Non‐Normal Responses and Fatigue Damage

A simple model of stationary nonnormal responses is proposed. Based on a Hermite series transformation of a normal process, the model requires knowledge of only limited, easily estimated response statistics (i.e., central moments). Applications to fatigue damage problems are considered. Conventional estimates of fatigue damage and life statistics are found to become increasingly unconservative as either the kurtosis coefficient or the stress-law exponent increases. A simple correction factor is developed to account for these effects, and is supported by the simulated behavior of rainflow-counted damage.