Fracture energy of CNT/epoxy nanocomposites with progressive interphase debonding, cavitation, and plastic deformation of nanovoids

Abstract

The characteristics of the debonding process zone involving macroscale, microscale, and nanoscale mechanisms along CNT interface influence the fracture behavior of nanocomposites and their structural integrity. In current article, a multi-scale and multi-mechanism modeling approach with a cylindrical RVE comprising CNT, interphase, and matrix is developed to assess such damage progression and energy dissipation occurring at the nanoscale. The model considers the dominant damaging phenomena emerging in CNT/epoxy nanocomposites, that is, CNT debonding with an interphase zone around nanoparticles, cavitation, and plastic deformation of nanovoids. Enhancement of fracture toughness with the weight fraction of CNT is investigated with a qualitative variation of geometric and mechanical properties of the interphase, cavitation, and plastic yielding adopting strain energy release rate procedures. The fracture energy is shown to be critically influenced by the stiffness ratio of interphase to the matrix, interphase thickness, and hardening exponent. The model is validated using experimental and analytical data.

Stiffness enhancement of polymer nanocomposites via graphene nanoplatelet orientation

“…As a result, these properties of polymer composites are also utilized in creating and UAVs at the NASA, where the primary focus is on prolonged, high-altitude flights. [1][2][3][4][5][6][7][8][9][10] However, epoxy resins have poor mechanical, chemical, and thermal qualities when uncured. Upon curing with an appropriate agent, they form a thermoset 3D cross-linked structure, significantly improving their properties.…”

“…With remarkable attributes such as large surface area, strength, conductivity, and flexibility, researchers have sought to integrate it into epoxy matrices to enhance material properties. 5,7,[9][10][11][12] Graphene-based epoxy composites exhibit exceptional mechanical characteristics due to the unparalleled properties of graphene. As a carbon allotrope, graphene manifests unparalleled strength, stiffness, and remarkable electrical and thermal conductivity.…”

Magnetic field induced alignment of graphene nanoplatelets in epoxy resin to develop model nanocomposite

“…In the last decade, several functional properties of polymer matrix have been modified at much lower loadings with reinforcement of graphene compared to conventional micro reinforcements. 4–10 Notwithstanding, the improvements in properties of the so constituted graphene nanocomposites are still much lower than the theoretical predictions. Meeting with little success, this has become a challenge to prepare with effectiveness a graphene base nano material for advanced structural applications.…”

“…The equation (10) may conveniently be used to calculate the amount of time required to get from the initial angular position of the easy axis ðθ i Þ to a generic angular position θ w.r.t magnetic field:…”

Experimental characterization optimizing the alignment parameter for GNP epoxy base nanocomposite via a weak DC magnetic field

“…This anisotropy contributes to the unique and exceptional properties of graphene, making it a highly sought‐after material for various applications. The discovery of graphene has revolutionized scientific research, offering new possibilities for developing advanced materials with unprecedented properties and opening doors to innovative technologies across multiple disciplines 1–9 …”