ON THE PARAMETER-IDENTIFICATION PROBLEM FOR FAILURE CRITERIA IN ANISOTROPIC BODIES

The elliptic paraboloid failure surface criterion (EPFS) is adopted in this paper to describe the failure behaviour of anisotropic bodies. A method is described, based on an inequality-constrained least square problem for the determination of the parameters of the EPFS criterion. After the discussion of the influence of the strength differential ef fect on the failure behaviour of the material, a neural network learni ng approach is introduced to the problem of extrapolating the given ex perimental results beyond the given range of experimental data by esta blishing an appropriate law of evolution of the failure surface Valid for the material up to fracture.