Fig. 1. Finite element simulation flowchart of friction stir welding (FSW) and laser peening (LP) composite process

Fig. 2. Finite element model. (a) Overall model; (b) meshing strategy

Fig. 3. Schematics of model boundary conditions. (a) Heat transfer analysis; (b) stress evolution analysis

Fig. 4. Diagram of pressure change over time^[21]

Fig. 5. Laser peening strategy

Fig. 6. Simulated stress distribution. (a) Whole stress distribution; (b) cross-sectional metallographic diagram^[25]; (c) cross-sectional stress distribution

Fig. 7. Comparison of experimental and simulated residual stress in the Y-axis direction after treating by friction stir welding. (a) Z=0 mm; (b) Z=6.4 mm

Fig. 8. Schematic of advancing side (AS) and retreating side (RS) of the friction stir welded plate

Fig. 9. Comparison of experimental and simulated residual stress in the Y-axis direction after treating by composite processing

Fig. 10. Residual stress distributions of welded sheet treated by different processes. (a) Friction stir welding; (b) laser peening; (c) friction stir welding+laser peening

Fig. 11. Comparison of simulated residual stress of welded sheet treated by different processes. (a) Data extraction paths; (b) residual stress along X direction; (c) residual stress along Y direction; (d) residual stress along Z direction

Fig. 12. Comparison of simulated residual stress under different initial tensile stress states. (a) Data extraction path; (b) comparison chart of residual stress; (c) change trend of residual stress reduction value

Fig. 13. Attenuation trend graph of stress wave. (a) Laser peening; (b) friction stir welding+laser peening

Fig. 14. Comparison chart of absolute peak stress