Basic Tutorial 4 - 2D Analysis of Stage Constructed Embankment.pdf

1

Basic Tutorial 4

2D Analysis of Stage Constructed Embankment

GTS Basic Tutorial 4.


Contents

Starting GTS 1

Create Analysis Data 4

Attribute 4

2D Geometry Modeling 11

Rectangle, Polyline and Line 11

Intersect 13

2D Mesh Generation 14

Size Control 14

Map Mesh k-Edge Area 18

Analysis 22

Load 22

Apply uniform pressure load on top of embankment. 22

Support 24

Define Construction Stage 25

Solve 30

Post Processing, Result Display and Control 31

Displacement Contour 32

Stress Contour 35

GTS Basic Tutorial 4

1


In this tutorial we will model a two dimensional embankment and analyze with construction

stages. Then we will mesh the embankment with 4-node tetrahedral elements for analysis.

We will learn how to apply the load and how to define each construction stage. After

performing analysis, we will display the output in the form of p-q Diagrams and Stress

Contours. Finally, the analysis results will be verified using some of the unique post

processing features of GTS.

Starting GTS

Start the program.

1. Run GTS.

2. Start a new project by clicking File > New button.

3. Project Setting dialog box will appear.

4. Enter ‘Basic Tutorial 4’ in Project Title.

5. Enter ‘2D’ in Model Type.

6. Enter ‘X-Y Plane’ in Analysis Constraint.

7. Use default values for rest of the inputs.

8. Click button.

9. Select View > Display Option... in the Main Menu.

10. Select Mesh > Node Display as ‘False’ in the General Tab.

11. Click button.


2

Preview

The following model will be used in this tutorial. The ground is formed with 3 different

layers of materials, and the embankment is split into 3 stages. Each ground material and

embankment stage will be grouped separately in different Mesh Set, to easily manage and

define construction stage. The geometric shape and mesh formation is as follows:

GTS Basic Tutorial 4 - 1


2tonf/m

3@

3m

12m

12m

6m

39m

23m

50m25m

100m

25m

Soil 4 (Sand, SW)

Soil 1 (Silt, ML)

Soil 2 (Clay, CL)

Soil 3 (Silty Sand, SM)

Z

X


3

The Mesh Sets are generated as follows.


The Mesh Sets are defined as follows.

Mesh Set Name Attribute Name(ID) Material Name(ID)

Soil 1 Soil 1 (1) Silt (1)

Soil 2 Soil 2 (2) Clay (2)

Soil 3 Soil 3 (3) Silty Sand (3)

Embank 1

Embank (4)

Sand (4) Embank 2

Embank 3

GTS Basic Tutorial 4 - Table 1

The Ground properties are as follows.

ID 1 2 3 4

Soil Silt Clay Silty Sand Sand

Type MC MC MC MC

Modulus of Elasticity (E) [tonf/m2] 1000 600 2000 3000

Poisson’s Ratio () 0.35 0.35 0.3 0.3

Unit Weight () [tonf/m3] 1.7 1.6 1.8 1.8

Unit Weight (Saturated) [tonf/m3] 1.8 1.7 1.9 1.9

Cohesion (C) [tonf/m2] 2.0 3.0 1.0 1.0

Friction Angle () 20 10 30 33

Tensile Strength [tonf/m2] 2.0 3.0 1.0 1.0

* MC : Mohr Coulomb Model

GTS Basic Tutorial 4 - Table 2

Soil 3

Soil 1

Embank 1

Soil 2

Embank 3 Embank 2


4

Create Analysis Data

Attribute

We will now define the Attributes of the ground. In a two dimensional model, the type of

ground is always Plane.

1. Select Model > Property > Attribute…in the Main Menu.

2. Click button to the right of button in the Attribute dialog box.

3. Select ‘Plane’.

4. Make sure that Attribute ID is ‘1’ in the Add/Modify Solid Attribute dialog box.

5. Enter ‘Soil 1’ in Name.

6. Make sure that ‘Plane Strain’ is selected in Element Type.

7. In order to create Material, click button at the right of Material.

Attribute of ID 1 is Plane, and the ground material property is Soil 1. Plane Attribute does

not require to have Property, and only the type of Material needs to be defined.

