Properties and experimental verification of the paraboloid failure criterion with transversely isotropic materials

Abstract

A suitable criterion for describing the yielding and failure behaviour of transversely isotropic materials in the three-dimensional principal stress space, taking into account the strength differential effects of the material, has been recently established by representing this failure locus by an elliptic paraboloid surface, which has an axis of symmetry that remains parallel to the hydrostatic axis and lies on the principal diagonal plane containing the strongest strength axis (σ₃). The properties of the elliptic paraboloid surface have already been established for the general anisotropic body and its validity was tested by checking it with existing experimental results and comparing it with similar criteria. In this paper the elliptic paraboloid failure criterion was tested with typical fibre composites and other transversely isotropic materials in order to prove further its soundness and, moreover, to disclose the intimate connection between strength differential parameters and the coefficients of anisotropy of the material, and their influence on the size, position, form and orientation of the failure locus.