New 352-line test file for PerfectPlasticity material model:
- Tests material construction and parameter validation
- Tests state management (PlasticityState with ε_p, α, κ)
- Tests elastic loading (small strain, no plastic strain)
- Tests plastic loading and yield criterion enforcement
- Tests radial return mapping algorithm
- Tests hardening behavior (kinematic hardening via backstress)
- Tests incremental loading and Bauschinger effect
- Tests pure shear case
- Validates consistency (yield criterion f ≤ 0)
- Validates zero-allocation and type stability
Comprehensive test for J2 plasticity with return mapping essential
for nonlinear structural analysis beyond elastic limit.
Jukka Aho