8. Enter ‘1’ in ID.

9. Enter ‘Silt’ in Name.

10. In the Add/Modify Ground Material dialog box select ‘Mohr Coulomb’ in

Constitutive Model of Model Type.

11. Select Color .

12. Enter ‘1000’ in Material Parameters in Modulus of Elasticity (E).

13. Enter ‘0.35’ in Poisson’s Ratio () in Material Parameters.

14. Enter ‘1.7’ in Unit Weight () in Material Parameters.

15. Enter ‘1.8’ in Unit Weight (Saturated) in Material Parameters.

16. Enter ‘2.0’ in Cohesion (C) in Material Parameters.

17. Enter ‘20’ in Material Parameters in Friction Angle ( ).

18. Enter ‘2.0’ in Tensile Strength in Parameters of Constitutive Model.

19. Make sure that ‘Drained’ is checked in Drainage Parameters.

20. Click button.

For 2D analysis, the

ground should be

modeled using the

Plane Attributes.


5



6

21. Click button in the Material dialog box.

22. Make sure that ‘Silt’ has been generated in Material in the Add/Modify Plane

Attribute dialog box.

23. Click button.


24. Similarly, enter the Attributes for Soil 2, Soil 3 and Embank in Figures GTS Basic

Tutorial 4 – 6 ~ GTS Basic Tutorial 4 – 11. The values are given in GTS Basic

Tutorial Table 1 and Table 2.


7


GTS Basic Tutorial 4 – 7


8




9




10



11

2D Geometry Modeling

Rectangle, Polyline and Line

Draw outline of the model shape with Rectangle, Polyline and Line tools. First, full ground

model area will be created with the Rectangle tool.

1. Select Geometry > Curve > Create on WP > Rectangle (Wire)… in the Main Menu.

2. Make sure that Mode is set to in the Rectangle dialog box.

3. Make sure that the Method is set to ‘ABS x, y’.

4. Make sure that it says Input One Corner in the Rectangle dialog box.

5. Make sure that Make Face option is not checked.

6. Enter ‘-50,0’ in Location, and press Enter key.

7. Make sure that it says Input Diagonally Opposite Corner in the Rectangle dialog box.

8. Make sure that the Method is set to ‘REL dx, dy’.

9. Enter ‘100, -30’ in Location, and press Enter key

10. Click button and Click „Yes‟ to create new Polyline.

11. Click Zoom All in the View Point Toolbar.

Draw outline of the embankment with the Polyline tool.

12. Select Geometry > Curve > Create on WP > Polyline (Wire)… in the Main Menu.

13. Make sure that it says Input Start Location in the Polyline dialog box.


15. Enter ‘-25,0’ in Location and press Enter key.

16. Make sure that it says Input Next Location (RB to Stop) in the Polyline dialog box.

17. Make sure that the Method is set to ‘REL dx, dy’.

18. Enter ‘13.5,9’ in Location and press Enter key.

19. Enter ‘23,0’ in Location and press Enter key.

20. Enter ’13.5,-9’ in Location and press Enter key.

21. Make sure that Make Face option is not checked.

22. Confirm that Polyline has been generated in the Work Window.

23. Click button.

In this mode, the user can

draw a rectangle by

entering two corners. For

detailed information,

please refer to the Online

Manual.

Not only Polyline but also

almost all the functions

for creating curves

support various methods

of entering coordinates,

such as „ABS x,y‟ and

„REL dx, dy.‟ For detailed

information, please refer

to the Online Manual.


12

Draw Lines which represent the construction stages and multiple strata.

24. Select Geometry > Curve > Create on WP > Line… in the Main Menu.

25. Make sure that it says Input Start Location in the Line dialog box.


27. Enter ‘-50,-24’ in Location and press Enter key.

28. Make sure that it says Input End Location in the Line dialog box.

29. Make sure that the Method is set to ‘REL x, y’.

30. Enter ‘100,0’ in Location and press Enter key.

31. Repeat Steps 25~30 to draw a Line from ‘-50,-12’ to ‘100,0’.

32. Repeat Steps 25~30 to draw a Line from ‘-25,3’ to ‘50,0’.

33. Repeat Steps 25~30 to draw a Line from ‘-25,6’ to ‘50,0’.

34. Click button.



13

Intersect

In order to generate the mesh properly, all the Edges must be “broken” at locations where

they intersect with the other Edges. After “breaking” the Edges using the Intersect tool, we

will delete the unnecessary Edges.

