本研究旨在利用有限元素法模擬穿戴式醫療用3D列印客製化背架之靜態分析，藉由手持掃描儀對受試者身體軀幹建模後，觀察其靜態分析的結果設計客製化的背架模型，實際的背架成品使用PLA材料由3D列印機器以積層製造的方式製成。基於有限元素方法，實驗預先建立了身體軀幹與背架的幾何模型，確保兩者接觸面能吻合並與實際穿戴情況相符。使用電腦輔助軟體的實驗過程中，整體模型的靜態分析需要考量身體軀幹與背架接觸面之運動與受力，為求符合背架穿戴於受試者的實際情形而給予模擬分析時的條件限制、材料性質和軟體參數設定。進行靜態分析時，主要考量到背架與身體軀幹間的壓力，集中的壓力容易造成穿戴者的不適，甚至是受傷。身體軀幹穿戴上背架後分別對七種不同的姿勢，以壓力集中與否和位移大小作為分析依據，結果顯示客製化的背架確實能達到支撐卻不造成人體負擔的效果。除了模型的靜態分析之外，客製化背架也與市面上販售的一般背架進行比較，在各項指標數據上都顯示客製化背架更能符合受試者身體軀幹並給予更佳的幫助。在不影響客製化背架的功能下，本研究亦改善了背架的舒適度，以鏤空的方式，並加入厚度作為調整的變因，結果顯示僅犧牲微小的支撐性能下，客製化背架的透氣程度與重量都獲得大幅度地改善。

This study aims at the finite element static analysis of 3D printing customized back brace for medical purposes. The geometric model was created based on the profile of the trunk to ensure the surface of the brace fits the profile of the trunk. The contact model was also considered between the brace and the trunk composed of spine, ribs, hips and soft tissues. The material used in the simulation is PLA (Poly Lactic Acid). The comfortability wearing a back brace can be quantified by the pressure between the skin and the brace. In this study, the finite element model is used to simulate the pressures of the skin wearing the brace for seven trunk positions, including standing, flexion, extension, left rotation, right rotation, left bending and right bending. Pressure injury may occur for high pressures on the skin. We also calculated the displacements of the spine, which are used to evaluate the fixity to the trunk provided by the brace. In the simulation, the geometric parameters such as thickness and holes in the brace were considered to evaluate their effects on pressures and fixity. As a comparison, the finite element models of commercial back braces were also established. The simulation results showed that the wear of the customized brace can reduce the pressure on the skin by 11% to 58%, depending on which trunk positions are considered. The displacements of the spine, the simulations also revealed that the customized brace provides a maximum fixity increase of 8% higher than the commercial brace. We also found that the thickness and holes in the customized brace have little effects on both the pressure and fixity. The simulation results showed the large degree of freedom in geometric designs without decreasing the comfortability and fixity of the customized brace.

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