A Study about Effect of Crack Initiation Behavior on Lifetime by Crack Growth Simulation under Considering the Interference Effect of Multiple Cracks
Masayuki KAMAYA
Abstract:Multiple cracks distributed in a plane affect one another in growth. This interference effect accelerates the crack growth. Some studies have developed theMonte-Carlo simulation models, which simulate the crack growth considering thisinterference effect of multiple cracks. In these studies, the interference effect of multiple cracks was considered by introducing a simple rule of crack coalescence or growth arrest in their growth process, which was determined by their relative location. In this study, a simulation model was developed, which considered this interference effect by using the finite element method. This model useda finite element mesh generator for distributing multiple cracks in a voluntaryposition over a plane. The mesh generator was able to evaluate J value of each crack tip considering the interference effect in every timely step, and crack growth rate of each crack was calculated with the evaluated J value. This simulation model enabled us to assess the interference effect of multiple cracks and thefailure condition accurately. With this simulation model, the effect of crack initiation behavior in a lifetime was examined, and the fact that increase of crack initiation accelerated the crack growth and reduced the lifetime under not only constant load condition but also constant strain condition were found. Furthermore, the crack length distribution showed the compound Weibull distribution form when the interference effect of multiple cracks acted to a great extend. Key Words:Multiple cracks, Finite element method, Crack initiation, Crack growth simulation, Crack length distribution