Research On Pulsed Laser Bending Of Copper Alloy Based On Numerical Analysis And Experiments

Laser forming (LF) is realized by plastic deformation induced by thermal stress resulted from rapid laser heating and cooling. As a springback-free and noncontact forming process, it has many advantages compared with cold and mechanical processing which has good application prospects in the aerospace and microelectronics industries. Based on the numerical simulation and experiments, laser bending of copper alloy C194 is studied. The main contents are shown as follows:The mechanism of laser beam interactions with material was discussed, the absorption of the material energy transfer and heat conduction process were analyzed. On this basis, thermal elastic-plastic constitutive model was builded with finite element method, which provided a theoretical basis for further guidance of numerical simulation and experimental study.Based on understanding the effects of laser irradiation and high temperature properties of copper alloy C194, 3D thermal-mechanical finite element model for laser bending was established with the ABAQUS code, and then some key techniques including the establishment of pulsed laser heat source loading model, the stability and precision control in simulations were studies and solved, and approximate solution methods was used to complete the fully thermomechanical coupled finite element calculations. Laser forming processes with single-point and multi-piont were simulated, and the processes of dymanic change and steady distribution for the fields of temperature, stress& strain and displacement were studied.The pulsed laser forming experiments were investigated. The influence of single factor on the bending angle, such as laser power, scanning speed, scanning times and defocusing amount was studied. And then, orthogonal experiments were done with three factors and three levers. Pulsed laser process parameters were optimized by using Minitab software, the optimal parameters was chosen to conduct multiple-pass scanning, and the significant V-shape bending angle and arc curved surfaces forming of metal plate were obtained. After measuring the performance of the formed specimen, it was observed that tensile performance, hardness and degree of roughness have little change, which verified the feasibility of laser forming copper alloy.