Investigation of Dynamic Impact Response of PMMA-Graphene Layered Nanocomposite Films Using Molecular Dynamics Simulations

Polymer nanocomposite films show superior energy dissipation capability with the advancement of the micro-projectile impact testing method. However, the detailed stress wave propagation and dynamics failure mechanisms during the extreme rate impact loading process have remained elusive. We will report our recent effort to understand these mechanisms through the lens of molecular dynamics (MD) simulations. We have constructed representative layered nanocomposites consisting of PMMA and graphene phases by using their corresponding coarse-grained models and applied MD simulations to study their dynamic impact responses. A piston impact process has been simulated. By analyzing the spatiotemporal distribution of tensile stress and cross-section density, we find that the internal interfaces between graphene and PMMA can reflect, redirect, and attenuate the stress waves. Our results also indicate that the interfacial energy between PMMA and graphene plays an important role in the energy dissipation process, especially with densely distributed graphene layers. Our study provides insights into the design of nanocomposite films with excellent impact resistance through the configuration and distribution of the rigid nanofillers in a soft matrix and their interfacial interactions.