Study on Residual Stress Distribution of 7050 Aluminum Sheet with Groove after Laser Shock Peening

Abstract

In order to study the residual stress profile of 7050-T7451 aluminum sheet with groove after laser shock peening (LSP), the residual stress distribution was measured. It is shown that the residual stress decreases gradually from the center to the edge of groove; and then there is the minimum value at the edge of the groove bottom surface. By using ABAQUS software to establish three-dimensional finite element model for 7050 aluminum sheet with groove, and the load was applied by VDLOAD subroutine. The finite element analysis was performed and the analysis results were compared with the experimental measurements, in which the both the results agree with each other very well. And then the residual stress distribution of the sheet was analyzed after laser shock peening under different laser processing parameters. It is shown that the residual stress decreases firstly and then increases with the rise of laser power density from 0.84 GW/cm2 to 5.29 GW/cm2. And the residual stress obtains the minimum value -230 MPa at the laser power density of 3.06 GW/cm2. With the increasing of spot diameter from 4 mm to 6 mm, the residual stress increased from -214 MPa to -30 MPa. With the increasing of laser pulse width from 10 ns to 40 ns, the residual stress decreased from -21 MPa to -288 MPa; and the depth of the compressive residual stress increased too. For all simulations under different LSP parameters, the minimum surface residual stress achieved at the bottom surface of the groove as well.