Estimation study of structure crack propagation under random load based on multiple factors correction

Abstract

As the phenomenon of fracture damage is a common failure mode of equipment, the reliability evaluation and residual life prediction have become a hot-spot. And the precise estimation of crack propagation has become necessary. The common estimation study of crack propagation for structure under random load takes less influence factor into consideration, and cannot be quantitatively corrected by influence factors at the same time. An estimation approach of structure crack propagation is raised by combining the estimation approach of fatigue life, based on multiple factors correction with the threshold criterion of opening stress and closure stress. And the crack propagation of instance structure under the loading spectrum of single-peak overloading and the loading spectrum of multi-peak overloading are estimated. Also, the results estimated by corrected estimation approach are compared with the results estimated by fracture mechanics and the test data using acoustic emission device. Further, the probabilistic method based on Weibull distribution is selected as the statistical framework to evaluate the precision of corrected estimation approach. And the probability density of results estimated by corrected approach and results estimated by fracture mechanics is calculated by the probability density function. It can be shown from the comparisons that the result estimated by the corrected approach is more precise than the result estimated by fracture mechanics, which is more close to the test data.