Low-cycle fatigue properties of steel 42CrMo4

In structures subjected to heavy cyclic loading, fatigue damage of material during cyclic plasticity is one of the most frequent failure mechanisms. For determining the low-cycle fatigue lifetime, it is essential to know the elasto-plastical response of the material to a cyclic load, since the accumulated plastic strain has a direct influence on the lifetime of the material. The elasto-plastic response of the material under a cyclic load is described here by using the constitutive macroscopic model of small deformations. This model considers isotropic and kinematic hardening or softening in connection with material damage. The procedure of determining the material parameters by the described model is illustrated for normalised and tempered states of a low-alloy steel 42CrMo4 (ISO 683/1).