搅拌摩擦焊瞬态温度场数值模型的讨论

搅拌摩擦焊温度场数值模拟工作多侧重于产热模型及温度场分布规律等方面的研究,关于数值模型及其计算效率方面的报道相对较少。本文对AL6061-T6铝合金板材搅拌摩擦焊接过程瞬态温度场进行了模拟,对数值模型的相关问题进行了研究。在保证模拟结果与实验结果相符合的前提下,为提高计算效率,给出了合理的模型尺寸；分析了网格尺寸对温度场的影响；探讨了网格分区划分方案；分析了轴肩与搅拌针产热分配对温度场的影响。结果显示：模型宽度随板厚增加线性增大,而模型宽度与轴肩直径的比值随板厚的增加线性减小；有限元网格尺寸为1 mm时能有效地模拟温度场；焊缝中心处轴肩直径范围内的网格应当细化；合理的轴肩与搅拌针产热比例分别为75%和25%。

Discussion on numerical modeling of transient temperature in friction stir welding

Studies on the heat transfer in friction stir welding has been mainly focused on heat generation and temperature distribution, while fewer contribution discuss issues on the numerical modeling. In this paper, transient heat transfer of AL6061-T6 in frictions stir welding is simulated and some numerical issues are studied. On the premise that the simulation results are consistent with the experimental results, in order to improve the efficiency of the numerical simulation, the reasonable model size is given, the effect of mesh size and range on the temperature field are addressed, the influence of tool shoulder and pin heat distribution on temperature field is analyzed. It is shown that the width of numerical model adopted in the simulation should increase linearly with the increase of plate thickness, while the ratio of model width with shoulder diameter decreases linearly with the increase of plate thickness. The mesh size with 1 mm is proper and the fine mesh should be placed at the domain of the shoulder diameter. The proper shoulder and pin heat distribution is 75% and 25%, respectively.