Simulation And Experimental Research On Welding Residual Stress Relieving By Vibratory Stress Relief Technology

At present, vibratory stress relief technology is widely used and promoted in steel andother ferrous metals fields, many researches are carried on it and a lot of achievements areacquired, but researches on aluminum alloys and other non-ferrous metal fields are relativelyless. This subject will take hard aluminum alloy 2A11 butt welding plate as study object,adopt the method that combining numerical simulation with experiment, and carry research onwelding residual stress relieving by vibratory stress relief.Firstly, the mechanism generated by residual stress is comprehensively analyzed.Macroscopic mechanism of vibratory stress relief is elaborated in detail based on bauschingereffect, and the basis of choice of exciting force is determined. Microcosmic mechanism ofvibratory stress relief is sufficiently studied based on dislocation theory, the dislocationmotion of crystal and the release mechanism of internal residual stress are explained.Secondly, generation and distribution of welding residual stress and characteristics ofwelding fabrication are introduced. On the basis of deeply studying the theory of weldingtemperature distribution and stress-strain fields, thermal elastoplastic model of welding plateare established with ANSYS, welding numerical simulation of thermal-structure coupling arecarried with the element birth and death technology, and distribution results of temperaturefield and stress field that are in consistent with theory are obtained. On the basis of free modalanalysis and constraint modal analysis of specimens, technological parameters of vibratorystress relief are determined. The stress field results obtained by welding numerical simulationare imported into harmonic response analysis model as the initial load, numerical simulationanalysis are carried on the process of vibratory stress relief according to the relevantparameters confirmed. The analysis results show that the residual stress at the peak after vibration processing reduce about 30%, and the distribution of overall residual stress arehomogenized.Finally, experiment studies of vibratory stress relief are carried on weld assembly,residual stress values before and after vibration are measured respectively by using X-raymethod. The experiment results show that the residual stress values of aluminum alloywelding plate can be greatly reduced and homogenized by vibratory stress relief, and theeffectiveness and practicality of the technology are validated.