Learning Forum

[amirjalali58]

Dear All

I have a problem regarding prestressed modal analysis.

I needed to do pre-stressed modal analysis on a component rested on a rubber pad. For the rubber, I used nonlinear strain-stress curves for curve fitting in material properties and so, no Young's modulus was added directly. I successfully performed the static analysis under constant prestress loads. Then, I added modal analysis and wanted to perform modal analysis. For doing so, the software asked me to add density and Young's modulus and I did so. As soon as I refreshed the model to update material properties, all prestress values recalculated based on Young's modulus and the results (stresses) were no longer valid. 

is there any way to keep the prestressed tensions based on the stress-strain curves and do the modal analysis with Young's modulus on top of that?

[dlooman]

Definitely need density for a modal, but it seems odd that Young's Modulus is needed for the modal, but not the static.  Are you doing this in the Mechanical gui?