有限元素分析應用於Ti-6Al-4V鈦合金電漿電弧銲接參數最佳化研究
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2010
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Abstract
因近年來電腦性能越來越強大，使得有限元素分析軟體更為成熟，利用有限元素的方式進行銲接模擬可以大量的節省成本與時間。本論文利用有限元素軟體ANSYS，使用改良後之三維錐體移動熱源，對鈦合金板材Ti-6Al-4V進行銲接模擬分析，重現電漿電弧銲接過程，並探討體熱源之正確性與熱效率之大小。
本論文的內容對於銲接材料進行溫度場分佈、角變形與應力應變的模擬分析，為觀察銲接溫度場的分佈狀況與分析銲接熱應力的作用行為，在銲接過程中以熱電耦來記錄銲接熱循環曲線，再使用田口方法找出最符合實驗的溫度參數。而最佳化結果顯示，改良後的三維錐體熱源使用熱效率60 %，用於模擬三維的銲接過程的溫度場分佈，可以更接近實際的銲道熱源輸入情況與溫度場分佈。
在結構分析的部份，因銲道區的溫度梯度相當的高，熔池金屬處於熔融狀態，當熱源遠離之後，溫度急速的下降，產生不均勻的凝固收縮，使銲接區板材受到遠端材料的拘束，產生了殘留應力，而造成角變形。而對照模擬分析結果與實際量測數據，顯示出本研究之分析參數可準確模擬鈦合金薄板之電漿電弧銲接過程。
In recent years, the computer performance is more and more powerful, so finite element analysis software is getting mature. Using numerical analysis method could save a lot of time and cost and has become a trend. This paper uses finite element analysis software ANSYS to analyze, use the modified three-dimensional conical heat source to Ti-6Al-4V titanium alloy on welding material and reappeared the plasma arc welding process, and probe into the exactness of the heat source model and thermal efficiency size. The welding simulation focuses on temperature field, thermal stress residual distribution and angular distortion, in order to observe welding distribution of temperature field and thermal stress, record the curve of thermal cycle in the welding process, and Application of the Taguchi method to find the optimal of the temperature parameter. The optimized results show that the modified three-dimensional conical heat source using thermal efficiency 60%, used to simulation the temperature filed distribution, can be close to the actual situation of the welding heat input and temperature filed distribution. For the structure analysis, molten pool of metal in the molten state that the welding zone are due to high temperature gradient. when the heat source away, rapid decline in temperature to produce uneven solidification shrinkage. Therefore, Sheet by welding zone to accept on constrained around metal, to produce the residual stress, which leads to angular distortion Compare experimental data with results from simulation, it shows that the finite element analysis of this study can accurately simulate the plasma arc welding process for butt joint of titanium alloy.
In recent years, the computer performance is more and more powerful, so finite element analysis software is getting mature. Using numerical analysis method could save a lot of time and cost and has become a trend. This paper uses finite element analysis software ANSYS to analyze, use the modified three-dimensional conical heat source to Ti-6Al-4V titanium alloy on welding material and reappeared the plasma arc welding process, and probe into the exactness of the heat source model and thermal efficiency size. The welding simulation focuses on temperature field, thermal stress residual distribution and angular distortion, in order to observe welding distribution of temperature field and thermal stress, record the curve of thermal cycle in the welding process, and Application of the Taguchi method to find the optimal of the temperature parameter. The optimized results show that the modified three-dimensional conical heat source using thermal efficiency 60%, used to simulation the temperature filed distribution, can be close to the actual situation of the welding heat input and temperature filed distribution. For the structure analysis, molten pool of metal in the molten state that the welding zone are due to high temperature gradient. when the heat source away, rapid decline in temperature to produce uneven solidification shrinkage. Therefore, Sheet by welding zone to accept on constrained around metal, to produce the residual stress, which leads to angular distortion Compare experimental data with results from simulation, it shows that the finite element analysis of this study can accurately simulate the plasma arc welding process for butt joint of titanium alloy.
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電漿電弧銲接, 有限元素分析, Plasma arc welding, Finite element method