ISSN   1004-0595

CN  62-1224/O4

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皮质悬吊装置和股骨间微动磨损有限元分析

Finite Element Analysis of Fretting Wear between the Cortical Suspension Device and the Cortical Bone

  • 摘要: 研究了皮质悬吊装置的钛板和股骨表面的皮质骨承受交变载荷发生的微动行为. 基于钛/皮质骨材料建立了球/平面微动磨损有限元模型,通过与Hertz接触理论和已有试验结果进行对比,验证了有限元方法的正确性;同时研究了位移幅值、摩擦系数和法向力对钛球/皮质骨接触面间微动磨损行为的影响. 最后把已验证的模型和方法用于研究前交叉韧带(ACL)重建手术中的皮质悬吊装置和股骨间的微动磨损情况. 发现随着微动位移幅值从2 μm增大至10 μm,磨损状态由部分滑移向完全滑移转变,最大磨损深度由0.195 μm逐渐增大至14.13 μm,磨损体积由5.69×104 μm3增大至1.41×106 μm3;在位移幅值为5和10 μm时,磨损深度、磨损面积和磨损体积都表现出随摩擦系数增大而减小的趋势;在位移幅值为5 μm时,磨损深度随法向力的增加逐渐减小,在位移幅值为10 μm时,磨损深度随法向力的增加逐渐增大. 通过研究交变载荷下皮质悬吊装置/皮质骨微动磨损模型的微动磨损行为发现:磨损深度最大值在皮质骨隧道孔边缘的应力最大值处,并且与球/平面微动磨损模型预测趋势相同,可以通过增加皮质悬吊装置和皮质骨隧道孔边缘接触面间的摩擦系数来提高皮质骨的抗微动磨损能力,提高ACL重建手术成功率.

     

    Abstract: Anterior cruciate ligament (ACL) requires ACL reconstruction after rupture because of its inability to regenerate. Cortical suspension device is one of the most common fixation devices for ACL reconstruction at the femoral. The purpose of this paper was to study the fretting wear behavior of the cortical suspension device. Considering the fretting behavior of contact surfaces between the titanium plate in the cortical suspension device and the cortical bone of the femur due to the alternating load, the finite element method for the fretting wear of titanium/cortical bone was proposed, and the fretting wear behavior between the cortical suspension device and the femoral surface was predicted by this method. Firstly, the ALE adaptive mesh and the UMESHMOTION subroutine in the ABAQUS finite element software and the Archard model were used to establish a ball/plane fretting wear model of titanium/cortical bone material. And the correctness of the finite element method had been verified by comparing with results of Hertz contact theory and experiment. The effects of displacement amplitude, friction coefficient and normal force on the fretting wear were researched. Finally, a titanium plate/cortical bone fretting wear model was established using validated models and methods to study the fretting wear behavior between the cortical suspension device and the femur. By studying the fretting wear behavior of the ball/plane fretting wear model, it was found that with the increase of fretting displacement amplitude from 2 μm to 10 μm, the wear state gradually changed from partial slip to complete slip; the wear depth increased from 0.195 μm to 14.13 μm and the wear volume increased from 5.69×104 μm3 to 1.4×106 μm3. The wear depth decreased from 8.38 μm to 2.17 μm and the wear state changed from complete slip to partial slip with the increase of the friction coefficient from 0.3 to 0.7 when the displacement amplitude was 5 μm; the wear depth decreased from 15.25 μm to 10.96 μm and the wear state was in complete slip when the displacement amplitude was 10 μm. With the increase of the normal force from 40 N to 120 N, the wear depth decreased from 6.06 μm to 2.71 μm and the wear state changed from complete slip to partial slip when the displacement amplitude was 5 μm. However, the wear depth increased from 10.9 μm to 15.2 μm and the wear state was in complete slip when the displacement amplitude was 10 μm. By studying the fretting wear behavior of the titanium/cortical bone fretting wear model under alternating load, it was found that the wear was at the edge of cortical bone tunnel hole and the maximum CPRESS stress was. As the friction coefficient increases from 0.3 to 0.7, the wear depth gradually decreased from 12.6 μm to 4.4 μm, which was the same as the prediction trend of ball/plane fretting wear model. By increasing the friction coefficient between the cortical suspension device/cortical bone tunnel hole edge contact surface, the anti-fretting capacities of cortical bone could be improved, which could improve the success rate of ACL reconstruction.

     

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