Experimental Study on Fatigue Fracture Damage of Symmetric Spur Gear Tooth

Abstract

There are many studies on the involute profile symmetric gears in the literature. In many studies done, the critic tooth root stress was emphasized. Studies have been carried out on the calculations of tooth root stress and these studies have been tried to be verified by using the finite element method. Although there are different approaches to calculate the tooth root stress, the most widely used equations are those expressed in ISO and AGMA standards.The studies in the literature have mostly been carried out on the gears that have trochoid curve in the tooth root. In parallel with these studies, experimental studies were done to determine the fatigue life performance of these gears.In this work, involute gears tooth root was manufactured using the circular fillet method which have better tooth root stress than trochoid according to static analyses in literature. Fatigue damage on symmetric gear tooth under cyclic loading and effect of material hardness on fatigue life of gear tooth were investigated.Fatigue tests were performed with specially designed single-tooth bending fatigue test (STBFT) apparatus. The results obtained from fatigue tests at low cycles and high cycles were evaluated comparatively.