ローカルアプローチの適用による構造用綱の動的破壊靭性評価 : 破壊制御設計へのローカルアプローチの展開(第3報)

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Fracture toughness of high strength steels of 490 MPa strength class under dynamic loading has been evaluated on the basis of the Local Approach. The critical CTOD at brittle fracture initiation decreases generally with increasing the loading rate. This is due to the elevation of a local stress near the crack tip at high rates of loading. The test temperature also exerts an influence on the critical CTOD. By contrast, it has been shown that the brittle fracture resistance evaluated in terms of the Weibull stress, an integrated stress over a highly stressed region near the crack tip, would be a material property independent of the loading rate and test temperature. Using the Weibull stress, the dynamic fracture toughness can be predicted from static toughness results at a given temperature. Predicted results of dynamic toughness of high strength steels were almost consistent with experimental data. For the characterization of flow properties of materials under different loading rates and temperatures, the rate-temperature parameter proposed by Bennett and Sinclair was useful.
社団法人日本船舶海洋工学会の論文