压力容器接管区应变分布模拟试样(ECT)的低周疲劳裂纹扩展

摘要

设计了一种含局部减薄半椭圆缺口的紧凑拉伸试样(ECT),以模拟压力容器接管区结构,并对16MnR钢的ECT试样进行了不同应力比的恒幅低周疲劳裂纹扩展试验.结果表明:ECT试样具有类似压力容器接管区的高应变分布场;低周疲劳裂纹扩展速率与由线积分定义计算的循环J积分,△J在双对数坐标中呈良好线性相关,且回归的材料参数与相同材质的高周疲劳试验获得的Paris常数基本一致.%An especial compact tension (ECT) specimen with locally thinned elliptical notch was designed to simulate the structure at the junction of pressure vessel and nozzle, and the low cycle fatigue (LCF) crack growth in the new specimens of 16MnR steel during different load ratios was investigated. The results show that the characters of the strain distribution in ECT specimen are similar to that of vesselozzle junction. The values of cyclic J-integral, △Jj/i calculated from a path independent integral are seen to properly correlate well with LCF crack growth in ECT specimens during constant-amplitude loading, and it may describe LCF crack propagation directly using Paris' constants obtained by high cycle fatigue (HCF) tests.