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

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.

Automated summary

The present study showed that the saturated cyclic stress-strain behavior under a given strain path is not significantly affected by loading history, while the transient material behavior is history dependent. The Fatemi-Socie (FS) and Arora et al. models accurately predicted fatigue life under both loading categories.