1 Reply Latest reply on May 1, 2012 9:18 PM by Jerry Steiger

    How to model a compressible foam with SW-simulation.

    Joseph Eimer

      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!

        • Re: How to model a compressible foam with SW-simulation.
          Jerry Steiger

          Joseph,

           

          I'm not familiar with how SolidWorks Simulation handles hyperelastic material models, but I believe that you will need better data than you have in your data sheet. You need to send a suitable sample of the material to a materials testing laboratory where they can do the specialized testing to get the material data needed to set the material parameters in any of the hyperelastic models. Axel Products, Inc. is one we have used. It typically costs about $1000, although that was a numbe of years ago. They have a program where you can take a class and test your own material. That seems like a really good idea.

           

          Blatz-Ko may be a good model. You won't know until you try to fit the data.

           

          Jerry Steiger