Johnson-Cook Constitutive Model

An empirical constitutive law for ductile metals that expresses flow stress as a separable function of equivalent plastic strain, plastic strain rate, and temperature; commonly written as σ = [A + B(εp)^n][1 + C ln(ε̇p/ε̇0)][1 − (T*)^m], where εp is equivalent plastic strain, ε̇p the plastic strain rate, ε̇0 a reference rate, T* a homologous temperature normalized between a reference and melting t