Ghazal,

Several questions:

Did you try putting a lower modulus value in to see if the value went
down, which in theory should make the resonance drop? Might be a way to
see if it is reading correctly. Same for relaxation time, did you try
increasing the relaxation time to see if you could get a lower
resonance?

I would also ensure that your values for the polymer that you are
working with are accurate.

Best Regards,

Joel
Engineered Materials Systems, Inc.

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Hakemi, Ghazal [SAS]
Sent: Tuesday, June 30, 2009 10:01 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Polymer modeling

Dear MEMS colleagues,

I have a question regarding viscoelastic materials. I am trying to model
a device which has polymeric parts in it. With Modal analysis model in
ANSYS Workbench, the resonance of the device is larger if the shear
modulus is considered in the simulation. Does anybody know why resonance
would increase once this term along with the relaxation time are
included? I would have thought it would have the opposite effect.

Best Regards.

Ghazal