Welding distortion control of aluminum alloy carriage roof based on high-efficiency numerical simulation

摘要

The welding distortion control of large welded structures is more serious due to the long welded-lines and complex geometries. Numerical simulation is considered as a powerful tool in welding distortion control. But low computational efficiency hinders the application of this technique in large welded structures. The three-dimensional finite element model of 12m long aluminum alloy carriage roof was employed in controlling welding distortion. Segmented temperature function method (STFM), was applied in the model to shorten the computing time. By means of FEA study and experiments, it was found that the main welding distortion pattern was the transverse distortion across the transverse section of carriage roof. Then the process optimization, in which proper reverse deformation was preset on transverse section of carriage roof, was proposed to reduce welding distortion. Two different optimized carriage roofs were proposed and compared based on high-efficiency numerical simulation. The computed results showed that the optimization scheme A, in which the transverse section of carriage roof was optimized integrally, was better than optimization scheme B at welding distortion control. Structure with the same transverse section as optimization scheme A has been produced and its distortion was measured. The errors between computed results and measured results were no more than 20%. The welding distortion after optimization was reduced to 20% of that of original structure.