摘要
热疲劳裂纹网中主裂纹的应力强度因子可反映构件的损伤程度,然而由于裂纹间的屏蔽效应,直接计算裂纹网中主裂纹的应力强度因子是困难的。根据热疲劳试验提出假设:①主裂纹不会位于裂纹网的边缘;②裂纹网中的裂纹互相平行,且垂直于约束方向。定义主裂纹的屏蔽剩余百分数s,裂纹的比间距n,裂纹长度比f。分别研究两条长度相等裂纹、两任意长度裂纹、三条裂纹和多条裂纹屏蔽效应的规律。发现s-f-n有确定的关系,这一关系由裂纹网的结构确定,而与边界条件、裂纹尺寸等因素无关。利用屏蔽效应的规律可由单条裂纹时的应力强度因子推算裂纹网中屏蔽效应发生时主裂纹的应力强度因子。算例表明此方法精确、简便、快捷。
The stress intensity factor of the main crack in crack net can reflect the damage degree of components. However, it is difficult to calculate the stress intensity factor directly due to the shielding effect between cracks. It is supposed that the main crack cannot locate in the edge of the crack net, and the cracks in the net parallel to each other and perpendicular to constraint direction. The shielding residual percent s of main crack, the cracks＇ space ratio n and the crack length radio fare defined. The rule of shielding effect between two same length cracks, two random cracks, three cracks and multi-cracks is studied. The relation ofs-f-n is definitive, and it is independent of the boundary conditions, size of cracks and other factors. The stress intensity factor of main crack can be calculated by the factor of single crack by using this rule when shielding effect happens. The example shows that this method is accurate, simple, convenient and fast.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2009年第12期279-283,共5页
Journal of Mechanical Engineering
基金
总装备部预研资助项目(9140A19020206BQ0601)
关键词
热疲劳
裂纹网
应力强度因子
屏蔽效应
Thermal fatigue Crack net Stress intensity factor Shielding effect
