Analytical model to predict the fatigue life of tubular welded structures subjected to compressive loading 2020-01-0185
It has been well documented that welded components can fail under pure compression under fatigue loading conditions (R=-∞). Unlike non-welded components, the mean stress effect has shown to have little impact (Gurney, 1979). Currently, most weld prediction procedures does not involve mean stress effect and the relationship involves stress range (or strain range) plotted against the number of cycles to failure. Two case studies were performed to understand the mean stress effect of tubular welds. First case was weld under compressive pre-stress (caused by bolt pretension) subjected to tension and compressive loading. Second case was weld under no pre-stress subjected to the same tension and compressive loading. It was observed that the welds under compression for tubular structures (eg; an axle tube) demonstrated significant resistance to fatigue failure.
Traction structural stress method has proven to be very effective for the fatigue life prediction of welded structures. However, the predictions for the two case studies considered in this research were under-predicting the fatigue life significantly. This paper propose an analytical model to capture the weld behavior under compression through a modified structural stress approach.
Anoop Vasu, Shizhu Xing, Jifa Mei, William Webster, Scott Jacob, Jerry Chung, Ravi Desai