Study On New Design Methodology For Individual Hip-joint-prothesis Coupling System Optimization

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.