Damage accumulation model for low cycle fatigue

This paper presents the description of damage accumulation for analysis of fatigue life of structural elements under non-proportional loading states. Damage accumulation rule has been formulated incrementally and connected with a monotonic work-hardening curve. The numerical algorithm is decomposed into two calculation blocks. The first presents method for calculation components of stress and strain tensors using a multisurface hardening rule proposed by Mroz. The second block, containing the damage accumulation function and the material failure criteria, is designed for estimating variations of the measure of damage accumulation. Increment of damage accumulation depends on increment of dissipation of energy and condition of stress. The proposed model of damage accumulation enables to define the number of cycles or the time of safe application of complex fatigue loads to arbitrarily shaped machine components.