Connelly G M, Rimnac C M, Wright T M, Hertzberg R W, Manson J A
J Orthop Res. 1984;2(2):119-25. doi: 10.1002/jor.1100020202.
The relative fatigue crack propagation resistance of plain and carbon fiber-reinforced ultrahigh molecular weight polyethylene (UHMWPE) was determined from cyclic loading tests performed on compact tension specimens machined from the tibial components of total knee prostheses. Both materials were characterized by dynamic mechanical spectroscopy, X-ray diffraction, and differential scanning calorimetry. The cyclic tests used loading in laboratory air at 5 Hz using a sinusoidal wave form. Dynamic mechanical spectroscopy showed that the reinforced UHMWPE had a higher elastic storage modulus than the plain UHMWPE, whereas X-ray diffraction and differential scanning calorimetry showed that the percent crystallinity and degree of order in the crystalline regions were similar for the two materials. Fatigue crack propagation in both materials proved to be very sensitive to small changes in the applied cyclic stress intensity range. A 10% increase in stress intensity resulted in approximately an order of magnitude increase in fatigue crack growth rate. The fatigue crack propagation resistance of the reinforced UHMWPE was found to be significantly worse than that of the plain UHMWPE. This result was attributed to poor bonding between the carbon fibers and the UHMWPE matrix and the ductile nature of the matrix itself.
通过对全膝关节假体胫骨部件加工而成的紧凑拉伸试样进行循环加载试验，测定了普通超高分子量聚乙烯（UHMWPE）和碳纤维增强超高分子量聚乙烯的相对疲劳裂纹扩展阻力。两种材料均通过动态机械光谱、X射线衍射和差示扫描量热法进行表征。循环试验在实验室空气中以5Hz的正弦波形加载。动态机械光谱表明，增强型UHMWPE比普通UHMWPE具有更高的弹性储能模量，而X射线衍射和差示扫描量热法表明，两种材料的结晶度百分比和结晶区域的有序度相似。两种材料中的疲劳裂纹扩展都被证明对施加的循环应力强度范围的微小变化非常敏感。应力强度增加10%会导致疲劳裂纹扩展速率增加大约一个数量级。发现增强型UHMWPE的疲劳裂纹扩展阻力明显低于普通UHMWPE。该结果归因于碳纤维与UHMWPE基体之间的粘结不良以及基体本身的韧性。
