submodeling using ansys workbench

Submodeling using ANSYS Workbench ANSYS Workbench

v12.1

Patrick Cunningham1/18/20111/18/2011

2009 CAE Associates

Submodeling in ANSYS Workbench

Although submodeling using the ANSYS Workbench environment is not Although submodeling using the ANSYS Workbench environment is not currently supported at release v12.1 it can be accomplished using APDL command blocks.

The method involves setting up the global model and the submodel in the The method involves setting up the global model and the submodel in the same Workbench project as shown here.

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The general procedure is as follows: The general procedure is as follows: 1. Generate the solution on the global model using the Mechanical tool. 2. Create the submodel in a separate Mechanical window and use a command

block to generate a node fileblock to generate a node file. 3. Go back to the global model and use command blocks to perform the cut

boundary interpolation forcing Mechanical to not regenerate the solution. 4. Go to the submodel and use a command block to read the cut boundary y

displacements. 5. Generate the submodel solution.

One advantage to using Workbench for submodeling is that both the global model and submodel can be open during the process. The v12 license manager will share the Mechanical license with the two models. g

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The following example problem is used to illustrate the set up in detail The following example problem is used to illustrate the set up in detail.

Submodel region

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The submodeling method for Workbench v12 1 is as follows:The submodeling method for Workbench v12.1 is as follows: 1. Bring the CAD geometry into DesignModeler and defeature the global

model as needed. For illustration purposes the cut boundaries are included in the global geometry model (not required)included in the global geometry model (not required).

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2 Bring the DesignModeler geometry into the Mechanical tool Set up the2. Bring the DesignModeler geometry into the Mechanical tool. Set up the model as needed (material assignment, mesh control, loads, supports, etc.).

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3 Add a command block to the Solution folder with a command to copy the3. Add a command block to the Solution folder with a command to copy the ANSYS result file to a known location using the /system command:

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4 Generate the solution for the global model:4. Generate the solution for the global model:

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5 Return to the Project page and duplicate the DesignModeler geometry:5. Return to the Project page and duplicate the DesignModeler geometry:

RMB

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6 Open the duplicate geometry item and cut out the submodel (suppress or6. Open the duplicate geometry item and cut out the submodel (suppress or delete the remainder). For this case a fillet was added to the submodel geometry.

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7 Drag and drop a new Structural Analysis system onto the submodel7. Drag and drop a new Structural Analysis system onto the submodelgeometry. Open the new Mechanical window, mesh the geometry and create a Named Selection consisting of the cut boundary faces. Note: Be sure to set the active unit system consistent with the globalNote: Be sure to set the active unit system consistent with the global model.

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8 Add two command blocks to the Static Structural folder of the submodel:8. Add two command blocks to the Static Structural folder of the submodel: a. 1st pass Write Node File

Selects the nodes attached to the Named Selection surfaces and writes a node file to a user defined location Adds a /eof command to halt the solutionnode file to a user defined location. Adds a /eof command to halt the solution process.

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8 Submodel command blocks continued:8. Submodel command blocks continued: a. 2nd pass Reads a cut boundary displacement file from a known location.

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9 Suppress the 2nd pass Read CBD command block and Solve to9. Suppress the 2 d pass Read CBD command block and Solve to generate the node file.

RMB - Suppress

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10 Return to the global Mechanical model and suppress the Solution10. Return to the global Mechanical model and suppress the Solution command block that copies the original result file.

RMB > Suppress

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11 Add a command block to the Static Structural folder that copies the11. Add a command block to the Static Structural folder that copies the original result file back to the solution directory. Exit the solution processor using the finish command to stop ANSYS from resolving the global model. Do not use /eof.global model. Do not use /eof.

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12 Add a command block to the Solution folder to generate a file with global12. Add a command block to the Solution folder to generate a file with global model displacements interpolated onto the cut boundary nodes. Note: For the sake of simplicity the CBD file is written to the same directory as the node file and the global rst filedirectory as the node file and the global .rst file.

node file CBD file

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13 Make sure that the 1st pass command block is suppressed and that the13. Make sure that the 1st pass command block is suppressed and that the 2nd pass command blocks (Static Structural and Solution) are active.

14. Solve.

Active

ActiveSuppressed

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15 Return to the submodel Mechanical window Suppress the command15. Return to the submodel Mechanical window. Suppress the command block used to write the node file in the first pass.

16. Add a command block in the Static Structural file reads the CBD file from the specified directorythe specified directory.

17. Solve.

Suppress

Add

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Check the submodel results for proper mapping of the displacements If Check the submodel results for proper mapping of the displacements. If the cut boundaries exist in the global model this is easily accomplished. Otherwise cut plane displays and the result probe can be used as an approximation.approximation.

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Use the result Probe to compare the stresses at the cut boundary Good Use the result Probe to compare the stresses at the cut boundary. Good agreement is an indication that the boundary is far enough away from the stress concentration.

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The example models have been provided in the ANSYS archive file The example models have been provided in the ANSYS archive file v12_submodel_example.zip.

The file should be opened using the File > Restore utility on the v12 project pageproject page.

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submodeling using ansys workbench

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