各種構造用材料のボイド発生・成長挙動に注目した延性き裂発生特性に関する考察

概要

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The importance of investigations of ductile crack initiation characteristics increases in the evaluation of the structure of integrity and the plastic forming of metal materials. A lot of examinations shout ductile crack initiation behavior for ferrite-pearlite steels have been carried out. However, for other structural materials, enough examination has not necessary been carried out. In this study, ductile crack initiation characteristics of SM 490 A, stainless steel SUS 316, high tension steel HT 950 and aluminum alloy A 5083(O) have been investigated by using notched round bar specimens. Dynamic tensile test has also been conducted for SUS 316. And the critical equivalent plastic strain as a function of the stress triaxiality at ductile crack initiation has been estimated by using FE analyses (ABAQUS ver. 5.7). The ductile crack initiation is triggered by the microvoid nucleation for SUS 316 and HT 950, and it was controlled by the void growth for SM 490 A and A 5083(O). The influence of stress triaxiality to critical equivalent plastic strain varies in the material. That relates to the process of ductile crack initiation of the material. The microvoid nucleation is seemed to be affected by stress triaxiality more strongly than the void growth.
社団法人日本船舶海洋工学会の論文