Hi all,
To have an apt material model is necessary to get good simulation results. Thus, you perform a tensile test/compression test to fit a suitable material model.
So far, you have got a nice colored picture in your FE solver. But still you need to interpret these results! From tensile tests, you have a critical stress and a critical strain, where plastic deformation or failure occurs. However, in a real setup and its simulation, you don't have pure tensile stress. You have a mix of tensile/compression and shear.
For metal, you can use the von-mises criterion or tresca for the failure criterion, what is very common. For plastics, on the other hand, I don't know such failure criterion.
So, is there a reasonable failure criterion available for plastics (e.g. in PolyUMod)? Implemented in a software or the theory for it somewhere published?
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Thank you
Jules
I like the failure model that is part of the PolyUMod TNV model. See the following page more info: https://polymerfem.com/tnv-model/
/Jorgen
@jorgen thanks for the prompt reply. I had a look in the theory described in the manual for strain and stress based failure predictions of the TNV model. I am just wondering, where do the formulas for the failure strain/stress come from? Did you postulate them?
The Hill Yield criterion is, as far as I know, a model for the beginning of plastic yield. So the failure is plastic deformation.Â
But when failure is not plastic deformation but initiating a crack, the Hill criterion is not really good, am I right?
Are there other failure models in polyumod available?
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Thanks
Jules