Theoretical Fatigue Life Prediction Using the Cumulative Damage Approach

A method is presented for conservatively estimating a total fatigue life through a prediction of crack initiation life using the cumulative damage approach. The procedure is based upon the use of Neuber’s Rule, a cyclic stress-strain function, and a histogram of nominal linearly elastic equivalent strain. This provides for actual cyclic stress-strain definition and crack initation life prediction at a particular point on a cyclically loaded body. Linear finite element stress analysis plays a major role in the solution. An outline for computer-aided implementation and a case history are included.