Physical description and model validation of welded joint fatigue damage evolution.

For welded structures, the concept of damage is highly abstract and difficult to describe, leading to a lack of physical foundation and universality for existing fatigue damage accumulation models. A new fatigue damage parameter definition based on remaining bearing capacity is proposed in this paper, which is constructed by the equivalent stress on the remaining bearing surface and the equivalent stress intensity factors along the crack front curve. Tension and three‐point bending fatigue tests under two‐level loading block sequences were conducted, and the real fatigue damage evolution processes were obtained by combining measured crack front information and FEA simulation. Five damage accumulation models were utilized to estimate the fatigue damage evolution processes of the two specimens. Results show that there are differences in describing the damage evolution processes and predicting the early fatigue lives. The Rege model is most consistent with the measured data, demonstrating its applicability and effectiveness. Highlights: The physical essence and description of the welded joint fatigue damage are investigated.A damage definition based on remaining bearing capacity for welded joints is proposed.Real damage evolution processes of two welded joints are obtained.Validation of four nonlinear damage accumulation models is carried out and discussed. [ABSTRACT FROM AUTHOR]