Export from ANSYS
In this tutorial we show you the steps to export your model from ANSYS.
- The modeling process begins with simplifying the geometry in CAD. This is necessary in order to reduce the amount of mesh elements needed in the FE model. Alternatively, simplification can also be accomplished with the SpaceClaim modeler from ANSYS.
- Launch ANSYS Workbench and create a new modal analysis.
- Import the simplified CAD geometry by right clicking on the Geometry tab of the modal analysis.
- Now open ANSYS Mechanical by double clicking on the Model Tab of the modal analysis. Now we need to divide the machine model into components. A component consists of all bodies, that move together as e.g. an axis or the machine basis. This results in a component for each axis and one for the base. If ball screws are used for the axis movement, a separate component for each ball screw spindle has to be created. Select all moving bodies of the Y-axis. Open the context menu by right click and select Create Named Selection and name it Y-axis. Repeat this step for all axes (and ball screw spindles).
- For a better overview, the components we are not working on can be suppressed. Select the components and open the context menu by right-clicking, select Suppress Bodies in Group.
- Each body in the model needs material properties. To assign the properties, select a body (or multiple) and select the desired material in the Assignment box on the bottom left.
- The modal analysis only supports the coefficient of thermal expansion as thermal property. To add additional thermal information to the material properties, add a thermal transient analysis to the project and link the engineering data of both analyses. The thermal properties of the selected material can now be changed by clicking on engineering data.
- In the next step we define contacts between all bodies (parts) of a component. Highlight Contacts in the model tree then select Contact in the top panel to create a new contact. Now select the two faces that are in contact, one for Contact and one for Target. Repeat until all contacts of each component are defined. However, do not create contact between components, as each component has to be free in space.
- Next, we need to generate the mesh for the FE analysis. Right-click on Mesh in the tree and select Generate Mesh. Depending on the geometry of the parts, it might be necessary to define finer mesh on some parts. This can be accomplished by using Mesh Control in the top tool bar. However keep in mind, that using finer mesh increases the amount of mesh elements. The speed of the following process of model order reduction depends heavily on the amount of mesh elements, which makes meshing a balance between speed and accuracy.
- To check that no contacts are missing, it is good practice to solve a modal analysis for each component. Suppress all but one component (explained in step 5). Now right-click on Modal Analysis in the tree and select Solve from the context menu. When the solving process is completed, click on Solution in the tree. In the table on the right hand side select all modes. Use Create Mode Shape Results in the context menu. Right-click on Solution in the tree and select Evaluate all Results. If all contacts were defined correctly the component has 6 rigid body modes (the frequency of the first six modes is close to 0Hz). Also check the mode shapes for missing/incorrect contacts. Repeat for each component.
- Now the model is ready to be exported for MORe. As each component has to be exported separately, suppress all but one component. Click on Modal Analysis in the tree to highlight it. Now click on Tools in the top menu bar and select Run Macro…. Navigate to the folder where MORe is installed (e.g. C:/Simulation/MORe) then navigate to the sub-folder /src/ansys and select exportForMORe. Click yes on the dialog box. When the export process is completed, a windows explorer window will pop up. Select all the files with the name with MORe.* and copy them to a folder named after the component exported (e.g. C:/Simulation/Machine1/Ansys_exports/X_Axis). Repeat for each component (the exported files for the Y-axis component are copied to /Ansys_exports/Y_Axis, and so forth).
- You should now have a folder containing one sub-folder for each component of the model. Each sub-folder contains the exported component from Ansys (MORe.mass, MORe.stiff, MORe.mapping, MORe.topo, MORe.cdb).