摘要
本文讨论了负超载对Al-2024铝合金材料疲劳裂纹扩展的影响,试验发现在大量负超载循环周次之后也有裂纹停滞现象发生。这种停滞现象的产生与剪切唇的形成有关。本文发现负超载期间的剪切唇(简称剪切唇Ⅰ)和负超载之后的剪切唇(简称剪切唇Ⅱ)对疲劳裂纹扩展速率影响的程度不同。从裂纹闭合的观点建立了负超载对疲劳裂纹扩展影响的计算模型。
Fatigue test with a large number of underloading were performed. Fatigue crack growth delay after the action of underloading was found. The delay was correlated to the development of shear lips on the crack surface. It was found that in stage one (during underloading) and in stage two (after underloading) the effect of shear lips on fatigue crack growth was different. The effect of the shear lips was much stronger in stage two than in stage one. A calculation model of fatigue crack growth including the effect of underloading was suggested based on the crack closure concept.
出处
《力学学报》
EI
CSCD
北大核心
1993年第2期232-236,共5页
Chinese Journal of Theoretical and Applied Mechanics
关键词
疲劳裂纹
负超载
裂纹扩展
铝合金
fatigue crack growth, underloading, shear lip, crack closure, fatigue test
