Research status and development of laser shock peening

Laser shock peening (LSP) is a noncontact surface strengthening technology. It has been widely used because of its advantages in applied scope and strengthening effects. LSP has made considerable progress during the past four decades, but some technical issues affecting their applications remain to be resolved, for instance, the utilization rate of laser shock energy is only about 50%, the processing adaptability of rigid confinement layer is poor, and the thickness of the flexible confinement layer represented by a water layer is difficult to control. In this paper, the current research status of LSP technology was reviewed, and an outlook was given toward further development of this technology. On this basis, a method to form composite shock waves by designing a cavity to confine the water layer is presented in this paper, which is expected to address the issues mentioned above. A preliminary simulation for analyzing the relationship between the strengthening effect and the characteristic parameters of the composite shock wave was carried out, and the simulated results were discussed. The results show that the time interval between the adjacent waves and the wave attenuation factor have significant influence on the strengthening effects, which is helpful to the cavity design.