John Doyle
Ansys Employee
If you have stress relaxation data (i.e. stress vs time), you can use this as input in curve fitter to calculate alpha and tau prony properties.nYou can use a shift function if material exhibits Thermal-Rheologically Simple (TRS) behavior, but you do not have to do this.nYou could also just generate separate Prony Coefficients for each temperature and use them directly. The shift function is more convenient when it applies (TRS behavior).nSee Section 4.7.2 of the MAPDL Material Reference for more details. You should also consult with Articles and/or text books about shift functions in general to get a better understanding of when and how to use. It is more of a material science question, not just an FEA question.n