熔滴填充位置对激光焊接熔池动态行为的影响

借助熔滴作用下的三维瞬态激光焊接热-流耦合有限元模型，对不同的熔滴填充位置下熔滴进入熔池过程的匙孔三维形貌、熔池金属流动特性进行研究。数值模拟计算结果表明，熔滴填充位置对激光焊接过程中匙孔三维形貌及熔池液态金属的流动行为的影响较大。当熔滴填充位置由0.5 mm增大到1.8 mm时，对匙孔三维形貌变化的影响减弱，熔池内部挤压匙孔前壁和后壁驱使匙孔闭合的流动趋势减弱而维持匙孔壁张开的流动趋势增强，匙孔底部液态金属流动速度的波动幅度减弱。

Effect of droplet filling position on dynamic behavior of molten pool in laser welding

With the three-dimensional transient thermal flow coupled finite element model of laser welding, the three-dimensional keyhole morphology and metal flow characteristics of the molten pool during the process of the droplet entering the molten pool at different droplet filling positions were studied. Numerical simulation results show that the droplet filling position had a significant effect on the three-dimensional morphology of keyhole and the flow behavior of molten pool during laser welding. When the droplet filling position was increased from 0.5 mm to 1.8 mm, the influence on the three-dimensional shape change of keyhole was weakened. The flow trend that the front and rear walls of the keyhole was squeezed inside the molten pool to drive the keyhole to close was weakened, while the flow tendency of maintaining the keyhole wall opening was enhanced, and the fluctuation amplitude of liquid metal flow velocity at the bottom of keyhole was weakened.