1 Reply Latest reply on May 26, 2017 12:09 PM by Ryan Dark

    Underconstrained bodies in Solidworks PREMIUM simulation Add-in

    Tony Hornsby

      I am attempting to calculate the deflection in the attached stainless steel gr304 frame using the simulation add-in with Solidworks PREMIUM 2017.


      I have attached the files with 60000n force applied to each of the 2 large plates and 3000n force applied to each of the four smaller plates.


      The frame sits on the floor on the open ends of the four vertical weldments (2 x250mm and 2 x 100mm)


      I can attached a fixed geometry to the base joint of the 100mm vertical weldments but this option is not available for the 250mm vertical weldments.


      How can I attach fixed geometry to stop the issue with under-constrained bodies when creating the mesh and running the study?

        • Re: Underconstrained bodies in Solidworks PREMIUM simulation Add-in
          Ryan Dark

          Hi Tony,

          This is a common question that comes up a lot on this forum.  The model is definitely unstable but tracking down how it is unstable is the real problem.  I went through a quick stability diagnosis in a duplicate of your study like this:


          1. Go into the study 'Properties'

                    Turn on 'Use soft springs to stabilize model'

                    Turn off 'Compute free body forces'

                    Turn off 'Large displacement mode'

          2. Suppress all loads and apply only 'Gravity'

          3. Mesh/Run the study

          4. When the solver stops (if it stops) due to large displacements and prompts to put the study into 'Large Displacement mode' declined this offer.  The solver will dump what results it has so far

          5. Inspect the displacement plot in the results to find the unrestrained body


          The results showed several bodies were not attached to the main structure:

          You may want to create specific bonded contact sets attaching these pieces to the main structure.