压力容器高应变区应变疲劳裂纹扩展试验研究

An Experimental Research on the Strain Fatigue Crack Propagation in High-strain Region of Pressure Vessels

针对压力容器几何结构不连续高应变区断裂和疲劳破坏特点,本文通过对应变循环条件下疲劳裂纹扩展影响因素和控制参量的理论分析,提出将ΔJ作为应变循环条件下疲劳裂纹扩展速率的控制参量,并在EPRI弹塑性断裂分析工程方法基础上,提出了ΔJ的工程计算方法,并通过模拟应变疲劳裂纹扩展的SCT试样试验,验证了ΔJ工程计算方法的可靠性.根据SCT试样应变疲劳裂纹扩展试验研究结果,在考虑了压力容器高应变区几何形状和材质变化对应变疲劳裂纹扩展参量影响后,提出了一种压力容器高应变区应变疲劳裂纹扩展速率工程估算方法.

With respect to the characteristics of fracture and fatigue failure for the high-strain region of pressure vessels containing geometrical discontinuities, it is proposed that ΔJ may be taken as the control parameter for the propagation rate of fatigue cracks under strain cycling condition, and the engineering calculation method for ΔJ is proposed based on EPRI′s method. The reliability of ΔJ calculation is verified by a test with the special CT specimen (SCT). According to the research results, an engineering estimation method for propagation rate of strain fatigue cracks in high strain region of pressure vessel is established.