本文目的在利用Hwang[22]所提出的流線函數，來解析雙金屬中空擠製加工，以建構複合材對擠製問題的上界限解析模式。首先利用塑性不可壓縮定理，求取在環狀襯套及蕊材進、出口端之剛塑界面函數，並以上界限理論進而求得擠製消耗總功率，本文數值分析係利用IMSL[10]最佳化程式〝NCONF〞以求得上界限解，將其解與Chitkara[6]所提出的理論、實驗加以比對和驗証，進而探討直線模、曲線模擠製加工的面積減縮率、半模角及摩擦因子等條件對擠製壓力與出口端半徑比之關係。

The purpose of this investigation is to discuss bi-material tubes extrusion using Hwang[22] proposed stream fuction. Building a model of bi-material upper bound method for extrsion problem. First, using incompressible plastic method to obtain sleeve layer and core layer of rigid/plastic interface fuction, by using upper bound method obtain extrusion of the total power. This investigation is number solution analyse utilize IMSL optimization procedure NCONF to request upper-bound solutin, The solution with Chitkarara[6] proposed theory and experiment prove. Discuss line die and curve die is reduction of area ,the friction factor, the semi-die angle and ect. to counter to with the effect of extrusion pressure and final radius ratio.

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