General Mechanical

General Mechanical

Convergence problem for visco-hyperelastic sealing simualtion

    • Christian_
      Subscriber
      Dear all,I try to analyze the sealing behavior of high-pressure loaded elastomers at low temperatures. Therefore, I use a 2D axysymmetric visco-hyperelastic material model with Prony-series and WLF-shift function.nHowever, I have huge problems to get it converged. The elements of the seal getting highly distorted and the main errors are too much penetration and volumetric compatibility is not satisfied for U-P elements. I use linear element order and a high number of substeps. I already tryed to refine the mesh but it also did not help. I also played a bit with the step time close to real conditions as I want to see the relaxation (over time and depending on temperature) and hence less contact pressure.n1) Does anyone have a solution to get it converged? I was thinking about artificial compressibility, loosening the tolerance on volumetric compatibility, reduced integration but I am not sure and running out of time to try everything.n2) I am using ANSYS WB 2019 R3. Would it help to download the newest version regarding my problem?n3) I am using a thermal condition and as result the contact pressure tool. A nonlinear adaptive mesh could help but is not available when using thermal condition. Without a thermal condition, the contact tool is not available when using a nonlinear adaptive mesh. How could I manage this issue?nI am looking forward to your answers.nThank you very much! nbest regards nChrisn
    • Ashish Khemka
      Ansys Employee
      Hi Chris,nFor the queries above _ I can comment on points 1 and 2:nnFor mixed u-P elements, the volume constraint equation is checked for each element of a nonlinear analysis. The number of elements in which the constraint equation is not satisfied is reported in the output file. The default tolerance for the volumetric compatibility or volume constraint check is 1.0 x 10-3. You can try changing this value using CNVTOL command.nI think you might see the same issue in latest version as well.nnRegards,nAshish Khemkan
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