在经受静态和循环加载的高度交联 UHMWPE 中，从临床相关的切口开始出现裂纹。
Crack initiation from a clinically relevant notch in a highly-crosslinked UHMWPE subjected to static and cyclic loading.
机构信息
Microsoft Hardware Group, One Microsoft Way, Redmond, WA 98052, United States.
Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH 44106, United States.
出版信息
J Mech Behav Biomed Mater. 2019 Mar;91:366-372. doi: 10.1016/j.jmbbm.2018.12.032. Epub 2018 Dec 28.
Crosslinked Ultra High Molecular Weight Polyethylene (UHMWPE), which is used as a bearing material in total joint replacement components, is subjected to static and cyclic loads in vivo. Resistance to crack initiation from a notch as a function of static and cyclic loads is not well understood for crosslinked UHMWPE. This study estimated the resistance of crosslinked UHMWPE (crosslinked with 100 kGy gamma radiation and remelted to extinguish free radicals) to crack initiation for a clinically relevant notch under both static and cyclic loading conditions. For cyclic loading, four frequencies were applied with a sine waveform and two frequencies were applied with a square waveform to independently estimate the effect of frequency and rate of loading on crack initiation. Crack initiation time and cycles to crack initiation were determined. Crack initiation time for fatigue loading conditions was substantially lower compared to static loading conditions. Crack initiation time decreased with an increase in test frequency. A square wave resulted in shorter crack initiation time compared to a sine wave. The results suggest that crosslinked UHMWPE is more resistant to crack initiation from a notch under static loading conditions compared to fatigue loading conditions.
交联超高分子量聚乙烯（UHMWPE）用作全关节置换部件的轴承材料，在体内受到静态和循环载荷的作用。对于交联 UHMWPE，其作为切口起始阻力的静态和循环载荷的功能尚未得到很好的理解。本研究评估了交联 UHMWPE（用 100kGy 伽马射线交联并重熔以消除自由基）在静态和循环加载条件下对临床相关切口起始裂纹的阻力。对于循环加载，应用了正弦波的四个频率和方波的两个频率，以独立估计频率和加载速率对起始裂纹的影响。确定了裂纹起始时间和裂纹起始循环数。与静态加载条件相比，疲劳加载条件下的裂纹起始时间大大降低。随着测试频率的增加，裂纹起始时间减少。与正弦波相比，方波导致较短的裂纹起始时间。结果表明，与疲劳加载条件相比，交联 UHMWPE 在静态加载条件下更能抵抗切口起始裂纹。
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