【作者】 周峰；

【导师】 龚宪生；

【作者基本信息】 重庆大学 ， 机械设计及理论， 2010， 硕士

【摘要】 本文研究人造髋关节内置假体耦合系统优化新设计方法。假体置入人体后,其结构形态、几何尺寸、材料属性以及与股骨接触界面形式等因素与股骨的自适应重建存在动态的内在联系,假体和股骨等成为一个耦合动态系统。研究将把机械设计理论及方法、生物力学、机械动力学、骨生长重建理论、骨力学、材料学、最优化理论和方法及技术与医用CT技术、CAD和CAE技术和计算机可视化仿真理论及技术等结合起来,构建人造髋关节假体——股骨系统耦合动态数学和有限元仿真模型,在计算机可视化仿真中研究和探讨关节假体与股骨等耦合相互作用时,假体外部形状、结构形态、材料属性和几何尺寸等不同机械设计参数以及假体与股骨髓腔等部位的接触耦合形式对股骨生长重建的影响,在改变这些机械设计参数以及假体与股骨髓腔等部位接触耦合形式过程中来设计关节假体,这样设计的假体有利于股骨生长重建并形成稳定结合,以此建立关节假体耦合系统自适应优化新设计方法。本文的研究工作主要包括以下几个方面:①通过专业医学软件Mimics和CAD软件,运用以股骨CT图像数据为基础的图像处理与轮廓线提取技术,反求股骨计算机三维实体模型。②根据股骨CT图像数据,设计符合个体特征的个性化定制型髋关节假体。对定制型髋假体进行四套方案设计:四线法、中心线法、拉伸法和扫描法,并在髋假体设计好后进行虚拟置换,创建个性化髋关节假体耦合系统。③依据和利用股骨CT扫描数据和其表观密度以及弹性模量之间的关系,创建了接近股骨真实力学性能的有限元材料模型。④通过对有限元仿真计算和股骨加载实验的数据进行对比,不仅获得了自然生理状态下的股骨应力应变分布规律,且检验和改善前期建模及有限元分析工作。⑤对髋关节假体的静态、动态及疲劳特性进行研究。用四种方法设计的髋关节假体,与Charnley型常用假体进行比较分析。⑥采用非线性骨再造速率方程和有限元方法、Visual C++平台结合,引入拓扑优化思想,在个性化髋关节假体耦合系统中研究分析了不同物理参数的内置假体植入股骨髓腔后,对股骨重建的影响。从股骨单元细胞数目变化和应力应变分布入手,分析对比不同假体的结构形态、材料属性、几何尺寸和接触形式等参数对骨重建的影响。更多还原

【Abstract】 New design methodology for individual hip-joint-prosthesis coupling system optimization is studied in this thesis. After prosthesis is implanted, dynamic internal relationships between parameters, such as structural shapes, physical dimensions, material properties, contact interface forms with femur and so on, and femoral self-adaptive reconstruction exist. Therefore, the prosthesis and femur are integrated as a coupling dynamic system. This study combines mechanical design theory and method, biomechanics, mechanical dynamics, the theory of bone reconstruction, bone mechanics, material science, and optimization theory and method, with the technics of medical CT, CAD, CAE and computer visual simulation theory and technology, to construct dynamic mathematics and finite element simulation models of individual hip-joint-prosthesis coupling system. When the coupling interaction of joint prosthesis and femur, the effect of different mechanical design parameters, which include prostheses’structural shapes, physical dimensions, material properties, etc. and the contact coupling forms of prostheses with femoral medullary cavities, on femoral growth and reconstruction is studied and discussed in computer visual simulation. Then joint prostheses can be designed during the process of changing these mechanical design parameters and the contact coupling forms of prostheses with femoral medullary cavities. Therefore, the designed prostheses in this way are beneficial to bone growth and reconstruction, and to form stable integration. As a result, the new design methodology for individual hip-joint-prosthesis coupling system optimization can be established.To sum up, the primary study contents in this thesis are described as following:①Utilizing Mimics and CAD software, as well as the technics of processing images and picking up contour lines based on femoral CT images, the 3D solid computer model of femur is designed in reverse.②According to the CT images of the femur, design custom-made prostheses. Four methods which are four-line method, center-line method, stretching method and sweeping method are brought forward. After prostheses are designed, virtual assembly is done to construct individual hip-joint-prosthesis coupling system.③Utilizing the relationships between femoral CT data and apparent density, elastic modulus, the finite element material model of the femur which is more similar to real mechanical properties is reconstructed.④By comparing the results of finite element simulation calculation and the load experiment of the femur, the femoral stress-strain distribution under natural physiological condition is obtained, and checking up and improving the works, such as modeling and finite element analysis are also done.⑤Static, dynamic and fatigue behavior of hip-joint prostheses are studied. The prostheses are designed by four different methods, compared with that of a commonly used prosthesis developed by Charnley.⑥This study adopts the connection of nonlinear bone-reconstruction rate equation with finite element analysis method and Visual C++ platform, and introduces topology optimization thought, in order to analyze the effect of endoprostheses of different physical parameters which are implanted femoral medullary cavities, on femoral reconstruction. According to the number change of femoral unit cells, and stress-strain distribution, the effect of the different prostheses’structural shapes, material properties, physical dimensions, contact forms and so on, on bone reconstruction is compared and analyzed in the system.更多还原