18. 2D Solid Modeling (Arm) 216

Exercise 18a. Structural Analysis of the Arm Using 2D Model 219

Exercise 19. Surface Modeling (Support) 225

Exercise 19a. Structural Analysis of the Support Using Surface Model 230

Exercise 20. Line Modeling (Space Truss) 234

Exercise 20a. Structural Analysis of the Space Truss 240

2 Preface

Preface

Use of the BookThis book is designed for those who want to learn how to create parts and assembly models using ANSYS

DesignModeler. The author assumes no previous CAD/CAE experiences to begin with the book.

This book is mainly designed as an auxiliary tutorial in a course using ANSYS as a CAE platform. In particular,

this book can serve as a preparation to the author's another book Finite Element Simulations with ANSYS Workbench 14,

which emphasizes on finite element simulations rather than geometry modeling such that the exercises on geometry

modeling (especially assembly modeling) may not be adequate.

ANSYS DesignModelerANSYS DesignModeler is a CAD program running under ANSYS Workbench environment. The DesignModeler can

create geometries as sophisticated as any other CAD programs. Yet, many engineers choose to create geometry

models using other CAD programs (e.g., Pro/Engineer, SolidWorks) and then import them into an ANSYS simulation

module (such as Mechanical) for simulations. One of the reasons may be that, other than the training materials

provided by the ANSYS Inc., there exist no tutorials in the bookstore. That is the main reason that I created this book.

The DesignModeler is designed specifically for creating models which can be seamlessly imported into an ANSYS

simulation modules (such as Mechanical). Therefore, if a geometry model is solely used for ANSYS simulations, I

strongly suggest that we create the model from scratch using DesignModeler, rather than other CAD programs, to

avoid any unnecessary incompatibilities.

Structure of the BookThere are 20 exercises and 8 appendices in the book; each of them is designed in a step-by-step tutorial style. The 20

exercises involve creating parts and assemblies models, while the 8 appendices show how to perform simulations using

some of the models. If you are not currently interested in simulations, you may freely skip the 8 appendices without

affecting the learning of the 20 exercises.

An assembly consists of two or more parts. Each part can be viewed as boolean operations (union, subtraction,

etc.) of simpler 3D bodies. Each of the 3D bodies usually can be created by a two-step operation: drawing a 2D sketch

on a 2D plane and then generate the 3D body by extrusion, revolution, sweeping, or skin/lofting.

The book is divided into 4 sections. Section A lets students familiarize with sketching techniques. Section B

contains exercises of part modeling. Section C consists of exercises of assembly modeling. The last section introduces

the creations of concept models, including 2D models, surface models, and line models. A concept model is a

simplification of a 3D models, and is usually easier to create and more efficient to be simulated.

Preface 3

Companion WebpageA webpage dedicated to this book is maintained by the author:

http://myweb.ncku.edu.tw/~hhlee/Myweb_at_NCKU/ADM14.html

The webpage contains links to finished project files of each exercise and appendix. If everything works smoothly, you

do not need them at all. Every model can be built from scratch according to the steps described in the book. The

author provides these project files just in some cases you need them. For examples, if you have troubles to follow the

geometry details in the textbook, you may need to look up the geometry details from the project files.

Huei-Huang Lee

Associate Professor

Department of Engineering Science

National Cheng Kung University

Tainan, Taiwan

[email protected]

myweb.ncku.edu.tw/~hhlee

4

Section A. Sketching 5

Section ASketching

An assembly is a combination of parts. From manufacture point of view, a part is a basic unit for manufacturing process. Many parts can be created by a two-step operation: drawing a 2D sketch on a plane and then generate a 3D body by extrusion, revolution, sweeping, or skin/lofting.

The exercises in Section A are designed to introduce the 2D sketching techniques provided by the DesignModeler. Each part created in Section A involves drawing a sketch and then extrude to generate a 3D solid body representing the part.

Although it can be used as a general purpose CAD software, the DesignModeler is particularly designed for creating geometric models to be analyzed (simulated) under the ANSYS environment. To let the readers understand what it means by analysis (simulation) as early as possible, an exercise (Exercise 1a) is appended right after Exercise 1 to perform a structural analysis for the part created in Exercise 1. However, the reader has option to skip Exercise 1a without affect the subsequent learning of geometric modeling.

6 Exercise 1. Arm

X

Y

1.375

2.2

5

Unit: in.

Thickness: 0.125 in.

R0.5

3×D0.25

R0.313

R0.25

R0.313

[2] Details of the arm.

[3] The global coordinate

system.

[1] The arm is a part of a clamping mechanism.

Exercise 1Arm

In this exercise, we will create a 3D solid model for an arm, which is a part of a clamping mechanism [1]. The clamping mechanism will be introduced in Exercise 17 and simulated in Exercise 17a.

The arm model consists of a single solid body, which can be generated by extruding a sketch by a thickness of 0.125 inches [2].

Before creating a geometry model, we must set up a global coordinate system. For this exercise, we arbitrarily choose the global coordinate system as shown [3]. Note that the origin is on the back surface of the part.

1-1 Introduction

Exercise 1. Arm 7

[2] The <Workbench GUI> (graphical user interface) shows up.

[3] Click the plus sign (+) to expand <Component

Systems>. The plus sign becomes minus sign.

[4] Double-click to create a <Geometry> system.

[7] Double-click <Geometry> to start up the DesignModeler.

[6] You may click here to show the messages from ANSYS Inc. To hide the message, click it again.

[1] Launch ANSYS Workbench.

1-2 Start Up DesignModeler

[5] A <Geometry> system is created in the <Project

Schematic> area.

8 Exercise 1. Arm

[10] Click <OK>. Note that, after clicking and

entering DesignModeler, the length unit cannot be

changed anymore.

[9] Select <Inch> as length unit.

[8] <DesignModeler GUI> shows up.

Speech Bubbles1. In this book, each exercise is divided into subsections (e.g., 1-1, 1-2). In each subsection, speech bubbles are ordered with numbers, which are enclosed by pairs of square brackets (e.g., [1], [2]). When you read, please follow the order of speech bubble; the order is significant.2. The square-bracket numbers also serve as reference numbers when referred in other text. When in the same subsection, we simply refer to a speech bubble by its number (e.g., [1], [2]). When in the other subsections, we refer to a speech bubble by its subsection identifier and its bubble number (e.g., 1-2[1]).3. When a circle is used with a speech bubble, it is to indicate that mouse or keyboard ACTIONS are needed in that step [1, 3, 4, 7, 9, 10]. A circle may be filled with white color [1, 4, 7] or unfilled [3, 9, 10]. A speech bubble without a circle [2, 8] or with a rectangle [6] is used for commentary only, i.e., no mouse or keyboard actions are needed.

Workbench KeywordsA pair of angle brackets is used to highlight an Workbench keyword (e.g., <Component Systems> in [3]). Sometimes, if the angle brackets do not add any clarity, they may be dropped (e.g., DesignModeler).

Clicking and SelectingWhen we say "click" or "select," we mean left-click the mouse button.

Exercise 1. Arm 9

1-3 Prepare to Draw a Sketch on <XYPlane>

[1] By default, <XYPlane> is the current sketching

plane (active plane).

[2] Click to switch to <Sketching Mode>. Note that there are 5

toolboxes available: Draw, Modify, Dimension, Constraints, and Settings.

<Draw> is the default toolbox.

[3] Click <Look At Face/Plane/

Sketch> to rotate the view angle so

that you look at the current sketching

plane.

[4] By default, the ruler is on. In the next step, we will turn off the ruler to make

more sketching space.

[5] Select <View/Ruler> to turn it off. For the rest of this

book, we always leave the ruler off.

[6] This is the global coordinate system.

[7] This is the plane (local) coordinate

system.

10 Exercise 1. Arm

1-4 Draw a Circle with Dimension

[1] Select <Circle> tool.

[2] In case you don't see the <Circle> tool, scroll down to reveal

the tool.

[3] It gives you hints for using the tool.

[4] Move the mouse around the origin until a <P> (Point) appears

and then click the mouse to locate the center of the circle.

The ability to "snap" a point is a feature of the DesignModeler, called <Auto Constraints>.

[5] Move the mouse away from the center and then click the mouse to

create a circle with arbitrary radius.

[7] Select <Dimension>

toolbox.

[8] Select <Diameter> tool.

[9] Select the circle, move the mouse

outward, and then click to create a dimension.

Note that the circle turns blue, meaning the circle

has fully constrained (fixed in the space).

[10] In the <Details View>, type 0.25 for

the diameter.

[11] It is possible that the circle becomes too small. Select <Zoom to

Fit> tool to fit the sketch into the graphics window. Now, we may need to adjust (move) the position of the

dimension.

[6] As soon as you begin to draw, a name

is assigned to the sketch and it becomes

the active sketch.

Exercise 1. Arm 11

[12] Select <Move> tool. Remember to scroll

down to reveal a tool if you don't see the tool.

[13] Select the dimension, move to a suitable position, and

then click again.

[14] Whenever necessary, select <Zoom to Fit> tool to fit the

sketch into the graphics window.

[15] Select <Display> tool. You may need to scroll down to reveal

the tool if you don't see the tool.

[16] Click <Name> to turn the dimension name off. Note that

<Value> automatically turns on.

[17] Instead of displaying dimension name, now the dimension value is

displayed. For the rest of the book, we always display dimension values

instead of name.

12 Exercise 1. Arm

1-5 Draw Two More Circles

[1] Click anywhere in the graphics window and then scroll the mouse wheel down to zoom out the sketch roughly like this.

[2] Select <Draw> toolbox.

[4] Move the mouse around the horizontal

axis until a <C> (Coincident) appears

and then click the mouse to locate the center of the circle.

This center is snapped on the horizontal axis.

[5] Move the mouse until an <R> (Radius) appears and then click the

mouse. The radius dimension is constrained to be the same as the first circle. Note that the circle is

greenish-blue, meaning it is not fully fixed in the space yet. A

horizontal location is needed to fully defined the circle.

[6] Create another circle in a similar way. Make sure a <C> and an <R> appear before clicking. A vertical location is needed to fully

defined the circle.

[3] Select <Circle> tool.

Exercise 1. Arm 13

[7] Select <Dimension> toolbox

and then select <Horizontal> tool.

[8] Select the vertical axis. Note that the shape

of the mouse cursor changes when your mouse

is on the axis.

[9] Select the center of the circle. Note that the

shape of the mouse cursor changes when your

mouse is on the point.

[10] Move the mouse upward roughly here and click to locate a horizontal

dimension. Note that the circle turns blue (fully constrained).

[11] In the <Details View>, type 1.375 for

the horizontal dimension.

[12] Remember that you always can use <Zoom to Fit> and scroll the mouse wheel [1] to zoom in/out the view. Also, to "pan" the view, simply move the mouse while holding the

control-middle-button.

[13] Select <Vertical> tool.

[14] Select horizontal axis, select the center of the lower

circle, move the mouse leftward roughly here, and click to locate a vertical dimension.

The circle turns blue.[15] In the <Details View>, type 2.25 for

the vertical dimension.

[16] Before going further, make sure you familiarize the two most frequently used view

operations: scrolling the mouse wheel to zoom in/out the view and moving mouse with control-middle-button to pan the view.

14 Exercise 1. Arm

1-6 Draw Three Concentric Circles

[1] Select the <Draw/Circle> tool, and draw a

concentric circle. Make sure a <P> appears before defining the center.

[2] Select the <Dimension/Radius> tool, and create a radius dimension for the circle. In the <Details

View>, type 0.313 for the radius.

[3] Select the <Draw/Circle> tool, and draw a concentric circle with the

same radius as the previous circle. Make sure a <P> appears before defining the center and an <R>

appears before defining the radius.

[4] With the <Draw/Circle> tool still selected, draw a

concentric circle. Make sure a <P> appears before defining

the center.

[5] Select the <Dimension/Radius> tool, and create a radius dimension for the circle. In the <Details View>, type 0.5 for the

radius.

Exercise 1. Arm 15

1-7 Draw Tangent Lines

[1] Select the <Draw/Line by 2 Tangents> tool, and

then select the two circles to be tangent to. A tangent

line is created.

[2] Create additional three tangent lines in a

similar way.

16 Exercise 1. Arm

1-8 Draw a Fillet

[1] Select the <Modify/Fillet> tool, and type 0.25

for <Radius>.

[2] Select these two lines. A fillet is created. Note that the fillet is not blue-

colored. We need to specify the radius. The

radius typed in [1] is not necessarily the final

dimension; it just serves as a default dimension.

[3] Select the <Dimension/Radius> tool, and create a radius dimension for the fillet. You don't need to type in the <Details View>, since the default value

[1] is automatically used. Note that the color turns blue now.

Exercise 1. Arm 17

1-9 Trim Away Unwanted Segments

[1] Select the <Modify/Trim> tool, and turn on <Ignore Axis>, meaning

that the axes will not serve as trimming tools.

[2] Click the circle roughly here to trim away the arc. Note that when you select an edge (a line or a

curve), the remaining edges will serve as

trimming tools.

[3] Click to trim away two other

arcs.

[4] The sketch after trimming.

18 Exercise 1. Arm

1-10 Extrude the Sketch to Create the Arm

[1] Select <Extrude> tool.

[2] It automatically switches to

<Modeling Mode>, in which a <Tree

Outline> is displayed, which will be explained later.

[3] Click the little cyan sphere

to rotate the view into an

isometric view.

[4] Type 0.125 for the <Depth>.

[6] Click <Generate> to produce a 3D solid

body.

[7] Click <Display Plane> to turn off the

display of XYPlane (and the sketches it contains).

1-11 Save the Project and Exit Workbench

[1] Select <File/Close DesignModeler>. The <DesignModeler GUI>

disappears.

[2] In the <Workbench GUI>, save the project

as "Arm."

[3] Select <File/Exit> to quit

from the Workbench.

[5] The active sketch is automatically taken as

<Geometry>.

Exercise 1. Arm 19

Global Coordinate SystemBefore creating a geometry model, you must set up a global coordinate system (1-1[3], 1-3[6]).

Workbench GUIIn the <Workbench GUI> (1-2[2]), you can create a system (1-2[4]) and start up DesignModeler (1-2[7]). Other capabilities will be introduced later.

Project SchematicCreated systems appear on the <Project Schematic>, an area in the <Workbench GUI>.

DesignModeler GUIGeometries are created entirely within the <DesignModeler GUI> (1-2[8]).

Length UnitBefore creating a model in the DesignModeler, you must choose a length unit (1-2[9, 10]). The length unit cannot be changed thereafter.

Mouse OperationsClick -- Left-click the mouse button.Select -- Left-click the mouse button.Double-Click -- Left-click the mouse button twice.Zoom In/Out -- Scroll the mouse wheelPan -- Move the mouse while holding control-left-button.Other mouse operations will be introduced later.

Current Sketching PlaneEach sketch is stored in the current sketching plane (1-3[1]). Manipulating (switching, creating, etc.) sketching planes will be introduced later.

Sketching Mode v.s. Modeling ModeTools for sketching are provided in the <Sketching> mode (1-3[2]), while tools for creating and manipulating bodies are provided in the <Modeling> mode (1-10[2]). There are 5 toolboxes available: Draw, Modify, Dimension, Constraints, and Settings. Tools in <Modeling> mode includes <Extrude> (1-10[1]). Some tools are available in both modes, e.g., <Zoom To Fit> (1-4[11]).

Look At Face/Plane/SketchClicking this tool to rotate the view angle so that you look at the current sketching plane (1-3[3]).

RulerThe ruler (1-3[4, 5]) is to help you obtain a better feeling of the drawing scale. In this book, we always leave the ruler off to make more sketching space.

Plane Coordinate SystemEvery plane has its own coordinate system (1-3[7]); it is also called a local coordinate system. The plane coordinate system will be explained further later.

1-12 Review

20 Exercise 1. Arm

ScrollingIn case you don't see a tool in a toolbox, scroll down/up to reveal the tool (1-4[2]). There is also a scrolling controller for the <Details View>.

Tools in <Draw> ToolboxCircle -- Draw a circle, giving the center and the radius (1-4[1, 3-5]).Line by 2 Tangent -- Draw a line tangent to two curves (including circles and arcs) (1-7[1, 2]).

Tools in <Dimension> ToolboxRadius -- Specify a radius dimension by selecting a circle (1-4[6, 8-10]) or an arc (1-8[2]).Move -- Move (relocate) a dimension name/value by dragging the name/value (1-4[12, 13]).Display -- This tool is to toggle the display of dimension name and the dimension value (1-4[15-17]).