1. Select Zoom All in the Dynamic View Toolbar.

2. Select Geometry > Curve > Intersect… in the Main Menu.

3. Select Displayed in the Selection Toolbar.

4. Click button.

5. Click to close the Intersect dialog box.

6. Select Edge A, B, C & D in the Work Window as shown in GTS Basic Tutorial 4 - 14.

7. Enter Delete key.

8. Click in the Delete dialog box.


Edge A

Edge C Edge D

Edge B

In the Delete dialog

box, the user can see

the list of deleting

items, but one cannot

add or remove items.


14

2D Mesh Generation

Size Control

In this section, proper mesh size will be defined along the Edges prior to generating a

mapped mesh. In order to obtain accurate results, it is necessary to generate fine mesh

around the embankment.

1. Select Mesh > Size Control > Along Edge… in the Main Menu.

2. In button, select Edge A, B, C and D as shown in

GTS Basic Tutorial 4 - 15.

3. Select ‘Number of Divisions’ in Seeding Method.

4. Enter ‘25’ in Number of Divisions.

5. Click (Preview) button to check if the seeding would be distributed correctly.

6. Click button.

7. In button, select Edge E, F, G, H, I and J as shown

in GTS Basic Tutorial 4 - 15.



10. In button, select Edge K and L. as shown in GTS

Basic Tutorial 4 - 15.



13. Click button.


A B C

D

E

G F

H

J I

K L

M N

O


15

The display can be set up to view the Seeding by selecting Mesh > Size Control > Display

Mesh Seed in the Main Menu. The Seeding can also be viewed as follows:

14. Select Displayed in the Selection Toolbar to select all the Edges.

15. Invoke the Context Menu by right-clicking the mouse.

16. Select Display Mesh Seed.

17. Make sure that ‘Show Mesh Seed’ is checked.

18. Click button.


Match Edge Seed function will duplicate mesh size information of the Edge(s) that were

previously seeded using the Size Control function. In order to copy the seeding information

at the top Edges to the bottom, we will use the Match Edge Seed function.

19. Select Mesh > Size Control > Match Edge Seeds… in the Main Menu.

20. In button, select Edge M as shown in GTS Basic

Tutorial 4 - 15.

21. In button, select Edges D, K and L as shown in GTS


22. Select ‘Projection’ in Match Method.

23. Make sure that Re-assign Size Control is checked.

24. Make sure that ‘Unseeded Only’ is checked.

25. Enter ‘Element Size’ as ‘4’ in Mesh Size.


27. Click button.

The function also can

be invoked by selecting

Mesh > Size Control >

Display Mesh Seed… in

the main menu.


16

The two assigned source Edges (K and L) which have been seeded with a Size of 4 has now

been Projected to a target edge, in particular edge M. This procedure will be repeated for

edges N and O.


28. In button, select Edge N as shown in GTS Basic

Tutorial 4 - 15.

29. In button, select Edge M as shown in GTS Basic

Tutorial 4 - 15.



32. In button, select Edge O as shown in GTS Basic

Tutorial 4 - 15.

33. In button, select Edge N as shown in GTS Basic

Tutorial 4 - 15.



36. Click button.

Project…


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37. Select Displayed in the Selection Toolbar to select all the Edges.

38. Select Mesh > Size Control > Display Mesh Seed… in the Main Menu.

39. Select Hide Mesh Seed.

40. Click button.


18

Map Mesh k-Edge Area

We will now generate a 2D Mesh using Mapped Mesh Generation. The k-Edge Area

function will fill the closed area with 2D elements, which are defined by boundary 2D

Edges.

1. Select Mesh > Map Mesh > k-Edge Area… in the Main Menu.

2. Make sure that ‘Auto-Map’ is checked.

3. In button, select Edges N, R, O and U as shown in


4. Enter ‘2’ in ‘Division’ in Mesh Size.

5. Select Attribute ID as ‘3 : Soil 3’.

6. Rename ‘Map-Mesh(2D)’ in Mesh Set and enter ‘Soil 3’.


8. Click button.

9. In button, select Edges M, Q, N and T as shown in


10. Enter ‘3’ in ‘Division’ in Mesh Size.


12. Rename ‘Soil 3’ in Mesh Set and enter ‘Soil 2’.

13. Make sure that Merge Nodes is checked on.


15. Click button.

16. In button, select Edges D, K, P, M, S and L as shown

in GTS Basic Tutorial 4 - 19.


