Research On Complex-Section Profile Roll-bending Process Of Al-Li Alloy

As one of the bend-forming methods, profile roll bending process is used for producinglightweight structures that can reduce the weight and improve the strength. Nowadays, it has beenwidely used in many fields, such as the aerospace, vehicle, shipbuilding and other industries. In thecompleted years, with the gradual perfection of the sheet metal roll bending process, further researchneed to be done on the irregular profile roll bending process.In order to solve the technical problems that the large passenger aircraft faced with, roll bendingprocess of2099-T83Al-Li alloy has been studied in this paper. Through chemical element analysis,mechanical parameter test and microscopic structure observation, the performance of2099-T83Al-Lialloy was analyzed. With knowledge of Al-Li alloy, profile roll bending process was studied by meansof theoretical analysis, FEM(Finite Element Method) and experiment research, the main contents andresults are as follows:Based on the theoretical principle of the plastic forming, material constitutive model of the stressand strain to2099-T83Al-Li alloy are established. Based on the bend-forming theory, geometricalparameters of the given profiles are calculated. Spring-back formula of the profile bending process isdeduced in the base of elastic-plastic theory.FEM software ABAQUS is used for the roll bending simulation. According to the simulationresults, laws of the stress and strain distribution are analyzed. Causes of the defects that occurred inthe process are discussed, corresponding measures have been taken to deal with them. By adding arigid roller or polyurethane filler in the blank to eliminate the section distortion was proposed, resultsturn out that polyurethane with a hardness of80A can prevent the section deformation effectively. Thetrouble of wrinkle can be overcame through setting reasonable clearance between the roller andprofile. The problem of torsion was tackled by imposing the profile extra boundary conditions.Influence of the punch value, side rollers distance and forming courses to the spring-back value wasstudied. With the optimized parameters, the curvature-changing roll bending process was conductedeffectively.The experiment was carried out by the MC4P numerical controlled roll bending machine. Resultsturn out that the experiment reached a consensus with theoretical analysis and FEM simulation results.The research also offered a significant reference to the profile roll bending process.