In this book, we always turn off the dimension name and turn on the dimension value.Horizontal -- Specify a horizontal dimension by first selecting a or a point (or a vertical line) and

then a second point (or a vertical line) (1-5[7-10]).Vertical -- Specify a vertical dimension by first selecting a or a point (or a horizontal line) and

then a second point (or a horizontal line) (1-5[13, 14]).

Tools in <Modify> ToolboxFillet -- Create a fillet by selecting two lines or curves (1-8[1-3]).Trim -- Trim away unwanted segments (1-9[1-4]).

Auto ConstraintsP -- The mouse cursor snaps to a point (or the origin) (1-4[4]).R -- The radius is the same as another circle (or arc) (1-4[5]).C -- The mouse cursor is coincident to a line (or an axis) (1-5[4, 6]).Other auto constraint features will be introduced later.

Color CodesGreenish-blue -- Under-constrained (1-8[2])Blue -- Fully constrained (fixed in the space) (1-4[9], 1-5[10,14]).Red -- Over-constrained

Zoom To FitClick this tool to fit the entire sketch (in the <Sketching> mode) or entire model (in the <Modeling> mode) into the graphics window (1-4[14]).

ExtrudeThis tool extrude a sketch by a specified depth to create a 3D body (1-10[1-5]). More exercises will be given later.

Isometric ViewClick the little cyan sphere of the triad will rotate the view into an isometric view (1-10[3]). Other view controls will be introduced later.

Display PlaneThis tool is to toggle the display of current sketching plane and the sketches it contains (1-10[6]).


[2] This is the deformed structure under the design loads. The wireframe is the underformed configuration. Note that, for visual effects, the deformation has been

exaggerated.

Appendix:

Exercise 1aStructural Analysis of the Arm

Although it can be used as a general purpose CAD software, the DesignModeler is particularly designed for creating geometric models to be analyzed (simulated) under the ANSYS environment. The purpose of this exercise is to let the readers understand what it means by analysis (simulation). However, the reader has option to skip this exercise without affect the subsequent learning of geometric modeling.

In this exercise, we will perform a static structural analysis for the arm created in Exercise 1. The objective is to find the deformation and stresses under the working loads.

The clamping mechanism is entirely made of steel and is designed to withstand a clamping force of 450 lbf [1]. After a structural analysis of the entire mechanism [2] (also see Exercise 17a), the results show shows that, to withstand a clamping force of 450 lbf, the arm is subject to external forces as shown [3] (also see 17a-13). Note that the external forces are in a state of static equilibrium.

The analysis for the entire clamping mechanism will be perform in Exercise 17a. In this exercise, we will only perform a analysis on the arm. The purpose is to make sure the stresses are within the allowable stress of the steel, which is 30,000 psi.

The analysis task cannot not be performed in DesignModeler. Rather, it is carried out with <Mechanical>, another Workbench application program.

1a-1 Introduction

[1] The clamping mechanism is

designed to withstand a clamping force of

450 lbf.

281 lbf 126 lbf

264 lbf 187 lbf

407 lbf

77 lbf

[3] The external forces on the arm. These forces are

calculated according to

17a-13.

22 Exercise 1a. Structural Analysis of the Arm

[2] Open the project "Arm," which was saved in Exercise 1.


1a-2 Start Up <Mechanical>

[3] Double-click to create a <Static Structural>

analysis system.

[4] Drag <Geometry>...

[5] And drop here. A link is created, indicating that both <Geometry> share

the same data.

[6] Double-click to start up the

<Mechanical>.


[7] This is the <Mechanical> GUI. Note that the model is automatically brought into <Mechanical>. By default, the body

is assumed to be made of steel.

[8] Make sure the length unit is <in.>. If not,

select the right unit from the pull-down menu <Units> (see [9]).

[9] If the length unit is not <in.>, select <Units/U.S. Customary (in,

lbm, lbf, F, s, V, A)>. Unlike DesignModeler, the units can be changed any time as you like in

<Mechanical>.


1a-3 Specify Loads

[1] Click to highlight <Static Structural>.

[2] Select <Loads/Force>.

[3] A <Force> object is inserted under the <Static

Structural> branch.[4] Select this

cylindrical face.

[5] Click <Apply>.

[6] Select <Components>.

[7] Type -187 (lbf) for <X Component>, and 126 (lbf)

for <Y Component>.

[8] Select <Loads/Force> again.

[9] A <Force 2> object is inserted.

[10] Select this cylindrical face.

[11] Click <Apply>.


[13] Type 264 (lbf) for <X Component>, and 281 (lbf)

for <Y Component>.


[1] Select <Supports/Fixed Support>.

[2] A <Fixed Support> is inserted.

[4] Click <Apply>.


1a-4 Specify Supports

1a-5 Insert Result Objects

[1] Click to highlight <Solution>.

[3] A solution object is inserted under the <Solution> branch.

[2] Select <Stress/Equivalent (von-Mises)>.


1a-6 Solve the Model[1] Click <Solve>.

[7] Click to close the <Message> window.

[8] Click <Play> to animate the deformation.

[9] Click <Stop> to stop the animation.

[2] Click the Z-axis to rotate the view so that you look into the

<XYPlane>.

[3] The maximum stress is 29,690 psi, slightly below

the allowable stress (30,000 psi). Note that the

maximum stress can be reduced by increasing the

radius of the fillet.

[6] For visual effect, the

deformation is automatically

enlarged 49 times. [5] Undeformed shape.

[4] Select <Edges/Show Undeformed

WireFrame>.


1a-7 Save the Project and Exit Workbench

[1] Select <File/Close Mechanical>. The <Mechanical GUI>

disappears.

[2] In the <Workbench GUI>, save the project as

"Arm-a".

[3] Select <File/Exit> to quit from the Workbench.

28 Exercise 2. Ratchet Stop

Exercise 2Ratchet Stop

The ratchet stop is used to control a ratchet wheel so that the ratchet wheel rotates in a certain direction only [1, 2]. The ratchet wheel will be created in Exercise 3. In this exercise, we'll create a 3D solid model for the ratchet stop.

The details of the ratchet stop are shown in the figure below [3]. Note that the coordinate system is also shown in the figure.

2-1 Introduction [2] The ratchet stop is used to control the

rotational direction of the ratchet wheel.

[1] The ratchet wheel.

Y

X

0.57

0.1

25

Unit: in.


R0.56

R0.188

R0.34

0.16 S

lop: 4

0 [3] Details of the

ratchet stop.


[2] Double-click <Geometry> cell to start

up the DesignModeler. Select <Inch> as the length

unit (1-2[9, 10]).

[1] Launch ANSYS Workbench and create a

<Geometry> system (1-2[1-5]).


2-3 Draw a Circle on XYPlane

[1] Switch to <Sketching

Mode> (1-3[2]).

[2] Rotate to XYPlane view

(1-3[3])

[3] Draw a circle centered at the plane origin

(1-4[1-5]).

[4] Select <Dimension/Radius> tool and specify a radius of 0.188 (in.) for the circle.

Remember to turn on the display of dimension value (1-4[15-17]). Also remember to use

<Dimension/Move> to move the dimension to a suitable position (1-4[12, 13]).


2-4 Draw a Line

[1] Select <Draw/Line> tool and

draw a line roughly like this.

[2] Select <Dimension/General> tool and create a length

dimension by simply selecting the line segment and move the

mouse upward. Specify a dimension value of 0.16 (in.).

[3] Select <Dimension/Horizontal> tool and specify a horizontal

dimension of 0.57 (in.) (1-5[7-11]).

[4] Select <Dimension/Vertical> tool and specify a vertical dimension of 0.125 (in.) (1-5[13-15]).

[5] The line is not blue-colored, meaning it isn't fully defined in the space yet. We

now specify an angle dimension for the line.

2-5 Specify an Angle Dimension

[1] To specify an angle dimension, you need to select two lines (or axes). When you select a line (or axis), the end near where you click become the "arrow end" of the line. The angle is then measured from the first

line to the second line in a counter-clockwise fashion.

[2] Select <Dimension/Angle> tool and then click the X-axis on the

positive side.[3] Click the line here near the

upper-right end.

[4] Click here to create an angle dimension.

Type 40 (degrees) in the <Details View>. Note

that the angle is measured counter-

clockwise from the first line to the second. Also

note that the line is blue-colored now.

[5] If you made mistakes (click on wrong ends or in a wrong order) and the angle is not what you meant, right-click anywhere in the graphics window to

bring up a <Context Menu> and choose <Alternate Angle>. Repeat this before you click to locate the angle dimension until the correct angle appears.


2-6 Draw Arcs

[1] Select <Draw/Arc by Center> tool and then click roughly here to

define the center.

[3] Click to define another end roughly here on the circle.

[2] Click the upper-right end of the line to define an end of

the arc.

[4] An arc is created.

[5] Select <Dimension/Radius> tool and specify a radius

dimension of 0.56 in. [6] Select <Constraints/Tangent> tool and then select

the arc and the circle. A <Tangent> constraint is

imposed between the arc and the circle. Note that the arc

turns blue.

[7] Also note that the center of the arc moves to a new location to accommodate the constraint.


[8] Select <Draw/Arc by Center> tool again and

define the center roughly here.

[9] Click the lower-left end of the line to define an end of the

arc.

[10] Click to define another end roughly here on the circle.

[11] Select <Dimension/Radius> tool and specify

a radius dimension of 0.34 in.

[12] Select <Constraints/Tangent> tool and impose a

<Tangent> constraint between the newly created

arc and the circle.



[1] Select <Modify/Trim> tool and make sure <Ignore Axis> is turned on (1-9[1]). Click here to trim away the arc segment.

[2] The finished sketch.

2-8 Extrude the Sketch to Create the Ratchet Stop

[1] Extrude the sketch 0.125 in. to create the

ratchet stop (1-10[1-6]).

Wrap UpClose DesignModeler, save the project as "Stop," and exit the Workbench (1-11[1-3]).


Context MenuWhen you right-click the mouse, a menu pops up. The contents of the menu depends on when and where you right-click the mouse. The menu is thus called the <Context Menu> (2-5[5]). Try to right-click anywhere in the graphics area, <Details View>, or <Tree Outline> (1-10[2]), to see the contents of the <Context Menu>.

<Dimension/General> ToolThis tool can be used for any type of dimension. For a line, the default is to create a <Length> dimension (2-4[2]). For a circle or arc, the default is to create a diameter dimension. If the default is not what you want, right-click anywhere in the graphics window to bring up the <Context Menu> [1] and choose a dimension type.

<Dimension/Angle> ToolTo specify an angle dimension, you need to select two lines (or axes). When you select a line (or axis), the end near where you click become the "arrow end" of the line. The angle is then measured from the first line to the second line in a counter-clockwise fashion (2-5[1-4]).

If you made mistakes (click on wrong ends or in a wrong order) and the angle is not what you meant, right-click anywhere in the graphics window to bring up the <Context Menu> [2] and choose <Alternate Angle>. Repeat this until the correct angle appears before you click to locate the angle dimension (2-5[5]).

<Draw/Line> ToolThis tool draws a line by defining two end points (2-4[1])).

<Draw/Arc By Center> ToolThis tool draws an arc by defining its center and two end points (2-6[1-4]).

<Constraints/Tangent> ToolThis tool impose a <Tangent> constraint between two curves or between a line and a curve (2-6[6, 12]).

2-9 Review

[1] This is the <Context Menu> when <Dimension/General> is

activated.

[1] This is the <Context Menu> after you select two lines (or axes) and

before you click to create an angle dimension.

Exercise 3. Ratchet 35

Exercise 3Ratchet Wheel

In this exercise, we'll create a 3D solid model for the ratchet wheel mentioned in Exercise 2 [1]. The details of the ratchet wheel are shown in the figure below [2].

3-1 Introduction

[1] The ratchet wheel.

Y

X

Unit: in.

Thickness: 0.25 in.

D0.25

1.00

15

60

[2] Details of the ratchet

wheel.

36 Exercise 3. Ratchet



unit.


<Geometry> system.


3-3 Draw Two Concentric Circles

[1] On XYPlane, draw two concentric circles with

diameters of 0.25 in. and 1.00 in. respectively.


3-4 Draw Lines with Angle Dimensions

[1] Draw a line passing the origin like this.

[2] Specify an angle dimension of 15 degrees. Remember to select the line first and then

the axis. Clicking positions are also important (2-5[1-5]).

[3] Draw another line like

this.

[4] Specify an angle dimension of 60

degrees.



[1] Draw a circle which passes through an end point of the line.

When you define the radius, remember to snap (with a <P>

constraint) the end point of the line. The circle serves as a construction

(temporary) circle.

[2] Trim away unwanted segments.

Remember to turn on <Ignore Axis> (1-9[1]).

[3] After trimming, a single tooth remains.


3-6 Duplicate Teeth

[1] Select <Modify/Copy>.

[2] Select these two lines. To select multiple entities, hold Control key while click the

entities sequentially. You also can "sweep select" multiple entities, i.e., holding left mouse button

while sweep through the entities. After the selection, the entities

are highlighted with yellow color.

[3] Right-click anywhere in the

graphics window to bring up the

<Context Menu>, and select <End/Use Plane

Origin as Handle>. Now the tooth has been copied to a

"clipboard."

[4] The <Modify/Paste> tool is automatically activated. Type 15

(degrees) for the <r>, meaning that the rotating

angle is 15 degrees.


[5] Bring up the <Context Menu>,

and select <Rotate by -r Degrees>. Note that a negative angle

is to rotate clockwise. [6] Bring up the

<Context Menu> again, and select <Paste at Plane

Origin>.

[7] The tooth is rotated 15 degree clockwise (using plane origin as

center of rotation) and

pasted.

[8] Repeat steps [5, 6] four more times. Press <Esc> to end the tool or choose <End> from the <Context Menu>.


[9] Select <Modify/Copy> again, and

select all the teeth, using "sweep

select" [2]. From the <Context Menu>, select <End/Use Plane Origin as Handle> [3].

[10] Type 90 (degrees) for the rotating angle.

[11] Repeat steps [5, 6].

[12] Repeat steps [5, 6] two more times. Press <Esc> to

end the tool or choose <End> from the <Context Menu>.


3-7 Extrude the Sketch to Create the Ratchet Wheel

Wrap UpClose DesignModeler, save the project as "Ratchet," and exit the Workbench.

[1] Extrude the sketch 0.25 in. to create the ratchet

wheel.


Selection of Multiple EntitiesThere are several ways to select multiple entities. Two of them are <Control-Select> and <Sweep Select>.

Control-Select -- Click the entities sequentially while holding the Control key.Sweep Select -- Hold the left mouse button and sweep through the entities.Box Select -- Select <Select Mode/Box Select> [1], and use mouse to define a box.

All entities inside the box are selected.

3-8 Review

<Modify/Copy> and <Modify/Paste> Tools<Modify/Copy> copies the selected entities to a "clipboard." A <Paste Handle> must be specified using one of the methods in the <Context Menu> (3-6[3]). After completing the <Copy> tool, the <Paste> tool is automatically activated.

<Modify/Paste> pastes the entities in the "clipboard" to the graphics window. The pasting location corresponds to the <Paste Handle> specified in the <Copy> tool. To define the pasting location, you either click on the graphics window or choose from the <Context Menu> (3-6[6]). Many options also can be chosen from the <Context Menu> (3-6[5]), where the rotating angle <r> and the scaling factor <f> can be specified with the tool (3-6[4]). A positive rotating angle is to rotate counter-clockwise.

<Modify/Replicate> Tool<Replicate> is equivalent to a <Copy> followed by a <Paste>.

Ending a ToolYou can press <Esc> to end a tool (3-6[8, 12]). Besides, the <Context Menu> often provides an <End> option to end a tool (3-6[5, 6]).

[1] One way to select multiple entities is to

turn on <Select Model/Box Select>.

44 Exercise 4. Cover Plate

Exercise 4Cover Plate

In this exercise, we'll create a 3D solid model for a cover plate, of which the details are shown in the figure below [2].

4-1 Introduction

Y

X

Unit: in.


8 ×R0.15

2.0

0

[1] Details of the cover plate.

0.376 1.

25

0.7

5

0.2

5 0

.25

0.562

1.50

6 ×R0.06

0.312 0.312

2 ×R0.188 2 ×D0.201




unit.


<Geometry> system.


4-3 Draw Circles

[1] On XYPlane, draw a circle centered at the

origin and with a diameter of 0.201 in.

