双丝GMAW焊熔滴过渡对焊缝形状影响的研究

双丝共熔池GMAW(twin-wire co-pool gas shielded metal arc welding, TCGMAW)熔滴过渡对焊缝成形的影响体现在对熔池的作用上，熔滴对熔池的作用在于向熔池传输能量、动量和质量，最终会影响到焊缝的成形和质量。本文根据高速摄影结果，建立双丝GMAW焊接熔滴过渡的运动轨迹，从理论上分析了熔滴过渡的特点，并根据分析结果建立了贴体坐标系下熔滴带入熔池的热量和动量的数学模型，研究了熔池各个表面上的动量和能量边界条件, 在此基础上进行了焊缝形状的数值模拟，并与实验结果进行了对比分析。结果表明，建立的数学模型是可行的，与实际的试验结果比较吻合。

Effects of droplet transfer on the weld appearance of TCGMAW process

The droplet transfer of twin-wire co-pool gas shielded metal arc welding (TCGMAW) process takes great effects on the behavior of the molten pool by transferring energy, momentum and fluid flow to the molten pool which will affect the weld appearance. Based on the high speed photographing results, the droplet transfer characteristics in TCGMAW process is explored, and the droplet transfer state and rules are analyzed theoretically and experimentally. The heat and momentum input models caused by droplets entering the molten pool are set up based on the analyzing results. The momentum and energy boundary conditions on every surface of the molten pool are carefully studied, and a necessary condition for the numerical simulation of the molten pool behavior of the TCGMAW process is established. The numerical simulation and experiment result indicate that the heat and momentum input models established are feasible.