CAJ | 학술논문

基于增量步和成组法低周疲劳试验，研究了1Cr18Ni9Ti不锈钢管道焊缝金属在240℃下的循环变形行为。结果表明，材料为循环软化材料，具有轻微Non-masing行为特征。相同总应变范围的循环应力-应变(CSS)行为存在很大分散性，意味着任何外载，即使恒幅载荷也将导入一个随机应变载荷史，现有确定性方法可能导致偏于危险的设计分析，有必要引入概率方法表征材料的循环变形行为。基于验证的应力幅统计分布——正态分布，建议了概率Ramberg-Osgood CSS曲线的描述方法。文中试验结果分析验证了方法的有效性。
기우증량보화성조법저주피로시험，연구료1Cr18Ni9Ti불수강관도한봉금속재240℃하적순배변형행위。결과표명，재료위순배연화재료，구유경미Non-masing행위특정。상동총응변범위적순배응력-응변(CSS)행위존재흔대분산성，의미착임하외재，즉사항폭재하야장도입일개수궤응변재하사，현유학정성방법가능도치편우위험적설계분석，유필요인입개솔방법표정재료적순배변형행위。기우험증적응력폭통계분포——정태분포，건의료개솔Ramberg-Osgood CSS곡선적묘술방법。문중시험결과분석험증료방법적유효성。
An experimental study on the cyclic deformation behaviour of a nuclear engineering material, 1Crl8Ni9Ti stainless steel pipe-weld metal, is performed on a basis of incremental step test and group test of low-cycle fatigue under temperature of 240℃. The results reveal that this material is a cyclic softening material and it exhibits a non-Masing behaviour. In addition, the cyclic stress-strain (CSS) responses under a same load show a significant scatter. This implies that a stochastic applied strain history should be introduced under any of loading modes even a deterministic loading history and the previous deterministic characterization to the CSS behaviour might give a non-conservative evaluation of design. Therefore, it is necessary to introduce a probabilistic description. Based on a statistical analysis result that the normal distribution can give an appropriate description to the cyclic stress amplitudes of present material, probability-based Ramberg-Osgood CSS curves are suggested to characterizing the stochastic CSS behaviour. Availability of this characterization has been verified by the analysis of present test data.