[2] Draw another circle with the same diameter.

Make sure an <R> appears when you define the radius

(1-5[5]).

[3] Use <Dimension/Horizontal> to specify a dimension of 0.376 in.

[4] Use <Dimension/Vertical> to specify a

dimension of 2 in.


[5] Draw a concentric circle with a radius of

0.188 in.

[6] Draw a concentric circle with the same radius. Make sure an <R> appears when you define the radius.

4-4 Draw Rectangles and Lines

[1] Select <Draw/Rectangle> and draw a

rectangle with dimensions a shown.


[2] Select <Draw/Polyline> and draw three segments like this. Select <Open End> from the <Context Menu> after you

define the fourth point. Note that the three segments are either horizontal or vertical,

therefore make sure an <H> or a <V> appears before clicking.

Specify the dimensions as shown.

[3] Select <Draw/Line> again and draw a line like this. Note that the two end points coincide with

the Y-axis.

[4] Trim away this extra segment.

[5] Trim away this extra segment.


[6] Use <Draw/Line> again to draw a vertical

line and specify a horizontal dimension as

shown.

[7] Trim away this segment.




4-5 Draw Fillets

[1] Select <Modify/Fillet>

and type 0.06 (in.) for the <Radius>.

[2] Create 6 fillets with the same radius

(1-8 [2]).

[3] Create a radius dimension for

anyone of the fillets (1-8[3]).

[4] Select <Modify/Fillet>

again and type 0.15 (in.) for the <Radius>.

[5] Create 4 fillets with the same

radius.


[6] With <Modify/Fillet> tool still activated, create this fillet by clicking the horizontal line and the circle. Note that the

horizontal line is automatically trimmed.

[7] Repeat the last step to create this fillet.

[8] Use <Draw/Line> to re-create the

trimmed segment.

[9] Repeat the last step to re-create this line.



[10] Use <Modify/Fillet> to create this fillet (with the same radius as before) by

clicking the horizontal line and the circle.

[11] Repeat the last step to create this fillet.

[1] Select <Modify/Trim> and turn on <Ignore Axis>, then

trim away this segment.

[2] And this segment.

[12] Create a radius dimension for anyone

of the 8 fillets.


4-7 Extrude the Sketch to Create the Cover Plate

Wrap UpClose DesignModeler, save the project as "Cover," and exit the Workbench.

[3] The final sketch.

[1] Extrude the sketch 0.046 in. to create the

cover plate.


<Draw/Rectangle>Draws a rectangle by defining two diagonally opposite points. The edges of the rectangle are either horizontal or vertical. To draw a rectangle at an arbitrary orientation, please use <Draw/Rectangle by 3 Points>.

<Draw/Polyline>This tool allows you to draw a series of connected lines, called a polyline. The polyline can be closed or open. After defining the last point, choose <Open End> or <Closed End> from the <Context Menu>.

Auto ConstraintsH -- HorizontalV -- Vertical

4-8 Review

Note:For a comprehensive description of sketching tools, please refer to the following ANSYS on-line reference:ANSYS Help System//DesignModeler User Guide//2D Sketching

54 Section B. Part Modeling

Section BPart Modeling

As mentioned in the opening of Section A, many parts can be created by a two-step operation: drawing a 2D sketch on a plane and then generate a 3D body by extrusion, revolution, sweeping, or skin/lofting.

A more complicated part often can be viewed as a series of the two-step operations; each two-step operation either add material to the existing body or cut material from the existing body. The exercises in Section B are designed to introduce the 3D modeling techniques for more complicated parts.


Exercise 5Crank

In this exercise, we'll create a 3D solid model for a crank, of which the details are shown in the figure below. Note that a global coordinate system is set up and shown in the figure.

The crank model can be viewed as a series of three two-step operations; each involves drawing a sketch on XYPlane and then extrude the sketch to generate a material. The materials are either add to the existing body or cut from the existing body.

5-1 Introduction

Y

X

Unit: mm.

75

65

Y

Z

20 8

R22

D30

D20

R10

2 ×R10 2 ×D10

56 Exercise 5. Crank


up DesignModeler.


<Geometry> system.


5-3 Draw a Sketch on XYPlane

[1] On XYPlane, draw 5 circles and 4 tangent lines (using <Draw/Line by 2

Tangents>) like this. Specify the dimensions.

[3] Select <Millimeter> as the

length unit.


[2] Use <Modify/Fillet> to draw a fillet

with a radius of 10 mm.

[3] Trim away these three arc segments.


5-4 Extrude to Create a Solid Body

[3] Click <Extrude>.

[4] It automatically switches to

<Modeling Mode>.

[1] The active plane.

[2] The active sketch.

[6] Click <Apply>. The active sketch is automatically taken for <Geometry>.

[7] Type 8 (mm) for <Depth>.

[9] Click <Generate>.

[8] Click the small cyan

sphere to rotate the view into an isometric view.

[10] Click <Display Plane> to turn off the plane display.

[12] Click all the plus signs <+> to expand the model

tree.

[11] The <Tree Outline> displays a

tree structure for the geometry model,

called <Model Tree>.

[13] Under the XYPlane, we've created a sketch

(Sketch1)

[14] The <Extrude1> uses <Sketch1> as the base geometry.

[5] An <Extrude1> object is inserted in

the model tree.

[15] This is the body we've

created so far.


5-5 Create a New Sketch on XYPlane

[3] Click to switch to <Sketching

Mode>.

[2] A new sketch (Sketch2) is created. Note that, for the first sketch of a plane, you don't need to explicitly click <New

Sketch>. However, for additional sketches on the same plane, you need to click <New Sketch>. Remember that the

drawing entities always belong to the active sketch.[4] Click <Look At

Face/Plane/Sketch>.

[5] Click <Display Model> to turn off

the solid model display.

[6] Draw a circle with a diameter of 30 mm. This is the only entity in <Sketch2>. Note that both

Sketch1 and Sketch2 are on the same plane (XYPlane).

[1] Click <New Sketch>.


5-6 Add Material to the Existing Body


[2] Click <Apply>.

[3] Type 20 (mm).[5] Click

<Generate>.

[6] The newly created material is simply a

cylinder; it adds to the existing body to form a

single body.

[4] The default <Operation> is <Add

Material>.

[8] Click the plus sign <+> to

expand <Extrude2>.

[9] <Extrude2> uses <Sketch2> as

the base geometry. The <Extrude2> is

simply a cylinder.

[10] The body after adding

material.

[7] <Sketch2> is added under

XYPlane.


5-7 Create Another New Sketch on XYPlane


Mode>.

[2] A new sketch (Sketch3) is created. [4] Click <Look At

Face/Plane/Sketch>.

[5] Click <Display Model> to turn off

the solid model display.

[6] Draw a circle with a diameter of 20 mm. This is the only entity in <Sketch3>. Note that all three sketches are on

the same plane (XYPlane).

[1] Click <New Sketch>.


5-8 Extrude to Create a Third Simple Body

Wrap UpClose DesignModeler, save the project as "Crank," and exit the Workbench.


[2] Click <Apply>.

[4] Select <Through All>.


[6] The newly created material is simply a

cylinder; The material is cut from the existing body.

[3] Select <Cut Material>.

[10] The body after cutting

material.

[7] <Sketch3> is added under

XYPlane.

[9] <Extrude3> uses <Sketch3> as

the base geometry. The <Extrude3> is

simply a cylinder.

[8] Click the plus sign <+> to

expand <Extrude3>.


<Plane> and <Sketch>A sketch must be created on a plane; each plane, however, may contain multiple sketches. In the beginning of a DesignModeler session, three planes are automatically created: XYPlane, YZPlane, and ZXPlane. You can create new planes and new sketches as many as needed.

<Active Plane> and <Active Sketch>The currently active plane and active sketch are shown in the toolbar (5-4[1, 2]). New sketches are created on the active plane, and new drawing entities are created on the active sketch. You may change the active plane or active sketch by selection from the pull-down list, or simply clicking the names on the model tree.

Modeling ModeIn the modeling mode (5-4[4]), several modeling tools become available, including Extrude, Revolve, Sweep, Skin/Loft, Thin/Surface, Blend, Chamfer, Point, etc. In addition, a <Tree Outline> is displayed.

Model Tree<Tree Outline> (5-4[11]) contains an outline of the model tree, the data structure of the geometric model. Each branch of the tree is called an object, which may contain one or more objects. At the bottom of the model tree is a part branch, which is the only object that will be exported to <Mechanical>. By right-clicking an object and selecting a tool from the context menu, you can operate on the object, such as delete, rename, duplicate, etc.

The order of the objects is relevant. <DesignModeler> renders the geometry according to the order of objects in the model tree. New objects are normally added one after another. If you want to insert a new object BEFORE an existing object, right-click the existing object and select <Insert/...> from the context menu. After insertion, <DesignModeler> will re-render the geometry.

<Add Material> and <Cut Material>With <Add Material> operation mode, the created material adds to the existing active body (i.e., they form a union). With <Cut Material> operation mode, the material is cut from the existing active body. An active body is one that is not frozen (to be defined later).

5-9 Review

64 Exercise 6. Geneva Gear Index

Exercise 6Geneva Gear Index

In this exercise, we'll create a 3D solid model for a Geneva gear index, of which the details are shown in the figure below. Note that a global coordinate system is set up and shown in the figure.

6-1 Introduction

Y

X

Unit: in.

Y

Z

0.25

D0.5

0.44

D0.25

D1.25

D2.47

5 × 0.2 5 ×R0.63

1.529


[2] Double-click <Geometry> cell to start up the

DesignModeler. Select <Inch> as the length unit.


<Geometry> system.


6-3 Draw a Sketch on XYPlane

[1] On XYPlane, use <Draw/Arc by Center> to draw an arc centered at

the origin and with a radius of 1.235 (in.) like this.

[2] draw two lines, each connects the origin to an

end point of the arc.

[3] Specify an angle dimension of 72 (degrees) for the

sector.

[4] Use <Draw/Arc by Center> to draw another arc with a radius of 0.625

(in.) like this.

[5] draw two circles centered at end points

of the new arc and with the same radius

of 0.1 (in.).


[8] Apply a <Constraints/Tangent> on the lower circle and

the horizontal line.

[7] Draw a line connecting the upper circle to the outer arc like this. The line is parallel to the adjacent line,

therefore make sure a <//> (indicating parallel auto constraint)

appears before clicking.

[9] Apply a <Constraints/Tangent> on the upper

circle and the parallel line.

[6] Draw a line connecting the lower circle to the outer arc like this. The

line is horizontal, therefore make sure an <H> appears before clicking.


[10] Draw a line starting from the origin like this. Then, make the outer arc symmetric about the newly created line. To do

this, select <Constraints/Symmetric>, and then

subsequently click the line and the two end points of the arc.

[11] Use <Dimension/General> to specify a length dimension of

1.529 (in.).

[12] Use <Draw/Arc by Center> to draw an arc

centered at one end of the new line. Specify the radius

dimension of 0.63 (in.).


6-4 Extrude to Generate 1/5 of the Gear Index

[1] Extrude the sketch 0.25 in.

[13] Trim away unwanted segments. This is the sketch after trimming. Note that,

although the the sketch is no more blue-colored, all the

dimensions are not changed.


6-5 Duplicate the Body Circularly

[1] Select <Create/Pattern> from the pull-down menu.

[2] In the <Details View>, select

<Circular> for <Pattern Type>.

[3] Click the yellow area to bring up <Apply/Cancel> buttons.

[4] Select the body.

[5] And click <Apply>.

[6] Click the yellow area to bring up <Apply/Cancel> buttons.

[7] Select this edge.


[9] Type 4 for <Copies>.



6-6 Create the Hub

[1] Select <Create/Primitive/Cylinder> from

the pull-down menu.


[2] Type 0.44 (in.) for the <Axis Z

Component>.

[3] Type 0.25 (in.) for the <Radius>.

[5] Select <Create/Primitive/Cylinder> again.

[7] Type 0.44 (in.) for the <Axis Z

Component>.

[8] Type 0.125 (in.) for the <Radius>.

[6] Select <Cut Material> for <Operation>.


Wrap UpClose DesignModeler, save the project as "Geneva," and exit the Workbench.


Auto Constraints: <//>It is applicable to a line, indicating that the line is parallel to another line in the same plane (6-3[7]).

Sketching Tools: <Constraints/Tangent>It can be applied on two edges (lines or curves), one of them must be a curve, to make them tangent to each other (6-3[8, 9]).

<Create/Pattern>This tool allows you to create copies bodies in three types of pattern: Linear, Circular, and Rectangular (6-5).

<Create/Primitive/Cylinder>This tool creates a cylinder by specifying its origin, axis, and radius (6-6). The origin and axis are defined by referring to the active plane coordinate system (1-12).

6-7 Review

72 Exercise 7. Yoke

Exercise 7Yoke

The yoke is a part of a universal joint [1]. In this exercise, we'll create a 3D solid model for the yoke, of which the details are shown in the multiview drawings below. Note that a global coordinate system is also shown in the figure.

7-1 Introduction

Y

X

Unit: in.

Y

Z

R1.00

X

Z

D0.75

D1.20

2 × 0.75

R1.00

1.50

3.5

5[1] The yoke is a part of a universal joint.

Exercise 7. Yoke 73




<Geometry> system.


7-3 Create a U-Shape Body

[1] On XYPlane, use <Draw/Arc by Center> tool to draw two concentric arcs. Specify

the radius dimensions (1.00 in. and 1.75 in. respectively).[2] Use <Draw/

Polyline> tool to draw a 3-segment polyline,

starting from this point.

[5] Click the last point and then select <Open End> from the <Context Menu>. If the last segment is not vertical,

use <Constraints/Vertical> to make it vertical.

[3] Click the second point. Make sure the first segment is vertical.

[4] Click the third point. Make sure the

second segment is horizontal.

[6] Use <Dimensions/General> to

specify a length of 2.50 (in.).

74 Exercise 7. Yoke

[7] Draw two vertical lines.




[10] Select <Both - Symmetric>.

[11] Type 1 (in.) for <Depth>. Note that, the sketch is extruded

by 1.0 in. for both sides of XYPlane,

therefore the total depth is 2.0 in.

Exercise 7. Yoke 75

7-4 Create Rounds

7-5 Create Holes

[1] Select <Blend/Fixed Radius>

from the toolbar.[2] Control-

select these 4 edges.

[3] Click <Apply>.

[4] Type 1 (in.) for <Radius>. [5] Click

<Generate>.

[1] Select <Create/Primitive/Cylinder> from

the pull-down menu.


[2] Click to bring up <Apply/Cancel> buttons, then select <YZPlane>

from the model tree and click <Apply>. Now the

global Y-axis becomes local X-axis, and the global Z-axis becomes local Y-axis.

The origin and the axis are defined using the local

(plane) coordinate system.

76 Exercise 7. Yoke

7-6 Create Shaft[1] Click <New Plane> to create a new plane.

[2] A new plane (Plane4) is inserted into

the model tree.

[3] Click to bring up <Apply/Cancel> buttons, then select <ZXPlane> from the model tree and click <Apply>. Now the

global Z-axis becomes local X-axis, and the global X-axis becomes local Y-axis.

[4] Select <Offset Z> for <Transform 1>. Note that it refers to the local Z-axis.

[5] Type 3.55 (in.) for <Value>.


[7] The new plane become active plane.

[8] The global coordinate system.

Note that the Workbench uses RGB

colors to represent XYZ axes respectively.

[9] The local coordinate system of the new plane.

Note that, in a local coordinate system, the Workbench also uses

RGB colors to represent XYZ axes respectively.

Exercise 7. Yoke 77

[1] Click to switch to the <Sketching

Mode>.

[2] Click to look at <Plane4>.

[3] Click to turn off model display.

[4] Draw a circle with a diameter of

1.2 (in.).



[6] Select <Reversed> for

<Direction>. Now, the extrusion

direction is the -Z direction.

[7] Select <To Next>. Now the

sketch will be extruded up to the

next face.

Wrap UpClose DesignModeler, save the project as "Yoke," and exit the Workbench.

78 Exercise 7. Yoke

Extrude DirectionThere are four options you can choose for the extrusion direction: <Normal>, <Reversed>, <Both -- Symmetric>, and <Both -- Asymmetric>. In <Normal> case, the extrusion direction is the Z-direction of the sketching plane. When <Reversed> is selected, the extrusion direction reverses to the -Z-direction (7-6[6]). For <Both -- Symmetric>, the extrusion is along both +Z and -Z directions with the same depth (defined by <Depth>) (7-3[10]). For <Both -- Asymmetric>, the extrusion is along both +Z and -Z directions with the different depths (defined by <Depth> and <Depth 2>).

