Constitutive analysis of elastic-plastic crystals at arbitrary strain

A time-independent constitutive framework is constructed for crystals capable of crystallographic shearing. No restrictions are placed on their elasticity or on the amounts of slip. In deriving properly-objective relations due account is taken of the separate motions of the material and lattice. A precise specification of the structure of the flow rule leads to conditions for the existence of plastic potentials, as well as to an exact statement of the slip criterion required for normality of the plastic strain-increment in conjugate variables. Objective hardening laws are also examined and sufficiency conditions obtained for uniqueness of the slip magnitudes.