陶瓷髋关节球头与臼杯分离引起边缘负载的动力学仿真模拟

Dynamic simulation of the edge load caused by the separation of the ceramic cup and femoral head

背景:关节分离引起的边缘负载接触造成极大的应力集中,进而产生大量磨损。髋关节分离引起的边缘接触是股骨头接触在臼杯边缘并快速滑进臼窝的动态过程,需要一个动态的接触力学模型。目的:建立陶瓷髋关节在分离状态下臼杯边缘负载接触的动态力学仿真模型,为髋关节边缘负载状态下的磨损分析提供接触力学基础,为假体设计以及医师手术提供理论依据。方法:结合Solid Works三维建模软件和ADAMS动力学仿真软件,建立陶瓷髋关节股骨头与髋臼杯发生动态边缘负载接触的动力学仿真模型,用数值方法对边缘负载接触变形进行验证,对臼杯外展角与初始分离距离对边缘负载接触的影响进行分析。结果与结论:(1)该模型所使用的接触刚度系数值合理有效,可以用来进行影响髋关节边缘负载接触的参数研究;(2)过大的臼杯外展角与初始分离距离会增加边缘负载接触的严重性;(3)研究表明,初始分离距离和臼杯外展角是影响边缘负载接触的两个重要因素。

BACKGROUND:The edge load contact caused by joint separation causes great stress concentration and then produces a large amount of wear.The edge contact caused by hip joint separation is a dynamic process of femoral head touching the rim of the acetabulum and sliding into the acetabulum quickly,so a dynamic contact mechanical model is needed.OBJECTIVE:To obtain the dynamic mechanical simulation model of ceramic acetabulum under the edge load contact,so as to provide the contact mechanics foundation for the wear analysis of hip joint under the condition of edge load,and provide theoretical basis for prosthesis design and surgeon operation.METHODS:By using 3D modeling software SolidWorks and dynamic simulation software ADAMS,edge load contact dynamics simulation model of ceramic femoral head and acetabular cup was established to verify the edge load contact deformation by numerical method.The effects of acetabular abduction angle and initial separation distance on edge load contact were analyzed.RESULTS AND CONCLUSION:(1)The contact stiffness coefficient used in the model is reasonable and effective.This model can be used to study the parameters that influence the edge load contact of hip joints.(2)The excessive cup inclination angle and initial separation distance will increase the severity of the edge load.(3)Acetabular cup inclination angle and initial separation distance are two important factors that affect the edge load contact.