切欠き形状の全範囲に対して正確な応力集中係数を与える計算式 : 円弧形および60°V形切欠きを有する帯板の面内曲げ試験片

In this work, stress concentration factors (SCFs) of a round bar with a circular-arc or V-shaped notch Kt are considered on the basis of exact solutions for special cases and accurate numerical results. First, for the limitting cases of deep and shallow notches, the body force method is used to calculate the SCFs ; then the formulas are obtained as Ktd and Kts. On the one hand, upon comparison of Kt and Ktd, it is found that Kt is nearly equal to Ktd if the notch is deep or blunt. On the other hand, if the notch is sharp or shallow, Kt is mainly controlled by Kts and the notch depth. The notch shape is classified into several groups according to the notch radius and depth ; then, the least squares method is applied for calculation of Kt/Ktd and Kt/Kts. Finally, a set of convenient formulas useful for any shape of notch in a round test specimen are proposed. The formulas yield SCFs with less than 1% error for any shape of notch.