<Blend/Fixed Radius>This tool can be used to place rounds or fillets on a body (7-4). The fillets are specified on edges, while the rounds can be specified on edges or faces. When faces are specified for rounds, the rounds are placed on the enclosing edges.

Create New Planes from Existing PlanesThere are many ways to create a new plane [1]. Creating new plane from an existing plane (7-6[1-9]) involves selecting the existing plane and then transforming the existing plane to a new position and orientation.

7-7 Review

[1] There are many ways to create a plane.


0.375

[1] The support is a part of a clamping

mechanism.

Exercise 8Support

The support is a part of the clamping mechanism mentioned in Exercise 1 [1]. In this exercise, we'll create a 3D solid model for the support, of which the details are shown in the multiview drawings below. Note that a global coordinate system is also shown in the figure.

8-1 Introduction

Y

X

Unit: in.

Y

Z

X

Z

6 ×D0.25

2.500

R0.313

0.8

75

1.250

2 ×R0.100

1.25

0 0

.750

R0.100

0.6

25 0.125

0.375

0.125

0.250 0.219

1.250 0.375

0.250

0.375

Slope: 45 R0.156

1.000

80 Exercise 8. Support




<Geometry> system.


8-3 Create Vertical Plate

[1] On XYPlane, draw three circles of the same

radius. Specify their locations (two horizontal dimension of 1.25 and one vertical dimension of 1.25)

[2] Specify a diameter of 0.25 in. for any one of

the circles.

[3] Use <Draw/Polyline> to draw a

polyline starting from roughly here.

[4] Click the second point, making sure the last segment is

vertical.

[5] Click the third point, making sure the last segment is

horizontal.

[6] Click the fourth point, making sure the last segment is vertical. Then select <Closed

End> from the <Context Menu>.

[7] Specify all dimensions so that all entities become blue-colored: length dimensions of 2.50 and 0.625; a horizontal dimension of

0.375, a vertical dimension of 0.875, and an angle dimension of 45 degrees.


[8] Draw two more circles, specify their radii (0.156 and

0.313) and locations (horizontal dimensions of 0.219 and 0.250; vertical

dimensions of 0.25 and 0.75)

[9] Trim away unwanted segments.


[10] Draw two fillets with the same radius of

0.1 in.



[12] Type 0.125 (in.) for <Depth>.


8-4 Create Horizontal Plate

[1] Click <New Plane>.

[4] Click the yellow area to

bring up <Apply/Cancel> buttons.

[2] Select <From Face>.

[6] Click <Apply>.

[7] Click <Generate>; a <Plane4> is created.

[5] Click this face at a location near this circle. A plane coordinate system shows up like this (the X axis points to global -X

axis). Note that the location you click

determines the origin and the axes of the plane

coordinate system. If the coordinate system is not like this, simply re-click again until it is correct.

[8] Click to switch to <Sketching Mode>.


[10] Click to turn of the model

display.

[11] This is <Plane4>; it is called an <Outline

Plane> since it includes an outline. The outline is not part of a sketch

but can be used as references.

[12] Draw a rectangle like this. Note that three sides of the rectangle coincide with plane's outline. Specify a length dimension of 0.125 in.

so that the rectangle become blue-colored.

[3] The default <Subtype> is

<Outline Plane>.

X Y

Z




[14] Type 1 (in.) for <Depth>.


8-5 Create Holes on the Horizontal Plate

[6] Click <Generate>; a <Plane5> is created.


bring up <Apply/Cancel> buttons.[2] Select

<From Face>.

[5] Click <Apply>.

[4] Click this face at a location near this corner so that the plane coordinate system is like this (the

X axis points to global X axis). Remember, if the coordinate

system is not like this, simply re-click again until it is correct.

X

Y

Z



Mode>.


[9] Click to turn of the model

display.

[10] This is <Plane5>; it includes an

outline.

[11] Draw three circles of the same diameter (0.25 in.) and specify their positions (horizontal dimensions of

0375, 0.375, and 1.25; vertical dimensions of 0.375, 0.375, and 0.125)



[13] Select <Cut Material>.

[15] Select <Through All>.

[14] The <Direction> automatically

becomes <Reversed>.


8-6 Create the Round

[1] Select <Blend/Fixed Radius>

from the toolbar.


[2] Click this edge.

[3] Click <Apply>.

[4] Type 0.1 (in.) for <Radius>.

Wrap UpClose DesignModeler, save the project as "Support," and exit the Workbench.


Create New Planes From FacesYou can create a new plane from an existing face (8-4[1-7]). There are subtypes to choose: <Outline Plane> and <Tangent Plane>. The only difference is that a <Tangent Plane> doesn't include the outline of the face. In either subtype, the plane coordinate system is determined according to how you click the face. The origin is usually located at the closest corner point or the center of a circle (or an arc); The Z-axis always points out of the face; The X-axis is usually parallel to the closest edge.

An outline plane include the outline of the face (8-4[11]). The outline is not part of a sketch but can be used as references (datum). Without the outline, the only references are two exes (X-axis and Y-axis of the plane). However, you can copy the outline (or part of the outline) into a sketch, using the sketching tool <Modify/Duplicate>.

8-7 Review

88 Exercise 8a. Structural Analysis of the Support

[2] This is the deformed structure under the design loads. The wireframe is the underformed configuration.

Appendix:

Exercise 8aStructural Analysis of the Support

In this exercise, we will perform a static structural analysis for the support created in Exercise 8. The objective is to find the deformation and the stresses under the working loads, and make sure the stresses are within the allowable level (30,000 psi).

As mentioned in Exercise 1a, the clamping mechanism is entirely made of steel and is designed to withstand a clamping force of 450 lbf [1]. After a structural analysis of the entire mechanism [2] (which is performed in Exercise 17a), the results show shows that, to withstand a clamping force of 450 lbf, the support is subject to external forces as shown [3] (also see 17a-4). Note that the holes on the horizontal plates are fixed to the ground [4].

The analysis task will be carried out with <Mechanical>.

8a-1 Introduction

[1] The clamping mechanism is designed to withstand a clamping force of 450 lbf.

62 lbf

163 lbf

380 lbf

[3] The external force on the arm.

See 17a-14.

380 lbf

[4] The horizontal plates are fixed to

the ground.


[2] Open the project "Support," which was saved in

Exercise 8.




analysis system.

[4] Drag <Geometry>...

[5] And drop here. A link is created, indicating that both <Geometry> share

the same data.

[6] Double-click to start up the

<Mechanical>.


[7] Make sure the length unit is <in.> (1a-2[8, 9]).

8a-3 Specify Loads

[1] Click to highlight <Static Structural>.



[4] Click <Apply>.



for <Y Component>.




[9] Click <Apply>.



for <Y Component>.

[1] Select <Supports/Frictionless Support>.

[2] Control-select the three cylindrical

faces on the horizontal plate.


[3] And control-select

this face.




[3] A solution object is inserted under the <Solution> branch.


[4] Click <Apply>. Totally 5 faces are set to <Frictionless Support>.

[5] Select <Supports/Displacement.

[6] Control-select the four cylindrical faces on

the vertical plate.

[7] Click <Apply>.

[8] Type 0 (in.) for <Z

Component>.


8a-6 Solve the Model[1] Click <Solve>.



[3] The maximum stress is 20,608 psi,

well below the allowable stress

(30,000 psi).


WireFrame>.

Wrap UpClose <Mechanical>, save the project as "Support-a," and exit the Workbench.

94 Exercise 9. Wheel

Exercise 9Wheel

The main purpose of this exercise is to introduce another modeling tool (than <Extrude>): <Revolve>, which takes a sketch as the profile and revolves about an axis to create a 3D solid body.

We'll create a 3D solid model for a wheel, of which the details are shown in the multiview drawings below. A global coordinate system is also shown in the figure.

Note that the wheel is axisymmetric. An axisymmetric body can be created by drawing a profile then revolting about its axis to generate the 3D solid body.

9-1 Introduction

X

Unit: in.

Y

Z

D4.00

Y

0.25

0.50

0.75

45

D3.50

D1.50

D1.00





<Geometry> system.


9-3 Create the Profile

[2] and ending here. Select <Open End> from the context menu. Specify all

dimensions as shown.

[1] On XYPlane, use <Draw/Polyline> to

draw a polyline starting from here.

96 Exercise 9. Wheel

[3] Use <Modify/Replicate> to "mirror copy" everything about the Y-axis. The procedure is as follows:

(a) select all segments;(b) select <End/Use Plane Origin as Handle> from the context menu;(c) select <Flip Horizontal> from

the context menu;(d) select <Paste at Plane Origin>

from the context menu;(e) finally select <End> from the context menu (or press <Esc>).


9-4 Revolve the Sketch about X-Axis

[4] On the graphics window, select the X-axis

and click <Apply>.

[1] Click <Revolve> in the toolbar.

[2] Rotate to an isometric view.


[6] Click to turn off the plane

display.

Wrap UpClose DesignModeler, save the project as "Wheel," and exit the Workbench.

[3] Click <Apply>. The active sketch is automatically taken

as the profile.

9-5 Review

Modeling Tool <Revolve>It takes a sketch as the profile and revolves about an axis to create a 3D solid body (9-4[1-5]). The angle of revolution can be specified.

98 Exercise 10. Transition Pipe

Exercise 10Transition Pipe

10-1 Introduction

Y

Z

Y

Unit: in.

8 ×D0.25

2 ×D2.50

2 ×D3.50

2 × 0.25 R2.50

X

D1.00

R3.50

The transition pipe is used to connect two pipe segments. In this exercise, we'll create a 3D solid model for the transition pipe, of which the details are shown in the multiview drawings below. A global coordinate system is also shown in the figure.

The main purpose of this exercise is to introduce another modeling tool: <Sweep>, which takes a sketch as the path and another sketch as the profile; the profile then "sweeps" along the path to create a 3D solid body.

Note that it is possible to create the curved pipe by using of <Revolve> tool (Exercise 9), however, as an exercise, we decide to create the curved pipe by using <Sweep>.

R1/8"

R1/16"

Exercise 10. Transition Pipe 99




<Geometry> system.


10-3 Create a Sketch for the Path

[1] On the XYPlane, draw an arc like this . This sketch will be used as the sweeping path

of the curved pipe.

10-4 Create a Sketch for the Profile

[1] On the ZXPlane, draw two concentric circles like this. This

sketch will be used as the profile of the curved pipe.

[1] Select <ZXPlane> (or click ZXPlane in the model tree).


10-5 Create a Body Using <Sweep>

[1] Click <Sweep> on the

<Toolbar>.


[2] Select <Sketch2> (from the model tree) for the <Profile> and

select <Sketch1> (from the model tree) for the

<Path>.

10-6 Create a Plane on One End of the Pipe



[4] Click this face. Note that the local Z-axis (blue) points out of the face, and the local

X-axis (red) points to the global -Z direction.

[3] Click the yellow color area to bring up <Apply/Cancel>

buttons. [6] Click <Generate>.

[5] Click <Apply>


10-7 Create an End Plate

[1] On the new plane (Plane4), create a sketch like

this (see next two steps). Remember to impose two <Symmetry> constraints to make the four small circles

symmetric about X-axis and about Y-axis.

[2] The sketch includes a circle

that overlaps with the inner circle of the plane outline.

[3] The sketch doesn't include this circle, which is

the outer circle of the plane outline.



[5] Select <Add Frozen>. This generates a

separate body.


10-8 Create Another End Plate by Duplication



[3] Click the yellow color to bring up <Apply/Cancel>

buttons.

[4] Click this face. Note that the local Z-axis (blue) points

out of the face.

[6] Click <Generate>. <Plane5> is

created.[5] Click <Apply>.

[7] Select <Create/Body Operation>.


[9] Select the existing end plate.

[10] Select <Plane4> from the model tree.

[11] Select <Plane5> from the model tree.

[8] Select <Move>.


10-9 Unite All Bodies into One Body

[1] Select <Create/Boolean>.

[3] Control-select all three bodies.


[2] <Unite> is the default <Operation>.

10-10 Create Fillets

[1] Select <Blend/Fixed Radius>.

[3] Click <Apply>.

[2] Control-select these two

edges.



10-11 Create Rounds


[3] Click <Apply>.

[2] Control-select these two

edges.


10-12 Turn Off Edges

[1] Select <View/Shaded Exterior> to turn off

the edges display.

Wrap UpClose DesignModeler, save the project as "Pipe," and exit the Workbench.


10-13 Review

Modeling Tool <Sweep>The <Sweep> can be thought of a generalization of the <Extrude>. <Sweep> takes a sketch as the path and another sketch as the profile; the profile then "sweeps" along the path to create a 3D solid body (10-5). The <Sweep> also can be used to create spiral shapes, which will be demonstrated in Exercise 12.

Add FrozonA body is either in a state of active or frozen. The default state is active. Two overlapped active bodies would automatically join together to form a single body. If either of them is frozen, they wouldn't join together. Therefore, the only way to avoid overlapped bodies joining together is to make at least one of them frozen. In 10-7, we create the end plate as frozen body (separating it from the curved pipe), so that, in 10-8, we can copy the end plate alone without the curved pipe.

<Body Operation/Move>This tool moves a body (or a group of bodies) to another position and orientation in the same way that the source plane is move to coincide with the destination plane (10-8). If the <Reserve Bodies?> option is <Yes>, it essentially copies the bodies. This tool is useful for "assembling" parts together to form an assembly.

<Create/Boolean>Using boolean operations, bodies can be united, intersected, and subtracted.

106 Exercise 11. C-Bar

40

40

70

D10

120

30

20

20

R10

R50

100

Exercise 11C-Bar

11-1 Introduction

Y

Z

Y

Unit: mm.

The C-shaped steel bar is used as a dynamometer, a device to measure the magnitude of a force P [1]. A strain gauge is bonded to the surface of a location as shown [2]. The measured strain is then used to calculate the force P.

The details are shown below; a coordinate system is also included in the figure. In this exercise, we will create a 3D solid model for the C-bar. Due to the symmetry, we will create the upper half of the model and then complete the model by using a "mirror" (copy) operation.

P

P

[1] The C-bar is used to

measure a force P.

[2] A strain gauge is bonded to the surface here. The measured strain is used to calculate

the force P.

X

[3] The body has a thickness of 5 mm.

everywhere.

[4] All fillets have radii of 3 mm.

Exercise 11. C-Bar 107


DesignModeler. Select <Millimeter> as the length unit.


<Geometry> system.


11-3 Create a Sketch for the Path

11-4 Create a Sketch for the Profile

[1] On the XYPlane, draw a sketch like this.

[2] On the YZPlane, draw a sketch like this.

The sketch is symmetric about the

horizontal axis.

[1] Select <YZPlane> (or click YZPlane in the model tree).


11-5 Create a Body Using <Sweep>

[1] Click <Sweep> on the <Toolbar>.


[2] Select <Sketch2> and <Sketch1> (from the model tree) as the <Profile> and

<Path> respectively.

11-6 Create an Ear

[1] Select <XYPlane>

[4] Draw a sketch for the <Sketch3> like this. Note that

<Sketch1> is hidden now.

[2] Click <New Sketch>. <Sketch3>

is created on the <XYPlane>.

[3] Right-click <Sketch1> and select <Hide Sketch> from the context menu.

Exercise 11. C-Bar 109



[6] Extrude 2.5 mm both sides.

11-7 Create Fillets



[3] Click <Apply>.

[2] Control-select these two edges.


11-8 "Mirror" Copy the Body


[4] Select <ZXPlane> from the

model tree.


[6] Select <View/Shaded Exterior> to turn off

the edges display.

[3] Select the body and click <Apply>.

[2] <Mirror> is the default

operation type.

Wrap UpClose DesignModeler, save the project as "CBar," and exit the Workbench.


Appendix:

Exercise 11aDeformation of the C-Bar

11a-1 Introduction

P

P

[1] Applied force P.

[2] Strain gauge.

As described in Exercise 11, the C-shaped steel bar is used to measure the magnitude of a force P [1]. A strain gauge is bonded to the surface of the location as shown [2]. The location is chosen because the strain is relatively large and distributed quite uniformly, so that the measured strain is not sensitive to the variation of the location of the strain gauge. The measured strain ε is then used to calculate the force P. The idea also relies on the fact that the strain is linearly proportional to the force P, which is true when the deformation is small enough. In other words, if the measured strain is doubled, then the force must be doubled.

