Experimental And Numerical Simulation Research On Temperature Field Of Aluminum And Steel In Laser Welding

Automobile lightweight is one of the most effective way to reduce fuel consumption and vehicle exhaust emissions. Now the usage of high strength lightweight materials is one of the major measures to achieve automobile lightweight, use aluminum alloy instead of traditional steel, for example, to reduce the weight of the vehicle and achieve the goal of energy saving and environmental protection. In order to satisfy the basic requirement of lightweight, solve the problem of the connection between dissimilar metals such as aluminum and steel has become a current research focus. In recent years, in view of the connection between the dissimilar metals of different physical and chemical characteristic, a new kind of welding method-The laser welding-brazing develop rapidly, which provides a research idea for the connection between aluminum and steel. Detail research of this subject is as follows:Firstly, a finite element model was established based on ANSYS of aluminum-steel flat lap laser welding. Gauss heat source model was adopted, and APDL language was used to compile program to apply moving heat source load. Considering the impact of nonlinear material parameters, latent heat of phase transition and heat transfer boundary conditions,the temperature field in laser welding process was calculated. The temperature nephogram of surface temperature field, longitudinal section temperature field and the welding heat cycle curve of the node along the weld direction, perpendicular to the direction of the weld and along the thickness direction indicated the laser welding-brazing temperature field distribution characteristics.Secondly, the laser welding experiment was designed to verify the results of the simulation. The welding heat cycle curve was obtained with thermocouples. Comparision of the changes showed that the agreement between numerical simulation and experiment was good in terms of trends and magnitudes.Finally, the non-linear mapping relation between welding parameters and welding penetration of the laser welding-brazing was established based on the RBF artificial neural network. The RBF neural network was trained with the sample data of different welding parameters and the welding penetrations from orthogonal design. After training, the artificial neural network was used to predict the welding penetration under the condition of different parameters and the quantitative effect on welding penetration of the welding process parameters was analyzed.The reserch proposed a new investigative method for laser welding of dissimilar metal and provided the important theory and experimental foundation for the application and extension of aluminum-steel laser welding.