Session: 12-22-01: Multiscale Models and Experimental Techniques for Composite Materials and Structures

Paper Number: 144943

144943 - The High Strain-Rate Impact Energy-Absorption Characteristics of Graphene Using Molecular Dynamics (Md) Simulations 

In recent years, the design of lightweight composite materials for structural applications in military and transportation industries has attracted the attention of the engineering community and many materials research scientists. Graphene, one of the prominent 2D carbon nanostructures and lightweight materials, has been widely proposed for lightweight applications due to its strength, lightweight, compatibility with many other engineering materials, ability to perform in extreme environments that involve both very high and low temperatures, and excellent mechanical properties. For this reason, researchers have been gearing their efforts to use the current technology and this two-dimensional material to make super durable, light and strong composite products, for making protective devices for the military, such as helmets to protect the brain against concussions, bulletproof armor velvet for solders, and lightweight structures in the transportation industries. To accomplish this goal effectively, there is a need to understand the mechanical response of graphene to different forms of loading, including impact loading.

The present experimental methods are incapable of capturing some of the complex nanoscale mechanisms associated with the energy absorption process of graphene, which can only be realized through MD simulations. Nevertheless, there has been a limited understanding of the complex phenomena that accompanied the impact energy absorption of graphene using MD. In addition, the important variables such as the size effect of the graphene, the influence of the material characteristics of the projectile, and the effect of heat generated during the impact process remained unknown. These important variables, in addition to complex damage mechanisms, are required to deepen our understanding of this nanomaterial behavior. The primary goal of this work is to further reveal the underlying complex mechanisms that accompany the impact process and provide the influence of these variables on the energy absorption of single-layer graphene using large-scale molecular dynamics (MD) simulations.

The energy absorption characteristics of graphene at high velocity impact was obtained using MD simulations and open source Molecular/Massive Parallel Simulator (LAMMPS) package. The two ballistic projectiles consisting of diamond and cubic boron nitride were modeled with this package. Moreover, their microstructures were simulated with Tersoff potentials. Fundamentally, Tersoff potential combines bonded and non-bonded terms, but the values of the bonded terms are determined using the relative distance of the multiple atoms with respect to each other. For these reasons, we used Tersoff potential, which have been proved for its precision in representing atomic interaction bonding between boron, carbon and nitrogen of both projectiles and the graphene. We assessed its atomistic and the complex deformation and damage mechanisms, as well as its energy-absorbing capacity as a change in kinetic energy (KE) before and after impact using high velocity impact ranging from 1 to 10 km/s.

The contributions in terms of graphene deformation and fracture mechanisms, and the associated energy absorption phenomena have the potential to influence materials design and stimulate innovative ideas needed for developing future composite materials and structures for the next generation of impact protection devices.

Presenting Author: Olanrewaju Aluko University of Michigan-Flint

Presenting Author Biography: Olanrewaju Aluko earned his PhD in Mechanical Engineering from Howard University, Washington DC and he is cuurently a professor at University of Michigan-Flint.

Authors:

Olanrewaju Aluko University of Michigan-Flint
Rakesh Geddam University of Michigan-Flint