臺灣博碩士論文加值系統

Locked compression plates (LCP) have been widely used for a diaphyseal femoral fracture treatment and showed an improved fixation in osteoporotic bone. The clinical experiences have been used to investigate the fixation stability of the bone by considering several numbers and positions of the screws in the twelve-hole LCP. In fact, there are a lot of possible locations which can be placed in the plate holes. As an example, for six screws in the twelve-hole plate, there would be 924 possible locations of the screws. The purpose of this study is to discover the best screw configurations in the twelve-hole bone plate within two finite element (FE) models. A novel biomechanical optimization method namely Finite Element Analysis (FEA)-based Discrete Particle Swarm Optimization (DPSO) was used to find the optimum design.
The results showed that increasing the number of screws decreased the motion of the constructs, and the performance of three screws per main segment shows no about significant different, compared to all screws occupied the plate hole, this lead to a conclusions that the stability can be achieved by increasing the number of screws and three screws on either of the fracture provide sufficient stability while minimizing the complications of plate fixation. Moreover, this method is flexible and can be applied to various FE models with certain defined boundary and loading conditions.

ABSTRACT ....................................................................................................................... i
CONTENTS ...................................................................................................................... ii
LIST OF FIGURES .......................................................................................................... iii
LIST OF TABLES ........................................................................................................... iv
Chapter I INTRODUCTION ............................................................................................ 1
1.1 Motive .................................................................................................................. 1
1.2 ANSYS Parametric Design Language ............................................................... 3
1.3 Standard Particle Swarm Optimization .............................................................. 3
1.3.1 PSO’s Algorithm ......................................................................................... 4
1.3.2 The Parameters of PSO ............................................................................. 10
1.3.3 Constraint Handling .................................................................................. 11
1.4 Literatures Review ............................................................................................ 13
1.5 Structure of Dissertation ................................................................................... 21

Chapter II MATERIALS AND METHODS ................................................................. 22
2.1 Finite Element Analysis .................................................................................... 22
2.1.1 Preprocessing ............................................................................................. 23
2.1.1.1 Modeling..................................................................................... 23
2.1.1.2 Meshing ...................................................................................... 26
2.1.1.3 Applying Boundary Conditions ................................................ 27
2.1.2 Solution Phase ........................................................................................... 32
2.1.3 Post-Processing Phase ............................................................................... 32
2.2 Discrete Particle Swarm Optimization (DPSO) .............................................. 32
2.2.1 Design Variables........................................................................................ 35
2.2.2 DPSO’s Algorithm .................................................................................... 37
2.2.3 Parameters of DPSO .................................................................................. 40
Chapter III RESULTS ..................................................................................................... 41
3.1 Historical Results of DPSO .............................................................................. 41
3.1.1 Optimization Results for Simple Model .................................................. 41
3.1.2 Optimization Results for Femur Model .................................................. 54
3.2 Displacement Results ........................................................................................ 68

Chapter IV DISCUSSION .............................................................................................. 75

Chapter V CONCLUSIONS AND FUTURE WORKS ............................................... 78
5.1 Conclusions........................................................................................................ 78
5.2 Future Works ..................................................................................................... 79

APPENDIX A.................................................................................................................. 80

APPENDIX B .................................................................................................................. 84

REFERENCES ................................................................................................................ 85

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