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Accuracy of mesh elements
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1- Plate with a hole tutorial
2- Analysis results
3- Comparison between different mesh types
4- Conclusion
TABLE OF CONTENTS:
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Plate with a hole tutorial 1
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00
2-D Linear Static Analysis Model
- 1/4 symmetric Model
- Unit: N, mm
- Isotropic Elastic Material
- Membrane
Loads and Boundary Conditions
- Edge Pressure
- Constraint (Symmetric)
Results Verification
- Displacement/Deformation
- Probe Result
Problem
Problem reduction
due to symmetry
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Location : (0) ,
Click [Cancel].
Geometry > Point & Curve > >
Circle
Center : Enter (0) ,
Radius: Enter 20
Click [Cancel].
Click [Zoom All] button.
Geometry > Point & Curve > Rectangle
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5
Procedure
01
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6
( ): ABS coordinates in x, y,
< >: REL coordinates in dx, dy
(0) and (0, 0) are same
expressions.
[Esc] is the shortcut button for
[Cancel]
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Geometry > Point & Curve > Intersect
Click [ ] (Select All).
Click [Apply].
Click [Cancel].
Select 3 Edges marked with [ O ]
on the picture.
Press [Delete] button on
Keyboard.
Click [OK].
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6
3
Procedure
Select all by pressing Ctrl+A on
keyboard.
[Enter] is the shortcut button for
[Apply].
02
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6
1
4
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Click [ ] (Select All).
Mesh Size - Element Size: 5.2".
Property: Enter 1.
Mesh Set: Enter Quarter Plate.
Click [ ] button.
Element Type: Select Quad.
Click [OK]
Click [OK].
In Model Work Tree, right-click
[MeshMesh SetQuarter Plate],
select [Display > Node].
Mesh > Generate > 2D
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9
1
Procedure
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9
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Create: Select [2D].
Select [Membrane] tab.
ID: 1 , Name : Plane Stress
T/T1: Enter 1.
Click [ ] (Material).
Create: Select [Isotropic].
Select [Linear] tab.
ID: 2 , Name: Enter Steel.
Elastic Modulus: 2.1e5 N/mm2
Poissons Ratio: Enter 0.3.
Click [OK].
Click [Close].
Membrane : Select [2: Steel].
Click [OK].
Click [Close].
Mesh > Attribute > Property
Procedure
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14 5
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Select [Advanced] Tab.
Name: Enter Support.
Select 27 Nodes. (Refer to Picture)
Symmetry Plane Select [YZ].
Click [Apply].
Select 6 Nodes. (Refer to Picture)
Symmetry Plane Select [ZX].
Click [OK].
Static/Heat Analysis > Boundary > Constraint
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2
5
Procedure
Drag the mouse over the nodes to
be selected. (Area selection).
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8
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Select [Advanced] Tab.
Name: Enter Z-Dir.
Click [ ] (Select All).
DOF: Select [Tz].
Click [Apply].
Static/Heat Analysis > Boundary > Constraint
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5
Procedure
06
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Static/Heat Analysis > Static Load > Pressure
Select [Edge] Tab.
Name: Enter Tension.
Type: [2D Element Edge]
Select 10 Element Edges.
Direction Type: Select [Normal].
P or P1: Enter - 100 N/mm
Click [ ](Preview).
Click [OK].
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4
7
Procedure
Drag the mouse over the element
meshes to be selected. (Area
selection).
Line pressure is converted to
equivalent nodal load before it is
analyzed by the Solver.
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Title: Enter Tension Study.
Solution Type: Select [Linear Static].
Click [OK].
Analysis & Results > Analysis Case > General
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Procedure
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Analysis & Results > Analysis > Perform
Model Works Tree: Right-click
[Geometry ...] and select [Hide All].
Click File > [Save] to save file.
(Plate with a Hole.nfxa)
Click Analysis > [Perform].
Click [OK].
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4
Procedure
Analysis Message and ResultS
Summary are displayed when the
analysis is launched.
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Double-click [SHELL STRS VON
MISES BOTTOM].
Insert more analysis results by
right-clicking on Linear Static
(Required) and selecting Insert
Analysis Result.
Analysis & Results Works Tree : Plate with a Hole_Tension Study > Linear Static (Required) > Shell Element Stresses
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Procedure
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1
Depending on the version of the program and the mesh size used, the results may differ by small amount.
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2
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Check Cont. Line
Analysis & Results > Show/Hide > Cont. Line
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Procedure
11
1
Depending on the version of the program and the mesh size used, the results may differ by small amount.
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Click [Max].
ID: Enter 1164.
Select a node on the graph.
Click [Close].
Click [Initialize].
Analysis & Results > Advanced > Probe
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5
Procedure
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Depending on the version of the program and the mesh size used, the results may differ by small amount.
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Analysis results 2
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Comparison between different mesh types
3
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Firstly, we test element of different size
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For each FE-model, we use linear mesh and quadratic mesh
Linear Triangle mesh (TRI3)
Quadratic Triangle mesh (TRI6)
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Results for linear triangle elements - displacement
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Results for quadratic triangle elements - displacement
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Comparison between triangle elements - displacement
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Comparison between quad elements - displacement
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Results for linear triangle elements - stress
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Results for quadratic triangle elements - stress
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Comparison between triangle elements - stress
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To get better accuracy and be efficient (less number of elements),
we can use adapted mesh for this model
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-Always prefer linear quad elements to linear triangle elements
-To get superior accuracy for ordinary displacement analysis, use 2nd order triangle elements
-For stress analysis, linear elements converge more slowly than for simple displacement analysis -> When performing stress analysis, always use 2nd order elements
Conclusion 4
