OS2607 切欠き強度推定に及ぼす応力集中係数の精度の影響(OS26-2 西谷弘信セッション2,OS-26 西谷弘信セッション)

抄録

Stress concentration of V-shaped notches in round bar under bending is important especially for the test specimen used to investigate the mechanical properties of materials. For notched bars, Neuber proposed simple approximate formula K_<tN> useful for wide range of notch shape: 1/(K_<tN>-1)^m=1/(K_<ts>-1)^m+1/(K_<td>-1)^m and M=2. Here, K_<ts> and K_<td> are exact solution for shallow and deep notches, respectively. Previous study, by applying the least squares method to the ratio K_t/K_<tN> accurate formulae is proposed. The formulae proposed in previous paper is found to give the stress concentration factors K_t with better than 1% accuracy. In this study, first, the error of K_<tN> and K_t are considered. Next, the fatigue strength σ_<w1>, σ_<w2> used to K_<tN> and K_t is calculated. Finally, effect of accuracy K_<tN> and K_t on the estimate of σ_<w1>, σ_<w2> are considered, respectively.