複数き裂の相互作用を考慮したき裂進展シミュレーションによるき裂発生挙動の寿命へ与える影響の検討

抄録

Multiple cracks distributed in a plane affect one another in growth. This interference effect accelerates the crack growth. Some studies have developed the Monte-Carlo simulation models, which simulate the crack growth considering this interference 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 used a finite element mesh generator for distributing multiple cracks in a voluntary position 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 the failure 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.