In this section, we will assume a force of P = 2,000 N, and perform a simulation to establish a relation between the force P and the strain ε .

11a-2 Start Up

[1] Launch Workbench

[2] Open the project "CBar," which was saved in Exercise 11.

[3] Drag <Static Structural> and drop to <Geometry> cell of the <Geometry> system.

[4] A <Static Structural>

system is created.

[5] The two systems share the same

<Geometry>. You can edit up-stream cell but not the down-

stream cell.[6] Double-click

<Model> to start up <Mechanical> application.

112 Exercise 11a. Deformation of the C-Bar

[10] Pull-down-select <Unit/Metric (mm, kg N, s, mV, mA)>.

Unlike DesignModeler, the units in <Mechanical> can be

changed any time.

[8] Whenever necessary, pull-down-select <View/Windows/

Reset Layout> and select <Graphics> tab to bring back

the "standard" layout.

[7] <Mechanical GUI> shows up. If your GUI layout is not like

this, pull-down-select <View/Windows/Reset Layout> and

select <Graphics> tab., see [8].

[9] If the unit system is not like this, see [10].


11a-3 Generate Mesh

[1] Highlight <Mesh>.

[3] In the <Details>, select <Fine> for

<Relevance Center> and type "75" for <Relevance>.

[4] Select <Mesh/Generate Mesh>.

[6] Number of nodes and elements are shown in the Details view. Your

numbers may not be the same as here. Also note that in an academic teaching

version of ANSYS Workbench, the number of nodes or the number of

elements is limited to 30,000.

[5] Click "+" to expand

<Statistics>.

[2] Click "+" to expand

<Sizing>.


11a-4 Set Up Environment Conditions

MeshingThe process of dividing a body into small bodies is call meshing. The small bodies are called elements, or finite elements. The simulation method is thus called finite element simulation. The basic idea of finite element methods is to divide a body of rather complicated geometry into smaller elements of simple geometry, and the elements are assumed to be connected to each other through nodes. The element's geometry is so simple that a set of equations may be established easily for each element. All equations are then solve simultaneously for the displacements. Strains are then calculated from the displacements. And stresses are in turn calculated from the strains.

In general, the finer the mesh, the more accurate the solution (and more computing time). In this exercise, we control the mesh size by simply adjusting <Relevance Center> and <Relevance>.

Also, note that the Workbench will automatically generate a mesh right before it solves the problem if a mesh doesn't exist.

Limitation of Mesh CountIn this book, we will restrict the number of nodes or elements to be no more than 30,000, which is a limitation imposed by the <ANSYS Academic Teaching> version.

[1] Highlight <Static Structural>.

[2] Select <Supports/Fixed

Support>.

[3] Select this inner cylindrical surface.

[4] Click <Apply>.


[10] We've added these two environment

conditions.

[5] Select <Loads/Force>. [6] Select this inner

cylindrical surface.

[7] Click <Apply>.

[8] Select <Components> for <Define By> and type

-2,000 (N) for <Y Component>.



[1] Highlight <Solution>.

[2] Select <Strain/Normal> to insert a <Normal Elastic

Strain> result object.

[3] Select <Y Axis> for

<Orientation>.

[4] Right-click the result object as shown and

select <Rename Based on Definition> from the

context menu.

[5] The object is renamed for better readability.


11a-6 Solve the Model and View the Results

[1] Click <Solve>.



[4] Click <Probe>.

[5] Move the mouse around the model to display the strain value.

[6] Move the mouse to the location of the strain gauge and

click to put a label on the location. The strain is about 0.000296.


11a-7 Conclusion

The simulation results show that a force of P = 2,000 N produces a strain ε = 0.000296. We may establish a relation between the force P and the strain ε as follows:

P = 2000

0.000296ε

For example, if the measured strain in the strain gauge is ε

1 = 0.0001, then the force

P1 is

P1= 2000

0.0002960.0001= 676 N

Wrap UpClose <Mechanical>, save the project ("CBar"), and exit the Workbench.


[1] The threaded shaft is a part of a

clamping mechanism.

D0.625

Exercise 12Threaded Shaft

12-1 Introduction

X

Y

Unit: in.

The threaded shaft is a part of the clamping mechanism mentioned in Exercise 1 [1]. In this exercise, we will create a 3D solid model for the threaded shaft, of which the details are shown below.

.375-16UNC

[4] Thread form: Unified

national coarse

[2] Major diameterd = .375 in.

[3] Pitchp = 1/16 in.

H = ( 3 2)p = 0.0541266 in

p − H8= 0.0557342 in

H4= 0.0135316 in

D0.250

0.438 3.750

D0.266

0.875 M

ajor

dia

met

er d

Pitch p

p − H 8

H 4

H=

(3

2)p

H 8

Slope: 60

Slo

pe: 6

0

120 Exercise 12. Threaded Shaft




<Geometry> system.


12-3 Create the Shaft

[1] On the XYPlane, use <Draw/Polyline> to draw a sketch like this. Specify the dimensions.

[3] In the graphics window, select the X-axis for <Axis>.

[2] Click <Revolve>.



12-4 Create a Hole [1] Select <Create/Primitive/Cylinder> from

the pull-down menu.


12-5 Create Threads[1] Click to create a new

sketch (Sketch2) on XYPlane.

[2] Right-click <Sketch1> and select

<Hide Sketch>.

[3] Click <Sketch2> to make it active.

[2] The length is arbitrary as long as it is not less than

0.625 in.

122 Exercise 12. Threaded Shaft

[4] Draw a sketch <Sketch2> like this.

Specify the dimensions. This sketch will be

used as the sweeping profile.

[5] This is the horizontal

dimension measured from the Y-axis.

[6] This is the vertical dimension measured from the

X-axis.

[7] Click to create a new sketch (Sketch3) on

XYPlane.

[8] Hide <Sketch2> and make <Sketch3>

active.

[9] Draw a sketch <Sketch3> like this. The sketch is simply a horizontal line. The length of the line is arbitrary as long as it is not less than the total

length of the threads (3.75 in.). This sketch will be used as the sweeping

profile.


[11] Select <Sketch2> (from the model tree) as the

<Profile>.


[12] Select <Sketch3> (from the model tree) as the

<Path>.

[13] Select <Pitch> for <Twisting

Specification>.

[14] Type 0.0625 (in.) for <Pitch>.

[10] Click <Sweep>.

Wrap UpClose DesignModeler, save the project as "Shaft," and exit the Workbench.

124 Exercise 13. Lift Fork

[1] At the root, the cross section is 160x40 (mm.).

Exercise 13Lift Fork

13-1 Introduction

X

Y

Unit: mm.

The lifting fork is used in an LCD (liquid crystal display) manufacturing factory to handle glass panels. In this section, we will create a 3D solid model for the lift fork, of which the details are shown below.

The cross sections of the prongs (fingers) are not uniform along the length [1-3]. The tools <Extrude> or <Sweep> cannot be used to created the prongs. This exercise introduces a modeling tool, <Skin/Loft>, which takes a series of profiles from different planes and creates a 3D solid that fits through these profiles

1600

Z

200

2400

[3] At the midway, the cross section is

130x20 (mm.).

[2] At the tip, the cross section is 100x10 (mm.).

Exercise 13. Lift Fork 125




<Geometry> system.


[2] Extrude 200 mm. For details, see [3].

[3] Details view of the extrusion.

Remember to click <Generate>.

13-3 Create the Transversal Beam

[1] Draw a rectangle on <XYPlane>. The rectangle is symmetric about Y-

axis. Note that the top edge coincides with X-axis.


13-4 Create Three Planes Based on a Face of the Beam

Skin/LoftNow we want to create a single prong, or finger. The prong is then duplicated to create other prongs. The prong's cross section is not uniform. You cannot create the prong using <Extrude> or <Sweep>. A more general way to create a solid or surface of different cross sections along its path is using <Skin/Loft>. <Skin/Loft> takes a series of profiles from different planes and creates a solid that fits through these profiles.

You may view <Sweep> as a generalization of <Extrude>, and <Skin/Loft> as a generalization of <Sweep>.

[2] Create <Plane4>, see

[3].

[4] Create <Plane5>, see [5].

[6] Create <Plane6>, see [7].

[3] Details of <Plane4>.[5] Details of

<Plane5>.[7] Details of <Plane6>.

[1] All three planes will be created based on this face. When you select the face, make sure the coordinate system is attached at the

bottom-right corner and the directions of the axes are the

same as global axes.


13-5 Create a Sketch on Each Plane

[1] Create this sketch on <Plane4>. This

becomes <Sketch2>.

[2] Create this sketch on <Plane5>. This becomes

<Sketch3>.

[3] Create this sketch on <Plane6>. This becomes

<Sketch4>.

[1] Click <Skin/Loft> on

the toolbar.

[2] Control-select <Sketch2>, <Sketch3>, and <Sketch4> (the order is important) in the model tree, and click <Apply>. Note that a grey lofting guide

line appears. If your guide line is not correct, it can be resolved by right-clicking anywhere and selecting <Fix Guide Line>

to redefine the lofting guide line.

[3] Select <Add Frozen>.


[5] The prong is created as a frozen body, because we

don't want the prong to join the transversal

beam for now.


13-7 Duplicate the Prong Using <Pattern>

[1] Select <Create/Pattern>.

[2] Select the prong body.

[3] Click <Apply>.


bring up <Apply/Cancel>.


[8] Click <Apply>.

[6] If the direction is not like this...

[7] Click an arrow to switch the

direction.

[9] Type 480 (mm) for <Offset> and 3

for <Copies>.



13-8 Combine the Bodies Using <Boolean>

[1] Select <Create/Boolean>.


[3] Control-select all five bodies and

click <Apply>.

[2] The default operation is

<Unite>.

Wrap UpClose DesignModeler, save the project as "Fork," and exit the Workbench.

130 Exercise 14. Caster Frame

Exercise 14Caster Frame

In this exercise, we'll create a 3D solid model for a caster frame, of which the details are shown in the multiview drawings below. A coordinate system is also shown in the figure.

14-1 Introduction

X

Unit: mm.

Fillets and rounds: R3

Z

Y

D21.5

Y

X

Z

D32

92

28

50

D17.5 D25

D35

64

126

76

13 10

10

10

10

R10 R15 10





<Geometry> system.


14-3 Create A Quarter of Main Body

[1] Click <ZXPlane> to make it active.

[2] Click to switch to <Sketching Mode>.

[3] Draw a rectangle of 50x32 (mm.). In this

exercise, we'll sketch in 3D view (rather than

plane view).



[5] Select <Sketch1> in the model tree.

[6] And click

<Apply>.





[10] Click the yellow area to bring up <Apply/

Cancel> buttons and select the face with the coordinate system as

shown.


[12] Switch to <Sketching Mode> and use <Draw/

Polyline> to draw a sketch like this on the newly

created plane (Plane4).





[16] Select the face with the coordinate

system as shown.


[18] Switch to <Sketching Mode> and draw a sketch

like this on the newly created plane (Plane5).






[22] Select the face and the coordinate system as shown.


[24] Switch to <Sketching Mode> and draw a sketch

like this on the newly created plane (Plane6).




[27] Select <Create/Body Operation> from the pull-down menu and select the solid body.

[28] Select <XYPlane> from the model tree. Click <Generate>.

[29] Select <Create/Body Operation> from the pull-down menu and select the solid body.

[30] Select <YZPlane> from the model tree. Click <Generate>.


14-4 Create the Shaft

[1] Select <Create/Primitives/Cylinder> from the pull-down menu; click here to bring up

<Apply/Cancel> buttons and select <ZXPlane> from the model tree.

[2] Select <Create/Primitives/Cylinder> from the pull-down menu and select <ZXPlane> from

the model tree.


[3] Select <Create/Primitives/Cylinder> from the pull-down menu and select <ZXPlane> from

the model tree.

14-5 Create the Bearing[1] Select <Create/

Primitives/Cylinder> from the pull-down menu and select <YZPlane> from

the model tree.


[2] Select <Create/Primitives/Cylinder> from the pull-down menu and select <YZPlane> from

the model tree.

[3] Select <Create/Primitives/Cylinder> from the pull-down menu and select <YZPlane> from

the model tree.


14-6 Create Rounds


[2] Control-select these four edges.


[5] Select <Blend/Fixed Radius> again.


[6] Control-select these two edges.




14-7 Create Fillets




[3] Select <Extend Selection/Extend to

Limits>.

[4] The selection extends to its

limits.

[5] Control-select other edges. Totally 18 edges

(also see [8, 9]). Whenever necessary, rotate the view and use <Extend Selection/

Extend to Limits>.[6] Click <Apply>.

[8] Fillets viewed from top.

[9] There are 2 fillets if you view

from bottom.


[5] You can see all rounds if you view

from top.

14-8 Create Additional Rounds



[2] Control-select these edges. Totally 42 edges

(also see [5]). Whenever necessary, rotate the view and use <Extend Selection/

Extend to Limits>.

[3] Click <Apply>.

[6] Select <View/Shaded Exterior> to

hide all edges.

Wrap UpClose DesignModeler, save the project as "Caster," and exit the Workbench.

144 Section C. Assembly Modeling

Section CAssembly Modeling

An assembly consists of two or more parts. The DesignModeler assigns a color for each part in an assembly. Creating a simple assembly is straightforward, but you have to take case so that parts are not bonded together. This usually can be done by freezing the existing parts. Exercise 15 is an example of creating a simple assembly. Creating complex assemblies involves transformations (translations, rotations, etc.) of parts to appropriate positions. Exercises 16 and 17 demonstrate these techniques.


Exercise 15Threaded Shaft Assembly

In this exercise, we'll create a threaded shaft assembly [1] shown in the figure below. The assembly consists of four parts: the threaded shaft created in Exercise 12, a handle, and two hinges. We adopt a coordinate system which is the same as that used in Exercise 12. This assembly is simple enough that all parts can be created with referring to the same coordinate system. More complicated cases involve transformations (translations, rotations, etc.) of the parts (eg., Exercises 16 and 17).

15-1 Introduction

X Unit: in. Y

Z

D0.266

0.219

5.063

2.000

0.75

0.125

0.1875

3.000

0.375

D0.75

D0.25

D0.75

D0.25

[1] The threaded shaft assembly is a sub-assembly of a clamping mechanism.

146 Exercise 15. Threaded Shaft Assembly


[1] Launch ANSYS Workbench and open the project "Shaft," which was

saved in Exercise 12.

[2] Double-click <Geometry> to start

up DesignModeler. Due to the complexity of

the threads, it may take a while to open the

model.

[3] Right-click <Solid> and select

<Rename> from the context menu.

[4] Change the part name to

"Shaft."


15-3 Create the Handle

[3] Select <Create/Primitives/Cylinder> from the pull-down menu and set up the <Details

View> as shown. Click <Generate>.

Freeze Existing Bodies Before Creating New PartsRemember, a body is either active (non-transparent) or frozen (transparent). Active bodies are automatically join (unite) together to form a single body if they overlap each other. Here, we freeze the existing bodies, so that the newly created body doesn't join the existing bodies and, in effect, becomes a new part.

[1] Select <Tool/Freeze> from the pull-down menu. The body become <Frozen>. By default, frozen bodies are displayed as

transparent. This can be turned off by selecting <View/Frozen Body Transparency> from the

pull-down menu.

[2] A <Freeze1> object is inserted.

[4] Rename the new part as "Handle."


15-4 Create the End Hinge

[1] Select <Create/Primitives/Cylinder> from the pull-down menu

and set up the <Details View> as shown. Click <Generate>.

[2] The newly created body (which is active) doesn't overlap with the handle

(which is also active), therefore it becomes a separate part.

[4] The two newly created bodies (both are active) join

together to form a single part.

[3] Select <Create/Primitives/Cylinder> from the pull-down menu and

set up the <Details View> as shown. Click

<Generate>.

[5] Rename the new part as "EndHinge."


[6] Select <Create/Boolean> from the pull-down menu and select <Subtract>

for <Operation>.

[7] In the graphics window, select the body "EndHinge" as <Target Bodies>.

[8] In the graphics window, select the body "Shaft" as

<Tool Bodies>.

[9] Select <Yes> for <Preserve Tool Bodies>.


[11] Right-click "EndHinge" and select

<Hide All Other Bodies> from the context menu.

[12] The finished "EndHinge."[13] Right-click

anywhere in the graphics window and select

<Show All Bodies> from the context menu.


