General Mechanical

General Mechanical

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Hyperelasticity Model

    • giuliodalbello1997

      Good afternoon every one.

      I am working on a FE model in which I would like to reproduce a tensile test of the specimen reported in Figure 1. The material is hyperelastic and the experimental data that I have are the tension and compression test (points of Figure 2). I have settled the material model considering Mooney-Rivlin 9 parameters and the results of the calibration are shown in Figure 2 (it seems that the curve fit follow well the experimental data).

      Figure 1 – Fe model

      Figure 2 – Material model

      The model is composed by solid element (Solid185). The specimen has been fixed at one section and a force of 100 N has been applied in the other section (figure 3).

      Figure 3 – Load and constraint


      The problem is that the solution does not converge (Force criteria is not satisfied . Figure 4) and the errors are reported in figure 5. It seems like there is a lot of element distortion but, as shown in figure 6 and figure 7 (Von Mises and strain plot of the last convergence step) it not seems that there is distortion of those elements.

      Figure 4 – Force convergence plot

      Figure 5 – Errors

      Figure 6 – Von Mises stress

      Figure 7 – Normal elastic strain

      I tried to understand what could be the problem but I don’t find any solution. I really appreciate any suggestion.

      Thank you


    • Armin_A

      Hello Giulio,

      I have a suggestion for you: As your prescribed load might be too large, try pulling your specimen under a displacement-controlled BCs rather than force-controlled (you can set the maximum displacement to the one associated with the end of your test). This is also better in line with how actual tensile tests are performed in labs.

    • Desi Gustiani

      Hallo Mr Armin_A and Mr Giulio. 

      If you are willing can you help me? I really appreciate your help. I want to carry out a tensile test simulation with AISI 4140 material, actually I don't know the correct tensile test simulation process. Is there a video that you suggest or a discussion that I can learn from to carry out a tensile test simulation?

      And I want to ask if to fill in the force data, how many values do I need to input?
      Thank you very much all.

      • Armin_A

        Hi Desi,

        You should be able to find good resources online, such as the paper below:

        Once you started creating your model, you can ask your questions in a separate post in this forum and myself or someone else will be able to assist you. 

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