Wright T M, Hayes W C
J Biomed Mater Res. 1976 Jul;10(4):637-48. doi: 10.1002/jbm.820100420.
The purpose of this investigation was to apply the techniques of fracture mechanics to a study of fatigue crack propagation in compact bone. Small cracks parallel to the long axis of the bone were initiated in standardized specimens of bovine bone. Crack growth was achieved by cyclically loading these specimens. The rate of crack growth was determined from measurements of crack length versus cycles of loading. The stress intensity factor at the tip of the crack was calculated from knowledge of the applied load, the crack length, and the specimen geometry. A strong correlation was found between the experimentally determined crack growth rate and the applied stress intensity. The relationship takes the form of a power law similar to that for other materials. Visual observation and scanning electron microscopy revealed that crack propagation occurred by initiation of subcritical cracks ahead of the main crack.
本研究的目的是将断裂力学技术应用于致密骨疲劳裂纹扩展的研究。在牛骨的标准化标本中引发与骨长轴平行的小裂纹。通过对这些标本进行循环加载来实现裂纹扩展。裂纹扩展速率由裂纹长度与加载循环次数的测量值确定。根据所施加的载荷、裂纹长度和标本几何形状计算裂纹尖端的应力强度因子。实验测定的裂纹扩展速率与所施加的应力强度之间发现了很强的相关性。这种关系呈现出与其他材料类似的幂律形式。视觉观察和扫描电子显微镜显示，裂纹扩展是由主裂纹前方的亚临界裂纹引发的。
