How is the nonlinear quantity SRAT (PLNSOL,NL,SRAT) computed? After my first load step the value is 7, but after the 2nd load step SRAT is back to 1.0 as would be expected for a converged solution.


As the Theory Manual says, SRAT is the ratio of the trial stress to the yield stress. In the first load step, the trial stress is the 1st computed elastic stress which is above yield, so you get SRAT=7. With the second solve (with no load change), the trial stress is the stress on the yield surface (i.e., the stress from the previous converged solution) so SRAT=1.

The idea behind SRAT is that it is an indication of how fast you were loading and therefore how accurate the results are. SRAT>>1 is not considered good. We never made much of this quantity (it is a remnant of Rev. 3).





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