18. Rename ‘Soil 2’ in Mesh Set and enter ‘Soil 1’.


20. Click button.

21. In button, select Edges C, G, D and J as shown in


22. Select Attribute ID as ‘4 : Embank’.

23. Rename ‘Soil 1’ in Mesh Set and enter ‘Embank 1’.


25. Click button.

26. In button, select Edges B, F, C and I as shown in GTS

This Division will be applied

only to Edges R & U. Since

facing Edges must have the

same number of divisions,

seeding of Edge N will be

applied automatically to

Edge O.

For detail information of

Map Mesh k-Edge Area, refer

to the Online Manual.

Since all Edges are seeded

already, the mesh size is

meaningless here.

Since the connectivity in

this model must be

matched, Merge Nodes

must be turned on at all

time.


19


27. Rename ‘Embank 1’ in Mesh Set and enter ‘Embank 2’.


29. Click button.

30. In button, select Edges A, E, B and H in GTS Basic

Tutorial 4 - 19.

31. Rename ‘Embank 2’ in Mesh Set and enter ‘Embank 3’.


33. Click button.

Previously seeded Edges will not be affected by the size information that has been specified

during Mesh Generation.


A B C

D

E

G F

H

J I

K L

M N

O

P

Q

R

S

T

U


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As shown in the above figure, Mapped Mesh generates a better quality mesh. However, it

takes a longer amount of time to generate.

In this model, the user can also generate a 2D Mesh using the Auto Mesh Generation

function, by selecting Mesh > Auto Mesh > Planar Area in the Main Menu. Using Auto

Mesh Planar Area, all areas defined by boundary Edges can be meshed automatically.

1. Select Mesh > Auto Mesh > Planar Area… in the Main Menu.

2. In button, select Displayed in Selection

Toolbar.

3. Select ‘Loop Mesher’ in Mesher.

4. Select ‘Quadrilateral’ in Type.

5. Enter ‘4’ in ‘Element Size’ in Mesh Size.

6. Select Attribute ID ‘1 : Soil 1’.

7. Make sure that Register Each Area Independently is checked.


9. Click button.

All created Mesh Sets have been assigned with Attribute ID 1. In order to perform the

correct analysis, the user should apply proper Attribute to each Mesh Set.

This step only shows the

steps for performing Auto

Mesh Generation. The

rest of this tutorial will

use the mesh generated

by Map Mesh.

For detailed information

on Auto Mesh Planar

Area, please refer to the

Online Manual.


21


Since we will not be using all the Geometry entities any further, we will hide them.

1. Select Geometry in the Works Tree.


3. Select Hide All.


22

Analysis

Load

In this model, two load cases will be created. General self weight of the ground and uniform

pressure load on top of the embankment will be applied. Since these two loads will be

induced at different construction stages, it is necessary to create separate load cases for each

load.

Self weight will be created first.

1. Select Model > Load > Self Weight… in the Main Menu.

2. Enter ‘Self Weight’ in Load Set.

3. Enter Y as ‘-1’ in Self Weight Factor.

Apply uniform pressure load on top of embankment.

4. Invoke the Context Menu on Datum in the Works Tree by right-clicking the mouse.

5. Select Show All.

6. Select Zoom Window in the Dynamic View Toolbar.

7. The model is generated as shown in GTS Basic Tutorial 4 - 22.

8. Select Model > Load > Pressure Load… in the Main Menu.

9. Enter ‘Pressure’ in Load Set.

10. Select ‘Edge Pressure’ in Type.

11. Select ‘Element-Edge’ in Type in Object.

12. In button, select the 25 Element Edges by

dragging the mouse in the Work Window as shown in GTS Basic Tutorial 4 - 22.

13. Select ‘Add’ in Mode.

14. Select Direction in ‘Direction’.

15. Click button.

16. Select ‘Datum Axis (A)’ in the Selection Filter of the Selection Toolbar.

17. In button, select Datum > ‘Y-Axis’ in the Works Tree.

Note: The Y-Axis can be selected directly from the work window by selecting the

green perforated line. Datum must be shown in the work window.

