Category Archives: Modal Analysis

Modal Analysis of a Plate Structure

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This post about the modal analysis, “Meshed Connections” in Workbench and “Shared Topology” features in ANSYS.

Modal analysis is a powerful tool for finding out whether all the parts are connected in the way that they are intended to connect.

In the example below, a simple plate structure is modeled in Spaceclaim and first analyzed without any connections. When there are no connections, ANSYS gives an error for rigid body motion when you run it  through Structural Analysis, but in modal analysis, it gives zero frequency modes. This means that user gets the opportunity to see all the connections in the model. Not only zero frequency modes, the modes with unwanted motion of the connected parts.

The later part of the video is to add connections through the new feature in ANSYS 16.0 “Mesh Connections” and getting the mode shapes with the correct connections. Then I have suppressed the connections in Workbench and modeled the same connections in Spaceclaim. ANSYS gives different options to reach the same solution. In a perfect world, you only need one. But, sometimes ANSYS gives squeaky errors where the connections can’t be acheived with one method and it might come through with other method. It is always good to have all the options/methods under the armory.

Thanks for reading the post.

–Vamshi Goli