軸方向温度分布移動を受ける円筒の熱ラチェット解析 移動硬化則の影響

Abstract

When a cylinder is subjected to a temperature front moving cyclically in the axial direction, the circumferential plastic strain may accumulate with the increase of the number of cycles. This is a thermal ratchetting problem induced by a liquid surface moving in a cylinder, and it is important especially in designing fast breeder reactors. In the present paper, the effect of kinematic hardening rule on the thermal ratchetting analysis is discussed by implementing the following four kinds of kinematic hardening rules in a finite element analysis; the perfectly plastic model (PP), the linear kinematic hardening rule (LKH), the classical nonlinear kinematic hardening rule of Armstrong and Frederick (AF), and the rule proposed recently by Ohno and Wang (OW). It is shown that disregard of transient hardening after yieding leads to overstimating the thermal ratchetting, that a rule predicting larger mechanical rathcetting under uniaxial cyclic loading makes the thermal ratchetting more serious, and that the Ohno and Wang rule can render the analysis most realistic among them.