Inelastic analysis by symmetrization of the constitutive law

This paper deals with the transformation of the inelastic continuum problem from the differential to the variational form. Due to the lack of symmetry of the constitutive law, the variational formulation of the problem has been, above all, obtained using techniques of symmetrization of the overall problem operator (as with Tonti's techniques). In the present paper, instead, the adopted method is based on the symmetrization of the constitutive law only. On this basis, taking into account the consequent transformations to be done on the equilibrium and on the compatibility boundary condition operators, a symmetric global operator for the original problem is achieved. This leads to a new 'enlarged' formulation and then, by the choice of a suitable operator, to a new wide class of variational principles and, by specialization, to classical and recent variational principles.