Study On The Laser Compound Forming Of Sheet Metal Based On Finite Element Simulation And Experiment

A new sheet metal plastic forming technology-laser compound forming (LCF) based on the concepts of laser thermal-stress combining laser shock wave technologies was proposed in this paper. LCF used the thermo-mechanical coupling effects of continuous laser and the force effect of the high-energy pulsed laser to form the sheet metal into complex shapes very rapidly, and the formed pieces would have good surface quality and mechanical performance. In this paper, the primary process and mechanism of LCF were studied in detail at the beginning, and then it would greatly emphasized on studying the numerical simulations and experiments of the LCF process. Main contents of this paper are showed as following:Thermo-mechanical coupling theories and the decoupling equations of the LCF process were investigated. Then the dynamic response of sheet metal acted on the high power laser peening and the generation principles of residual stress induced by laser shock wave were discussed respectively. The bending deformation of sheet metal in the LCF process was also studied.Finite element method (FEM) was applied to the investigation of the LCF process. An appropriate analysis mode for the FE simulation of LCF was established with ABAQUS code, and then some key technical issues in the simulations were studied and solved. The simulation process for LCF was also designed in this paper. Laser process parameters of the LCF were optimized by using Minitab code and orthogonal design of experiments (DOE) for the simulations. Based on the analysis modules of ABAQUS/Standard and ABAQUS/Explicit, numerical simulations of LCF for plates with simple V-shape or some typical complex profiles were performed using fully coupled thermal-stress analysis technique and combined explicit and implicit analysis technique.On the basis of FEM analysis of LCF process, the corresponding LCF experiments of AISI-1008 steel were performed to validate the simulation results taking V-shape forming as an example. By measuring the deformation and surface quality of the fomed plates after LCF, the bending deformation, forming precision and the variation of surface qualities were mainly studied. Finally, the plates with some typical complex profiles were also formed trially in experiment by using LCF technique. Results of the experiments demonstrated that the LCF process can realize the precision forming of complex surface rapidly and efficiently. Distribution of the surface residual stress and the surface qualities of the formed workpieces were all under good control.The experimental results indicated a good agreement with that of simulations, which demonstrated that the FEM could be a useful way for the research of LCF process. The gained conclusions would have great and positive guidances for the development of the research of laser compound forming.