6 Replies Latest reply on Jan 28, 2012 3:44 PM by Sheldon Wong

    URGENT - Stressed Skin Laminate Chassis Analysis

    Sheldon Wong
    Sheldon Wong Jan 15, 2012 5:57 PM

      Hi all, we (University of California, Merced) have been working on this chassis for a long time now and cannot get any further with the analysis.

      If we cannot get this working in a couple days, then we will have to scrap this chassis for our project so if anyone could help us out, we would greatly appreciate it.

       

      In the model, I have only included the inner skin. The outer skin was removed for simplicity. And I don't even want to think about how to model and analyze the Laminate Core...

       

      I have tried using the soft relief function, contact sets, different ways of modeling the chassis, and etc with no avail.

      For now we would like to fix the rear of the chassis and apply a 1000lb load normal to the front face of the front bulkhead.

       

      Thank you!

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        • Re: URGENT - Stressed Skin Laminate Chassis Analysis
          Anthony Botting
          Anthony Botting Jan 15, 2012 7:05 PM (in response to Sheldon Wong)

          In SW 2011, the 'skins' show up as solids in the analysis tree (i.e., they will be meshed with solid elements). I presume your team does not want to model skins using solid elements (I may be wrong, here). A more traditional route to the skins is to mesh them with shell elements. Apparently, the software "converted" the skins to use solid elements because there is applied "thicken" features to the skins. An approach might be to make a separate configuration of the model and suppress the "thicken" features, then assign the skin surfaces as shells with manually-defined FEA shell thickness. They would likely need manual bonding contact definitions to the beam elements, too. The VAR servicing your institution is obligated to help you, and should do so because there is not an insignificant learning curve on mixed mesh FEA. This model needs to accept different element types, which mandates peculiar junction connections, and learning the contact bonding rules. There is a potential for a rather heavy amount of effort required on this particular model, for which the servicing VAR can help.

          • Re: URGENT - Stressed Skin Laminate Chassis Analysis
            Jerry Steiger
            Jerry Steiger Jan 27, 2012 4:15 PM (in response to Sheldon Wong)

            Sheldon,

             

            I'm afraid I can't help much, as I don't use Simulation much, don't have access to it right now, and don't work with stressed skins. I can say that I think that trying to run the analysis with just one skin is pretty much pointless, other than showing that you apparently have problems getting the bonded contacts working correctly as well.

             

            You might be able to model the full skin as an orthotropic solid with different characteristics in plane and out of plane, but I suspect that may be overly simplified as well. You would have to run analyses of small areas of skin under various loads and compare those to some test results to get some kind of workable model.

             

            It seems to me like you have a very difficult to analyze problem.

             

            Jerry Steiger