材料の機械的特性からの延性亀裂進展抵抗予測手法

抄録

The aim of this study is to propose the prediction approach of ductile crack growth resistance of cracked component with steels, based on ductile crack growth simulation using only mechanical properties of material obtained from tensile test for a round-bar specimen. Ductile crack growth was simulated in accordance with nonlinear damage accumulation model with stress triaxiality dependency of critical strain derived from void growth analyses of unit cell. In terms of simplicity, the prediction formula of the stress triaxiality dependency of critical strain using mechanical properties of material was proposed in this paper. In order to confirm the applicability of proposed prediction approach, ductile crack growth simulations were performed with elasto-plastic finite element analyses implementing nonlinear damage accumulation model using tensile test result for a round-bar specimen. As a result, it was found that ductile crack growth resistance could be predicted with high accuracy by the proposed approach. In addition, it was confirmed that the proposed approach was also applicable to steels with different mechanical properties and could reproduce the effect of plastic constraint related to specimen dimension to ductile crack growth resistance.