A new methodology to establish the relationship between equivalent shot velocity and air pressure by surface roughness for shot peening

The study of shot peening process by numerical simulation is becoming mature and efficient. Shot velocity is very important, which is related to the accuracy of simulation results. However, the actual shot peening process was directly controlled by air pressure and other parameters, instead of shot velocity. This paper details a new method to obtain the equivalent shot velocity as initial velocity used in simulation corresponding to air pressure in the actual shot peening. Firstly, under the same shot peening parameters, the linear relationship between the roughness and air pressure, and the linear relationship between the roughness and equivalent shot velocity were obtained by experiment and simulation, respectively. Secondly, the relationship between equivalent shot velocity and air pressure is established by the intermediate surface roughness. At last, the validity and reliability of the relationship be verified by arc height, residual stresses, coverage, and existing literature. In addition, this paper introduces a new method to calculate the number of shots used in combined discrete element model (DEM) and finite element model (FEM), taking into account the mass flow, nozzle movement speed and nozzle-workpiece distance, and other parameters. In this way, it is of significance to characterize the shot peening equipment rapidly and obtain the equivalent shot velocity used in the simulation to optimize the shot peening parameters in the aerospace and automotive industry.