Multiaxial high-cycle fatigue criterion for hard metals

This paper describes a multiaxial low cycle fatigue parameter for correlating lives under nonproportional loadings. Constant amplitude low cycle fatigue tests were carried out under 14 proportional and complex nonproportional cyclic strain paths using type 304 stainless steel hollow cylinder specimens at room temperature. In nonproportional loading tests, fatigue lives are decreased by as much as a factor of 10 in comparison with those in proportional loading tests with the same strain range. Reduction in fatigue life due to nonproportional loading is closely related to additional nonproportional cyclic hardening. The product of the maximum principal stress and strain ranges correlated the nonproportional fatigue data. A nonproportional cyclic hardening parameter computed from the strain path is also proposed that allows life estimates to be obtained directly from the strain history without the need for a cyclic plasticity model.

Nonproportional Low Cycle Fatigue Criterion for Type 304 Stainless Steel

A micromechanical approach to inelastic behaviour of metals

Multiaxial fatigue assessment using a simplified critical plane-based criterion

Mechanical and microstructural investigations of an austenitic stainless steel under non-proportional loadings in tension–torsion-internal and external pressure

This paper describes the cyclic strain hardening behaviour and dislocation structures of material in biaxial low cycle fatigue at elevated temperatures. In this study, push-pull, reversed torsion and combined push-pull/reversed torsion tests were carried out using a type 304 stainless steel in air. While there was no significant difference between the cyclic stress amplitudes in the push-pull and reversed torsion tests on a von Mises' base, combination tests exhibited a 40% increase in stress amplitude. Most of the dislocations in the first two types of test adopted ladder or maze structures, while in the later case cells were found. Changing the loading mode at a certain cycle, for example, from push-pull to reversed torsion, revealed that stress amplitude depended mainly on the concurrent applied strain mode and furthermore, that the strain mode before the interchange had little or no effect on the stress amplitude after the interchange. Tests were also performed in order to examine how prestrained material hardened in the three different loading modes, with the following results: prestrained material in push-pull or in reversed torsion exhibited an anisotropic stress response, while the material in the combined tests exhibited an isotropic response. These cyclic responses are discussed in connection with the dislocation structure.

Microstructural study of cyclic strain hardening behaviour in biaxial stress states at elevated temperature

A design procedure for assessing low cycle fatigue life under proportional and non-proportional loading

Crack opening displacement approach to assess multiaxial low cycle fatigue

Biaxial Low Cycle Fatigue for Notched, Cracked, and Smooth Specimens at High Temperatures

Effect of Changing Principal Stress Axes on Low-Cycle Fatigue Life in Various Strain Wave Shapes at Elevated Temperature

Naomi Hamada

Papers

Microstructural study of cyclic strain hardening behaviour in biaxial stress states at elevated temperature

A design procedure for assessing low cycle fatigue life under proportional and non-proportional loading

Crack opening displacement approach to assess multiaxial low cycle fatigue

Biaxial Low Cycle Fatigue for Notched, Cracked, and Smooth Specimens at High Temperatures

Effect of Changing Principal Stress Axes on Low-Cycle Fatigue Life in Various Strain Wave Shapes at Elevated Temperature