Numerical Simulation Of Aluminum Alloy LB-VPPA Hybrid Welding

The paper mainly studied 7010 aluminum alloy, using special welding simulation software-SYSWELD to simulate LB-VPPA hybrid welding thermal process. LB-VPPA hybrid welding is a new welding method. It has some characteristics, such as energy more focused, small welding wire input and a big Weld depth width ratio. However, due to the equipment of hybrid welding is much complex, it is difficult to debug the appropriate parameters. By means of numerical simulation technology, we can not only optimize the parameters, but also shorten the test period.On the basis of mastering SYSWELD software, according to the process characteristics of VPPA welding, use Fortran language to develop the heat source model secondly. In order to achieve achieve a positive and negative polarity VPPA asymmetric arc energy and form alternating load. According to the characteristics and mechanism of LB-VPPA hybrid welding, Using Gauss + double ellipsoid + Gauss cylinder composite heat source model to simulate the thermal process of LB-VPPA hybrid welding. In gauss plane, the double ellipsoid and gaussian cylinder energy ratio is 0.39:0.47:0.14, the sectional shape of the pool is closer to reality.The simulation and experimental results showed that: For 6mm thick 7010 aluminium alloy board, when the welding speed is 3mm/s, in the flat position, the LB-VPPA hybrid welding need effective total power is 2250 w, while single VPPA welding effective total power is 2400 w. The result confirmed that the LB-VPPA hybrid welding energy is more concentrated, and the welding can be realized in the horizontal position, while the single VPPA welding can hardly be realized in the horizontal position. Based on the simulation of temperature field, the stress field is calculated and the stress distribution of the work piece at different time is obtained. Compare the stress field of LB-VPPA composite welding with the single VPPA welding, we found that residual stress of LB-VPPA composite welding is less than VPPA. The welding advantages of LB-VPPA composite welding are obvious in aluminum alloy welding.