摘 要 焊接型波紋管(Welded Bellows)為半導體真空設備重要之零件,其構造是由數個成型中空環片,以內外緣焊接的方式組合而成的中空管件,作動方式為往復拉伸運動,所以常見的破壞模式為膜片間焊道疲勞破壞,因此如何降低焊道之最大應力,為首要解決的目標。本研究以有限元素軟體ANSYS,將圓形波紋管膜片斷面以二維的方式模擬,並配合最佳化設計演算法以迭代的方式,在焊接型波紋管承受拉伸的狀態下,產生焊接型波紋管最佳膜片斷面形狀,使得波紋管所承受的最大應力為最小。 本研究以設計控制點位置的方式,用兩種最佳化設計演算法執行波紋管膜片斷面最佳化設計,首先利用類似梯度法的傳統數值最佳化設計演算,接著嘗試使用模糊比例微分控制概念,對迭代步長作控制。這兩種方法雖然迭代定義不同,但都可以將最大應力降低11%左右。 關鍵字:波紋管、形狀最佳化
ABSTRACT The welded bellow is an important component of the semiconductor vacuum equipment. It is composed of several hollow rings assembled by welding. The welded bellow often fails in the welding zone. The main purpose of this thesis is to find the optimal cross-sectional shape which reduces the stress in the welding zone. The cross-sectional shape optimization is done by varying the location of the control points. Two algorithms were used. One is a gradient type algorithm, and the other is by the Fuzzy proportional derivative Controller method. With both methods, we can get the cross-sectional shape which to reduces the maximum stress for about 11%.