A MICRO‐MECHANICS ANALYSIS FOR SHORT FATIGUE CRACK GROWTH
A MICRO‐MECHANICS ANALYSIS FOR SHORT FATIGUE CRACK GROWTH
复制标题
短疲劳裂纹扩展的微观力学分析
DOI：
--
复制
发表时间：
1985
期刊：
影响因子：
--
通讯作者：
K. Miller
中科院分区：
文献类型：
--
作者：
E. R. Rios;H. J. Mohamed;K. Miller
采用塑性复型和扭转加载方法研究了完全退火0.4%碳钢的疲劳裂纹萌生和早期扩展。
在由珠光体和铁素体的70/30混合物组成的组织中，可以看到裂纹最初沿着铁素体相中的滑移带发展和生长。精力充沛的考虑导致制定的模型，同时表征短裂纹扩展速率，也认为这些微观结构变量相关的疲劳裂纹萌生和早期裂纹扩展。裂纹扩展的驱动力由滑移带的能量提供;相应地，每个循环的裂纹扩展与滑移带的强度成比例。
在短疲劳裂纹区域，裂纹最初以快速速率生长，但减速迅速发生，并且取决于应力水平，它们在临界长度处停止或暂时停止。这个临界长度被证明是一致的裂纹扩展的阈值长度的值在LEFM条件下。
Crack initiation and early growth of fatigue cracks in a fully annealed 0.4% carbon steel was investigated using plastic replicas and torsion loading.
In a structure consisting of a 70/30 mixture of pearlite and ferrite the cracks are seen to develop and grow initially along slip bands in the ferrite phase. Energetic considerations lead to the formulation of a model which, while characterizing short crack growth rate, also considers those microstructural variables relevant to fatigue crack initiation and early crack growth. The driving force for crack growth is provided by the energy of the slip band; correspondingly crack growth per cycle is proportional to the strength of the slip band.
In the short fatigue crack region, cracks grow initially at a fast rate but deceleration occurs quickly and, depending on the stress level, they either arrest or are temporarily halted at a critical length. This critical length is shown to coincide with the value of the threshold length for crack growth under LEFM conditions.