15-5 Create the Middle Hinge

[1] Select <Create/Primitives/Cylinder> from the pull-down menu

and set up the <Details View> as shown. Click <Generate>.

[2] Select <Create/Primitives/Cylinder> from the pull-down menu and


<Generate>.

[4] Rename the new part as "MidHinge."

[3] The two newly created bodies (both are active) join

together to form a single part.


[5] Select <Create/Boolean> from the pull-down menu and select <Subtract>

for <Operation>.

[6] In the graphics window, select the body "MidHinge" as <Target Bodies>.

[7] In the graphics window, select the body "Shaft" as <Tool Bodies>.

[8] Select <Yes> for <Preserve Tool Bodies>.


[10] Hide all bodies except the "MidHinge."

[11] Show all bodies.

[12] Select <View/Frozen Body Transparency> to turn off the transparent display

of the frozen bodies.

Wrap UpClose DesignModeler, save the project ("Shaft"), and exit the Workbench.

152 Exercise 16. Universal Joint

Y

Z X

Exercise 16Universal Joint

In this exercise, we'll create a universal joint shown in the figure below. The assembly consists of four kinds of parts [1-4], of which the yoke [1] was created in Exercise 7. A coordinate system for the assembly is also shown in the figure [5]. The assembly created in this exercise is simple enough that we will create all parts in a single <Geometry> system. For more complicated cases (eg., Exercises 17), multiple <Geometry> systems may be a better management scheme.

The universal joint is adapted from a working drawing in the book Technical Graphics Communication, by G. R. Bertoline, E. N. Wiebe, C. L. Miller, and J. L. Mohler.

16-1 Introduction

Unit: in.

[1] 2 x Yoke (created in Exercise 7).

[2] Swivel. OD1.00,

ID0.50, L2.15.

[3] 4 x Bushing. OD0.75, ID0.50,

L0.60.

[4] 4 x Pin. D0.50, L1.35.

[5] Coordinate system for the

assembly.


Y , ′Y

′Z ′X

X Z


[1] Launch ANSYS Workbench and open the project "Yoke,"

which was saved in Exercise 7.


up DesignModeler.

[2] Save the project as a new name

"Joint."

Coordinate SystemsThere is a coordinate system for the entire assembly, called a global coordinate system; each part has its own coordinate system, called a local coordinate system.

Here, the coordinate system set up in 16-1 is the global coordinate system [4], and the coordinate system defined in 7-1, used to create the yoke, is a local coordinate system [5].

In order to position the yoke in the global coordinate system, we need to move the yoke upward (in Y direction) by 1.50 in.

[5] The coordinate

system of the part.

[4] The coordinate

system of the assembly.


16-3 Move the Yoke Upward

[1] Select <Create/Body Operation> from the pull-down menu and select <Translate>.

[2] In the graphics window, select the solid body.

[3] Select <Coordinates> for <Direction Definition>.[4] Type 1.5 (in.) for

<Y Offset>. It refers to the global coordinate

system. Click <Generate>.

[5] Rename the body as

"UpperYoke."

[6] Select <Tools/Freeze> to freeze the upper yoke.

16-4 Create Lower Yoke

[1] Select <Create/Body Operation> and select

<Mirror>.

[2] Select "UpperYoke,"

either from the model tree or

from the graphics window.

[3] Select <ZXPlane> from the model tree. Click <Generate>.

[4] Rename the new body (which is

also frozen) as "LowerYoke."



[6] Select <Rotate>.

[7] Select "LowerYoke."

[8] Type 90 (degrees).

[9] Select <Selection Filter: Model Faces>.

[10] Select this circular face. This defines a direction, which is normal to the face, i.e., a vertical

direction. You also can click <Display Plane> to turn on the

plane display, and then define the direction by selecting the

vertical axis.

[12] Click the yellow area and click <Apply>.


[14] Now, the lower yoke rotates 90

degrees.

[11] You can click here to switch the direction.

However, in this case, it doesn't matter whether it is

upward or downward.

Selection FiltersBy activating a selection filter [9], you can make one of four types of entities (points, edges, faces, and bodies) selectable. By right-clicking the graphic area, selection filters can also be accessed through the context menu, where additional filters are available [15]. Multiple filters can be activated at the same time.

[15] More selection filters can be

accessed through the context menu.


16-5 Create the Swivel[1] Select both bodies and right-click-select

<Hide Body>. In order to focus on the swivel, we hide the existing bodies.

[2] Select <Create/Primitives/Cylinder> from the pull-down menu and set up

the <Details View> as shown. Click <Generate>.

[3] The body is active (non-

transparent), since it is created with <Add

Material> option.

[4] Select <Create/Primitives/Cylinder> and set

up the <Details View> as shown. Click <Generate>.

[5] The new material adds to the existing

active body.






[10] Right-click anywhere in the

graphics window and select <Show All

Bodies>.[8] Rename the body as "Swivel."

[9] Select <Tools/Freeze> to freeze

the swivel.


16-6 Create a Pin[1] Select <Create/

Primitives/Cylinder> and set up the <Details

View> as shown. Click <Generate>.

[3] The cylinder extends to the

negative direction.

[4] The cylinder's outer face aligns with a yoke's face. Also, the cylinder is created as frozen to avoid joining the bushing to be

created next (16-7).

[2] The cylinder starts from a yoke's

face (see [4]).

16-7 Create a Bushing

[1] Select <Create/Primitives/Cylinder> and


<Generate>.

[3] The cylinder's inner face aligns with a swivel's face. Also, the cylinder is created as active because we haven't finished the

part (the part has a hole).

[2] The cylinder starts from a swivel's

face (see [3]).

[5] Rename the body as "Pin1."

[4] Hide all other bodies.


[8] Rename the body as "Bushing1."

[5] Select <Create/Primitives/Cylinder> and


<Generate>.

[6] The material is cut from the active bodies.

[7] Show all bodies.

16-8 Create Other Pins and Bushings

[1] Select <Create/Pattern> and select

<Circular>.

[2] Select both "Pin1" and "Bushing1". You

can either select them from the model tree or from the graphics

window.

[3] In the graphics window, select the vertical axis. If the

coordinate axes doesn't display, see [5].

[4] Type 3. The bodies are duplicated 3 times.

Click <Generate>.

[5] If the coordinate axes doesn't display,

click <Display Plane>.


[6] Rename the bodies as shown.

[7] Hide "UpperYoke" and "LowerYoke" to

view the details inside.[8] Show all bodies and select <View/Frozen Body Transparency>.

[9] The objects here records the history of creating the model.

[10] The parts (bodies) here are to be exported

outside the DesignModeler, for

example, to <Mechanical>.


16-9 Create an Exploded Model


[2] In the model tree, control-select UpperYoke, Bushing2,

Bushing4, Pin2, and Pin4.

[3] Select <Coordinates> for <Direction Definition>.

[4] Type 5 (in.) for <Y Offset>. Remember, it

refers to the global coordinate system. Click

<Generate>.

[5] Select <Create/Body Operation> and, in the model

tree, control-select LowerYoke, Bushing1,

Bushing3, Pin1, and Pin3.

[6] Type -5 (in.) for <Y Offset>. Click <Generate>.


[7] Select <Create/Body Operation> and, in the

model tree, control-select Bushing2 and Pin2. Set up

other options and click <Generate>.











[11] Select <Create/Body Operation> and, in

the model tree, select Bushing2. Set up other

options and click <Generate>.











[15] Control-select the last 10 objects

and right-click-select <Suppress>.

Suppress Objects vs. Hide BodiesWhen a body is hidden, the body is not deleted from the model; it is just a visual effect to keep from being seen; the body still exists.

When an object is suppressed, however, it has exactly the same effect as being deleted. We usually prefer "suppress" to "delete," since a suppressed object always can be "unsuppressed."

Now, select the 10 objects again and right-click-select <Unsuppress> from the context menu; the model would explode again. Using this method, you can explode or un-explode a model as you like.

Wrap UpClose DesignModeler, save the project ("Joint"), and exit the Workbench.


Appendix:

Exercise 16aDynamic Simulation of the Universal Joint

16a-1 Introduction

In this exercise, we'll perform a dynamics simulation for the assembly created in Exercise 11. The assembly is entirely made of steel, which is the default material used in <Mechanical>.

We assume a hinge set up at the top of the upper yoke, such that the whole assembly can swing in the XY plane and behaves like a double-pendulum [1]. Initially, the lower yoke is raised to form an angle of 30 degrees with the vertical axis, and then released [2]. The only external force, other than the reaction forces at the hinge, acting on the assembly is the gravitational force. We want to observe the double-pendulum behavior of the assembly.

Since our concern is the double-pendulum behavior of the assembly, the body deformation can be neglected. Therefore, we assume all bodies are rigid. We'll use a built-in system in the Workbench, called <Rigid Dynamics>, which assumes all bodies are rigid and has capabilities of performing rigid-body dynamic simulations.

We'll further assume that the combination of the swivel, four bushings, and four pins is an integrated part, i.e., they are bonded together. This assumption should be reasonable as long as the double-pendulum behavior is the only concern. This assumption not only simplifies the model setup in <Mechanical> but also reduces computation time.

30

[1] In this simulation, we'll assume a hinge set up

here, such that the whole assembly can swing in the XY plane and behaves like

a double-pendulum.

X

Y

[2] Initially, the lower yoke is raised to form an angle of 30 degrees with the vertical

axis, and then released.

166 Exercise 16a. Dynamic Simulation of the Universal Joint

16a-2 Group 9 Parts to Form an Integrated Part

[1] Lunch Workbench and open the project "Joint," which was

saved in Exercise 16. [2] Double-click <Geometry> to start up <DesignModeler>.

[3] Select all bodies except "UpperYoke" and

"LowerYoke," and right-click-select <Form New Part>.

[4] This is called a multi-body part. In <Mechanical>, it is treated as an integrated part, i.e., all bodies are

bonded together. Close <DesignModeler>.



[1] Drag <Rigid Dynamics> and drop to <Geometry> cell of the <Geometry> system.

[2] A <Rigid Dynamics>

system is created.

[3] The two systems share the same <Geometry>. You can edit up-stream cell but not the down-stream cell.

[4] Double-click <Model> to start up <Mechanical>.

[6] If the unit system is not like this, pull-down-select

<Unit/U.S. Customary (in, lbm, lbf, F, s, V, A)> (11a-2[10]).

[5] <Mechanical GUI> shows up. If your GUI layout is not like this, pull-down-select <View/Windows/Reset Layout> and select

<Graphics> tab (11a-2[8]).


16a-4 Create a Revolute Joint

[1] Select <Contacts> and right-click-select <Delete>

from the context menu.

Why Delete Contacts?When a model is first time brought into <Mechanical>, the <Mechanical> automatically sets up connections between parts; these automatic setups are often not adequate. Here, we decide to manually set up the connections. That's why we deleted the automatic setups.

[5] Click to activate <Body Views>.

[2] While <Connections> in the project tree is still highlighted, select <Body-

Body/Revolute>.

[3] A revolute joint is created.

[4] In <Details View>, we need to specify a reference body and a mobile body.

[6] The graphics window splits into three windows. The upper-

right window will show the reference body, and the lower-

right window will show the mobile body.


[8] Click anywhere on the

upper yoke.

[7] Click the yellow area to bring up <Apply/Cancel>

buttons.

[9] Select this cylindrical face (to define a reference coordinate system). Zoom-in or rotate the view if necessary. Make sure the Z-axis of the

reference coordinate system is in the cylinder axis; directions of the other two axes are not important. A revolute joint allows the mobile

body rotates in Z direction (see [10]).

[11] Click <Apply>.

[10] A revolute joint allows the

mobile body rotates in Z direction.


buttons.

[15] Click <Apply>.

[13] Click the swivel (or anywhere of the

integrated part).

[14] Select this cylindrical face (to define a rotational axis). Zoom-in or

rotate the view if necessary. Note that the reference coordinate system defined

in [9] also shows here.


[15] This completes the creation of a revolute joint, in which the axis of the "Bushing2" allows to rotate in the axis of the cylinder hole. We now proceed

to create other revolute joints.

16a-5 Create Other Revolute Joints[1] Select <Body-Body/Revolute>.

[2] Select the cylindrical face of another hole of the upper yoke to define a reference

coordinate system (see the upper-right window). Remember to make sure the Z-

axis of the reference coordinate system is in the cylinder axis; directions of the other two

axes are not important.

[3] Select the cylindrical face of the "Bushing4" to define a rotational axis (see

the lower-right window).


[7] Select <Body-Body/Revolute>.

[4] Select <Body-Body/Revolute>.

[8] Select the cylindrical face of another hole of the

lower yoke to define a reference coordinate

system (see the upper-right window).



[5] Select the cylindrical face of a hole of the lower yoke to define a reference coordinate system (see the

upper-right window).




[10] We've defined 4 revolute joints.

16a-6 Create the Hinge

Now, we proceed to create a hinge at the top of the upper yoke (16a-1[1]). In a normal case, this hinge can be modeled by a body-to-ground revolute joint. However, since we don't have any geometric entities (faces, edges, or points) to define the rotational axis, we choose to create a "general" body-to-ground joint and then specialize to a revolute joint.

[1] Select <Body-Ground/General>.

[2] Click the yellow area to bring up <Apply/

Cancel> buttons.

[4] Click <Apply>.

[3] Click this circular face. This selects the upper yoke as mobile body and, as the

same time, defines a reference coordinate system.

[5] Select <Free Y> for <Rotations>. This allows the mobile body to

rotate in Y direction.


[1] Click to de-activate <Body

Views>.

[2] Select <Revolute - LowerYoke to

Bushing1>.

[3] Click to rotate the view to look at

the XY plane.

[4] Click <Configure>.

[5] Drag the handle until the lower yoke becomes 30 degrees (or 330 degrees).

[6] Or, a better way is that you type 30 (degrees) here.

[7] If you make any mistakes, click

<Revert> and go back to step [4].

[8] When you satisfy your initial

configuration, click <Set>.

16a-7 Set Up Initial Configuration


16a-8 Apply Gravitational Force


[1] Click to highlight <Transient>.

[2] Select <Inertial/Standard Earth

Gravity>.

[4] Select <-Y Direction>.

[3] An environment condition is inserted.


[2] Select <Deformation/

Total>.

[3] A results object is inserted.


16a-10 Set Up <Analysis Settings>


[1] Click to highlight <Analysis Settings>.

[2] Type 3 (s) for <Step End

Time>.

[1] Click <Solve>.

[2] Click to highlight <Total Deformation>.

[5] Click <Play> to animate the results.


Wrap UpClose <Mechanical>, save the project ("Joint"), and exit the Workbench.

[3] Click <Result Sets>.

[4] Totally 442 frames, each from

a result set.

[7] By clicking <Export Video File>, the animation can be

save as an AVI file.

176 Exercise 17. Clamping Mechanism

0.75

0.375 0.25

Pin B

Pin A

Pin C

Unit: in.

Grip

Exercise 17Clamping Mechanism

In this exercise, we'll create the clamping mechanism mentioned in Exercises 1, 8, 12, and 15. Some parts that are not created in the previous exercises are detailed in this page.

Comparing with previous exercises, this exercise is rather complicated. For a complicated model like this, we need more efficient way of handling multiple parts and transforming parts. We'll demonstrate how a geometry can be exported from a <Geometry> system and imported to another <Geometry> system. We'll also demonstrate a more general way of transformation parts. In this way, we need two planes: a source plane and a destination plane. A part then can be transformed just like the source plane is transformed to the destination plane.

The clamping mechanicsm is adapted from a working drawing in the book Technical Graphics Communication, by G. R. Bertoline, E. N. Wiebe, C. L. Miller, and J. L. Mohler.

17-1 Introduction

0.7

5

1.375

0.375

0.3

75 Part Name: Grip

D0.312

0.75

0.375

D0.312 D0.25

Part Name: Pin A

0.75

1.125

D0.312 D0.25

Part Name: Pin B

1.125

0.375

D0.25 D0.312

Part Name: Pin C


17-2 Export the Arm, Support, and Shaft Assembly

[1] Launch ANSYS Workbench and open the project "Arm,"



up DesignModeler.

[3] In DesignModeler, select <File/Export...>.

[4] Select <Parasolid Text> as the file type.

[5] Type "Arm" as the file name. The exported

geometry will be saved as "Arm.x_t."

[6] Select <File/Close DesignModeler>.


[9] Open the project "Support," which was saved in

Exercise 8.


up DesignModeler.



[13] Type "Support" as the file name. The exported geometry will be saved as

"Support.x_t."


