6061铝合金薄板的焊接变形数值模拟.pdf

上海交通大学 硕士学位论文 6061铝合金薄板的焊接变形数值模拟 姓名：张庆移 申请学位级别：硕士 专业：材料加工工程 指导教师：楼松年 20040101 R 6061 K q v /F B*q v /h 2 K 9.5 10 7 cm 3 /J 17 10 7 cm 3 /J x 5 10 6 cm 3 /J 8 10 6 cm 3 /J 2 3 THE NUMERICAL ANALYSIS OF THE 6061 ALUMINUM ALLOY SHEET WELDING ABSTRACT Aluminum alloys are ideal materials to make the automobile lightened in order to save the energy and improve the safety. But some factors prevent Aluminum alloys from being used more wildly in the automobile and it is an important one that the suitable welding technique is difficult to find. The aluminum alloy‘s rigidity is smaller than the steel’s, and it will be softened in the welding. So more factors should be considered and some constraints should be modified in the simulation of the aluminum alloy welding. Currently the heat elastic-plastic method is widely used in the welding deformation prediction of the carbon steel structure, and the inherent strain method is successful to simulate the big rigidity welding structure. The whole welding process can be traced by the first method, but it will take so much time that sometimes it is unacceptable in the engineering. So the second one is developed quickly and used more often because of its fast speed and precision. With the heat elastic-plastic method, more factors should be considered because that the rigidity of the aluminum alloy structure decreases seriously especially in the weld zone. Some researches on the heat effective coefficient and the heat source effective zone radius and the rule to apply the heat source are completed in this paper. And it is proved that the simulation with softening is more reasonable than the one without softening according to the comparison between the welding test data and the calculation results, which can be consulted in the 6061 aluminum alloy welding deformation prediction. In the inherent strain method, it is a key step to get the longitude shrinkage coefficient K and the latitude shrinkage coefficient in the preprocessing. Only the carbon steel’s K and curves for the carbon steel can be gotten from the articles, which limits the use of this method. So the K and curves for the aluminum alloy are given according to the welding test data. It proves that K is between 9.5 10 7 cm 3 /J and 17 10 7 cm 3 /J and x is between 5 10 6 cm 3 /J and 8 10 6 cm 3 /J, which are about 3 times of the corresponding ones of the steel. KEY WORDS: 6061 aluminum alloy, welding deformation, FEM, heat elastic-plastic, inherent strain, soften 2004 2 14 。