機車鋁合金車架之應力分析與結構最佳化

Abstract

本研究主要利用電腦模擬分析的技術探討一機車鋁合金車架的新設計，來預知其結構上的缺陷，並且提供設計者修改的方向， 進而得到一個較佳的結構設計。 本研究利用有限元素法(Finite Element Method)分析一機車車架原型設計受力的模式，包含車架的強度與剛性分析以及車架結構的最佳化設計。模擬車架結構在四種包含強度及剛性的負荷條件下受力變形的情形，以求出車架結構所需加強之部份。其後，利用尺寸最佳化設計，首先給定重量最小化之設計目標，在不影響最後車體組裝限制的前提下，給予參數化之設計，並出原型結構的尺寸最佳化設計。最後，利用拓樸最佳化，在與原型設計相同的負載條件的剛性要求下，獲得一最佳化車架結構的概念設計。

This study concentrates on using the computer-aided engineering analysis technique in the design of a motorcycle frame made of Aluminum alloy. The structure deficiencies can be found, and a modification strategy can be provided to obtain a better structure in terms of both the strength and stiffness. The finite element analysis technique is employed to simulate the prototype of a motorcycle frame. The strength and stiffness are evaluated using commercial software CATIA. The statically weak regions are identified by applying static loads, and are then strengthened by adding stiffeners. With minimum weight set as the design objective, the geometrical design variables are defined and parametrized. Under the constraints of specified strength and stiffness, the optimal structure can then be obtained. At last, The concept design of a new motorcycle frame is obtained by using the topology method under stiffness requirement for the same load condition.