Statistical Analysis of Fatigue Failure Due to Flow Noise Excitations

The power spectrum of the stress induced by a narrow-band (vortex shedding) and broad-band (impingement, near field) flow noise on a simply supported square plate is used to determine the fatigue failure probability of that plate. A lognormal distribution of the material properties and a Rayleigh distribution of the stress peaks are implied in the statistical model. The Poisson failure rate and reliability are computed for several crack propagation factors and statistical distributions of the initial strength of materials. The plate fatigue lifetime obtained by statistical analysis is generally shorter than the one given by a deterministic Palmgren-Miner cumulative model for narrowband and broad-band excitations. The two models predict similar fatigue lifetime for cases corresponding to small initial material cracks or low rates of crack propagation.