Cyclic Metal Plasticity Model Parameters with Limited Information: Constrained Optimization Approach

Tensile test data for structural steels are ubiquitous. However, the information monotonic loading provides with respect to material’s characteristics is limited. Notably, features of inelastic response cyclic loading, such as Bauschinger effect, cannot be determined without testing a load reversal protocol. This study aimed at addressing this shortcoming by formulating constrained optimization problem that provided best-fit material parameters tensile while simultaneously imposing representative properties steels. Recommendations on constraints were given. Results demonstrated improvements can achieved when compared to: (1) direct fits and (2) input model from same steel but different batches calibrated wide range strain-based protocols. Given available data, it concluded simpler models one backstress tend perform best proposed constraints.