Application of the orthogonality principle to the endochronic and Mroz   models of plasticity
  A new description of the endochronic and the Mroz model is discussed. It is based on the definition of a suitable pseudo-potential and the use of the generalized normality assumption. The key-point of this formulation is the dependence of the pseudo-potentials on state variables. 
Nelly Point (UR Navier), Silvano Erlicher (UR Navier)