The effect of coating layer in liquid–solid impact problem

The repeating impacts of high-velocity water drops have an enormous effect on the mechanical properties of the base solid surface during its service. A mathematics physics model to solve the liquid–solid impact problem is built and emphasis is put on the effect of coating layer. The pressure distribution inside the water drop and the transient equivalent stress field inside the base solid are obtained by numerical simulation. The impact stress concentration presents on the solid surface and certain internal section under the surface. The coating layer on the base solid can decrease the dimensionless equivalent stress in the solid, which can be helpful to prevent the fracture of the base solid. The dimensionless equivalent stress fields in the base solid under the coating layers of various thickness (1 µm, 2 µm, 5 µm, 10 µm) are compared and the economical coating thickness suggested is about 5–10 µm. The relationship between the dimensionless equivalent stress and the impact Mach number is also provided. These results based on the fundamental solution of liquid–solid impact may improve the performance of the coating layer that protects the base solid from liquid drop impact.