Bootstrap analysis of FCGR, application to the Paris relationship and to lifetime prediction

Dealing with fatigue crack propagation, this paper aims to report on a statistical method to determine the coefficients C and n of the Paris relationship and the range along which the equation holds. The Probability Density Function (PDF) of those coefficients was calculated using a bootstrap technique. Then a 3-segment piece-wise linear regression FCGR was used to modelize the whole fatigue crack growth data. The statistical results are finally applied on a classical fracture mechanic problem to obtain the PDF lifetime prevision. The PDF lifetime obeys a Gaussian or lognormal PDF which depends on the variance of the initial crack's length. (C) 1999 Elsevier Science Ltd. All rights reserved.