A study of the effect of microstructure on liquid-solid impact

Liquid drops hit against solid surface, which has an enormous influence on the mechanical properties of base solid surface during its service. Impact of the droplet makes the solid surface and some internal section of the base solid material generate high stress. The conical microstructure may decrease the dimensionless equivalent stress in solid. We investigated the effect of the microstructure with three different sizes by numerical simulation. In the paper, detail theoretic analyses of liquid-solid impact were carried out. Here the mathematics physics model was built to solve the liquid-solid impact problem The numerical method coupling liquid and solid region was designed and the impact procedure of spherical droplet to solid materials was simulated. We acquired the pressure distribution inside water drop and the transient equivalent stress field inside solid. High stress at the solid surface and some internal sections arose from impact of the droplet. The sections in solid with highest stress can be classified into the contact edge and the axis due to stress superposition. The stress in solid declined slightly at the condition with the microstructure (5μm high and a diameter of 1μm). The microstructure (50μm high and a diameter of 10μm) in this paper considerably decreased the average stress in solid. They may store liquid and yield a liquid film higher than the thickness of the microstructure, undertaking the droplet impact and acting as a cushion to the stress concentration in solid. These results may play a role in evaluating the base solid service properties based on the fundamental solution of liquid-solid impact and be valuable to understand the internal mechanism of liquid-solid impact, and are helpful to prevent the erosion of droplet to the solid materials. © 2015 The Japan Society of Mechanical Engineers.