Endoprosthesis topological optimization mathematical model construction method and topological optimization design method

Abstract

The invention discloses an endoprosthesis topological optimization mathematical model construction method and a topological optimization design method, and relates to the technical field of orthopedicprostheses. The endoprosthesis topological optimization mathematical model construction method comprises the steps: calculating reference strain energy, calculating the sum of the strain energy, calculating normalized strain energy, establishing the maximum material retention rate and the maximum normal form stress of an endoprosthesis, calculating the average material retention rate of all unitsand the maximum value of the stress of geometric centers of all finite element units in a prosthesis containing area; and establishing and enabling the partial derivative of the normalized strain energy by a stiffness matching function to be zero to obtain a value of a weighting factor, substituting the value into the stiffness matching function, and establishing a topological optimization mathematical model. Healthy bones are used as reference of prosthesis design, the stiffness of the prosthesis is controllably adjusted to be close to reference strain energy by utilizing a weighting factorand an increase and decrease function, extreme value regulation and control of an optimization model function are realized by utilizing the mutual consumption effect of the increase and decrease function, so that convergence is stable, an optimal solution is conveniently obtained, and application of actual engineering is facilitated.

Description

technical field [0001] It relates to the technical field of orthopedic prosthesis. Background technique [0002] Bone injury is a type of orthopedic disease caused by congenital bone abnormalities or acquired factors. Bone replacement reconstruction surgery is often an effective means of treating bone injuries. Common bone replacement prostheses include autologous bone, allogeneic bone, and artificial endoprosthesis. Although autologous bone grafting has a good bone fusion effect, it has the disadvantages of limited bone source and easy secondary trauma to patients; it is difficult to heal after implantation of allograft bone and there is a risk of infection; with the development of science and technology, artificial The clinical application of endoprosthesis is more and more extensive, especially metal endoprosthesis. [0003] Metal endoprosthesis has high strength, good biocompatibility and fatigue resistance, but the elastic modulus of metal (such as titanium alloy, stai...

AI Technical Summary

Problems solved by technology

The topology optimization design with the maximum stiffness as the objective function has the characteristics of simple mathematical expression, easy sensitivity solution, and good convergence of the optimization process. It needs to be achieved by minimizing the amount of material used. Obviously, taking the maximum stiffness as the objective function is not only contradictory to minimizing the stiffness of the prosthesis so that it is close to the stiffness of the healthy bone, but also leads to a poor match between the stiffness of the prosthesis and the stiffness of the surrounding healthy bone.

If the topology optimization design with the minimum stiffness as the objective function does not have a unique optimal solution, it is difficult to converge in theory, that is, it is difficult to obtain the optimal solution, so it is difficult to be practically applied in engineering

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