Simulated Fatigue Sample for Bending Fatigue Test of Gear

Traditionally gear fatigue performance is evaluated using single tooth bending fatigue test, which is time-consuming and expensive. Alternatively, cantilever bending test is performed to screen materials and heat treat processes for gear applications. This paper reports a modified bending test specimen that mimics a gear tooth surface by placing a representative crown on the flat surface and gear root radius. This design ensures that the fatigue failure does not start from the edge of the root. Also, the height and width of the specimen are selected such that it captures the case-transition zone-core microstructures appropriately after heat treatment process. Finite element analysis of static loading is presented along with a comparison of single tooth bending results with bending fatigue results from the new specimen.