General Mechanical

General Mechanical

I cant find the correct results For Non Lineer Static Analysis

    • Eddie2324
      Subscriber

      Hello, I have assembled the bracket group, spot welds have been used to tie brackets and due to that I defined bonded contact and used face to face contact for model spot welds(I don't need to see stress values in welds so bonded should be fine for me). I did modal analysis and connections worked completely fine as I expected.

       

      My problem is, these brackets were analyzed before in two different programs(Marc and Optistruct), and two of these results are really close to each other, however, I solved the non-linear static analysis for the system but my stress results way too high when compared to older results and not make any sense. Boundary conditions and multi linear isot. material curves are exactly the same. I tried to use smaller elements, I used both linear and quadratic elements but I still get high stresses.

      Most of my elements are quad but I have a few tetras as well because the geometry is kind of complex, I could not figure it out where to split and fully mapple the face.

      Stress results is local but still high, is it because of mesh? I used edge sizing, when I used smaller elements than 0.5 mm solver gives error about element lentgh/thickness. I am waiting for any advice, thanks much

       

    • Ankush Choudhary
      Subscriber

       

      Hi,

      This could happen due to a contact singularity. Which contact formulation are you using in bonded contact? Does the other part have sharp edges in the contact region?

      Thanks,

      Ankush

       

      • Eddie2324
        Subscriber

        I am using MPC bonded contact with proper pinball radius, but stresses are not in the contact regions also my contact regions do not have sharp edges because I bonded them from circular faces to simulate similarly to spot welds.

         

        • bhagwantP
          Ansys Employee

          Thanks Ankush for suggestions.

          @Eddie,

          What if you keep contact formulation as program controlled and see averaged/unaveraged stresses at this location. looks like a very local stress though.

          It will be great if you could share more details about loads/boundary conditions to get more clarity for how load is transferred till this part.

           

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