Eden O R, Lee A J C, Hooper R M
Department of Engineering, University of Exeter, UK.
Proc Inst Mech Eng H. 2002;216(3):195-9. doi: 10.1243/0954411021536405.
This paper describes tests that were carried out to model the stress relaxation behaviour of polymethylmethacrylate (PMMA) bone cement. Stress relaxation of bone cement is believed to be a significant factor in the mechanism of load transfer in the femoral stem of a polished, collarless taper-fit replacement hip joints. It is therefore important that this condition and its implications are understood. Stress relaxation was carried out on PMMA samples of varying age in four-point bending configuration. It was shown that the samples stiffened with age and that the amount of stress relaxation reduced as the samples aged. The experimental results of the stress relaxation were accurately modelled on the double exponential of the Maxwell model so that long-term predictions of the stress condition could be made from short-term mechanical tests.
本文描述了为模拟聚甲基丙烯酸甲酯（PMMA）骨水泥的应力松弛行为而进行的测试。骨水泥的应力松弛被认为是无颈抛光锥柄型人工髋关节股骨柄载荷传递机制中的一个重要因素。因此，了解这种情况及其影响很重要。在四点弯曲配置下，对不同老化程度的PMMA样本进行了应力松弛测试。结果表明，样本随着老化而变硬，且应力松弛量随着样本老化而减少。应力松弛的实验结果通过麦克斯韦模型的双指数函数得到了精确模拟，从而可以根据短期力学测试对长期应力状况进行预测。
