本研究利用有限元素法建立一套應用於家用空調迴轉式壓縮機幫浦缸體與外殼組裝三點銲接之電腦輔助工程分析技術。首先利用三點順序銲接建立一套模擬三點銲接之有限元素分析模型，並透過實驗驗證模擬分析結果，確認該有限元素分析模型的有效性。之後，再將該模型進一步應用於三點同步銲接，預測相關零件的溫度分佈、殘留應力及變形。最主要觀察的部分為葉片槽的變形及幫浦在銲接後真圓度的改變。

有限元素分析模型計算求得三點順序銲接溫度分布，與實驗量測結果比對，不管在溫度變化趨勢或是數值都相當吻合，因此確認有限元素分析模型的有效性。藉由此三點順序銲接模擬手法，應用於三點同步銲接分析，計算結果發現於三點同步銲接過程，最大von-Mises等效應力主要存在於銲料區外側，隨著銲接過程結束，進入冷卻，最大等效應力區域逐漸移至熱影響區，最終，熱影響區殘留應力值會超過所使用材料降伏強度值，因此，此區域預期可能會發生塑性變形。同時從位移的模擬結果中，可以看出缸體的真圓度並未改變，因其節點位移並無太大變化，此乃這些區域並無太大溫度梯度所致。而葉片槽在冷卻後，其槽寬的尺寸略有變化，但仍在可接受的範圍內。

  Finite element method (FEM) is applied to developing a computer-aided engineering (CAE) technique for simulating the welding process in assembly of a household air-conditioning rotary compressor. An FEM model in simulation of joining pump cylinder and outer shell is established first for sequential three-point welding, and the simulation results are compared with experiments to verify the FEM modeling. The validated FEM modeling is then applied to simulating simultaneous three-point welding to predict temperature distribution, residual stress, and deformation in related parts. In particular, deformation of the vane slot and the change of roundness of the pump after welding are investigated.

FEM simulations and experiments show good agreement in temperature distribution in the sequential three-point welding of pump cylinder and outer shell. The constructed FEM model is thus proved to be effective in analysis of three-point welding. The three-point welding simulation technique is then applied to the simultaneous three-point welding process. The calculation results show that during the simultaneous three-point welding, the maximum von-Mises equivalent stress mainly exists outside the weld zone. When the welding process is completed and the cooling process begins, the maximum von-Mises equivalent stress region gradually moves to the heat affected zone (HAZ). The residual stress in the HAZ exceeds the yield strength. Therefore, plastic deformation might take place in the core region of HAZ. At the same time, the simulation results of deformation show that the roundness of the cylinder has not changed, because the node displacement does not change much. This is because the temperature gradient is quite small in these regions which are far away from the welding zones. Although a slight change in the vane slot width is found after welding, it is still in the acceptable range.