The effect of graphene and graphene oxide on defective single lap adhesively bonded joints

Abstract

The addition of nano-additives provides a path to improve joint performance. However, it is not clear if the use of these materials can alter the susceptibility of bonded joints to the presence of defects. This work aims to shed some light on this matter, by testing the performance of defective joints bonded with adhesives modified with nano-additives. Two different kinds of carbon-based nano-platelets, including graphene (G) and graphene oxide (GO), were used in this work as additives for adhesives used to bond single lap joints (SLJs). Bulk specimens, as well as three geometrically different SLJs were manufactured and tested. One configuration was manufactured without defects (WO), another with a disbond defect in the middle of the overlap, and another with a disbond defect on the edge of the overlap, known as a side defect (SD). These specimens were bonded with a neat epoxy adhesive and with the same adhesive modified with the addition of 0.3 wt% of G and GO. The addition of G and GO was found to improve Young’s modulus and the strength of the epoxy adhesive, while also decreasing its toughness. Dual effect of G and GO addition on improving the strength of the neat epoxy and WO SLJs while reducing the strength of some defective SLJs is also discussed using FT-IR and Raman spectrometry as well as scanning electron microscope pictures of the fracture surfaces.

Investigating the energy absorption properties of sandwich panels filled with shear thickening fluid with a weight fraction of 35% under low-velocity impact

“…This design imparts the composite with a blend of high strength and diminished weight, serving as a fundamental characteristic of sandwich panels. 24,25 In this study, an investigation was conducted involving aluminum honeycomb sandwich panels encompassing diverse skin types, including aluminum sheets, 5-ply epoxy glass composites, and 5-layer STFimpregnated glass fabrics. These panels were subjected to testing under two distinct impact velocities and subsequently compared.…”

“…This design imparts the composite with a blend of high strength and diminished weight, serving as a fundamental characteristic of sandwich panels. 24,25…”

Experimental Study on the Effect of Bonding Area Dimensions on the Mechanical Behavior of Composite Single-Lap Joint with Epoxy and Polyurethane Adhesives

“…Their mechanical behavior, performance, and failure mechanisms have been the subject of numerous research studies and industrial applications. For instance, studies have focused on the mechanical performance and failure analysis of SLJs bonded with normal or smart epoxy adhesive [20][21][22]. Although there are international standards that define the geometry and testing conditions for various materials [23], different geometries and boundary conditions are used to take into account the effective working condition of the adhesive joints.…”