超弾性モデルに基づく結合力埋込型弾塑性損傷構成則を用いたボイドおよび破壊靭性値に関する不確実性評価

抄録

The contribution of this study is to assess dispersion of fracture toughness in ductile-brittle transition region due to interaction of uncertainties between ductile and brittle failure in a metallic material by cohesive traction embedded damage-like constitutive law based on hyperelastic model. For realizing the complex fracture behavior in the ductile-brittle transition region, the cohesive traction embedded damage-like material constitutive law, which has been proposed by combining Gurson-Tvergaard-Needleman (GTN) model with cohesive zone model, is extended into hyperelastic model. GTN model enables us to represent the shrink of the yield surface depending on the void volume fraction. On the other hand, the cohesive zone model realizes stress release process due to the brittle crack propagation after the stress reaches tensile strength. The probability distributions of the initial void volume fraction and the tensile strength are approximated by normal distributions. Several numerical examples demonstrate that our developed damage-like material constitutive law with stochastic collocation method enables us to predict the dispersion of the fracture toughness in the ductile-brittle transition region.