Fatigue strength CAE system for three-dimensional welded structures

ABSTRACT Fatigue strength assessment methods are applied to practical arc-welded structural features that have complex three-dimensional geometry. Two methods are investigated in the present research. The criterion of the first method is cyclic plastic zone size, which is calculated from stress singularity parameters. The criterion of the second method is hot spot stress. These fatigue strength criteria are proved to be applicable to the fatigue strength assessment of practical arc-welded structural features. These criteria enable a critical point at which fatigue cracks are most likely to initiate to be specified for each type of welded joint and load. Consequently, the critical point simplifies the classification of various welded joints. Furthermore, a fatigue strength computer-aided engineering system, which includes functional engines for the evaluation of the fatigue strength of a designed shape, is proposed.