Model preparation for tabular modal damping¶
Run a damped modal analysis in ANSYS to get the modal damping ratios that can be used in the tabular modal damping model.
Modal analysis¶
Add a modal analysis to the project. A modal analysis is used to check if components for MORe have only 6 rigid degrees of freedom.
Analysis Settings¶
Change the value in the damped field of solver controls to yes. This will open a new drop down menu called damping controls.
Damping Properties¶
The following properties can be defined when using tabular modal damping. They can be defined either locally as material-specific properties (in the Workbench Engineering Data section) or as global solver settings to affect the entire component.
Material Dependent Damping, the Constant Structural Damping Coefficient (i.e. the loss factor)
The \(\alpha\)-coefficient (Mass Proportional Damping Coefficient)
The \(\beta\)-coefficient (Stiffness Proportional Damping Coefficient)
Local material properties:
Global solver settings:
Constant structural damping¶
Apply a constant structural damping (loss factor) locally to a material or globally to the whole component. For the material property, the user input is taken as a damping ratio and the constant structural damping coefficient is always twice the damping ratio value. The damping ratio input is only available as a material property, not as a global solver setting (here, only constant structural damping coefficient is visible). However the two values achieves exactly the same effect, being related by the factor 2.
Stiffness/Mass coefficient¶
Change the damping of the component to the rayleigh damping method, where \(\alpha\) is the mass coefficient and \(\beta\) is the stiffness coefficient.
\[D = \alpha \cdot M + \beta \cdot K\]
Export¶
First select the damped modal analysis, then export the component by using the Export for MORe ACT Extension. The ANSYS Mechanical solver will then calculate the modal damping ratios, then the component will be exported. After successful export, the following files should be created and in the .wbmore-file:
MORe files: MORe.cdb, MORe.mass, MORe.stiff, MORe.topo, MORe.mapping
Additionaly: MORe.DAMP (if thermal information was exported)
The modal damping table: mode_damping.csv
Import¶
New component¶
Right-click on components and select import ANSYS model. Go to the .wbmore-file and click on it to start the import.
Existing component¶
Right-click on the component and select reload ANSYS model or reload ANSYS mode damping and go to the folder with the .wbmore-file and click on it to start the reload. Selecting reload ANSYS model reloads the whole component, clicking on reload ANSYS mode damping reloads only the mode damping table.
Use of tabular modal damping inside MORe¶
For further details on how to use tabular modal damping inside MORe, see Tabular modal damping
License requirements¶
A higher ANSYS Mechanical license is required for the export of tabular modal damping ratios. Please check the Installation section for more information.