The Carbon Nanotubes Effect into Single-lap Joint Failure Modes and Load Capacity: a Macromechanical Analysis

Monteiro, Elvis C.; Ávila, Antônio F.

doi:10.1590/1980-5373-mr-2017-0442

Cited by 11 publications

(3 citation statements)

References 26 publications

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“…A comparison was performed between the current investigation results and that found in the literature for SLJs modified with 0.5 wt% MWCNTs. Monteiro and Avila 52 found improvement in the peak force of 6.0%, 5.4%, and 6% of SLJs with bond line thickness of 0.05, 0.15, and 0.4 mm, respectively. The improvement in the maximum contact force (15.6%) and absorbed energy (15.2%) of the current study are close to those obtained for the shear strength (15.4%) of SLJs modified with 0.5 wt% MWCNT.…”

Section: Resultsmentioning

confidence: 96%

Experimental analysis of composite scarf adhesive joints modified with multiwalled carbon nanotubes under bending and thermomechanical impact loads

Khashaba

Othman

Najjar

2019

Proceedings of the Institution of Mechanical Engineers, Part L:

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Scarf adhesive joints have attracted an increasing attention in joining/repairing of carbon fiber reinforced epoxy composite structures due to their zero eccentricity, which provides lower stress distribution across the adhesive layer and better aerodynamic surfaces compared to other bonded joints. The main objective of this study is to evaluate the performance of the scarf adhesive joints in carbon fiber reinforced epoxy composites under thermomechanical impact loads, which is very important for the aerospace and automotive industries. The adhesive was modified with optimum percentage of multiwalled carbon nanotubes. The impact tests were performed at 25 ℃, 50 ℃, and 75 ℃. The residual flexural properties of the unfailed impacted joints were measured using three-point bending test. Results from impact tests at 25 ℃, 50 ℃, and 75 ℃ showed improvement in the impact bending stiffness of the modified scarf adhesive joints by 8.3%, 7.4%, and 11.8% and maximum contact force by 15.6%, 21.3%, and 18.9%, respectively. The energy at failure of the modified scarf adhesive joints with multiwalled carbon nanotubes was improved by 15.2% and 16.4% respectively at 25 ℃ and 50 ℃. At test temperature of 75 ℃, the scarf adhesive joints have hysteresis load–displacement behavior and energy–time curve with rebound energy of 35% and absorbed (damage) energy of 65%. The residual flexural strength of the modified and unmodified scarf adhesive joints is 98.2% and 86.1% respectively, while their residual moduli have remarkable decrease to 71.7% and 81.3%.

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Section: Resultsmentioning

confidence: 96%

Experimental analysis of composite scarf adhesive joints modified with multiwalled carbon nanotubes under bending and thermomechanical impact loads

Khashaba

Othman

Najjar

2019

Proceedings of the Institution of Mechanical Engineers, Part L:

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“…The addition of CNTs to epoxy systems can also improve mechanical properties, i.e., tensile strength, Young's modulus, and fracture toughness [17]. Monteiro and Avila [18] credited the load-bearing enhancement to the homogeneous distribution of carbon nanotubes around the adhesive/adherent interface. Oliva and Avila [19] even reported an increase in load bearing by around 116% for a 2.0 wt% of CNT in addition to epoxy-based adhesives.…”

Section: Introductionmentioning

confidence: 99%

Nano-Modified Epoxy Based Adhesive Testings: An Investigation into Apparent Shear Strength, Failure Modes, Chemical Functionals, and Microstructural Failure

Reis

Paixão

Monteiro

et al. 2023

Engineering Science & Technology

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Single lap joints are the most used bonded joints in engineering. Unfortunately, modeling correlations between apparent shear strength and failure modes is not an easy task. This paper tries to address relationships between apparent shear strength, failure modes, and micro-structural failures. To be able to establish a correlation between chemical changes and the failure morphology of an industrial epoxy-based adhesive nano-modified by carbon nanotubes, a series of single-lap joints were prepared and tested. For this adhesive, the ductile-like fracture is controlled by changes in the aromatic ring (C-O stretching at 1,176 cm-1, C-C stretching at 1,514 cm-1, and C = C stretching at 1,593 cm-1) and ethers group (C-O-C stretching at 1,247 cm-1). Changes in the ethers group, however, have less influence than the ones in aromatic rings. Variations in oxirane groups (C-O-C stretching at 836 cm-1, and rotations of CH2 at 695 and 756 cm-1) are more related to brittle-like microscopic failure. A small number of chemical bonds, specifically characterized by low chemical functional intensity, are associated with premature or brittle-like failure. However, concurrently, another mechanism that existed simultaneously was the ability of carbon nanotubes to alter the path of propagating cracks. This phenomenon was experimentally spotted. The macroscopic cohesive failure is controlled by the ductile-like failure at microscopic failure, while the adhesive failure is related to the brittle-like failure. Moreover, for the first time two different conditions, i.e., macroscopic quantities, apparent shear strength, failure modes, and microscopic quantities of brittle/ductile areas aspect ratios are combined in a mathematical model. This model can predict single-lap joint failure strength based on microscopic quantities.

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“…Shim et al 9 discovered that when the addition of MWCNTs reached 6% (volume fraction), the bending strength of the composites reached the maximum and had the smallest coefficient of friction. Elvis Carneiro Monteiro et al 10 studied the effect of CNTs on the failure mode and carrying capacity of single lap joints and indicated that CNTs reduced the nucleation and propagation of cracks through interactions with polymer chains, thereby improving the adhesion between adhesives. Shi c. Zhang et al 11 studied the densification of CNT‐ceramic Al 2 O 3 ceramics through nonpressure sintering and found that when the composites contained 1 vol% CNTs, their bending strength increased by 35% relative to pure Al 2 O 3 .…”

Section: Introductionmentioning

confidence: 99%

Improvement in mechanical properties of enamel via carbon nanotube addition

Wang

Zhang

et al. 2020

Int J Applied Ceramic Tech

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Enameled metal equipment exploits the strength of metal materials and the corrosion resistance of enamel; therefore, it is widely used in the chemical industry. However, the mechanical properties of the enamel restrict its service life. Multi‐walled carbon nanotubes (MWCNTs) are one‐dimensional nanomaterials with high‐specific surface area, C–C bond structure, and SP2 hybrid orbital. Herein, the effect of the dosage of MWCNTs on the mechanical properties of enamel is studied by adding MWCNTs to improve the mechanical properties of the enamel. Microscopic observation showed that the toughening mechanism of MWCNTs was mainly manifested in fracture and pull out behaviors. According to three‐point bending test, when 0.4 wt% carbon nanotubes were added, the reinforcing effect of enamel layer reached the best state. These results provide reference for optimizing the formulation of enamel and extending the service life of enamel.

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The Carbon Nanotubes Effect into Single-lap Joint Failure Modes and Load Capacity: a Macromechanical Analysis

Cited by 11 publications

References 26 publications

Experimental analysis of composite scarf adhesive joints modified with multiwalled carbon nanotubes under bending and thermomechanical impact loads

Experimental analysis of composite scarf adhesive joints modified with multiwalled carbon nanotubes under bending and thermomechanical impact loads

Nano-Modified Epoxy Based Adhesive Testings: An Investigation into Apparent Shear Strength, Failure Modes, Chemical Functionals, and Microstructural Failure

Improvement in mechanical properties of enamel via carbon nanotube addition

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