The smoothed particle hydrodynamics (SPH) method, one of meshfree methods, is developed to simulate the interaction between multi-droplets and substrate with solidification. However, the SPH method for this complicated problem needs a large amount of computing time, since it has to use a large number of the SPH particles to represent multidrops and substrate. All-pair search and linked list algorithms are popular in the neighbor search, which is the most time consuming part of the SPH calculation. Both algorithms are tested in this paper. For the solidification process, since the volume of the melt is decreased continuously, a new method is proposed to speed up the SPH calculation. The new treatment is used to handle the particles near the free surface and near the solidification interface Multi-droplets impinging on a smooth substrate in 2D and 3D are simulated to demonstrate the capability of current numerical method on simulating the spreading and solidification of multi-droplets.

Numerous studies have addressed the effect of grain size of materials on the overall penetrating performance of warheads. However, the use of the forging process to illustrate the grain heat-treatment refining technology has not been reported. In this experiment, the grain size of copper was observed and evaluated during the main processes of preparing copper shaped charge liners using the die forging process. Through this study, the evolution law for the structure of copper shaped charge liners was examined. In the as-cast condition, the grains of the copper ingots were mostly evenly distributed large flaky equiaxed crystal. Pre-forging and die forging make the grains appear more like strips. After the recrystallization heat treatment, the grain size of the copper shaped charge liner was refined and more uniform. Using these results, this study presents an evolution curve for copper shaped charge liners prepared using the forging process. The results can be used as a technical reference to solve the problem of grain size deviation in the production process of copper shaped charge liners.