The materials are all linear elastic, so no plasticity.
In Workbench, Drag and Drop a Modal Analysis onto the Model cell of the Transient Structural analysis.
Click Solve and reply with the frequency of the first mode. You should compare this frequency with the frequency in the Imported Load.
I can help you calculate the frequency in the imported load. In Mechanical, right click on the Mesh branch then Clear Generated Data. File Save, then File Archive which will create a .wbpz file. Attach that file to your reply and I can open your model.