Requirements of amount of carbon nanotubes for damage detection in large polymer composite structures

Naghashpour, Ali; Hoa, Suong V.

doi:10.1016/j.polymertesting.2017.08.013

Cited by 6 publications

(6 citation statements)

References 15 publications

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“…The uniformity of the electrical resistances across grid points in the composite structure depends on the amount of CNTs used and the degree of mixing. 18,23,24 It is important to assure that there is a certain degree of uniformity of electrical resistance between the grid points before the mechanical loading. This is to eliminate any effect of non-uniform loading on the occurrence of random failure.…”

Section: Resultsmentioning

confidence: 99%

“…By attaching the conductive grid points made from silver-epoxy paste on the surface of composite coupon samples, it was then possible to detect the occurrence of damages within the composite coupon samples in situ. For larger composite structures, it has been shown that an optimal amount of CNTs should be used to provide the uniformity of electrical conductivity and connectivity (course mesh) 23 for the detection and location of through-hole and impact damages in large composite structures. 24,25 The same methodology has been used to detect and locate the crack jumping, and the relationship between the location of the first matrix crack and the final location of failure in large composite panels.…”

Section: Introductionmentioning

confidence: 99%

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A technique for in-situ detection of random failure in composite structures under cyclic loading

Naghashpour

Hoa

2019

Journal of Composite Materials

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A technique to detect the random failure in composite structures is presented. The epoxy matrix material is made conductive by the incorporation of carbon nanotubes. The modified matrix is used to fabricate glass fiber/epoxy/carbon nanotubes composite panels. Conductive grid points made from silver-epoxy paste are attached on the surface of the composite panels, so that electrical resistances in the regions between the grid points can be measured. The increase in electrical resistance between grid points is used to determine the increase in deformation (and possibly cracks) at the region between the grid points. It is found that the location of maximum increase in electrical resistance jumps from point to point as the number of cycles during fatigue loading is increased. This shows the random nature of the development of damage in the composites. The technique can detect the occurrence of early failure, usually in the matrix materials. The result of this work brings out the random nature of the early failure in composites. This also sheds light into whether the concept of crack initiation in composites is valid, since the early cracks jump around. When the paths of the final cracks reach stability, there is rapid crack propagation leading to fast final failure.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A technique for in-situ detection of random failure in composite structures under cyclic loading

Naghashpour

Hoa

2019

Journal of Composite Materials

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“…A new method for the measurement of the through-thickness strains by adding CNTs in glass-epoxy composite laminates has been reported by Naghashpour and Hoa [57]. They also pointed out that adding more CNTs would reduce the sensitivity for damage detection when the number of CNTs met a certain lower limit requirement [58]. Aly et al [59] embedded aligned carbon nanotube sheets into the interlaminar region of fiber-reinforced polymer composites to function as damage detecting and strain sensing elements.…”

Section: Damage Sensing or Structural Health Monitoringmentioning

confidence: 99%

Towards next-generation fiber-reinforced polymer composites: a perspective on multifunctionality

Luan

Movva

Wang

et al. 2019

Funct. Compos. Struct.

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Polymer composite materials and structures with multiscale additives have great potential applications in various fields due to their outstanding features, such as extraordinary mechanical, thermal, electrical, and other properties. Multifunctionality can be achieved by exploiting these properties for practical applications. Next-generation fiber-reinforced polymer (FRP) composites will have significant secondary functions besides their conventional primary feature-high strengthto-weight ratio. A key concept that would enable the large-scale manufacturing and application of multifunctional FRPs is 'design for multifunctionality', which uses material design tools, such as integrated computational materials engineering (ICME), to facilitate innovations in materials. In this review, we examined recent research and studies on novel functions of FRPs and the matrices, reinforcements, and fillers that enable these functions. The functions included in the scope of this study include sensing, actuation, self-healing, heat resistance, thermal insulation/dissipation, electrical isolation/conduction, energy harvesting, electromagnetic shielding, etc. In addition, the design, modeling, and manufacturing processes of these functional FRPs were discussed. This review aims to serve as a collection of knowledge that supports the ICME of next-generation FRPs and a catalog of function enablers from the novel material developers' perspective.

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“…On the other hand, 2D studies are relatively new and mostly focus in using carbon nanotubes with glass‐fibre reinforced panels to detect circular damages (holes) . Dealing with 2D evaluation of the data, most research groups concentrated on the electrical impedance tomography (EIT) method for damage assessment on electrically conductive panels.…”

Section: Introductionmentioning

confidence: 99%

“…The results show that the method was successfully detecting and locating the damages although the detected sizes are always overestimated. Naghashpour et al used a technique consisting of two sets of grid points (electrodes) that were mounted on the surface of carbon fibre/MWCNT/epoxy panels of size (22 in. × 13 in.).…”

Section: Introductionmentioning

confidence: 99%

Self‐sensing damage in CNT infused epoxy panels with and without glass‐fibre reinforcement

Ikikardaslar

Delale

2018

Strain

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The objective of the study is to utilise a material's inherent electrical conductivity as means of damage quantification and damage location detection. After determining the percolation threshold for a carbon nanotube (CNT)‐epoxy mixture, an optimum concentration was chosen to infuse it into glass‐fabric reinforced panels to make them electrically conductive. Two different multiwalled CNT‐epoxy composites were manufactured for this study: CNT enhanced epoxy resin and glass‐fabric reinforced CNT epoxy resin. Epoxy resin‐based glass‐fabric reinforced composite panels enhanced with carbon nanotubes were manufactured with embedded electrodes and then subjected to damages. Rectangular panels of various proportions were studied. Disks made out of copper foil were affixed to surfaces of CNT epoxy panel, whereas in glass‐fabric CNT epoxy specimen, total of 64 electrodes (grid of 8 × 8) were embedded inside the composite panel under the top layer of the 10‐ply fabric. The disks acted as electrodes, enabling voltage measurements using in‐line 4‐probe technique, which minimises contact resistance between the electrodes and the material. Two different configurations of electrode network were employed to scan voltage change in the entire composite panel. The networks included evenly spaced (3 in. for inner ones) electrodes that spanned the surface of the panel. To further investigate influence of electrodes distribution, finite element simulations were used to solve the electrical potential distribution in the panel for various damage sizes and location. Predamage and postdamage voltage field was used as gauge in sensing the damage and its extent for quantification. The finite element method simulation results matched the experimental data closely. The results indicate that there is a consistent behaviour that can be correlated to the size and location of the damage. As spacing between electrodes is increased, they become less responsive to smaller damages. Forty‐eight electrodes (out of 64) were actively used and were enough to confirm that the method can be used as an alternative to electrical tomography method where fewer (boundary) electrodes per area are employed but at a higher cost of computational cost. One important aspect of this study with embedded and distributed electrodes is the fact that the method can be applied to larger panels increasing its utility in practical applications.

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Requirements of amount of carbon nanotubes for damage detection in large polymer composite structures

Cited by 6 publications

References 15 publications

A technique for in-situ detection of random failure in composite structures under cyclic loading

A technique for in-situ detection of random failure in composite structures under cyclic loading

Towards next-generation fiber-reinforced polymer composites: a perspective on multifunctionality

Self‐sensing damage in CNT infused epoxy panels with and without glass‐fibre reinforcement

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