General Mechanical

General Mechanical

Hyperelastic simulation (Yeoh 3rd model) order fails to converge

    • Zeinab

      Hi all,
      I am carrying out a hyperelastic simulation with Ecoflex-30 as a material (Yeoh 3rd degree model, with the following characteristics: C1 = 17 kPa, C2 =-0.2kPa , C3 = 2.3e-2 kPa).
      As shown in the following photo, I am carrying the simulation on a thick cylinder of internal radius ri = 8 mm and external radius rex = 10 mm. The total length of the cylinder is 58mm. One end of the cylinder is fixed while its interior is pressurized with air.
      The simulation is carried out with 100 steps (auto time stepping on. Initial, Minimum, and Maximum substeps all set to 100. Large deflections are activated. I set Keyopt(6) = 1 for the body as I have seen that it helps the solution to converge. The mesh is tetrahedral.
      No matter what I do the simulation always fails at the same point (at 58%). I tried increasing the number steps from 100 to 250, refining the mesh, activating/deactivating the nonlinear adaptive region, increasing the number of substeps, etc... but the solution always fails at the same point (58%).
      Before, the error stated that SOLID187 is experiencing high distortion but after some modifications the error only says that the solution can't converge at a substep of this step...
      Do you have any idea how can I fix this problem?
      Thanks in advance.
      Note: I have to use a yeoh model for the ecoflex-30

    • Mike Rife
      Ansys Employee

      Hi Zeinab

      Perhaps the model is collapsing and losing its ability to carry any additional load?  Have you thought about turning on some stabilization or running this as a slow transient?

    • peteroznewman
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