Computational design of graphene sheets for withstanding the impact of ultrafast projectiles

Molecular dynamic studies into the comparative optimization of thermo-mechanical characters of nano-composites of Ag and Cu reinforced by Graphene

This article fundamentally aims at the comparative study of thermo-mechanical characters of Gr/Ag and Gr/Cu nano-composites. For demonstration purposes, three dimensions that is, (1 0 0), (1 1 0) and (1 1 1), of the metals attached with single layer Graphene sheet are considered. The study is facilitated by the adaptation of the molecular dynamic simulations of the soft LAMMPS to mimic the broad range of experimental environment. The attributes of each structure and their orientations are elaborated over wide range of experimental states, encompassing temperature ranging from 300 K to 1500 K, to assess the melting behavior. The thermal and structural properties are explored by employing mean square displacement (MSD) and radial distribution function (RDF). Furthermore, the mechanical characters are elaborated along both arm-chair and zigzag directions. The findings are supported by producing relevant graphical displays of stress-strain curves and generating extravagant depictions of various dislocations with the application of visual molecular dynamics (VMD) tool. On the basis of intense and careful computational investigations, we witnessed that the Gr/Cu (1 1 1) orientation produced most profound melting characteristics along with distinctive strengthening and fracture mechanism. These outcomes are consistent in comparison of both Gr/Metals layered structures and also with respect to all considered metallic orientations. The findings are discussed thoroughly in a well-structured and synchronized fashion throughout the article.

Dynamic penetration behaviors of single/multi-layer graphene using nanoprojectile under hypervelocity impact

Single/multilayer graphene holds great promise in withstanding impact/penetration as ideal protective material. In this work, dynamic penetration behaviors of graphene has been explored using molecular dynamics simulations. The crashworthiness performance of graphene is contingent upon the number of layers and impact velocity. The variables including residual velocity and kinetic energy loss under different layers or different impact velocities have been monitored during the hypervelocity impact. Results show that there exists deviation from the continuum Recht–Ipson and Rosenberg–Dekel models, but these models tend to hold to reasonably predict the ballistic limit velocity of graphene with increasing layers. Besides, fractal theory has been introduced here and proven valid to quantitatively describe the fracture morphology. Furthermore, Forrestal–Warren rigid body model II still can well estimate the depth of penetration of multilayer graphene under a certain range of velocity impact. Finally, one modified model has been proposed to correlate the specific penetration energy with the number of layer and impact velocity.

Theoretical study of collision dynamics of fullerenes on graphenylene and porous graphene membranes

A comparative study regarding the behavior of graphene, porous graphene and graphenylene monolayers under high energy impact is reported. Our results were obtained using a computational model constructed to perform investigations of the dynamics of high velocity fullerenes colliding with free standing sheets of those materials. We employed fully reactive molecular dynamics simulations in which the interatomic interactions were described using ReaxFF force field. During the simulations, free standing monolayers of the investigated materials were submitted to collision with a C60 fullerene molecule at impact angles within the range 0°≤θ≤75°. We considered kinetic energies in the range 0eV≤E_k≤1500eV, that corresponds to a projectile velocity v in the range 0Å/fs≤v≤0.2Å/fs. Also, the failure dynamics of each one of the 2-dimensional materials is described in a comparative analysis in which relevant differences and unique features observed in the mechanical stress dissipation processes are highlighted. Finally, performing hundreds of simulations we were able to map many possible scenarios for these collisions and to construct diagrams that elucidate, for each one of the materials, the possible behaviors under the action of a highly energetic C60 projectile as a function of energy and incident angle.