環状き裂を有する円筒の一次元温度分布下応力拡大係数簡易評価式

抄録

A simole equation to approximately calculate the stress intensity factor of the circumferential crack of cylinders under axisymmetric bending was derived first. By applying it, and equation to evaluate the stress intensity factor for the same crack under thermal stress distribution with practically sufficient accuracy was deduced theoretically. The latter equation is valid for arbitrary axisymmetric temperature distribution, which has its gradient in the radial direction. The effect of the length of the cylinder on the stress intensity factor can be evaluated by using the equation. Investigation of the characteristics of the stress intensity factor of cylinders under radial temperature distribution was conducted, by using the equation. It was shown that the stress intensity factor is in proportion to the'equivalent moment, 'which is calculated from the temperature distribution. In addition, for cylinders with practical dimensions such as R_m/W<20 (R_m : mean radius, W : thickness), the stress intensity factor showed a peak value with the increase of the crack length. The reason the stress intensity factor shows a peak value, was concluded to be because of the fundamental characteristics of the structure of the cylinder, which produces reaction force to close the crack.