Xiao Zhongmin, Wu Longfei, Wu Wenqiang, Tang Ruizhi, Dai Jietao, Zhu Dachang
School of Mechanical and Electrical Engineering, Guangzhou University, Guangzhou 510006, China.
Materials (Basel). 2023 Apr 17;16(8):3151. doi: 10.3390/ma16083151.
Hip replacement femoral implants are made of substantial materials that all have stiffness considerably higher than that of bone, which can cause significant bone resorption secondary to stress shielding and lead to severe complications. The topology optimization design method based on the uniform distribution of material micro-structure density can form a continuous mechanical transmission route, which can better solve the problem of reducing the stress shielding effect. A multi-scale parallel topology optimization method is proposed in this paper and a topological structure of type B femoral stem is derived. Using the traditional topology optimization method (Solid Isotropic Material with Penalization, SIMP), a topological structure of type A femoral stem is also derived. The sensitivity of the two kinds of femoral stems to the change of load direction is compared with the variation amplitude of the structural flexibility of the femoral stem. Furthermore, the finite element method is used to analyze the stress of type A and type B femoral stem under multiple conditions. Simulation and experimental results show that the average stress of type A and type B femoral stem on the femur are 14.80 MPa, 23.55 MPa, 16.94 MPa and 10.89 MPa, 20.92 MPa, 16.50 MPa, respectively. For type B femoral stem, the average error of strain is -1682με and the average relative error is 20.3% at the test points on the medial side and the mean error of strain is 1281με and the mean relative error is 19.5% at the test points on the outside.
髋关节置换股骨植入物由大量材料制成，这些材料的刚度均远高于骨骼，这可能会因应力屏蔽导致显著的骨吸收，并引发严重并发症。基于材料微观结构密度均匀分布的拓扑优化设计方法可形成连续的力学传递路径，能更好地解决降低应力屏蔽效应的问题。本文提出了一种多尺度并行拓扑优化方法，并推导了B型股骨干的拓扑结构。同时，使用传统拓扑优化方法（带惩罚的实体各向同性材料，SIMP）推导了A型股骨干的拓扑结构。将两种股骨干对载荷方向变化的敏感度与股骨干结构柔度的变化幅度进行了比较。此外，采用有限元方法分析了A型和B型股骨干在多种工况下的应力。模拟和实验结果表明，A型和B型股骨干在股骨上的平均应力分别为14.80MPa、23.55MPa、16.94MPa以及分别为10.89MPa、20.92MPa、16.50MPa。对于B型股骨干，在内侧测试点处应变的平均误差为 -1682με，平均相对误差为20.3%，在外侧测试点处应变的平均误差为1281με，平均相对误差为19.5%。
