Incremental Multiaxial Neuber Correction for Fatigue Analysis

Estimations of the elastic-plastic stress states at notches from elastic finite element results based on Neuber type of correction method have proven very useful for many engineering problems. While this approximation technique has been regularly used in simple fatigue analysis of components subjected to predominantly uniaxial loading, its extension into multiaxial cases has been limited to monotonic loading. This paper presents a technique which integrates the Neuber type of correction method with a three-dimensional cyclic stress-strain model. Three major elements are involved: 1) an assumed elastic-plastic loading path; 2) a one-to-one relationship between the given elastic and the corrected elastic-plastic loading history; and 3) a plasticity model for multiaxial cyclic stress-strain analysis. The technique is then illustrated to be capable of estimating complex yet stable cyclic stress and strain histories at a notch.