Influence of longitudinal magnetic field on metal transfer in MIG arc welding

Metal transfer is an important phenomenon in metal inert gas (MIG) arc welding with longitudinal alternating magnetic field. It is of great significance to observe the metal transfer modes under different excitatory currents and frequencies. However, it is very difficult to view the metal transfer process directly during welding, due to the strong interference from the arc light. To obtain the relationship between the metal transfer modes and the different magnetic fields, a high-speed video camera was used to acquire the images of globules. Different metal transfer modes under the conditions of different magnetic fields and welding parameters were studied. The experiment shows clear images of droplet transfer as well as influence of longitudinal magnetic field on both metal transfer and globule shape.     

典型飞机构件焊接数值模拟系统研制

针对典型飞机焊接构件,研制焊接热过程、应力应变以及变形的模拟系统.提出并利用面向网格划分的数据抽象造型方法,实现模拟过程的自动化.解决一般有限元软件模拟飞机构件焊接温度场和应力/应变场过程中操作繁琐的问题.系统采用面向对象方法设计.利用文中系统,用户只需输入构件模型几何参数,网格尺寸、热源参数、装夹位置和焊接顺序.这些参数经过系统核心类计算,生成温度和应力/应变模拟的自动化信息.自动化信息由系统转化为Marc的命令流文件,自动被导入到后台运行的Marc中计算,并对结果分析,实现对典型飞机构件焊接温度、应力/应变以及变形预测和分析.     

基于后处理再造型的连续制造工艺过程仿真技术

制造工艺仿真技术目前仅应用于单点工艺分析,缺乏在连续工艺实施中考虑应力和变形等变化对前后工序的影响,不能实现连续的制造工艺仿真,因此提出一种基于后处理再造型(PostProcessing Re-Modeling,PPRM)的仿真技术.该技术利用前道工序仿真结果的后处理数据重构后道工序的仿真模型,从而可以系统、连贯地考虑各制造阶段的工艺变形、应力和应变等,实现连续制造工艺过程仿真.将这项技术应用于船体结构部件装焊变形的仿真计算中,计算多个零件连续装焊工艺过程的焊接变形积累,从而预测并监控多道装焊工艺前后工序之间的互相影响干涉.该技术在船体制造中的肋板弯曲工艺、分段堆放和分段吊装等工艺中应用前景较好.