Effect of road conditions on the fatigue life of an automatic transmission output shaft

Abstract

The analysis reported compares the effects of different road conditions on the fatigue life of a transmission output shaft. Four routes having differing driving conditions were investigated and, of those routes, the route with most stop-start events resulted in the greatest reduction to fatigue life. In-vehicle loading data have been compared with shaft fatigue testing, indicating that the shaft should not fail by fatigue in service, despite a generous prediction of daily use. To introduce a theoretical failure, a load-scaling factor has been used, thus providing a factor enabling comparison of the routes.