Verification of Endochronic Theory for Nonproportional Loading Paths

Abstract

A procedure for the numerical integration of the constitutive equations of the endochronic theory of plasticity is presented. Methods are established for the determination of endochronic material functions from the results of cyclic uniaxial tests. The endochronic theory is examined for its ability in modeling random nonproportional tests on oxygen‐free, high‐conductivity copper. Qualitative response of the theory is studied under cyclic‐hardening, cyclic‐relaxation, and cyclic‐creep tests. Finally, an attempt is made to discover some typical plasticity properties of the endochronic theory by constructing equiplastic‐strain surfaces in the tension‐torsion stress space. In conclusion, the endochronic theory is a versatile tool for the constitutive characterization of isothermal, rate‐independent behavior of initially isotropic engineering materials.