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Nonlinearity in stress free and pre-stressed microbeams
Posted 2012年2月2日 GMT-5 11:19 Structural Mechanics Version 4.2 0 Replies
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I am trying to figure out how large the deflection of a pre-stressed double-clamped silicon nitride beam can be before it starts to become nonlinear.
First I made a model in which the beam is stress free. I simulated the deflection as a function of applied force using nonlinearity and without. Then is compared the deflections and when the two models starts do differ I assumes the nonlinearity become an issue.
Then I made a model where I used thermal expansion to create a stress (200 MPa) in the beam. Then I simulated deflections as before and compared the two simulation. In this case there is no match between the two models a low deflection. I have also tried to make a linear fit to the first part of the nonlinear curve and the see when they starts to differ. If I compare this amplitude with the one from the stress free beam, it is larger which I did not expect. I expected it to be smaller since the beam is pre-stressed from the beginning.
My questions are: Is it reasonable to do the simulations as I do? Does I need to include nonlinearity while simulating thermal expansion?
I hope someone can help me with my problem:-)
Best regards
Hello Tom Larsen
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