MPC contact warning on thermal problem

    • Laxyos


      I am working on a steady state thermal problem.

      I have a cylinder heated at 300°C and two blocks of isolation materials. Between each solid there are shell elements with a thickness of 0.2mm. Those shell elements are made of a heat conductive material.

    • Vinayak Vipradas
      Ansys Employee
      Hi Axel,
      MPC formulation can cause over constraint if applied to the same nodes more than once. The program may have not been able to completely bond the desired entities together. You may check the solution output located in the Worksheet of a Solution Information object to determine which pairs and nodes are affected by this condition. Specifically, this can happen when: A contact pair entity (either an edge or face) also has a Dirichlet (prescribed displacement/temperature) boundary condition applied to it. In this case, the MPC constraints will not be created at nodes that have prescribed conditions thus possibly causing parts to lose contact. Sometimes this warning may be disregarded in cases such as a large face with a fixed support at one edge and a contact pair on another. If it is determined that overlap does indeed exist consider relocating the applied support or using a formulation other than MPC. Two MPC contact pairs share topology (such as a face or an edge). Again it is possible for one or both of these pairs to lose contact. This message may especially occur when edge/face contact is automatically generated by the program because often 2 complementary contact pairs (that is edge part 1/face part 2 and edge part 2/face part 1) are created. Often in this case the message can be ignored after verifying result correctness and if necessary deleting/suppressing one of the inverse pairs. Consider reducing the Pinball Radius to avoid overlap or changing one or more of the regions in question to use a contact formulation other than MPC.

      Regards Vinayak
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