Investigating on the influence of multi‐walled carbon nanotube and graphene nanoplatelet additives on residual strength of bonded joints subjected to partial fatigue loading

Abstract

Adhesively bonded joints in engineering structures, especially automotive body structures, inevitably experience long or limited fatigue loading conditions. In this article, the shear strength of steel bonded lap joints reinforced by multi-walled carbon nanotube (MWCNT) and graphene nanoplatelet (GNP) were evaluated after being subjected to limited fatigue loading cycles. For this purpose, three specimen groups of neat, MWCNT, and GNP-reinforced joints (with 0.2, 0.5, 1.0, and 2.0 wt% contents) were prepared. After performing the static lap shear tests, fatigue testing of each specimen group was conducted under a maximum fatigue load of 50% of its average static failure load until complete separation of the substrates. Accordingly, limited fatigue loadings were applied to each specimen group for 30%, 50%, and 70% of its total fatigue life, and subsequently, a secondround static testing was performed to evaluate the residual strength of the joints.The results revealed that the maximum static shear strength improvements of MWCNT and GNP-reinforced joints were associated with incorporating 1.0 and 0.5 wt% particle contents. Moreover, for 0.2 and 0.5 wt% contents, the static strength of the joints reinforced by GNPs was 3.4% and 3.9% greater than that of MWCNTs reinforced joints. On the contrary, for 1.0 and 2.0 wt% filler contents, specimens including MWCNTs had 9.1% and 18.6% higher strength than GNP-reinforced ones. The highest fatigue life enhancements of 34.1% and 31% were obtained by adding 1.0 and 0.5 wt.% of MWCNT and GNP particles to the adhesive, respectively. It was concluded that, for 0.2 and 0.5 wt% contents, nanoparticle type did not have a noticeable effect on the residual strength of the joints after being subjected to fatigue loading for 30% of its total life. The specimens subjected to 50% and 70% of their total fatigue life indicated a minimum loss in the shear strength for the joints reinforced by dispersing 1.0 wt% of MWCNTs.

Investigation on the Properties of Multiwall Carbon Nanotube‐, Graphene‐, and Fullerene‐Reinforced Hot‐Extruded AA7075 Matrix Composites

“…Aluminium matrix and carbon reinforcements do not appear to react with one another. No intermetallic phases were found among aluminium alloy and nicotinamide (NCT) samples in this DSC investigation, and this is in contrast to the findings of [35].…”

Probing the effect of post-curing and halloysite nanotube reinforcement on thermo-mechanical properties of lightweight epoxy syntactic foam composites

“…The nanofiller reinforcing mechanisms such as load transfer and pull-out mechanism make the material bear more load before its failure, attributing to the enhanced mechanical properties of the composites, as previously reported. 61,62 Figure 12 shows the fractured surfaces of the post-compression test of RSF composites. In Figure 12(a), SF0 possesses rough exteriors upon its fracture.…”

Influence of moisture absorption on the compressive behavior of halloysite nanotube reinforced buoyant nanocomposite foams for maritime applications

“…The morphology of HNTs shown in Figure 7 depicts the crack‐pinning effect involving the creation of such a network of obstacles that impedes the propagation of cracks in the matrix. The reinforcement effect involves adding strength and stiffness to the matrix through the incorporation of high‐strength and high‐aspect ratios of nanofillers 66–68 . These mechanisms make epoxy composites with nanotubes better suited for high‐stress applications such as aerospace, automotive, and maritime industries.…”

“…The reinforcement effect involves adding strength and stiffness to the matrix through the incorporation of high-strength and high-aspect ratios of nanofillers. [66][67][68] These mechanisms make epoxy composites with nanotubes better suited for high-stress applications such as aerospace, automotive, and maritime industries. Figure 8 shows peculiar features of HNTs, showing a hollow lumen (Figure 8A), which is capable to carry epoxy resin into the lumen and thus exhibits efficient stress transfer in the composites, as corroborated by our previous study.…”