Fig. 1. Morphology of oxidation film on the aluminum alloy substrate

Fig. 2. Macro appearances of the substrate cleaned by nanosecond pulse laser with different frequencies.

Fig. 3. Surface morphologies of the substrate observed at 500 times magnification. (a) 5 kHz; (b) 10 kHz; (c) 20 kHz

Fig. 4. Cleaned interface with different pulse frequencies. (a) 5 kHz; (b) 10 kHz; (c) 20 kHz

Fig. 5. Geometric model and mesh generation

Fig. 6. Power density-time distribution of pulse laser

Fig. 7. Schematic of thermal boundary conditions

Fig. 8. Schematic of boundary conditions of solid mechanics module

Fig. 9. Temperature fields and ablation morphologies at different frequencies (t=0.001 s)

Fig. 10. Laser cleaning depth and ablative amount at different frequencies. (a) 5 kHz; (b) 10 kHz; (c) 15 kHz; (d) 20 kHz; (e) 25 kHz; (f) change of paint ablative amount with frequency

Fig. 11. Location of domain probe

Fig. 12. Maximum stress versus frequency for the interface between coating and substrate

Fig. 13. Variation of maximum thermal stress with pulse energy density

Fig. 14. Stress of probe point at different frequencies