摩擦與材料性質對推力向量噴嘴機構與奈米碳管複材的應力與位移的影響

Effects of Friction and Material Properties on the Deformation and Stresses in Thrust Vector Nozzles and Carbon Nanotube-reinforced Composites

莊忠諺(Zhong Yan Zhuang)

指導教授 ： 余念一

元智大學/工程學院/機械工程學系/碩士(2005年)

摘要

推力向量控制系統之噴嘴機構的材料性質及摩擦特性，是造成其位移偏差的原因之一。本文即在探討幾項重要的材料機械性質與摩擦參數，對噴嘴位移的影響，以得到噴嘴位移與材料機械性質和摩擦的定量關係，並釐清其交互作用。有限元素方法在本研究中被利用來模擬分析三維的噴嘴機構。結果顯示，摩擦對噴嘴位移的減少，影響最為顯著。
接著我們將研究噴嘴機構摩擦所獲得的經驗，運用在解析奈米碳管介面對奈米碳管複材中應力傳遞的效應。由文獻得知，多壁奈米碳管複合材料在受到一單軸向拉應力時，與基材相連接的碳管外層的介面，以及碳管內的層與層之介面，其接合情形可能對應力分佈影響甚鉅。因此本論文考慮三種介面接合情形：一、基材與碳管的介面，以及碳管內壁與壁介面均為強介面。二、基材與碳管介面為強介面，而碳管內部層與層之間為弱介面。三、所有介面均為弱介面。並以有限元素分析模擬介面對多壁奈米碳管複材應力傳遞的效應。

關鍵字

有限元素 ； 推力向量控制系統 ； 噴嘴 ； 摩擦 ； 機械性質 ； 多壁奈米碳管 ； 介面 ； 應力傳遞

並列摘要

In the present work, the effects of friction and material properties on the displacement of the nozzle in thrust vector control systems are firstly studied. Finite element analyses are performed to simulate the three-dimensional nozzle mechanisms in a thrust vector control system. The parameters associated with friction and material properties, such as static and dynamic coefficients of friction and yield strength, are varied in a systematic manner to study their effects on nozzle displacement. It is concluded that friction may be the dominant factor causing the actual nozzle displacement to be deviated from the designed one.
The second part of the present work is to study the interface effects on the stress transfer in carbon nanotube-(CNT-)reinforced epoxy-matrix composites subjected to uniaxial loading. Three interface conditions are considered: (1) all interfaces are strong, i.e., perfectly bonded; (2) the epoxy/CNT interface is strong, whereas the CNT wall/wall interface is weak, i.e., frictional sliding is allowed to occur; and (3) all interfaces are weak. Our results indicate that strong interfaces ensure the effective stress transfer in CNT-reinforced composites while weak interfaces degrade the load-carrying capabilities of multi-wall carbon nanotubes.

並列關鍵字

finite element ； thrust vector control system ； nozzle ； friction ； mechanical properties ； MWCNT ； interface ； stress transfer

參考文獻

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