平面応力平面ひずみ混在状態での切欠き先端近傍のひずみ分布

Abstract

Notched plates of 3%Si-Fe, 0.04%C steel and 7075-T6 Al alloy were stretched, and the distributions of longitudinal and in-thickness strains, εy and εz, were measured in the vicinity of notch tips. The results of strain distributions were explained using the analytical results of near-tip deformation for non-linear elastic materials, combined with a simple model of the plastic state under a mixed plane stress and plane strain condition.The main results were, summarized as follows:(1) The distribution of in-thickness strain, εz, ahead of the notch tip was divided into three regions designated by region I, II and III. In region I, the width of the plane strain region decreased linearly with the distance, x, from the notch tip. The strain distribution in region II had a singularity of -1/(1+n) th power of x.(2) The distribution of longitudinal strain, εy, ahead of the notch tip was divided into region I, II, III and IV. The strain value in region I was under a direct influence of the notch. The strains in region II and IV were proportional to -1/(1+n) th power of x. The region III was identified as a transition region from region II to IV.