4 Replies Latest reply on Jan 26, 2016 9:19 AM by Chris Penner

    Inaccurate result with simulation premium

    Richard Debarbouille

      I am new to nonlinear simulation and plastic.

       

      What should I do to get closer to real life performance.

       

      I set-up PP material with stress strain curve

      I set-up model with a single load and fixture

      I am testing plastic buckets.

      My simulation are showing very high stress.

      My plastic handle breaks with 1000 to 1200N in lab test.

      My FEA simulation is showing about 60N.

       

      My plastic bucket is failling with 10000N in real life.

      During simulation I reaching limit around 1000N and the simulation step because deformation are too large.

       

      I am using SP2.1  Solidworks 2015

        • Re: Inaccurate result with simulation premium
          Chris Penner

          I'm experiencing very similar results for one of my plastic parts. Solidworks is suggesting one of my parts has a 57mm deflection with a 100lb load applied, and in real world testing, that same load only causes a 12mm deflection. I have the material properties for the plastic entered exactly as found in the datasheet, and I'm certain I have my fixtures, connections, and forces entered properly. I'm not sure why the simulation has such a discrepancy with real world testing...

          • Re: Inaccurate result with simulation premium
            Janko Stellaard

            Hi Richard,

             

            The bucket is meshed far too coarse to do a stress analysis. Refine the mesh in high stress area's untill the stress value converges to a steady solution. You will see a drastic change in you results.

             

            Other aspects that can influence your solution:

            • too rigid fixture
            • incorrect / inaccurate material properties
            • incorrect assumed force(direction)
            • assuming small strains (large strain is off, so the stress area is not updated)

             

            Janko Stellaard

            Cadmes BV

            The Netherlands

              • Re: Inaccurate result with simulation premium
                Richard Debarbouille

                Janko,

                 

                I am running simulation again with a smaller mesh. The result is still very different from real life test.

                Do I need to use carefully between material parameter? When I select material type in material property they are a few option for non-linear plastic material. How can you select the right one for the simulation?

                I would hope to be within 20% of the real life case. What would be your expectation.

                I have reduce to a minimum the fixture and achieve lower stress but it is still 14 times higher than what I am experiencing.

                 

                Can you comment on the handle as well please?

                 

                Thanks,

                Richard Debarbouille

              • Re: Inaccurate result with simulation premium
                Chris Penner

                Hey Richard, were you able to figure out what the issue was? I'm still struggling with this when trying to calculate displacement from plastics...