ON THE SOLUTIONS OF ELASTIC-PLASTIC PROBLEMS WITH CONTACT-TYPE BOUNDARY-CONDITIONS FOR SOLIDS WITH LOSS-OF-STRENGTH ZONES

A formulation of a quasi-static problem of the mechanics of elastic-pl astic bodies with loss-of-strength zones and boundary conditions of co ntact type is given which enables the properties of the loading system to be taken into account. With certain constraints on the constitutiv e relations and using a condition for stability of the softening proce ss in a local zone, theorems are proved on the uniqueness of the solut ion of the boundary-value problem and on the maximum and minimum of th e functionals when the kinematically or statically possible and actual fields are the same. The corresponding generalized variational princi ples are given. (C) 1998 Elsevier Science Ltd. All rights reserved.