Parametric Study of Strain Rate Effects on Nanoparticle-Reinforced Polymer Composites

Crashworthiness, energy absorption capacity, and safety are important factors in the design of lightweight vehicles made of fiber-reinforced polymer composite (FRP) components. The relatively recent emergence of the nanotechnology industry has presented a novel means to augment the mechanical properties of various materials. As a result, recent attempts have contemplated the use of nanoparticles to further improve the resiliency of resins, especially when resins are used for mating FRP components. Therefore, a comprehensive understanding of the response of nanoreinforced polymer composites, subjected to various rates of loading, is of paramount importance for developing reliable structures. In this paper, the effects of nanoreinforcement on the mechanical response of a commonly used epoxy resin subjected to four different strain rates, are systematically investigated. The results are then compared to those of the neat resin. To characterize the mechanical properties of the nanocomposite, a combination of the strain rate-dependent mechanical (SRDM) model of Goldberg and his coworkers and Halpin-Tsai’s micromechanical approach is employed. Subsequently, a parametric study is conducted to ascertain the influences of particle type and their weight percentage. Finally, the numerical results are compared to the experimental data obtained from testing of the neat and the nanoreinforced epoxy resin

Changes in oriented graphitic carbon properties upon exposure to atomic hydrogen

The oriented carbon nanostructures deposited at low and high temperatures (OCLT and OCHT) containing distinct sp2 fractions are synthesized using filtered cathodic vacuum arc (FCVA) deposition system. Then, the effect of atomic hydrogen content on the degree of graphitization of carbon thin film is investigated over working temperature intervals from room temperature up to 200 °C using in situ Raman spectroscopy. In fact, above 120 °C, the Pt catalytic activity nonlinearly elevates according to spillover of plentiful hydrogen atoms. As a consequence, this gives rise to sp2-sp3 transition of OCLT nanostructure leading to drastic change of optical and electrical properties. Furthermore, we have shown that OCLT and OCHT behave reciprocally to change over sp2/sp3 ratios