[7] Click <New>.

[8] Click <No>.


[17] Open the project "Shaft," which was saved

in Exercise 15.


up DesignModeler.



[21] Type "Shaft" as the file name. The exported geometry

will be saved as "Shaft.x_t."


[15] Click <New>.

[16] Click <No>.



up DesignModeler.

[1] Click <New>.

[2] Click <No>.

17-3 Create a New Project

[3] Save the new project as "Clamp."

[4] Double-click to create a <Geometry>

system.

[6] Select <Inch> as the length unit.

[7] Click <Ok>.


17-4 Import the Support

[1] Select <File/Import External Geometry File...> and open the file "Support.x_t."


[3] The <Base Plane> determines how the imported

geometry positions in the current global coordinate system. Here, <XYPlane> means the imported geometry's coordinate system is to be coincident with the current

XYPlane.


[5] Click <Display Plane>.

[6] The imported geometry's coordinate

system is coincident with the current XYPlane.

17-5 Translate the Support


[2] Select the imported body and set

up other options as shown. Click <Generate>.

[3] Click X-axis to look at

YZ plane.

[4] Rename the body as "Support1."


17-6 Create the Other Support

17-7 Import the Shaft Assembly

[1] Select <Create/Body Operation> from the pull-down menu and

select <Mirror>.

[2] Select "Support1."

[3] Select <XYPlane> from the model tree and click

<Generate>.

[4] Click for a isometric view.

[5] Rename the body as "Support2."

[1] Select <File/Import External Geometry

File...> from the pull-down menu and open the file "Shaft.x_t." Select <Add Frozen>. Click

<Generate>.

[2] The shaft assembly consists of

4 parts (see [3]).


17-8 Translate the Shaft Assembly

[3] The shaft assembly consists of

4 parts.

Now, we want to translate the shaft assembly such that the part "MidHinge" is at its correct position. Calculation of the amount of translation is not a easy task. We now demonstrate a general way of transformation parts. In this way, we need two planes: a source plane and a destination plane. The shaft assembly will be transformed just like the source plane is transformed to the destination plane.



[4] Click the yellow area to bring up

<Apply/Cancel> button and click <Apply>. Click <Generate>.

[3] Click this ring-shaped face. Make sure the three axes have the same directions as the

global axes





buttons and click <Apply>.

[7] Click the inner face of the "Support1" at a location near the arc. Make sure the three axes are like this.

Now, we want to reverse the Z-axis so that the three axes have the same directions as the global axes.

X

Y

Z

[9] Select <Yes> for <Reverse Normal/Z-

Axis>. Click <Generate>.

[10] Now, the axes of the <Plane4> have the same directions as <Plane5>.


46.775

9.273


select <Move>.

[12] Select the four bodies of the shaft

assembly (Shaft, Handle, EndHinge, and

MidHinge), either from the model tree or from the graphics window.

[13] Select <Plane4> as <Source Plane>.

[14] Select <Plane5> as <Source Plane>. Click <Generate>.

[15] Now, we want to tilt the shaft assembly a certain angle. A tedious calculation

shows the angle is 9.273 degrees (see [16]).

[16] The two angles shown are calculated from the geometry of

the clamp. These angles are needed for the configuration of

the parts.


17-9 Rotate the Shaft Assembly[1] Select <Create/

Body Operation> from the pull-down menu and

select <Rotate>.

[2] Select the four bodies of the shaft

assembly (Shaft, Handle, EndHinge, and

MidHinge).

[4] Bring up <Apply/Cancel>

[3] Type 9.273 (degrees) for

<Angle>.[6] Select this

circular face. Its outer normal defines a

rotational axis (see next step).

[5] Click <Selection Filter: Model Faces>

[7] Click to reverse the direction.

[9] Now the shaft assembly is at its

correct position and orientation.

[8] Click <Apply>. Click <Generate>.


17-10 Import the Arm

[5] Select <File/Import External Geometry File...>

from the pull-down menu and open the file "Arm.x_t." Select

<Add Frozen>. Click <Generate>.

[6] By default, the currently active plane is

the base plane.

Remember that the origin of the arm is at the center of a hole (see 1-1). We now want to import the arm such that the hole connects to the "EndHinge" to form a revolute joint.



[4] Click the yellow area to bring up

<Apply/Cancel> button and click <Apply>. Click <Generate>.

[3] Click this ring-shaped face. Make sure the three

axes have the same directions like this.

[6]Next, we need to rotate the arm 46.775 degrees

clockwise (see 17-8[16]).


17-11 Rotate the Arm[1] Select <Create/

Body Operation> from the pull-down menu and

select <Rotate>.

[2] Select the arm.

[4] Bring up <Apply/Cancel>

[3] Type 46.775 (degrees) for

<Angle>.

[6] Select this cylindrical face. the

cylinder axis defines a rotational axis (see

next step).

[5] Click <Selection Filter: Model Faces>

[7] If necessary, click here to reverse the direction.

[9] Now the arm is at its correct position and

orientation.

[8] Click <Apply>. Click <Generate>.

[10] Rename the body as "Arm1."


17-12 Create the Other Arm


select <Mirror>.

[2] Select "Arm1."

[3] Select <XYPlane> from the model tree and click

<Generate>.

[4] The second arm.

[6] Rename the body as "Arm2."

[5] YZ plane view. Note that there is a gap between an arm

and a support.


17-13 Create the Grip




buttons.

[4] Select this face. Make sure the axes

are like this.

[5] Click <Apply>.

[6] Select <Align X-Axis with Global> for <Transform 1>.

[7] The X-axis rotates to align with

the global X-axis.

[7] Select <Offset Z> for <Transform 2>.

[8] Type 0.1875 (in.) for <Value>. Click <Generate>.


[10] In the newly created plane (Plane7), draw a sketch like this. The sketch consists of a

rectangle and a circle centered at the origin and with a diameter of 0.312 (in.).

[12] Extrude the new sketch (Sketch1) 0.125

(in.) both sides symmetrically.

[9] The plane should lie on the global XY plane.

[11] The plane outline.

[13] Rename the body as "Grip."


[4] Pin A.

17-14 Create Pin A

[1] Select <Create/Primitives/Cylinder> and select the new plane (Plane7) from

the model tree as the <Base Plane>. Set up the <Details View> as shown.

Click <Generate>.

[2] If you hide all other bodies, you would see the

new body like this.

[3] Select <Create/Primitives/Cylinder> and select the new plane (Plane7) from

the model tree as the <Base Plane>. Set up the <Details View> as shown.

Click <Generate>.

[5] Rename the body as "PinA."


[4] Pin B.

17-15 Create Pin B

[1] Select <Create/Primitives/Cylinder> and select the XYPlane from the model

tree as the <Base Plane>. Set up the <Details View> as shown. Click

<Generate>.


new body like this.

[3] Select <Create/Primitives/Cylinder> and selectXYPlane from the model tree

as the <Base Plane>. Set up the <Details View> as shown. Click

<Generate>.

[5] Pin B should be positioned here...

[6] And here.


[1] Select <Create/Body Operation> and select

<Translate>.

[2] Select the new body.

[3] Type -1.25 (in.) for <X Offset> (see the details in 8-1).

Click <Generate>.

[4] Select <Create/Body Operation>

and select <Translate>.

[5] Select the new body.

[7] Type 1.25 (in.) for <Y Offset> (see the details

in 8-1). Click <Generate>.

[6] Select<Yes> for <Preserve

Bodies?>

[8] Rename two new bodies as "PinB1" (lower pin) and "PinB2" (upper

pin) respectively.


[4] Pin A.

17-16 Create Pin C

[1] Select <Create/Primitives/Cylinder> and select XYPlane from the model tree as the <Base Plane>. Set up the

<Details View> as shown. Click <Generate>.


new body like this.

[3] Select <Create/Primitives/Cylinder> and select XYPlane from the model tree as the <Base Plane>. Set up the

<Details View> as shown. Click <Generate>.

[5] Rename the body as "PinC."


17-17 Enhance Visual Effects

[1] Select <Edge Coloring/Black>. It

instructs DesignModeler to render the model with

black edges.

[2] Select <View/Frozen Body Transparency> to turn off the transparent

display of the frozen bodies.

Wrap UpClose DesignModeler, save the project ("Clamp") and exit the Workbench.


Appendix:

Exercise 17aSimulation of the Clamping Mechanism

17a-1 Introduction

The clamping mechanism created in Exercise 17 is designed to provide clamping forces up to 450 lbf [1]. In this exercise, we'll perform a simulation to make sure that, under the clamping force of 450 lbf, the stresses everywhere are within the allowable stress of the steel, which is 30,000 psi. Remember that the clamping mechanism is entirely made of steel, which is the default material used in <Mechanical>.

We'll assume an initial configuration such that the grip merely contacts the clamped object and the clamping force is zero [2, 3]. As the handle rotates to increase the distance between two hinges, the clamping force also increases, until the clamping force reaches 450 lbf [4-6].

[1] The clamping mechanism is designed to provide clamping

forces up to 450 lbf.

[3] With the initial configuration, the grip merely contacts the

clamped object and the clamping force is zero.

[6] As the handle rotates to increase the distance between two hinges, the clamping force

also increases, until the clamping force reaches 450 lbf.

[2] The initial distance between

two hinges is 3.063 in (see 15-1).

[4] The middle hinge.

[5] The end hinge.

198 Exercise 17a. Simulation of the Clamping Mechanism

17a-2 Simplify the Model

[1] Launch ANSYS Workbench and open the project "Shaft," which was



up DesignModeler.

[3] Right-click <Sweep1> and select <Suppress>





[7] Type "Shaft1" as the file name. The exported

geometry will be saved as "Shaft1.x_t."


[4] The threads are removed. This is a simplification of the

model to make the simulation easier, without sacrifice too

much accuracy.

[11] Open the project "Clamp," which was saved in Exercise 17.

[12] Double-click <Geometry> to start up <DesignModeler>.

[9] In <Workbench GUI>, Click <New>.

[10] Click <No>.


[13] Select <Import2>, which is the shaft assembly.

[14] Double-click <Source>.

[15] Select "Shaft1.x_t," which was save in [5-7].



[17] Control-select "Shaft," "Handle," and

"EndHinge," and right-click-select

<Form New Part>.

[19] Control-select "Support1," "Support2,"

"PinB1," "PinB2," and "PinC," and right-click-

select <Form New Part>.

[18] Rename the new part as "ShaftAssembly." The three

bodies are now treated as an integrated part. It is not real; it is

a simplification to make the simulation easier.

[21] Control-select "Grip" and "PinA," and

right-click-select <Form New Part>.

[20] Rename the new part as "SupportAssembly." The five bodies are now treated as an

integrated part. Again, it is not real; it is a simplification to make the modeling easier.

[22] Rename the new part as "GripAssembly." The two bodies are now treated as an

integrated part. Close DesignModeler.

[23] Close DesignModeler.



[1] Drag <Static Structural> and drop to <Geometry> cell of the <Geometry> system.

[2] A <Static Structural>

system is created.

[3] The two systems share the same <Geometry>. You can edit up-stream cell but not the down-stream cell. [4] Double-click

<Model> to start up <Mechanical>.

[6] If the unit system is not like this, pull-down-select

<Unit/U.S. Customary (in, lbm, lbf, F, s, V, A)> (11a-2[10]).

[5]If your GUI layout is not like this, pull-down-select <View/Windows/

Reset Layout> and select <Graphics> tab (11a-2[8]).


[9] Select <Contacts> and right-click-select <Delete>

from the context menu. (See 17a-4).

[10] The project tree should look like this.

[11] Make sure <Connection> is

highlighted.

17a-4 Create Revolute Joints

There are 8 revolute joints to be created: [1] PinA to Arm1, [2] PinA to Arm2, [3] EndHinge to Arm1, [4] EndHinge to Arm2, [5] MidHinge to Support1, [6] MidHinge to Support2, [7] PinC to Arm1, and [8] PinC to Arm2.

[1] PinA to Arm1.[2] PinA to Arm2.

[3] EndHinge to Arm1.[4] EndHinge to Arm2.

[5] MidHinge to Support1.[6] MidHinge to Support2.

[7] PinC to Arm1.[8] PinC to Arm2.


[12] While <Connections> is highlighted, click to

activate <Body Views>.

[13], select <Body-Body/Revolute>.

[14] Select a cylindrical face of the PinA (see the red-colored face in the upper-right window).

[15] Select a cylindrical face of the Arm1 (see the blue-colored face in the

lower-right window).


[17] Select another cylindrical face of the

PinA (see the red-colored face in the upper-right

window).



Create [1] PinA to Arm1, and [2] PinA to Arm2.



[20] Select a cylindrical face of the EndHinge (see

the red-colored face in the upper-right window).





EndHinge (see the red-colored face in the upper-

right window).



Create [3] EndHinge to Arm1, and [4] EndHinge to Arm2.



[26] Select a cylindrical face of the MidHinge (see


[27] Select a cylindrical face of the Support1 (see the blue-colored face in the lower-right window).



MidHinge (see the red-colored face in the upper-

right window).

[30] Select a cylindrical face of the Support2 (see the blue-colored face in the lower-right window).

Create [5] MidHinge to Support1, and [6] MidHinge to Support2.



[32] Select a cylindrical face of the PinC (see the red-colored face in the upper-right window).





PinC (see the red-colored face in the upper-

right window).



Create [7] PinC to Arm1, and [8] PinC to Arm2.

[37] We've created 8 revolute joints.


17a-5 Create a Translational Joint [1], select <Body-Body/Translational>.

[2] Select a cylindrical face of the MidHinge (see


[3] Select the cylindrical face of the Shaft (see the blue-colored face in the


[4] We've created a translational joints.

[5] A translational joint restricts the mobile body sliding along the X direction

of the reference coordinate system.


[1] Highlight <Static Structural> and select

<Support/Fixed Support>.

[2] Select the bottom two faces as fixed supports


[3] Select <Support/Frictionless Support> and

select the bottom face of the grip as a frictionless support.

17a-7 Specify a Relative Translation between Shaft and MidHinge

[1] While <Frictionless Support> is still

highlighted, select <Loads/Joint Load> to insert a

joint load.

[2] Select <Translational -

MidHinge to Shaft>.

[3] Select <Displacement>.

[4] Type 0.003 (in.) for <Magnitude>.

This is an arbitrarily chosen value (see an explanation on

the right.

Why Specify an Arbitrary Displacement?Remember that the mechanism is to provide a clamping force of 450 lbf. (17a-1). But we cannot specify a vertical force on the grip, because the grip was fixed in the vertical direction (17a-6[3]). This is easy to understand because you cannot specify both displacement conditions and force conditions on the same face. You either specify a fixed (zero displacement) condition and try to evaluate the reaction force, or specify a force condition and try to evaluate the resulting displacement.

Our strategy is to specify an arbitrary value of displacement [4] for the relative translation between Shaft and MidHange, to simulate the advance of the shaft due to the rotation of the handle (17a-1[6]), and then to evaluate the clamping force. The displacement [4] then adjusts to give an exact clamping force of 450 lbf.


17a-8 Insert Results Objects[1] Highlight <Solution>.

[2] Select <Deformation/Total>.


[4] Select <Stress/Maximum Principal>.

[5] Select <Stress/Minimum Principal>.

[6] Select <Probe/Force Reaction>.

[7] Select <Frictionless

Support>.

17a-9 Solve the Model and View the Clamping Force

[1] Click <Solve>.

[2] While <Force Reaction> is still

highlighted, you can see the clamping force (425.52

lbf) in the details view.

[3] The clamping force is vertical, because the grip

is allowed to move horizontally.


17a-10 Adjust the Joint Displacement and Solve Again

[1] Highlight <Joint - Displacement>.

[2] Type 0.003173 (in.) for <Magnitude>.Note: 0.003/425.52x450 = 0.003173

[3] Click <Solve>.

[4] Now, the clamping force is 450 lbf.


17a-11 View Stresses and Animation

[1] Highlight <Equivalent Stress>.

[3] Select <Auto Scale>. [2] The maximum stress

is within the allowable value (30,000 psi).

[4] Click <Play> to animate the results.


17a-12 Evaluate Joint Forces

[1] Highlight <Solution>.

[2] Select <Probe/Joint> and, in the details view, select <Revolute - PinA to Arm1> for <Boundary Condition>.

[3] Select <Probe/Joint> and, in the details view, select <Revolute - EndHinge to Arm1> for <Boundary Condition>.

