Mapped Meshing

8/12/2019 Mapped Meshing

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Course in ANSYS

Example0702

Example0702 2

Example Plate with a hole

E = 210000N/mm2

= 0.3a = 200mm

b = 100mm

t = 10mm

r = 10mm

s = 100N/mm2

Objective:Determine the maximum stress in the x-direction forpoint A and display the deformation figureTasks:Create a submodel to increase the accuracy of the FEA

without increasing the computational effort significantly?

Topics:Element type, Real constants, modeling, mapped mesh,

plot results, output graphics, path operations,

submodeling

A


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Example0702 3

Steps in Submodeling The process for using submodeling is as

follows:

Create and analyze the coarse model.Create and analyze the coarse model.

Create the submodel.

Perform cut boundary interpolation (CBI).

Analyze the submodel.

Verify that the distance between the cutboundaries and the stress concentration is

adequate.

Example0702 4

Example - title

Utilit y Menu > File > Change Title

/title, Plate with a hole

Utility Menu > File > Change Jobname

/jobname, Example0702_coarse

Enter: Plate with a hole

Command line entryGUI

Enter: Example0702_coarse


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Example0702 5

Example Areas RectanglePreprocessor > Modeling > Create > Areas > Rectangle > By DimensionsCreate an area given by X=(0,100) and Y=(0,50)

Enter 0 or

leave empty

Enter 100

Enter 50Enter 0 or

leave empty

Note: Keypoints (4 kps) and lines(4 lines) are automatically generated(also numbered automatically)

Press OK

Example0702 6

Example Areas Rectangle


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Example0702 7

Example Areas CirclePreprocessor > Modeling > Create > Areas > Circle > Solid CircleCreate an area given by (X,Y)=(0, 0) and Radius=10

Enter 10

Note: Keypoints (4 kps) and lines(4 lines) are automatically generated

(also numbered automatically)

Press OK

Example0702 8

Example - Area


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Example0702 9

Example - OperatePreprocessor > Modeling > Operate > Booleans > Subtract > AreasCreate the final area by subtracting the circular area from the rectangular areaNote: Bottom left corner of ANSYS GUI

Press OK

Select the rectangular area and press OK

Note: Bottom left corner of ANSYS GUI

Select the circular area

Example0702 10

Example Areas


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Example0702 11

Example - Numbering

Switch on Keypoint, Line, and Area Numbers

Example0702 12

Example - List Menu

List Keypoint, Lines, and Areas


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Example0702 13

Example - Plot Menu

Plot Keypoint, Lines, and Areas

Example0702 14

Example Element TypePreprocessor > Element Type > Add/Edit/Delete

Press Add


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Example0702 15

Example - Element TypePreprocessor > Element Type > Add/Edit/Delete

Press Options

Press Help to learn more about the

element.

Select Plane strs w/thk

Example0702 16

Example Real ConstantsPreprocessor > Real Constants > Add

Place the cursoron the relevant

element and

press OK


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Example0702 17

Example - Real ConstantsPreprocessor > Real Constants > Add

Press OK

Press Close

to finish

Enter 10

Example0702 18

Example - Material PropertiesPreprocessor > Material Props > Material Models

Double Click

to step in the

material tree


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Example0702 19

Example - Material PropertiesPreprocessor > Material Props > Material ModelsEnter 210000

Modulus of elasticity

Enter 0.3

Poissons ratio

Click here

to Close

Press OK

Example0702 20

Example - MeshingPreprocessor > Meshing > Size Cntrls > ManualSize > Lines > Picked Lines

Select/PickLines to

specify

mesh sizefor

Pick the two

longest lines

Press OK when finish with selection

See next page


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Example0702 21

Example Mesh Size3 Element subdivisions

5 Element subdivisions


Example0702 22

Example Concatenate Lines

Select L2 and L3 to create

a topologically four sided

geometryPress OK


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Example0702 23

Example - MeshingPreprocessor > Meshing > Mesh > Areas > Mapped > 3 or 4 sidedSelect individual areasto be meshed

Select all areas defined

to be meshed

NB: It is often

necessary to Clearthe model for

example if Element

Type or model

geometry is to be

changed

Example0702 24

Example Mapped Mesh


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Example0702 25

Example Analysis Type

Solution > Analysis Type > New Analysis

File > Write DB log file

Enter example0702_coarse.lgw

Example0702 26

Example Define LoadsSolution > Define Loads > Apply > Structural > Displacement > On Lines

