| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 101 === Osteosynthesis plates have been used to treat various types of fracture in surgical operation. Locking plate can provide more stability than traditional dynamic compression plate because its locking screw can lock on plate by threaded hole . However, the notch of thread geometry often produces stress concentration that decreases the fatigue life of components. There are various materials with different notch-sensitivity that resulted the different effect on fatigue life. Thus the purpose of this study was to investigate the mechanical property of locking plate with different materials and thread design.
In biomechanical testing, both the yielding test and fatigue test were performed. In finite element analysis, a 3D finite element model was carried out to simulate the situation of biomechanical testing. Consequently the maximal tensile stress and displacement were calculated and compared with each other for both biomechanical test and finite element analysis.
From the results of biomechanical test, the titanium alloy plates with thread design significantly shorten the fatigue life . The fatigue life of stainless steel plate is not significantly shorten by thread design, because it's not sensitivity to notch. The finite element analysis shows the notch effect is cause of thread, while the tip of thread with maximal stress. Both stainless steel F1314 and stainless steel 316L have lower notch-sensitivity, but stainless steel F1314 has higher static strength, so its performance of fatigue life is the best in this study. The results of this study could directly provide the engineer for new design of improves the locking plate.
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