A SWT Fatigue Mean Stress Model for A356-T6 Cast Aluminum Alloy

This paper documents nonzero mean stress fatigue test data from an additional phase of the SAEFDE Round-Robin Test Program on A356-T6 cast aluminum alloy. The Smith-Watson-Topper (SWT) model was used to fit the original fully reversed fatigue test data and that fit was compared to the new nonzero mean stress fatigue data. This traditional model provides another representation for the fully reversed data besides the more conventional strain-life model, and it also satisfactorily predicts nonzero mean stress test results in the finite life region, industry can use the SWT model to assist in the design evaluation of cast aluminum alloy products where it is necessary to account for variable amplitude service loadings which may include mean stress effects and plastic deformations. The data will also be a useful baseline for additional research on cast aluminum alloy fatigue models.