摘要
本文针对压力容器接管部位高应变区的特点,试用一种双面开键形槽的三点弯曲试件模拟其特征,其中以弹塑性断裂参量CTOD(δ)作为控制该区内裂纹疲劳扩展的主要参量,并采用双引伸计法动态测量CTOD.试验结果表明:在循环载荷作用下,高应变区在亚临界裂纹扩展范围内,疲劳裂纹扩展速率(da)/(dN)在双对数坐标上与裂纹尖端的张开位移△CTOD(△δ)呈线性关系:△CTOD可以作为控制高应变区应力循环和应变循环条件下,疲劳裂纹扩展速率的力学参量,且与(da)/(dN)呈Paris定律的形式.
To counter the characters of high strain region in nozzle of pressure vessel,a new kind of three point crooked specimen——double edged and shaped of keyway——is used to imitate the feature. The CTOD is used to describe the fatigue crack propagation rate and is determined by means of dual clip-in gauge. The tests reported here show the results of the linear relation between fatigul crack propagation rate (da)/(dN) △CTOD on the double logarithmic coordinate.The △CTOD is a valid mechanics parameter to control the fatigue crack propagat ion rate in high strain region about the cycle of stress and starin and is the form of Paris formula with (da)/(dN).
关键词
压力容器
疲劳裂纹
高应变区
CTOD
CTOD
fatigne crack
crack Propagation
high strain, dual clip-in gauge
