A General Criterion for Low-Cycle Multiaxial Fatigue Failure

Abstract

A new, general criterion is proposed for multiaxial low-cycle fatigue failure. Contours of constant fatigue life on a plot of maximum shear strain against the tensile strain acting normal to the plane of maximum shear strain are represented by a parametric criterion of the form g(θ, Nf)=kf1(θ)f2(Nf). Here g is the magnitude of the vector from the origin to a point on the constant life contour, θ is the angle associated with g in this space, Nf is the number of cycles to failure, k is a constant and f1 (θ) and f2 (Nf ) are two separate functions of θ and Nf , respectively. It is shown that all previously proposed macroscopic criteria are particular cases of the failure function g (θ, Nf ). Experimental results from several authors are analyzed using the new criterion.