PROBABILISTIC FATIGUE LIFE PREDICTION USING ULTRASONIC INSPECTION DATA CONSIDERING EIFS UNCERTAINTY

摘要

A method for probabilistically predicting fatigue life in materials includes sampling a random variable for an actual equivalent initial flaw size (EIFS), generating random variables for parameters (ln C, m) of a fatigue crack growth equation  a  N = C  ( Delta   K ) m from a multivariate distribution, and solving the fatigue crack growth equation using these random variables. The reported EIFS data is obtained by ultrasonically scanning a target object, recording echo signals from the target object, and converting echo signal amplitudes to equivalent reflector sizes using previously recorded values from a scanned calibration block. The equivalent reflector sizes comprise the reported EIFS data.