The ''visco-plastic'' approximation to Hart's constitutive law for inelastic deformation (Q1819994)

Hart's constitutive law for inelastic deformation of metals in uniaxial loading is described. For sufficiently low temperature or high strain rates, Hart's constitutive law in uniaxial loading is accurately approximated by a simpler law termed the visco-plastic approximation. In the visco-plastic approximation Hart's ''plastic'' element reduces to a classical rate independent power-law work hardening plastic material. An error bound for the visco-plastic approximation is estimated. Analyses are carried out for some simple deformation histories, including a constant plastic strain rate test, to elucidate the content of Hart's law.