Research On The Mechanism Of Distortion Correction By Ultrasonic Shot Peening For Aluminum Alloy Welded Structure

In this paper,with the flange structure of 2219 aluminum alloy as the object,researches were carried out to discuss its distortion introduced by welding.The processes of distortion formation and its correction by ultrasonic shot peening were simulated using finite element software.The accuracy of simulation was verified and improved combining related tests.This paper studied the dynamic constitutive relationship of the material first.The static and dynamic tensile properties of each tiny area in the weld joint and the dynamic constitutive model were all achieved through welding experiment,quasi static tiny mechanical tensile test and dynamic tensile test.Experimental results show that there are great differences in strength of different regions of the weld joint.And the strength of a region also differs a lot under different strain rates,namely,it has a certain sensitivity to strain rate.The dynamic constitutive equations of 2219-T6 aluminum alloy weld joint were achieved by fitting the tensile test data,which will provide the basis for researching the mechanical performance of the material under high strain rate and simulating the behavior of the material under the condition of high speed impact.And then some experiments were done to the studied structure,such as welding,distortion and stress measurement after welding,and buckling distortion correction by ultrasonic shot peening.The distortion of the specimen was corrected to a great extent by ultrasonic shot peening treatment.The distortion reduced from 9.532 mm to 2.431 mm at the position of maximum deformation.Finally,using the finite element software ABAQUS to simulate the processes of flange structure welding and distortion correction by ultrasonic shot peening.The distribution of welding temperature field,stress field and distortion were obtained through the simulation of welding process.To improve the accuracy,the unreasonable settings of simulation were modified by comparing the simulation results with the experiment results.The distortion of the peened specimen was obtained through the simulation of ultrasonic shot peening process,which was basically consistent with the experimental results.The modified simulation process taking weld joint softening and strain rate sensitivity into consideration can be considered as an effective method to simulate the distortion correction process by ultrasonic shot peening.It has important significance to the simulation of engineering applications and guide practice.