This is my first time using the COSMOS Works package and I
have imported a Solidworks 2008 model of a FR4 substrate with four
board components(TSSOP, flip chip, and 2 BGA) with materials fully
defined. I have set parameters for a static study of stresses due
to thermal boundary conditions of -40 degrees C and 125 degrees C.
When I pressed "run", I got an error message saying "Poisson's
ratio should be less than 0.5". The problem with this error is that
I have gone through all the materials used in this assembly and
their properties but the highest poisson's ratio is 0.4 for the
Sn63 solder bumps. Has anyone encountered an error like this or
knows how to fix it? Thank you.