APPLICATION OF THE WEAKEST LINK THEORY IN THE MULTIAXIAL HIGH CYCLE FATIGUE REGIME

摘要

The stress gradient and the size of a component are known to influence the fatigue strength of metallic components and be responsible for changes in the fatigue limit. When dealing with multiaxial load conditions those effects still act but a relevant criterion must be used to account for the complex state of stress. The weakest link concept together with a multiaxial endurance criterion based on a microplasticity analysis are then combined to describe the fatigue limit distribution of different metallic materials. By means of the proposed model, all the known effects on fatigue strength can be reflected. Thus the endurance probability can be adequately predicted for any complex load conditions and stressed volume. Several uniaxial fatigue data from experiments carried out on a cast iron and on different steels are analysed with this new approach.