Please use this identifier to cite or link to this item: `http://hdl.handle.net/11455/1950`
 標題: 複合結構元件接合之設計與應力分析Design and Stress Analysis of the Connection of Composite Structures 作者: 吳雲生Wu, Yun Shen 關鍵字: 有限元素法;FEMs;固定器;Fixer 出版社: 機械工程學系 摘要: 摘 要 固定器可分為體外固定器( 簡稱外固定器)和體內固定器(簡稱內固定器)兩大類.一般常見的外固定器 有石膏固定,而內固定器種類良多,如:RF III,ISOLA,Kaneda SR, University Plate,VSP法等.而本研究是以有限元素法(FEMS)來模擬,分析 VSP內固定器受外力時的變化. 目前有許多有關於內固定器這方面的研 究報告,但大多用於動物的臨床實驗,此法僅能以x光觀察固定器的位置,或 是觀察固定器有無鬆脫現象,並無法得知內固定器在體內的變化,如變形, 應力集中等現象,也無法預測內固定器何時將會被破壞,而破壞發生時那些 元件會先損壞等.VSP內固定器包含了骨板(Bone Plates),骨釘(Bone Screws)等.本研究在探討二維時,骨板與骨釘受到不同外力時,兩元件間接 觸程度的變化.再將二維所得的結果應用到三維上,以求得骨釘與骨板及密 質骨間在不同外力下所產生不同的接觸面.並找到其應力集中的所在,進而 可得知破壞位置. 在二維模式中,發現骨釘與骨板接觸的程度在一個合 理的範圍,以不同外力來區分,外力作用在骨釘上時的最大角度是以骨釘為 中心上下各85.45度.另一個外力作用在骨板上時的最大角度是以骨釘為中 心上下各70.77度. 本研究發現體內固定器的破壞情形,與臨床的結果 吻合,在本模式中的四個元件, 骨釘,骨板,界面元素及密質骨中,以骨釘的 破壞機率最大,其次是骨板.根據研究結果顯示骨釘上表面部份最容易產生 應力集中,且因外力作用的位置不同,對骨釘,骨板產生的應力集中的位置 也是有所改變.ABSTRACT There are two categories of fixers appeared in the medical fields;body-outer fixer and body-inner fixer. The outer-fixers are usually fixedwith gypsum. But many the inner-fixers have been reported, such as RF III,ISOLA,University Plate and manners of VSP...etc. The object of thisproject is to study the stress distributions in the fixing structures usingthe finite element models (FEMs) with various VSP inner-fixers impacted byvarious external forces. Many investigations are given about the inner- fixers. However,mostof them are set on the clinical experiments of animals; these results areonly used to read the location of fixers through x-ray films,or to surveythe fixer loosening problems in the body. The transferring of loads, stressconcentrations and tendency of worn-out condition of fixers can not be understood at all. This report begins with two dimensional models to studythe changes of contacting degree between bone plates and bone screws undervarious external forces. Then we apply the conclusions obtained by two dimension; models to three dimensional models to easily find the contacting-faces in the structure formed by bone-screws, bone- plates and cortical-bone.Moreover, we study the site of stress concentrations, and understand theexact wearing-out position. In two dimensional models, we have found the contacting degree betweenbone screws and bone plates may up to 85.45 degrees while the loading appliedto the bone screw. And when external force are applied to the bone plates, themaximum contactangle is up to 70.77 degree. This study also finds that worn-out conditions of body-inner fixers aresignificantly matching the clinical results among four fittings of this FEMs;bone screws, bone plates, interface element and cortical-bone. Moreover, the maximum wearing-out rate is located firstly on the bone screws and secondly onthe bone plate. The Stress concentrations are located on the upper-surface of the bone screws. More results of stress distributions for various impact forces applied either to the bone screws or the bone plates are present anddiscussed. URI: http://hdl.handle.net/11455/1950 Appears in Collections: 機械工程學系所