Dear Mems experts,
 I think that you can find an answer in this publication:

Boutry, Bosseboeuf, Grandchamp,...
Finite element analysis of freesatnding microrings for thin filmstyle strain
measurement;  Journal of Micromechanical systems, 1997, vol6, 280-284.

"Microsystems optomecaniques pour la ditection de gaz" Paolo Bondavalli, Phd
Thesis (look at www.insa-lyon.fr site), Unfortunately it's in french...

I could tell you to read the Phd Thesis of Steffan Greek at Uppsala
University.

I think this information will help you.
Best Regards


Sjoerd Haasl a icrit :

> Hi Amar,
> I have previously modeled the residual stress in a thermal actuator by
> applying a temperature to it. In my case the residual stress caused a
> shrinkage, so  I applied a negative temperature. The temperature difference
> I applied on the part under stress was such that it would cause the same
> stress as the residual stress if held constrained.
> In formulas:
> sigma = E * epsilon
> epsilon = dT * TCE
> So: dT = sigma / (E*TCE)
> where epsilon is the relative expansion, TCE the coefficient of linear
> thermal expansion, E Young's modulus, sigma the residual stress and dT is
> the temperature difference I applied.
> I have no idea if this reasoning is correct, and have not had the
> simulations confirmed by experiments, but it gave me an idea of what to
> expect. I leave it open to the MEMS community to correct me.
> And then there is of course still the problem of thermal insulation if you
> have residual stress in only certain parts of your actuator.
>
> Good luck,
> Sjoerd Haasl
>
> Royal Institute of Technology
> Department of Signals, Sensors and Systems
> Microsystem Technology
> Stockholm, Sweden
>
> > ----- Original Message -----
> > Message: 10
> > Date: Mon, 24 Jun 2002 14:54:27 -0700 (PDT)
> > From: amar atre 
> > To: [email protected]
> > Subject: [mems-talk] residual stress application in ansys
> > Reply-To: [email protected]
> >
> > HI
> >
> > I am modeling a thermal actuator in ANSYS. i am trying to model the
> > residual stress in the actuator to get some initial deflection. but  dont
> > have any idea how to proceed. This question was asked before but i
> > didnt find a reply for it.
> >
> > Can anyone help me
> >
> > Thanks
> >
> > Amar
> > Sign-up for Video Highlights of 2002 FIFA World Cup
> >
> > --__--__--
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Dr. Paolo Bondavalli
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Disclaimer: Opinions expressed herein are my own and may
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