Model problems
Altair EmployeeHey,
i built a model and it is a really simple crash analysis but there are some elements which are producing negativ volume and I don't know why. Additionally the crash surface isn't really in contact with the other surface.
Hope you can help me.
Best,
Max
Answers
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Hi Max,
The NEGATIVE VOLUME error happens when solid elements are very deformed and their characteristic length goes to 0. For large strain formulation the time step of an element goes to 0 when the element is compressed. In RADIOSS Starter input file (Runname_0000.rad), use Ismstr =2 in the solid property and in RADIOSS Engine file (Runname_0001.rad) use the option/DT/BRICK/CST and provide Tmin value at which the solid elements will switch to small strain.This means that the solid elements using Ismstr =2 will use large strain formulation while their time step remains greater than tmin, and will then switch to small strain formulation.
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Hey,
thank you a lot. I did it but are there some new problems and I'm not really sure why I tried also option/DT/NODA/CST but it didn't work.
I get a little bit crazy of it, because other models are working well but not these.
Thanks for your help!
Best,
Max
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Hi Max,
Please check the model file attached. I made some modifications in the model.
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