*PPLA
This option turns on quantitative stress computation after the cool-down step, which results in the solver performing several nonlinear analysis steps at the end of the standard mechanical simulation cycle. This ensures higher accuracy of stress results at the expense of added solution time. Stresses are quantitative post-cool down, during bolt removal via *FSUB, heat treatment simulation, support structure removal, and post-process removal from the build plate.
If the build plate material is of a different material assigned by *PBS2 or *PBSN, ensure that a set of constant temperature plasticity properties are assigned to the build plate material block using the *PLAS card. Note that when using this card, stress results during processing will not be recorded.
Best practices: Use *PPLA whenever residual stresses are going to be analyzed or validated. Also use *PPLA whenever validation or analysis will be performed after build plate release (post *FSUB steps) or post build plate removal, as the excessive residual stresses used without *PPLA will cause excessive warping of these components. *PPLA is also required to perform a heat treatment simulation.
When using *PPLA, additional care may be necessary to ensure the mesh has converged. Notably it is advised that lower *PBLR values be used, 0 or 1, as higher values have exhibited non-converged, non-physical results.
It is advised that when using *PPLA, the *PBSS card not be used, as this adds additional constraints to the model, which may lead to poor simulation results.