不同材料赋值属性下髋关节有限元分析

Finite Element Analysis on the Hip with Different Material Assignment Properties

目的探讨3种不同建模方式对髋关节有限元模型生物力学特性的影响,研究出更符合实际的髋关节的材料属性赋值方法。方法对髋关节模型进行三维重建,分别采用皮-松质骨赋值法、均一赋值法和灰度赋值法完成材料参数赋值,设定相同的边界条件和载荷,模拟单腿站立位状态下髋关节受力情况,对比3组模型的髋关节应力和形变情况。结果3种不同建模方式下髋关节应力均集中于股骨颈内侧,皮-松质骨赋值法、均一赋值法、灰度值赋值法模型von Mises应力峰值分别为11.04、3.91、4.25 MPa。皮-松质骨赋值法模型最大形变位于股骨大粗隆上部,髋臼与股骨头处最大形变值为0.27 mm。均一赋值法模型及灰度值赋值法模型最大形变位于髋臼与股骨头处,最大形变值分别为0.11、0.12 mm。结论根据髋关节CT数据灰度值进行梯度赋值,使得髋关节模型材料属性分布更接近骨骼真实的材料属性。

Objective To investigate the effects of three different modelling approaches on biomechanical properties of the hip finite element model,and to investigate a more realistic method for assigning material properties to the hip joint.Methods The hip joint model was reconstructed in three dimensions,and the material parameters were assigned using the cortial bone and cancellous bone assignment method,the homogeneous assignment method and the gray value assignment method,respectively.The same boundary conditions and loads were set,the stress on hip joint during standing on one leg was simulated,and the stress and deformation of hip joint in three groups of models were compared.Results The hip stresses were concentrated in the medial femoral neck under three different modelling approaches,and the peak von Mises stresses were 11.04,3.91 and 4.25 MPa under the cortical bone and cancellous bone assignment method,the homogeneous assignment method and the gray value assignment method,respectively.The maximum deformation in hip model under cortical bone and cancellous assignment was at the upper part of the greater trochanter,with the maximum deformation value of 0.27 mm at the acetabulum and femoral head.The maximum deformation in hip model under the homogeneous material assignment method and the gray value assignment model was at the acetabulum and femoral head,with the maximum deformation values of 0.11 mm and 0.12 mm,respectively.Conclusions The gradient assignment based on gray value of the hip CT data makes material property distributions of the hip model closer to real material properties of the bone.