Select the

bottom straight

line

Press OK

Select UY to fix the plate in the y-direction


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Example0702 27


Select the left

straight line

Press OK

Select UX to fix the plate in the x-direction

Example0702 28

Example Define LoadsSolution > Define Loads > Apply > Structural > Pressure > On lines

Select the

right

straight line

Enter -100

Press OK

to finish

Note: Pressure acts normal andinward to a surface


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Example0702 29

Example - SaveDisplay of Analysis model

Save the model

Example0702 30

Example - SolveSolution > Solve > Current LS

Press OK


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Example0702 31

Example - SolvePress ClosePress here

to Close

Example0702 32

Example Contour PlotGeneral Postproc > Plot Results > Contour Plot > Nodal Sol

Select Stress

Select SX for stresses inx-direction


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Example0702 33

Example Contour Plot

Example0702 34

Example Select - Entities

See next page

for selection


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Example0702 35

Example Select Nodes

Select the

indicated

nodes

Enter OK when finished

Example0702 36

Example List Results

Select Stress, SCOMP

Press OK


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Example0702 37


Example0702 38

Example - Plot - Nodes

Plot Nodes

Only 11 FE nodes aredisplayed the same nodes as

selected previously


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Example0702 39


Select Pick All

Example0702 40


Plot Nodes


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Example0702 41


Example0702 42

Example Define Path

See next page for selection


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Example0702 43

Example Define Path - By Nodes

Select the

indicated

nodes

Note: the

selection

order isimportant start from the

hole


Example0702 44


Enter an appropiate name, e.g. SSX

Enter OK


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Example0702 45

Example Map onto Path

Select Stress, SX

Press OK

Example0702 46

Example Plot Path on Graph

Select SX

Press OK


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Example0702 47


Example0702 48

Steps in Submodeling

The process for using submodeling is as

follows:

Create and analyze the coarse model.

Create theCreate the submodelsubmodel..

Perform cut boundary interpolation (CBI).


Verify that the distance between the cut

boundaries and the stress concentration is

adequate.


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Example0702 49

Example - title

Utilit y Menu > File > Change Title

/title, Plate with a hole

Utility Menu > File > Change Jobname

/jobname, Example0702_fine

Enter: Plate with a hole

Command line entryGUI

Enter: Example0702_fine

Example0702 50

Example Areas RectanglePreprocessor > Modeling > Create > Areas > Rectangle > By Dimensions

Create an area given by X=(0,25) and Y=(0,25)

Enter 0 or

leave empty

Enter 25

Enter 25Enter 0 or

leave empty



Press OK


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Example0702 51

Example Areas Rectangle

Example0702 52

Example Areas CirclePreprocessor > Modeling > Create > Areas > Circle > Solid Circle

Create an area given by (X,Y)=(0, 0) and Radius=10

Enter 10



Press OK


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Example0702 53

Example - Area

Example0702 54

Example - OperatePreprocessor > Modeling > Operate > Booleans > Subtract > Areas

Create the final area by subtracting the circular area from the rectangular area


Press OK

Select the rectangular area and press OK


Select the circular area


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Example0702 55

Example Areas

Example0702 56

Example - Numbering

Switch on Keypoint, Line, and Area Numbers


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Example0702 59

Example Element TypePreprocessor > Element Type > Add/Edit/Delete

Press Add

Example0702 60

Example - Element TypePreprocessor > Element Type > Add/Edit/Delete

Press Options

Press Help to learn more about the

element.

Select Plane strs w/thk


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Example0702 61

Example Real ConstantsPreprocessor > Real Constants > Add

Place the cursor

on the relevant

element and

press OK

Example0702 62

Example - Real ConstantsPreprocessor > Real Constants > Add

Press OK

Press Close

to finish

Enter 10


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Example0702 63

Example - Material PropertiesPreprocessor > Material Props > Material ModelsDouble Click

to step in the

material tree

Example0702 64

Example - Material PropertiesPreprocessor > Material Props > Material Models

Enter:

Modulus of elasticity

Enter:

Poissons ratio

Click here

to Close

Press OK


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Example0702 65

Example - MeshingPreprocessor > Meshing > Size Cntrls > ManualSize > Lines > Picked Lines

Select/PickLines to

specify

mesh sizefor

Pick the twolongest lines

Press OK when finish with selection

See next page

Example0702 66

Example Mesh Size





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Example0702 67

Example Concatenate Lines

Select L2 and L3 to create

a topologically four sided

geometryPress OK

Example0702 68

Example - MeshingPreprocessor > Meshing > Mesh > Areas > Mapped > 3 or 4 sided

Select individual areasto be meshed

Select all areas defined

to be meshed

NB: It is often

necessary to Clear

the model forexample if Element

Type or model

geometry is to be

changed


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Example0702 69

Example Mapped Mesh

Example0702 70


Select the

bottom straight

line

Press OK

Select UY to fix the plate in the y-direction


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Example0702 71


Select the left

straight line

Press OK

Select UX to fix the plate in the x-direction

Example0702 72

Example - Submodel


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Example0702 73

Example - Steps in Submodeling

The process for using submodeling is as

follows:

Create and analyze the coarse model.

