Rahul,

It is very difficult to give a direct answer to your question. The maximum
pressure which you can apply depends on the failure strength of the material
( I assume your membrane is made of polysilicon). The strength of the
polysilicon varies widely between 700 MPa to 1000 MPa and it is very
difficult to give a precise value. The general rule of thumb is to allow a
factor of safety of 2 (i.e. failure strength/2) and estimate the pressure
corresponding to that value. Again you need to consider the compliant
bundary condition if any in your device besides the residual stresses when
you estimate the limiting pressure. This would allow you have a stable load
vs deflection during your measurement.

If you keep loading the device frequently, the device will fail due to
stress concentration caused by fatigue loading. So one has to
recalibrate the device periodically.

Thanks,
Prasanna

On Thu, Oct 1, 2009 at 9:36 AM, rahul goswami goswami  wrote:

> hi!
>   i have to characterize my pressure sensor membrane for up to 10 bar.
>  What is the procedure?  How much pressure would a 15 micron membrane
withstand?
>
> rahul