A PRESCRIPTION FOR THE IDENTIFICATION OF FINITE PLASTIC STRAIN

Although the concept of plastic strain is fundamental to the theory of plasticity, no satisfactory method has been previously given for its identification at arbitrary finite deformations. In the present paper, a procedure is described, by means of which plastic strain can be identified, both conceptually and experimentally. This, and other procedures or prescriptions, enable one to relate the concepts which appear in the rate-type constitutive theory to measurements of stress and strain. The procedure given for the identification of plastic strain also allows one to define a multiplicative decomposition of the deformation gradient which is free from the shortcomings of the one that has been usually employed during the past 20 years.