Unified Stress-Strain Model for Plasticity to the Structural Instability

A unified model for the work hardening Θσ and stress-strain σε behavior is presented that accounts for deformation under tensile loading, from the onset of yielding at the proportional limit up to the ultimate strength as defined at the structural instability. The origin of this approach is based on a negative exponential formulation for an asymptotic-curvilinear work-hardening model that accounts for the rapid strengthening of metals as well as the continuation of steady-state deformation to the instability.