Probabilistic elastic-plastic fracture mechanics analysis based on the R6 methodology

Abstract

An analysis is presented for calculating elastic-plastic failure probabilities. The approach is unified so that linear elastic and plastic collapse failures are covered by the same procedure. The main statistical variables considered are fracture toughness, flow stress and defect size. The analysis allows a sophisticated modelling of the failure process to be performed. A method is presented for calculating the service failure probability for a structure following a successful proof test. The method is general and may include the possibility of a change in dominant failure mode between plastic collapse and fast fracture as a result of crack growth, thermal stressing, radiation and temperature changes. Separate sections cover the basic analysis, the effect of prior loading and the effect of work hardening. The basic analysis includes a simple technique for determining the fit parameters for candidate materials property distributions. In each section a description of the technique is followed by a detailed numerical example.