Molecular Dynamics Study on Impact Resistance of Ag-PMMA Composite Films

It is very important for semiconductor manufacturing and small particle protection to study the dynamic impact response of nano-scale multi-layer composite structures. Molecular dynamics simulation was used to investigate the impact resistance of Ag-PMMA composite films supported with Si substrates in this paper. The energy dissipation mechanism of the metal polymer composite film supported on the substrate was explored through contact force response, kinetic energy loss, stress wave propagation, dislocation and damage evolution, and penetration depth. The results show that the impact process includes local compression stage and global deformation stage. During the local compression stage, the atoms in the contact region of Ag surface directly transform into amorphous structures due to the stress concentration effect under high-speed impact, so the contact force reaches the peak of the whole penetration process. The thickness of the film mainly affects the global deformation stage. The thinner composite film is obviously limited by the action of the substrate, and the penetrating damage occurs directly under the high-speed impact. However, the thicker composite film dissipates the kinetic energy of the bullet through a large number of Ag dislocations and PMMA elastic deformation, which can give full play to the material performance of each layer.