Nanoscale impact dynamics using molecular dynamics simulation

Molecular dynamics simulation is used to investigate dynamic impact behavior at the nanoscale. The classic many-body tight-binding potential is employed to model the atomic force acting between atoms. The impact model of a Cu sphere cluster hitting a Cu substrate is established. Investigated issues include dynamic cluster/substrate interactions, substrate deformation, substrate fracture characteristics, force transmission, energy transformation between cluster and substrate, cluster motion characteristics, debris cloud formation characteristics, and the characteristics of the dynamic impact behavior at different cluster incident energies. The results show that an elastic necking phenomenon behavior is found for the case of clusters landing at the relatively low incident energy of 0.1 eV/atom. The phenomenon of impact hole recovery, which is the result of interatomic attractive forces applied by the substrate on the cluster atoms, is observed at an incident energy of 2eV. In this situation, the cluster atoms join those of the substrate. At the higher incident energies of 5 and 50 eV, a significant number of the substrate atoms dissociate themselves from the substrate structure and form a debris cloud. Additionally, it is determined that unlike lower incident energy impacts, substrate deflection does not occur immediately upon cluster penetration of the substrate for elevated incident energies. Finally, it is found the substrate removal rate is a key factor in determining the distribution density of the debris cloud.