18. Make sure that Uniform is checked.

19. Enter ‘-2’ in P or P1.

20. Click (Preview) button to check if Pressure would be distributed correctly.

Various load cases can

be defined in each

construction stage.

This way, the user

does not require to

create a Load Set

manually. The program

will automatically

register defined self

weight in the “Self

Weight” Load Set.


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21. Click button.



24

Support

Define boundary conditions in this model. The bottom will be constrained with Hinge-type

supports, and the left and right side will be with Roller-type supports.

1. Select Zoom All in the Dynamic View Toolbar.

2. Invoke the Context Menu by right-clicking the mouse in the Work Window.

3. Select Toggle GCS Triad.

4. Select Model > Boundary > Supports… in the Main Menu.

5. Enter ‘Common Support’ in BC Set.

6. Select ‘Node’ in Object in Type.

7. In button, select the 18 nodes by dragging the mouse

‘A’ and ‘B’ in the Work Window as shown in GTS Basic Tutorial 4 - 23.


9. Select ‘UX’ in DOF.

10. Click button.

11. Select ‘Common Support’ in BC Set.

12. Select ‘Node’ in Object in Type.

13. In button, select the 38 nodes by dragging the mouse

‘C’ in the Work Window as shown in GTS Basic Tutorial 4 - 23.


15. Select ‘UX’ and ‘UY’ in DOF.

16. Click button.


This way, the user does

not require to create a

Boundary Set manually.

The program will

automatically register the

defined boundary

conditions in the

“Common Support”

Boundary Set.

Boundary condition

will be input based on

Global Coordinate

System. Therefore, it is

recommended to turn

the GCS Triad on as a

visual reference

A B

C


25

Define Construction Stage

Define construction stage for this model. The first construction stage will have only the

initial ground condition loaded with self weight.

1. Select Model > Construction Stage > Define Construction Stage… in the Main Menu.

2. Click button.

3. Enter ‘BT4 Stage 1’ in Stage Name.

4. Select ‘Construction’ in Stage Type.

5. Select Element > ‘Soil 1’, ‘Soil 2’, ‘Soil 3’ in Set Data of Tree.

6. Drag the Mesh Set into Activated Data.

7. Select ‘Activated’ in Show Elements.

8. Select Boundary > ‘Common Support’ in Set Data of Tree.

9. Drag the Boundary Set into Activated Data.

10. Select Load > ‘Self Weight’ in Set Data of Tree.

11. Drag the Load Set into Activated Data.

12. Make sure that Clear Displacement is checked.

13. Select Stage Water Level and enter 0 m.

14. Click button.

In the second construction stage, the first embankment will be constructed.

4. Click button.


6. Select Element > ‘Embank 1’ in Set Data of Tree.


8. Click button.


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In the third construction stage, the second embankment will be constructed.

9. Click button.




13. Click button.

In the fourth construction stage, the third embankment will be constructed.

14. Click button.




18. Click button.

In the fifth construction stage, the pressure loading will be applied.

19. Click button.


21. Select Load > ‘Pressure’ in Set Data of Tree.

22. Drag the Load Set into Activated Data.

23. Click button.

24. Click on Define Construction Stage dialog box.

On the screen, the

pressure loading will be

shown as the last stage

of the embankment is

generated. All load

display must be

attached to relevant

nodes and elements.

Despite the load display,

the actual loading will

not be entered in the

construction stage

analysis until the user

defines it. Therefore, the

user should not be

confused by the display

of pressure load.


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Stage 1

Stage 2

Stage 3

Stage 4

Stage 5


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Analysis Case

We will create an Analysis Case for performing analysis.

1. Select Analysis > Analysis Case… in the Main Menu.

2. Click button.


Input the values in Add/Modify Analysis Case dialog box.

3. Enter ‘Basic Tutorial 4’ in Name.

4. Enter ‘2D C/S Analysis’ in Description.

5. Select ‘Construction Stage’ in Analysis Type.

6. Click on button to the right of Analysis Control.


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In Analysis Control, we will define specific options for the Construction Stage Analysis.

7. Make sure that Initial Stage for Stress Analysis is checked in the Construction Stage

Tab of Analysis Control dialog box.

