Effect of Selective Laser Shock Peening on Vibration Response of 2024 Aluminum Alloy Blade

This work aims to investigate the influence of laser shock peening on the vibration performance of the 2024 aluminum alloy blade and to find the optimal shock parameters. The Johnson-Cook model was used to simulate the selective laser shock peening process. The residual stress field and gradient density generated in the laser shock peening process of 2024 aluminum alloy were imported into the finite element simulation to analyze the vibration response. The effect of laser shock peening on the vibration characteristics was quantified, and the influence of laser shock parameters on the vibration response was studied. The residual compressive stress field generated by laser shock peening is distributed in a nonuniform way on the surface that it only exists in the impact area, while the residual tensile stress exists in the regions out of the impact area. The maximum residual compressive stress is 273.5 MPa. Selecting the sixth vibration mode as the target mode, the finite element simulation matches the vibration test well at the same laser shock peening condition. The contribution of the residual stress is larger than gradient mass density on the change of the frequency and amplitude of the sixth vibration mode. By manipulating the laser shock peening parameters, the most significant improvement of vibration characteristics can be obtained when a larger circular laser spot with larger peak pressure is applied in the middle of the model; the most appropriate laser shock peening parameters can reduce the frequency of vibration by 118.87 Hz, the amplitude can be reduced by 94.37%.