Hello,

I'm trying to model a foam disk supported by an alluminum ring with atmosphere on one side and vacuum on the other (bonded interfaces).  The atmosphere will naturally distort the foam into a complicated diflected shape.  Some material characteristics of the foam are presented here: http://www.qualityfoam.com/docs/166_HD30.pdf 

I have several questions on how to properly model this system.

1) What is the appropriate non-linear material model to use?  I believe the Blatz-Ko model assumes too flimsy of a materail to be useful here.

2) The data sheet linked to above lists both compressive stess-strain and tensile strength.  How do you input this data into SW?  Do you assume a nonlinear model and use negative strains for compressive loads?

3) Since this situation involves cylidrical symmetry, I figured it would be more efficient to use a pie-slice of the structure with symmetry fixtures on the window and the support ring.  I would assume for a fixed mesh size, the result will be more acurate for a smaller slice of pie.  Is this correct? 

Thanks for any guidance!