6 Replies Latest reply on Mar 20, 2009 10:29 PM by 1-1KYWMD

    Double loading

    1-1KYWMD Mar 19, 2009 4:58 PM
      When I check the Result Force for an entire model of a static stress analysis I am getting double the resultant than the input. I am just putting a single face force in the Z direction. Eg 100 pound force on a single face. When I look at the Reaction force for the entire model it says 200 lbs. What might be the issue, or what am I not understanding? I am not using gravity. I did a small test case it works as I expected, it is just this model that is giving me the issue.
      Thanks
      Bruce
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        • Double loading
          1-DEXHLY Mar 19, 2009 5:54 PM (in response to 1-1KYWMD)
          Can you upload the file so I can check?
          • Double loading
            1-DEXHLY Mar 20, 2009 5:13 PM (in response to 1-1KYWMD)
            Bruce this may be the problem.
            When you specify the force magnitude you have two options, PER ITEM or TOTAL. If on the edge you have specified you have to arrows stating the load you are going to apply on your model be sure to select TOTAL otherwise you will have x2,x3,...,xN times the load you want to apply
            Hope is clear
              • Double loading
                1-1KYWMD Mar 20, 2009 5:20 PM (in response to 1-DEXHLY)
                Thanks - that was the first thing I looked at as in prior versions of Designstar I did not have the "total" option. I tried both ways total and per item but get the same result (it is only one face or edge I am applying the force to while I am trying to solve this issue).

                What is different for me in this study is that it is surfaces with shell mesh - I have mostly worked in solids before. Is there anything around that I may not be understanding? I Think I will recreate the study from scratch and see if it's a bug.
                I am unable to send the model because of confidentiality, but otherwise would.
                Bruce
              • Double loading
                1-DEXHLY Mar 20, 2009 5:27 PM (in response to 1-1KYWMD)
                Try to apply a force on a single edge and check Total as option and see your RF. Weird but if I cannot see what you did I cannot really help you.
                Good luck!!
                • Double loading
                  1-YJ1IM Mar 20, 2009 5:32 PM (in response to 1-1KYWMD)
                  There was a bug with pressures on surfaces with shell mesh doubling the load. This was fixed in 2009 Sp2.1. Did not test if force was doing the same thing.