8. Select ‘BT4 Stage 1’ in Initial Stage for Stress Analysis.

9. Select K0 Condition.

10. Click button.

11. Click button in the Add/Modify Analysis case dialog box.

12. Click button in the Analysis Case dialog box.



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Solve

We will now perform analysis.

1. Select Analysis > Solve… in the Main Menu.

2. Click in the Solver Manager dialog box.

All the messages during the analysis will be shown in the Output Window. Especially, one

needs to be very cautious about warning messages, because these messages indicate that the

analysis results may not be correct. The model is automatically saved before the analysis.

The result is saved as binary file(*.TA*) in the same folder as the model. The detail analysis

information is also saved in a text file(*.OUT).



31

Post Processing, Result Display and Control

Once the analysis is completed, we will begin Post-Processing. We will check the

Displacement Contour and Stress Contour.

1. Select Boundary in the Works Tree.


3. Select Hide All.

4. Select Geometry in the Works Tree.


6. Select Hide All.

7. Invoke the Context Menu in the Work Window by right-clicking the mouse when no

entity is selected.

8. Select Hide Datum & WP.

9. Invoke the Context Menu in the Work Window by right-clicking the mouse when no

entity is selected.

10. Select Hide All Labels.

In order to have a clean view of results, it is better to hide all the load labels, boundary

labels and other symbols.


32

Displacement Contour

We will first check the displacements in the X-direction at the last stage.

1. Select the Post-Works Tab in the Works Tree.

2. Select CS : Basic Tutorial 4 > BT4 Stage 5-001(1) > Displacement > ‘DX(V)’ in the

Works Tree.

3. Select the Post Data Tab in the Tabbed Toolbar.

4. Select ‘BT4 Stage 5-001(1)’ and click on Output Set in the Post Data Toolbar.

5. Make sure that Sensitive is checked on in the Output Set as shown in GTS Basic

Tutorial 4 – 29.

6. Click button.

- Post Data Toolbar -


With Sensitive is turned

on, the contour shape is

updated in real time as

stage changes.

Plot Type Mesh Shape Data Filter

Output Set Deformation Data Contour Data


33


We will now check the deformed shape in the Y-direction at the last stage.

7. Click Sensitive button in the Post Data Toolbar.

8. Unselect ‘DX(V)’ and select ‘DY(V)’ in Contour Data of the Post Data Toolbar and

click button.

9. Unselect ‘DX(V)’ and select ‘DY(V)’ in Deformation Data of the Post Data Toolbar.

10. Click Mesh Shape button.

11. Select Deformed + Undeformed.

Another feature of GTS is the Toolbar provided for Post-Processing. By selecting the

Property Window in the Post-Processing mode toolbar, the various options can be identified

and modified.

When button is

turned on, change in

any Post Data will be

automatically reflected

in the contour display.


34

12. Select ‘Deformation’ in the Property Window.

13. Select ‘True’ in Real Displacement in the Property Window.

14. Click in the Property Window.



35

Stress Contour

We will display the Stresses at the last stage. First, we will check the Sxx result of 2D

Elements. In addition, we will hide the Mesh Edges.

1. Select CS : Basic Tutorial 4 > BT4 Stage 5-001(1) > 2D Element Stresses > ‘SXX

Center’ in the Works Tree.

2. Click Mesh Shape button in the Post Data Toolbar.

3. Select Undeformed.

4. Select the Post Command Tab in the Tabbed Toolbar.

5. Click Edge Type in the Post Command Toolbar.

6. Select ‘No Edge’.

7. Select ‘Contour’ in the Property Window.

8. Select ‘True’ in Contour Line On/Off.

9. Enter ‘16’ in Band Number.

10. Click button in the Property Window.


In order to check the

stresses more accurately,

increase the contour

band color number


36

We will now check the Szz result of 2D Elements at the last stage.

11. Select CS : Basic Tutorial 4 > BT4 Stage 5-001(1) > 2D Element Stresses > ‘SYY

Center’ in the Works Tree.

12. Select the Post Command Tab in the Tabbed Toolbar.

13. Click Edge Type in the Post Command Toolbar.

14. Select ‘Mesh Edge’.

15. Select ‘Contour’ in the Property Window.

16. Select ‘False’ in Contour Line On/Off.

17. Click button in the Property Window.


Basic Tutorial 4 - 2D Analysis of Stage Constructed Embankment.pdf

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