延性薄板材一円孔変形形状の加工硬化指数による検討

概要

論文の詳細を見る
The growth of a circular hole in thin sheet material and its fracture mechanism were investigated with respect to its strain hardening exponent under a tensile test to obtain basic knowledge about a void growth and its fracture process in ductile material. The growth shape of the hole was measured exactly, and its deviation from an ellipse was found to be less than several percent. Their axial ratio and areal ratio increase almost linearly with the plastic strain before a crack is formed. The growth rate of d(a/b)/dε(a,b ; major and minor semi-axes of the ellipse, ε; strain) is shown to increase with a decrease in the strain hardening exponent. The growth rate is larger the bigger the pre-strain and, accordingly, the fracture strain is smaller the larger the latter. The results of the finite element method in a plane stress condition give good agreement with the experimental results. The theoretical relations for a plastic material by McClintock are also fairly consistent with the above results.
一般社団法人日本機械学会の論文
1986-05-25