2 Replies Latest reply on Feb 15, 2012 2:33 PM by John Smith

    Static FEA analysis for HDPE plastic

    John Smith

      Hi Ladies and Gents,

       

      I have a plastic component that i am trying to see how much it will stretch when i apply 700 pounds of weight to it. I am attaching the result.
      Each side of tab(3.33 square inches) recieves 52.25psi bringing the total to 700 pounds.

       

      My questions are rather simple. In real life when I test this in an aparatus i get approximately 1.5" of elongation after 30 seconds of the load applied to it...

       

      Why is solidworks showing me only approximatelly 0.15"??? What am i doing wrong? This is a static simulation if that makes any difference.

       

      Is my material specification wrong?

       

      Thank you for your help!

       

       

      Solidowrks 2010 Premium.

        • Re: Static FEA analysis for HDPE plastic
          Ryan Brumund

          Looking at your screen capture I see that you have a "Linear Elastic" material model.  In some cases you can get away with using that model for plastics, but in general they do not follow a "Linear Elastic" model.  To get a real good estimate you would probably need to use the non-linear or one of the Plastisity material models, especially since a lot of your part has stresses that appear to be close to the tensile strength.

           

          You should see if you can get your hands on a Stress-Strain curve for your material.  It will tell you if the Linear Elastic model is close and if it isn't close you can input the information into one of the other models.  However, that will require you to run a non-linear simulation, which I believe requires the Simulation Premium Package.

           

          Also on a side note, I think you should be able to apply the 700 lbs to the surfaces directly instead of calculating and applying a pressure.

            • Re: Static FEA analysis for HDPE plastic
              John Smith

              Ryan. You are correct. The reson i am not getting true deformation is becuase i only have solidworks professional. I cannot run but static linear simulations... ...

               

              There is a way to punch in the stress strain curve into my material but i do not think soldidworks even looks at this during the simulation... and it always gets lost.. even if i save it...

               

              you are also correct about applying 700lb as mass. Wow! awesome!