POLYFLOW - improving the stability of the solver for transient calculations, possibly with contact or with viscoelasticity
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Some transient calculations involving contact may fail at the contact, while some transient calculations involving viscoelasticity may fail at early steps. What can be done for possibly improving this? Transient calculations involving contact often exhibit a sensitive beahviour at the contact occurrence, since the contact involves a sudden change in the condiitons. Using the keyword CONVELOC in the .p3rc file or as a POLYDATA option defined in POLYMAN may improve this. In fact, it wil require the convergence of the velocity field, while that field will be discarded for the evaluation of precision. Transient calculations involving viscoelasticity may also exhibit a sensitive behaviour at the beginning, since stresses often exponentially grow from a zero value. This may affect the behaviour of the algorithm. By default in versions 3.122 and beyond, the convergence is checked for the viscoelastic variables, while the precision is discarded for transient calculations. If it is needed to check the precision, the keyword PRECISIONSTRESS should be included into the .p3rc file or as a POLYDATA option defined in POLYMAN. |
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