Graphene nanoplatelet (GNP)/poly(methyl methacrylate) (PMMA) nanocomposite solution was spray coated on a glass fibre reinforced polymer composite (GFRP) beam with different initial electrical resistance (R0). Scotch tape erosion method was used to tailor the R0 of the sensors. Beams and the sensors were characterized by computed tomography (CT) and scanning electron microscopy (SEM) respectively. The piezoresistive behaviour of these sensors was evaluated in monotonic, step and cyclic loading conditions. These spray coated sensors offered good sensitivity (38.5 times) as compared to a strain gauge. A gauge factor (GF) of 55±0.5, 70±2, and 77±1 was obtained for R0 of 1, 7 and 21 kΩ GNP layers, respectively. Sensors showed good response and stability under the step and cyclic loading conditions. The ease in the process of application coupled with good sensitivity demonstrates that the GNP/PMMA spray coated sensor can be a potential candidate for the futuristic multi-functional materials for structural health monitoring. © BME-PT.

Krishnan Balasubramaniam

Department of Mechanical Engineering

Debadatta Sethy

Coated materials

Coatings

Computerized tomography

Cyclic loads

Esters

Fiber reinforced plastics

Functional materials

Graphene

Nanostructured materials

Plastic coatings

Scanning electron microscopy

Strain gages

Structural health monitoring

Cyclic loading conditions

Electrical resistances

GLASS FIBRE REINFORCED POLYMERS

Methyl methacrylates

Multi-functional materials

Piezo-resistive

PIEZORESISTIVITY

Polymer composite

Polymer matrix composites

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Express Polymer Letters

Graphene-polymer nanocomposite films show good piezoresistive behaviour and it is reported that the sensitivity increases either with the increased sheet resistance or decreased number density of the graphene fillers. A little is known about this behaviour near the percolation region. In this study, graphene nanoplatelet (GNP)/poly (methyl methacrylate) (PMMA) flexible films are fabricated via solution casting process at varying weight percent of GNP. Electrical and piezoresistive behaviour of these films is studied as a function of GNP concentration. Piezoresistive strain sensitivity of the films is measured by affixing the film to an aluminium specimen which is subjected to monotonic uniaxial tensile load. The change in resistance of the film with strain is monitored using a four probe. An electrical percolation threshold at 3 weight percent of GNP is observed. We report non-monotonic piezoresistive behaviour of these films as a function GNP concentration. We observe an increase in gauge factor (GF) with unstrained resistance of the films up to a critical resistance corresponding to percolation threshold. Beyond this limit the GF decreases with unstrained resistance. © BME-PT.

Non-monotonic piezoresistive behaviour of graphene nanoplatelet (GNP)-polymer composite flexible films prepared by solvent casting

Functionalized graphene-polyvinylidene fluoride (f-G-PVDF) nanocomposite films were synthesized using a simple solvent casting technique. The investigation demonstrates the real time strain response of f-G-PVDF nanocomposites on the macro-scale under tensile loads and the use of this nanocomposite as strain sensor. This is ascribed to the variation of electrical properties of graphene-polymer upon mechanical deformation at the nanoscale. © 2011 The Royal Society of Chemistry.

Journal of Materials Chemistry

Functionalized graphene reinforced thermoplastic nanocomposites as strain sensors in structural health monitoring

The feasibility of imaging low-velocity impact damage in thin multi-layered composite plates using Lamb wave tomography is explored. Low-velocity impact damages (6-20 J) are induced by the drop-weight method on graphite fiber epoxy matrix composite laminates of cross-ply and quasi-isotropic lay-up and the damage assessment is carried out by conventional C-scans and ultrasonic Lamb wave tomography. Lamb wave based tomography based on modified cross-hole sensor configuration is used to image the damage as a function of impact energy for graphite composite plates. The reconstructed tomograms are able to capture the lateral extent of the damage even for impact energies as low as 11 J in a 2 mm graphite epoxy quasi-isotropic lay-up sample that can be classified as barely visible impact damage. Copyright © 2006 SAGE Publications.

Structural Health Monitoring

Structural health monitoring of fiber-reinforced composite plates for low-velocity impact damage using ultrasonic Lamb wave tomography

Nano Research

A low-cost, printable, and stretchable strain sensor based on highly conductive elastic composites with tunable sensitivity for human motion monitoring

Materials Research Express

Cyclic loading behaviour and crack monitoring potential of graphene nanoplatelet (GNP) based strain sensors in simple structures

Piezoresistive behaviour of graphene nanoplatelet (Gnp)/pmma spray coated sensors on a polymer matrix composite beam

Journal	Express Polymer Letters
Publisher	BME-PT and GTE
ISSN	1788618X
Open Access	Yes