YIELD DESIGN THEORY - AN EFFICIENT STATIC METHOD FORMULATION

Numerical formulations for determining extreme loads within the framew ork of yield design theory require non-linear optimization problems wi th constraints to be resolved. The difficulty which is presented by th ese optimization problems still greatly limits practical applications, in particular those concerning three-dimensional mechanical systems. For a class of materials whose strength domain is defined by positivel y homogeneous functions and contains in its interior the zero stress t ensor, a new formulation of the static method is established here. Thi s particular formulation leads to a minimax discrete problem without c onstraints which uses a reduced number of variables. Numerical resolut ion of this minimax problem is based on a regularization of the object ive function. Applications concerning the calculus of the macroscopic tensile strength of a periodically heterogeneous medium and the study of the stability of a vertical cut enables the performances of the pro gram developed to be analyzed. (C) Elsevier, Paris.