[4] Select <Probe/Joint> and, in the details view, select <Revolute - MidHinge to Support1> for <Boundary Condition>.

[5] Select <Probe/Joint> and, in the details view, select <Revolute - PinC to Arm1> for <Boundary Condition>.

[6] Select <Probe/Joint> and, in the details view, select <Translation - MidHinge to Shaft> for <Boundary Condition>.

[7] Select <Probe/Force Reaction> and, in the details

view, select <Fixed Support> for <Boundary Condition>.


[8] Rename the results objects like this, to make

them more readable.[9] Click <Solve>.

17a-13 Forces Acting on an Arm

56.048

225.04

379.95

61.91

379.94

163.13

[1] Details of "Force - PinA to Arm1."

[2] Details of "Force - EndHinge to Arm1."

[3] Details of "Force - PinC to Arm1."

Transform Force ComponentsIt is very easy to transform the above force components into the force components shown in 1a-1[3]. We need to know an angle [4] to accomplish the transformation. The angle can be calculated from 17-8[16].

[4] The angle is calculated from

17-8[16].


17a-14 Forces Acting on a Support

[1] Details of "Force - MidHing to Support1."

379.94 163.13

379.94 62.045

225.03

[2] Details of "Force on Bottom Faces." Note that, half of the force (450.06 lbf)

acts on a support.

[3] These force components from PinC have the same magnitudes and

opposite directions as those in 17a-13[3].

It is very easy to verify that the above forces acting on a support is self-balanced. Please also see 8a-1[3, 4].

[4] There are no forces from

PinB1.

[5] There are no forces from

PinB2.

17a-15 Compressive Forces in the Shaft

[1] Details of "Force - MidHing to Shaft" shows that a total compressive force of 769.61 lbf acts on the shaft.

Wrap UpClose <Mechanical>, save the project as "Clamp-a", and exit the Workbench.

Section D. Concept Modeling 215

Section DConcept Modeling

As mentioned, although it can be used as a general purpose CAD software, the DesignModeler is particularly designed for creating geometric models to be analyzed (simulated) under the ANSYS environment. So far, we've created many 3D solid models; each can be imported into an analysis application, such as <ANSYS Mechanical>. 3D solid models are not the only models that <ANSYS Mechanical> can analyze. Often, due to the efficiency (computing time and solution accuracy), we prefer using simplified models, such as 2D solid models, surface models, or line models. This section provides exercises for creating such simplified model.

216 Exercise 18. 2D Solid Modeling (Arm)

Exercise 182D Solid Modeling (Arm)

18-1 Introduction

When the geometric characteristics in a certain dimension (e.g., the thickness in Z-dimension) can be parameterized and the rest of the geometric characteristics (and the loads) can be expressed in a 2D space (in this example, XY-space), we often simplify the model into a 2D solid model, to facilitate the simulation task. The benefits of using a 2D solid model (over a 3D solid model) include reduced modeling time, reduced computing time, increased accuracy, increased post-processing efficiency.

In this exercise, we will create a 2D solid model for the arm, which has been modeled as s 3D solid model in Exercise 1


[1] Launch ANSYS Workbench and open the project "Arm,"


[2] Right-click here and select <Duplicate>


Exercise 18. 2D Solid Modeling (Arm) 217

[3] Double-click the name of the system (default to

"Geometry") and type "3D Model" to change the name.

[4] Double-click the name of the system (default to "Copy of Geometry") and type "2D Model" to change the name.

[5] Double-click to start up DesignModeler.

[6] Right-click <Extrude1> and select <Delete> from

the context menu.

218 Exercise 18. 2D Solid Modeling (Arm)

18-3 Create a 2D Model

[1] Now, the only object in the model tree is

<Sketch1>, which is on <XYPlane>.

[2] Select <Concept/Surfaces From Sketches>.

[3] Select <Sketch1> from the model tree.

[4] Type 0.125 (in.) for <Thickness>. This

information doesn't show in the geometry, but will

be brought to a simulation module, such as <Mechanical>.


[6] This is a 2D model for the arm. Note that the 2D

model is on XY-plane; <Mechanical> requires a 2D model resides on XY-plane.

Wrap UpClose DesignModeler, save the project as "Arm-2D" and exit the Workbench.


Appendix:

Exercise 18aStructural Analysis of the Arm Using 2D Model

18a-1 Introduction

In this exercise, we will perform a static structural analysis for the 2D model created in Exercise 18. We'll use the same boundary conditions (loads and supports) as in Exercise 1a (1a-1[3]). The results (stresses) should be the same as those obtained in Exercise 1a, except that a 2D model is computationally much more efficient.

18a-2 Start Up

[1] Launch Workbench and open the project "Arm-2D," which was saved in Exercise 18.

[2] Drag <Static Structural> and drop to <Geometry> cell of the

<2D Model> system.

[3] Right-click <Geometry> and

select <Properties>.

220 Exercise 18a. Structural Analysis of the Arm Using 2D Model

[4] Select <2D> for <Analysis Type>. It is

necessary for a 2D analysis, otherwise, by default,

<Mechanical> will perform a 3D analysis.

[5] Click to close the properties window.

[6] Click <Model> to start up

<Mechanical>.

[7] Click to close the message window.


18a-3 Specify Loads



[3] Select this circular edge.

[4] Click <Apply>.



for <Y Component>.



[9] Click <Apply>.



for <Y Component>.



[2] A <Fixed Support> is inserted.

[4] Click <Apply>.







18a-6 Solve the Model [1] Click <Solve>.

[2] The stress distribution is essentially the same as that is

Exercise 1a.


WireFrame>.




[7] There are 779 nodes in the model; that means a total degrees of freedom is 1558 (2x779; for 2D problems, each node has 2 degrees of freedom). The degrees of freedom

is an indication of problem size, and it is in turn an indication of computing time.

[8] Close <Mechanical>, and in the <Workbench GUI>, save the

project as "Arm-2D-a."


18a-7 Open the Project "Arm-a" [1] In the <Workbench GUI>, Open the project "Arm-a," and

start up <Mechanical>.


[7] There are 890 nodes in the model; that means a total degrees of freedom is 2667 (3x890; for 3D problems,

each node has 3 degrees of freedom). The ratio of the problem size between the 2D model and the 3D model

is 0.58 (1558/2667). That means, in this case, only approximately 58% of computing time is need for the 2D

model, to achieve the same solution accuracy.

Wrap UpClose <Mechanical> and exit the Workbench.


Exercise 19Surface Modeling (Support)

19-1 Introduction

When a body in 3D space is thin enough, we often simplify the body into a surface body, to facilitate the simulation task. The benefits of using a 3D surface model (over a 3D solid model), similar to a 2D solid over 3D solid, include reduced modeling time, reduced computing time, increased accuracy, increased post-processing efficiency.

In this exercise, we will create a 3D surface model for the support, which has been modeled as a 3D solid model in Exercise 8.


[1] Launch ANSYS Workbench and open the

project "Surface," which was saved in Exercise 8.

[2] Right-click here and select <Duplicate>


[3] Rename the original system as "3D Solid

Model."

[4] Rename the duplicated system as "3D

Surface Model."

[5] Double-click to start up DesignModeler.

226 Exercise 19. Surface Modeling (Support)

[6] Select Extrude1, Plane4, Extrude2, Plane5, Extrude3, and FBlend1 in the model tree and right-

click-select <Delete> from the context menu.

[7] We've deleted everything except

<Sketch1>, which is on <XYPlane>.


19-3 Create a Surface Body for the Vertical Plate


[2] Select <Sketch1> from the model tree.

[3] Type 0.125 (in.) for <Thickness>. This

information doesn't show in the geometry, but will be

brought to a simulation module, such as <Mechanical>.


[5] This is a surface body representing the vertical

plate.

[6] The global origin is here. Let's move the

body to a more convenient location.


[8] Select <Translate>.

[9] Select the vertical plate.

[10] Type 1.625 (in.) for <X Offset> and 0.875 (in.)

for <Y Offset>.


[12] The body translates so that its lower-left is at

the origin.

228 Exercise 19. Surface Modeling (Support)

19-3 Create a Surface Body for the Horizontal Plate

[1] Activate <ZXPlane>.

[2] Switch to <Sketching

Mode>.

[3] Draw a sketch like this. Note

that, in ZXPlane, the Z-axis is the

horizontal axis and the X-axis is the

vertical axis.

[4] If you click <Look At Face/Plane/Sketch> and

disable model display, you would see the plane view of

the sketch like this.


Wrap UpClose DesignModeler, save the project as "Support-Surface" and exit the Workbench.


[2] Select the newly created

skectch from the model tree.

[3] Type 0.125 (in.) for <Thickness>.


230 Exercise 19a. Structural Analysis of the Support Using Surface Model

[1] Launch Workbench and open the project "Support-Surface," which was saved in

Exercise 19.

[2] Drag <Static Structural> and drop to <Geometry> cell of the <3D Surface Model>

system.

Appendix:

Exercise 19aStructural Analysis of the Support Using Surface Model

19a-1 Introduction

In this exercise, we will perform a static structural analysis for the surface model created in Exercise 19. We'll use the same boundary conditions (loads and supports) as in Exercise 8a (8a-1[3, 4]).

19a-2 Start Up

[3] Click <Model> to start up

<Mechanical>.


19a-3 Specify Loads



[4] Select this arc edge.

[5] Click <Apply>.



for <Y Component>.

[3] Click <Edge>.



[10] Click <Apply>.



for <Y Component>.

232 Exercise 19a. Structural Analysis of the Support Using Surface Model


[4] Click <Apply>.

[3] Select the bottom face.


[5] Select <Supports/Displacement. [7] Select the 3

circular edges and an arc edge on the vertical

plate.

[8] Click <Apply>.

[9] Type 0 (in.) for <Z

Component>.

[2] Select <Face>.

[6] Select <Edge>.


19a-5 Insert Result Objects and Solve the Model



[3] Solve the model.

Wrap UpClose <Mechanical>, save the project as "Support-Surface-a," and exit the Workbench.

234 Exercise 20. Line Modeling (Space Truss)

Exercise 20Line Modeling (Space Truss)

X

Y

Z 0.5 m

0.5 m

1 m

1 m

1 m

1200 N

200 N

1

2

4

5

5 1

2

3

4

6

7

8 9

3

Consider a space truss subject to design loads as shown [1-4]. Note that each truss member and each connection node (spherical joint) is given an identification number. This example is adapted from a problem in the book Vector Mechanics for Engineers: Statics, by F. P. Beer, E. R. Johnston, and E. R. Eisenberg. The member forces calculated by the textbook are shown in the table below [5]. Note that a plus sign is used to indicate a tensile member force and a minus sign to indicate compressive member force.

The truss is a statically determinate structure, that is, the member forces can be solved using static equilibrium equations without any cross-sectional information. Here, we assume that all members have a circular cross-section of diameter 10 mm.

In this exercise, we'll create a line model for this space truss. In the Exercise 20a, as an appendix, we'll perform a structural analysis to calculate the member forces using this line model.

20-1 Introduction

[1] This node is supported in Y-

direction.

[2] This node is supported with a

hinge, i.e., displacements in all

directions are restricted.

[3] This node is supported in Z-

direction.

[4] This node is supported in Z-

direction.

Member MemberForce

1 +400 N

2 -600 N

3 -100 N

4 -200 N

5 0

6 -1342 N

7 +1500 N

8 +300 N

9 -566 N

[5] Member forces.


20-2 Start Up

[1] Launch <Workbench> and save the project as

"Truss."


system.

[3] Double-click <Geometry> to start up <DesignModeler>.

Select <Meter> as length unit.

[1] Select <Create/Point>.

[2] Select <Manual Input>.

[3] Type coordinates.


20-3 Create Points for Nodes


1

2

3

4

5

Point X Coordinate Y Coordinate Z Coordinate

1 0 m 0 m 0 m

2 1 m 0 m 0 m

3 1 m 1 m 0 m

4 0 m 1 m 0 m

5 0.5 m 0 m 1 m

[5] Repeat steps [1-4] for additional four

points (Points 2-5); type their respective

coordinates as shown in this table.

[6] The newly created points.

[7] The newly created points. (The numbers

are not part of the display.)

20-4 Create Line Bodies for Truss Members

[1] Select <Concept/Lines From Points>.

[4] Click <Apply>.

[2] Click the starting point

(Point1)...[3] And then

control-click the ending point

(Point2).




1 2

3

4

5

6

7

8

9

Line Start Point End Point

1 Point1 Point2

2 Point2 Point3

3 Point3 Point4

4 Point4 Point1

5 Point1 Point5

6 Point2 Point5

7 Point3 Point5

8 Point4 Point5

9 Point1 Point3

[7] Repeat steps [1-6] for additional 8 lines

(Lines 2-9). Each line is created by clicking the starting point and then

control-clicking the ending point. Each line is

created by <Add Frozen> operation, so that each line body is treated as a separate

part.

[8] Because of the <Add Frozen>

operation, each line body is treated as a

separate part.

[9] Rename the line bodies as shown.

[10] The newly created line bodies. (The numbers are

not part of the display.)


20-5 Create and Assign Cross Section for the Line Bodies

[2] In the <Details View>, type 0.005

(m) for <R>.

[4] Select all line bodies.

[5] In the <Details View>, select

<Circular1> for <Cross Section>.

[1] Select <Concept/Cross Section/Circular>.

[3] The sectional properties are automatically calculated.


[6] Turn off <View/Cross Section Alignments>.

[7] Turn on <View/Cross Section Solids>.

[8] Turn off <Display Plane>.

Wrap UpClose DesignModeler, save the project ("Truss") and exit the Workbench.

240 Exercise 20a. Structural Analysis of the Space Truss

Appendix:

Exercise 20aStructural Analysis of the Space Truss

20a-1 Introduction

In this exercise, we will perform a static structural analysis using the line model created in Exercise 20. We'll use the boundary conditions (loads and supports) described in Exercise 20 (20-1[1-4]). The resulting member forces should be consistent with those given by 20-1[5].

20a-2 Start Up

[1] Launch Workbench and open the project "Truss," which was


[2] Double-click <Model> to start up

<Mechanical>.


20a-3 Set Up <Connections>

[1] Highlight <Connection>.

[2] Select <Body-Body/Spherical>. A <Spherical>

joint allows the connecting members to independently rotate in

all directions.

[3] If the unit system is not like this, select <Units/Metric (m, kg, N, s, V, A).


[3] Click <Vertex>.

[4] Click this node.

[5] Four "selection panes" show up; each represents a vertex of a

connecting member. The currently selected vertex is highlighted (red-

colored) and arranged at the leftmost position. Let's leave the leftmost vertex

selected.

[6] Click to bring up <Apply/Cancel> and click

<Apply>.

[8] Click this node again.

[9] Select all the panes except the leftmost one.

[10] Click to bring up <Apply/Cancel> and

click <Apply>.

[7] Select <Deformable>.

[11] Select <Deformable>.


Now, we've set up a spherical joint at node 1. We'll repeat the above steps to set up the other spherical joints at nodes 2, 3, 4, and 5. When you click a node, make sure all selection panes representing involved vertices show up; if not, click again until all panes show up. Remember to leave the leftmost pane as <Reference> body and the other panes as <Mobile> bodies.

[12] Repeat steps [2-11] four more times

to set up spherical joints at nodes 2, 3, 4,

and 5.

20a-4 Set Up Supports

[1] Highlight <Static Structural> and select

<Supports/Displacement>.

[3] Select this node.

[4] And control-select this node.

[5] Click <Apply>.

[2] Select <Vertex>.

[6] Type 0 for <Z Component>.


[7] Select <Supports/Displacement> again.


[9] Click <Apply> and type 0 for <Y

Component>.


[12] Click <Apply> and type 0 for all

three components.

[10] Select <Supports/Displacement> again.


20a-5 Set Up Forces



[3] Click <Apply> and type the

component as shown.

20a-6 Set Up Result Objects

[1] Highlight <Solution> and select

<Deformation/Total>.

[2] Select <Beam Results/Axial

Force>.



[3] Select <Auto Scale>.


[1] Click <Solve>.

[2] Highlight <Total Deformation>.


[1] Click each member to display the axial force of each member.

These force values are consistent with the values in 20-1[5].

[6] Highlight <Axial Force>.

[7] Click <Probe>.

Wrap UpClose <Mechanical>, save the project as "Truss-a," and exit the Workbench.

ADM14

Documents

ansys simulations

geometry modeling

concept modeling

ansys simulation modules

surface modeling support

assembly models

structural analysis

geometry models