DIscrepancy of Gear Tooth Allowable Bending Stress Using the Extreme Value Distribution From Different Test Methods

The allowable bending stress S_e of a gear tooth is one of the basic factors in gear design. It can be determined by either the pulsating test or the gear-running test. However, some differences exist between the allowable bending stress S_e obtained from these different test methods. In this paper, the probability distribution functions corresponding to each test method are analyzed and the expressions for the minimum extreme value distribution are presented. By using numerical integration, S_e values from the population of the same tested gear tooth are obtained. Based on this investigation it is shown that the differences in S_e obtained from the different test methods are significant. A proposed correction factor associated with the different experimental approaches is also presented.