Multiaxial fatigue tests under variable strain paths and asynchronous loading and assessment of fatigue life using critical plane models

Abstract

In the present work, axial-torsion fatigue tests were performed under two loading categories, (i) variable strain paths sequential loading and (ii) asynchronous (different loading frequencies) conditions on low C-Mn steel. Variable strain paths tests brought out that saturated cyclic stress-strain behaviour under a given strain path, is insignificantly affected by loading history. However, transient material behaviour is history dependent.Three different critical plane models, Fatemi-Socie (FS), Smith-Watson-Topper (SWT) and Arora et al. (bi-axial SWT) along with linear damage accumulation rule were used to predict fatigue life. FS and Arora et al. model resulted in accurate assessments under both loading categories.