Investigation of the impact fracture behavior of multi-walled carbon nanotube/epoxy nanocomposite adhesively bonded joints using an energy-based method

The fracture behavior of adhesive joints reinforced with varying weight percentages of multi-walled carbon nanotubes (MWCNTs) was investigated under quasi-static and impact loads. A double cantilever beam specimen was used to analyze the opening-mode (mode-I) fracture behavior. The critical strain energy release rate was determined for the unfilled and MWCNT-filled adhesive joints using an energy-based method. The results showed that the incorporation of 0.3 wt% MWCNTs into the adhesive layer increased the fracture energy of the adhesive joint by 72% under quasi-static loading and 16.2% under impact loading, with corresponding increases in maximum force of 73.2% and 16% compared to the unfilled adhesive, respectively. Scanning electron microscope images of the fracture surfaces revealed nanofiller debonding and pull-out as the reinforcing mechanisms of MWCNTs. The fracture response of the specimens was simulated using a cohesive zone model and a bi-linear traction-separation law.