Caler W E, Carter D R
Mechanical Engineering Department, Stanford University, CA 94305.
J Biomech. 1989;22(6-7):625-35. doi: 10.1016/0021-9290(89)90013-4.
Creep and fatigue tests were performed on human femoral cortical bone and the results were compared to a cumulative damage model for bone fracture. Fatigue tests in tension, compression, and reversed loading with a tensile mean stress were conducted at 2 Hz and 0.02 Hz. Load frequency had a strong influence on the number of cycles to failure but did not influence the total time to failure. Bone displayed poor creep-fracture properties in both tension and compression. The fracture surfaces of the tensile creep specimens are distinctly different than those of the compressive specimens. The results suggest that tensile cyclic loading creates primarily time-dependent damage and compressive cyclic loading creates primarily cycle-dependent damage. However, data for load histories involving both tensile and compressive loading indicate lower time to failure than predicted by a simple summation of time-dependent and cycle-dependent damage.
对人体股骨皮质骨进行了蠕变和疲劳试验，并将结果与骨折累积损伤模型进行了比较。在2Hz和0.02Hz下进行了拉伸、压缩以及带有拉伸平均应力的反向加载疲劳试验。加载频率对失效循环次数有很大影响，但对失效总时间没有影响。骨在拉伸和压缩时均表现出较差的蠕变断裂性能。拉伸蠕变试样的断口与压缩试样的断口明显不同。结果表明，拉伸循环加载主要产生与时间相关的损伤，压缩循环加载主要产生与循环相关的损伤。然而，涉及拉伸和压缩加载的载荷历史数据表明，失效时间比通过简单累加与时间相关和与循环相关的损伤所预测的时间要短。