Create the submodel.

Perform Cut Boundary Interpolation (CBI).Perform Cut Boundary Interpolation (CBI).


Verify that the distance between the cutboundaries and the stress concentration is

adequate.

Example0702 74

Example CBI Steps

The following tasks are involved in

performing the cut boundary

interpolation:1.1. Identify and write the cutIdentify and write the cut --boundary nodesboundary nodes

2. Restore the full set of nodes, write the database

to Jobname.DB

3. To do the cut boundary interpolation restore the

coarse model

4. Enter POST1

5. Point to the coarse results file

6. Read in the desired set of data from the results

file


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Example0702 75

Example CBI: Step 1

Plot Nodes

Example0702 76

Example CBI: Step 1

See next page

for selection


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Example0702 77

Example CBI: Step 1

Example0702 78

Example CBI: Step 1

Plot Nodes


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Example0702 79

Example CBI: Step 1

Example0702 80

Example CBI: Step 1

Enter example0702_cutboundaryPress OK


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Example0702 81

Example - CBI Steps The following tasks are involved in performing

the cut boundary interpolation:1. Identify and write the cut-boundary nodes

2.2. Restore the full set of nodes, write the database toRestore the full set of nodes, write the database to

Jobname.DBJobname.DB

3. To do the cut boundary interpolation restore the coarse

model

4. Enter POST1


6. Read in the desired set of data from the results file

7. Initiate cut-boundary interpolation

8. All interpolation work is now done

Example0702 82

Example CBI: Step 2

Select Pick All


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Example0702 83



2. Restore the full set of nodes, write the database to

Jobname.DB

3.3. To do the cut boundary interpolation restore theTo do the cut boundary interpolation restore the

coarse modelcoarse model

4. Enter POST1



7. Initiate cut-boundary interpolation


Example0702 84

Example CBI: Step 3Enter example0702_coarse.db

Press OK


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Example0702 87

Example CBI: Step 4-6

Browse to find the result file

see next page

Select All items

Example0702 88

Example CBI: Step 4-6

Enter example0702_coarse.rst

Read the First Set


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Example0702 89



2. Restore the full set of nodes, write the database to

Jobname.DB

3. To do the cut boundary interpolation restore the coarse

model

4. Enter POST1



7.7. Initiate cutInitiate cut--boundary interpolationboundary interpolation


Example0702 90

Example CBI: Step 7

Press OK Browse to findexample0702_cutboundary


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Example0702 91

Example CBI: Step 7

Enter example0702_fine.db Press OK

Example0702 92

Example CBI: Step 7

Load the example0702_fine.cbdo

Press OK


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Example0702 93

Example CBI: Step 8

Example0702 94

Example - SolvePress Close

Press here

to Close


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Example0702 95

Example Contour PlotGeneral Postproc > Plot Results > Contour Plot > Nodal SolSelect Stress

Select SX for stresses inx-direction

Example0702 96

Example Contour Plot


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Example0702 97


See next page

for selection

Example0702 98

Example Select Nodes

Select the

indicatednodes



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Example0702 99


Select Stress, SCOMP

Press OK

Example0702 100



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Example0702 101


Plot Nodes

Only 21 FE nodes aredisplayed the same nodes as

selected previously

Example0702 102


Select Pick All


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Example0702 103


Plot Nodes

Example0702 104



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Example0702 105

Example Define Path

See next page for selection

Example0702 106


Select the

indicatednodes

Note: the

selection

order is

important start from the

hole



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Example0702 107


Enter an appropiate name, e.g. SSX

Enter OK

Example0702 108

Example Map onto Path

Select Stress, SX

Press OK


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Example0702 109


Select SX

Press OK

Example0702 110



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Example0702 111

File menu

Clears (zeros out) the database stored in

memory. Clearing the database has the same

effect as leaving and reentering the ANSYS

program, but does not require you to exit.

You can include commands to be

executed when the program starts up in

the start71.ans file.

Documents

Mapped Meshing