关键词: 高斯热源, 焊缝余高, 生死单元技术, 双椭球热源, 能量耗散, 疲劳性能, 损伤机理, 高周疲劳

Abstract: The finite element analysis software ANSYS has been applied to calculate the thermal process in the carbon dioxide gas shielded arc welding. The solid model of weld reinforcement is made in Preprocessor based on experimental results, and the technique of element birth and death is used to deal with the weld reinforcement, which are totally taken as “dead” elements first and are activated step by step in Solution Processor. Comparing the results for three different cases (without considering the weld reinforcement, taking account of the weld reinforcement but simplifying the process as a non-consumable electrode welding, and adopting the technique of element birth and death to deal with the weld reinforcement), it is found that the weld reinforcement, which takes up no more than 3% volume of the base metal, has a great influence on the temperature distribution, especially on the numerical analysis precision of the weld profile and the high temperature zone. Two methods (adjusting the heat flux distribution parameter of 2-D Gaussian heat source, and adopting 3-D double-ellipsoid heat source) have been carried out to improve the analysis precision. According to comparison between the predicted results and the experimental ones, it is found that adopting 3-D double-ellipsoid mode of heat source is better to improve the prediction accuracy in modeling consumable electrode arc welding process. All the above work can lay a foundation for multi-pass welding of thick pieces.

Key words: Double-ellipsoid heat source, Element birth and death technique, Gauss heat source, Weld reinforcement, Damage mechanism, Energy dissipation, Fatigue behavior, High-cycle fatigue