非弾性解析による弾性追従係数の算定方法の検討

抄録

For the components of Fast Reactor, the effect of the elastic follow-up during the stress relaxation by creep is considered in the creep-fatigue damage evaluation. When Primary stress is low, the elastic follow-up coefficient “q” is defined as equal to 3 in JSME standard. To expand the design criterion, this paper presented the concrete calculation method for the elastic follow-up coefficient “q_r” by inelastic analysis. The load cycle is set from the continuity of plant operation and the thermal transient conditions including the two time points related to strain range. The constitutive equation of elastic perfectly plastic model is applied in the elasto-visco-plastic analysis. Additionally, the applicability of the evaluation method was confirmed through the comparison of the creep damage. The creep damages by the evaluation method using ”q_r” were larger than those of actual stress relaxation by inelastic analysis. The former method was conservative against the actual behavior.