MWCNT and nano-silica hybrids effect on mechanical and fracture characterization of single lap joints of GFRP plates

Abstract

The current study aimed to explore the effects of nanoparticle hybridization on the shear and flexural performance of single lap joints (SLJs) of glass fiber reinforced polymer (GFRP) substrates. To this end, the hybridizations of multi-walled carbon nanotubes (MWCNT) and silica nanoparticles at various concentration rates were incorporated into the epoxy adhesive. Three-point bending tests and single-lap shear tests were performed to analyze in detail the effects of hybrid nanoparticle inclusions on adhesion performance under different loads. The maximum values for both shear and flexural strengths were achieved from the samples containing the combination of 0.5 wt.% MWCNT and 0.25 wt.% Nano-silica particles. The enhancements in shear strength and flexural strength were 45.4% and 63.2%, respectively, compared to pure samples. Furthermore, damage surfaces were examined via scanning electron microscopy (SEM) to investigate fracture mechanisms and failure modes. The findings demonstrated that almost all nanoparticle-doped samples, regardless of hybrid or single nanoparticle, exhibited higher load-bearing capability by increasing the adhesion ability of the additive and the adhesive. It was observed that the failure mechanisms such as crack deviation, crack pinning, pull out, bridging, etc. occurred in the nanoparticle doped adhesive joints as seen in SEM images.