1 Reply Latest reply on Apr 5, 2011 11:11 AM by Loic Ancian

    Setting up assemblies in Simulation - Best practices

    Hari Padmanabhan

      SolidWorks Simulation allows you to directly take your assembly and perform a Structural Simulation (Stresses, frequency, fatigue etc. ) on your assemblies. But in reality people have always made assumptions, simplified their model or loading, etc to run a Simulation. Whenever I visit customers users are always asking me tips and best practises in setting up assemblies in Simulation. I thought I would start this discussion with some useful tips but I want to hear from all our users on this issue.

       

      Here are somethings I have recommended customers on my recent visits:

      1. Material - Where can I get all the material properties for any specific material?

          Ans. Here are some of my sources for material:

                  1. SolidWorks material database shipped with the software

                  2. Matweb (www.matweb.com) - It lists a lot of materials and they even allow you to export the material to a file in solidworks material format for a fee. But many people have told me that many materials do not have all the structural properties all the time.

                  3. Datapoint labs (www.datapointlabs.com) - They are a material testing lab and have an online database of materials as well.

                  4. Campus plastics - (www.campusplastics.com) - They have a huge selection of plastic materials. You need to download their software to the local machine and download the files from different manf.

                  5. Granta design - (www.grantadesign.com) - Database of material database. Not much experience but I have heard that they have a good source of material standards.

                   6. Atlas of Stress- Strain curves - 2nd edition - edit by H.E. Boyer - Good source for stress strain curves for steel and aluminum when doing nonlinear analysis.

                   7.  Atlas of Fatigue curves - - H E. Boyer

                               Tip: I use a nifty program called plot Digitizer (http://www.southalabama.edu/physics/software/plotdigitizer.htm published by the department of physics at university of South Alabama tp extract data from a picture.

       

      2. Understanding contacts -  People seem to have some confusion in understanding contacts. Think of contacts as interaction between two bodies. In the software there are three level's of contact:

                  a. Global level (It is set inside the component contact definition) - You set one contact condition for the whole assembly - Works well solids with coincident touching faces. sheet metal parts touching other solids or sheet metal parts, beams (structural members) stiffning solids and thin plates. These can be over-ridden by individual component contacts.

                  b. Component level - You can set the contact conditions between any two or more components. This contact can over-ride the global contact but can be over-ridden by a contact set.

                  c. Contact set - This is the most basic level of contact where you can select individual entities (faces, edges, vertices, beam joints, etc.) to create a contact. This is given the highest priority by the software and can over-ride the global and component level.

                

           In general global contact works well for solids and sheet metal parts.

       

      3. Mesh - Most users in 2010 I have visited seem to use the default standard mesher for meshing. The only tip I have is to have for users try the curvature based mesher if meshing fails for any complicated geometry.. If you think it has created too many elements play with the maximum and minimum mesh size in the mesh defintion to get a reasonable mesh.

       

      This is going to be a never ending list for each area in simulation like Boundary conditions, loads, mesh, results, etc.

       

      Each problem is unique so please share your thoughts on all the assumptions, clean-ups, references, tips and tricks you use to perform a successful Simulation using SolidWorks Simulation for Assemblies.

       

      Thanks.

       

      Hari Padmanabhan

      SolidWorks Product Definition

        • Re: Setting up assemblies in Simulation - Best practices
          Loic Ancian

          Hello,

          Very interesting topic.

          You are right about contacts but as soon as you work with mixed meshing (specially shells), this is much complicated because global contact is useless. And choice between source and target is also important.

          Usually I avoid automatic mid surface from sheet metal features because performance are poor and there is no control of contact at borders. So I recreate surfaces from solids and deactivate solid bodies.

           

          A question I often get is "how do I compute stresses in my welds?".

           

          Loic