Kousseil:

You can use the CMATRIX macro to calculate capacitance before and after any
deformation.  If you run an electrostatic-structural simulation, you just need
to update the geometry stored in the database to correlate to the deformed shape
and then issue CMATRIX.  The capacitance will then be calculated for the
deformed shape.  CMATRIX operates on the geometry active in the database.

In Release 8.0, you can perform a coupled-field electrostatic-structural
simulation either using the ESSOLV macro or the multi-field solver.  If you use
ESSOLV, the deformed shape is automatically stored in the database.  If you use
the multi-field solver, then you need to use the UPCOORD command to update the
geometry in the database to conform to the displaced shape.  I recommend using
the multi-field solver, although ESSOLV will also work.

Regards.

Daniel Shaw
ANSYS, Inc.
************************************************


-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of
kousseil
Sent: Thursday, April 01, 2004 1:52 PM
To: [email protected]
Subject: [mems-talk] I need information about how to calculate
thecapacitance


Hi all,
I am having difficulty in simulating a tunable capacitance modeled in Ansys
8.0. My main concern is measuring the capacitance change for a change in
displacement of my mobile plate.
Can anyone help me understand the process that should be followed to extract
the capacitance after the deformation has occurred due to some structural
force acting on one plate by using coupled field.
How can I calculate the capacitance using the CMATRIX macro for a static
model  I  need suggestion for the coupled analysis of the model. first
structural and then electrostatic.
I would appreciate if anyone can help me out.
Thanking you

-----------------------------------------
Kousseil Ben Ahmed
École de technologie supérieure
Téléphone: +1 (514) 396 8800 ext:7657
-----------------------------------------