Olaf Hertel, Michael Vormwald, Timm Seeger, Ralph Döring, Jens Hoffmeyer
May 28, 2013
An extension of several algorithms is presented for estimating elastic-plastic notch stresses and strains for metallic materials under cyclic multiaxial nonproportional loading. The extension allows for using advanced models of incremental plasticity. The accuracy of the algorithms, i.e. the structural yield surface approach according to Köttgen et al. and the incremental Neuber approach according to Glinka et al., is shown by comparisons with finite element calculations and notch strain measurements. The accuracy of both approaches is comparable. The differences in predicted stress-strain paths are in the same order as those to measured and FE-calculated paths. These differences lead to a factor of up to two in calculated fatigue lives. Glinka's approach can be applied much more easily; Köttgen's approach offers the opportunity for further improvements in accuracy.