A critical review on multiaxial fatigue assessments of metals

Multiaxial fatigue analysis is categorized into five viewpoints, i.e. empirical formulas and modifications of the Coffin-Manson equation, application of stress or strain invariants, use of the space averages of stress or strain, critical plane approaches, and use of energy which has accumulated on the materials. Garud(1) (J. Test. Evaluations 1981, 9, 165) reviewed the results of multiaxial fatigue researches proposed up to 1980 in chronological order and evaluated them. In this paper multiaxial fatigue researches which have been suggested after 1980 were classified into the five viewpoints and some problems which existed in those studies were examined. During these periods major progresses in multiaxial fatigue analysis are the consideration of anisotropy of materials and the suggestion of the energy method using Mohr's circles. Additionally, existing equations or parameters were modified to consider the mean stress, loading path, etc. There have also been some trials for the generalization of the existing theories.