切欠の鈍い試験片における切欠引張強さ比とひずみ硬化指数の関係

Abstract

In order to develop the relationship between the notch strength ratio, defined as the notch tensile to tensile strength ratio, and the strain hardening exponent, the rate of increase in stress with elongation was investigated on the notched specimens associated with strain hardening ability of the materials. The plastic constraint resulting from strain localization due to low rate of strain hardening raised the stress-elongation curves distinctly. Hence, the stress increase rate increased with decreasing strain hardening exponent for the notched specimens with widely different notch acuity. The useful correlations were thus established to estimate the tensile load required to break the blunt notch specimens as well as the sharp notch specimens from strain hardening exponent.