Compressive piezoresistive behavior of carbon nanotube sheets embedded in woven glass fiber reinforced composites

Aly, Karim; Li, Ang; Bradford, Philip D.

doi:10.1016/j.compositesb.2016.11.002

Cited by 32 publications

(20 citation statements)

References 53 publications

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“…Unlike the response of the CNT sheets to the axial compression that showed negative piezoresistivity in a previous study by the authors, 14 the CNT sheets reaction to the flexural induced compression was the opposite. Likely, the piezoresistive behavior difference resulted from the complex stress field created by the bending-induced compression.…”

Section: Monotonic Flexure Loadingcontrasting

confidence: 79%

“…The number of CNT sheets used in the current study was determined based on the results of two previous studies conducted by the authors, where the six CNT sheets layer structures exhibited very good sensitivity under the influence of both axial tension and compression. 5,14 Throughout this article, the abbreviation ''CNT layer'', is used to refer to the CNT layer consisting of six aligned CNT sheets. The localization of the CNT sheet layers was completed as follows; a stack of prepreg layers was placed on the top of a jack.…”

Section: Composite Fabricationmentioning

confidence: 99%

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In-situ monitoring of woven glass fiber reinforced composites under flexural loading through embedded aligned carbon nanotube sheets

Aly

Bradford

2018

Journal of Composite Materials

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In practical situations, the flexural loading of fiber reinforced composites is one of the most common types of loading for structures. Nonetheless, carbon nanotubes, which have been used extensively to study in-plane strain sensing in composites, have rarely been employed to monitor flexural induced strains. With this motivation, this paper introduces a novel method for localizing aligned carbon nanotube sheet layers in three selected locations inside a laminated composite structure. These top, middle, and bottom locations are more prone to damage since they experience maximum flexural induced tension, compression, and interlaminar shear stresses. The composite structural performance is monitored by establishing an electromechanical coupling between the developing strain and the three carbon nanotube sensing elements’ in-plane electrical resistance changes that are measured simultaneously. The results of the monotonic and dynamic flexural loading tests suggest that carbon nanotube sensing materials exhibit a high level of sensitivity. The results also show that the resistance change of the three embedded carbon nanotube layers appeared to track the mechanical state of the host structure well. The carbon nanotube layer embedded in the middle section showed a piezoresistive behavior in response to the growing complex stress state with a few electrical resistance change spikes corresponding to damage developing inside the laminated structure. This flexural sensing behavior may considered as useful for real applications because in addition to sensing strain, this technology may help in predicting the failure of the composite component before the actual end of service life.

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Section: Monotonic Flexure Loadingcontrasting

confidence: 79%

Section: Composite Fabricationmentioning

confidence: 99%

In-situ monitoring of woven glass fiber reinforced composites under flexural loading through embedded aligned carbon nanotube sheets

Aly

Bradford

2018

Journal of Composite Materials

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“…Furthermore, the contact area of adjacent CNT bundles changes and new conductive paths are constructed due to the distance change between neighboring CNTs at CNT junctions. [28] Additionally, the studied nanocomposite is not fully dense. This may facilitate CNTs movement and make it easier for them to come in closer contact under compression loading specially in the areas where CNTs are partially coated with PDMS.…”

Section: Piezoresistive Response Of Pdms Filled Nanocomposites Under Compression Cyclic Loadingmentioning

confidence: 99%

“…Reaching the tunneling distance within multiple local CNT networks causes the overall electrical resistance of the nanocomposite to decrease. [28] Further, the reorganization of the CNT nanofillers within the polymer matrix under mechanical deformation is also contributing to the electrical resistance change reduction. This may be understandable in light of the fact that at high strain values, the PDMS filled nanocomposite samples are compressed enough that more contact points are formed between CNTs.…”

Section: Piezoresistive Response Of Pdms Filled Nanocomposites Under Compression Cyclic Loadingmentioning

confidence: 99%

One‐step fabrication of bulk nanocomposites reinforced by carbon nanotube array fragments

2021

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Vertically aligned carbon nanotube (VACNT) array growth is an established process where high aspect ratio carbon nanotubes (CNTs) are produced. This work demonstrates one-step approach to fabricate bulk polymer nanocomposites using CNT array fragments'. Here, 4.5 mm long CNTs were collected post VACNTs synthesis. Next, CNT array fragments were coated with pyrolytic carbon (PyC) and infused with polydimethylsiloxane (PDMS) matrix to create porous CNT/PDMS nanocomposite with a CNT weight fraction of 20%. Achieving similar weight fraction with super long bundled CNTs using dispersion techniques is extremely difficult. The compression and dynamic mechanical behaviors and piezoresistive response of the PDMS filled nanocomposite were assessed. The results revealed the potential of the synthesized structure to serve as fatigue-resistant pressure sensors with high damping and self-sensing capabilities. The proposed fabrication technique is versatile, as it can work with thermosetting and thermoplastic polymers in addition to allowing for mass production of PDMS filled nanocomposites.

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“…They found that the embedded CNT presented the same tensile properties compared to those without embedding. In addition, Aly et al [20] introduced a novel embedding CNT technique for laminated composite structures to improve the sensibility, stability, and repeatability of CNT sensing layers. The mechanical test results showed that composite coupons with embedded CNT sensing networks exhibited linearity in tension and nonlinearity in compression.…”

Section: Introductionmentioning

confidence: 99%

Structural Integrity Assessment of Composites Plates with Embedded PZT Transducers for Structural Health Monitoring

Feng

2021

Materials

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Active sensing using ultrasonic guided waves (UGW) is widely investigated for monitoring possible damages in composite structures. Recently, a novel diagnosed film based on a circuit-printed technique with piezoelectric lead zirconate titanate (PZT) transducers has been developed. The diagnostic film is a replacement for the traditional cable connection to PZT sensors and has been shown to significantly reduce the weight of the host structure. In this work, the diagnosed films were embedded into composite structures during manufacturing using a novel edge cut-out method during lay-up, which allowed for edge trimming after curing. In this paper, the effect of fatigue loading on the integrity of PZT transducers is initially investigated. The electro-mechanical impedance (EMI) properties at different fatigue loading cycles were used as the diagnostic measure for the performance of the sensors. At the same time, the behaviours of UGW were investigated at different fatigue loading cycles. It was found that the EMI properties and active sensing behaviours remained stable up to 1 million cycles for the force ranges of 0.5~5 kN and 1~10 kN. Next, the effect of embedding the diagnosed film on the mechanical properties of the host composite structure was investigated. Tensile and compressive tests were conducted and the elastic modulus of composite coupons with and without embedded PZT diagnosed films were compared. The elastic modulus of composite coupons with PZT diagnosed films embedded across the entire coupon reduced by as much as 20% for tensile tests and just over 10% for compressive tests compared to the coupons without embedded sensors. These reductions are considered the worst-case scenario, as in real structures the film would only be embedded in a relatively small area of the structure.

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Compressive piezoresistive behavior of carbon nanotube sheets embedded in woven glass fiber reinforced composites

Cited by 32 publications

References 53 publications

In-situ monitoring of woven glass fiber reinforced composites under flexural loading through embedded aligned carbon nanotube sheets

In-situ monitoring of woven glass fiber reinforced composites under flexural loading through embedded aligned carbon nanotube sheets

One‐step fabrication of bulk nanocomposites reinforced by carbon nanotube array fragments

Structural Integrity Assessment of Composites Plates with Embedded PZT Transducers for Structural Health Monitoring

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