Micromechanical simulations and experimental characteristics of randomly distributed carbon nanotubes reinforced Mg matrix composites

Abstract

In this study, finite element analysis was performed using representative volume elements (RVE). The cohesive zone model was implemented to govern the failure behavior of the CNTs/matrix interface. The RVE to understand the micromechanical response and damage behavior of randomly distributed carbon nanotubes (CNTs)/Mg matrix composites (MMCs). The cohesive zone model was implemented to govern the failure behavior of the CNTs/Mg interface. The RVE for macroscopic structural analysis was strained under assumed boundary conditions, where it provided a stress-strain curve for the composite. The simulation data can achieve excellent agreement with the experimental results. The simulations and experimental results indicate that the initial damage in the composite occurs in the vicinity of CNTs. The stress concentration at the CNT end increases with the increasing tensile load, resulting in interfacial debonding, the main form of crack growth of the CNTs/Mg composite. The CNTs can passivate the crack tip and change the propagation direction of the main crack, causing a delay in fracture. CNTs played an important role in governing the fracture pattern of composite. The pullout and bridging of CNTs were the main strengthening mechanisms of the composites, which was beneficial for improving strength and toughness.