Structural health monitoring relies on routine inspection and maintenance to ensure safe operation and optimized service life of critical structures. Surface strain measurements can provide an important indicator of structural condition. Established strain sensor technologies, such as resistance strain gages and fiber Bragg grating (FBG) sensors, as well as some newer ones, [1–3] are all point-wise, unidirectional, and contact sensing methods that require physical connections in order to obtain strain readings. Some existing full-field non-contact optical methods have also been developed, such as interferometric techniques, non-interferometric techniques,[5–7] and Raman spectroscopy. The interferometric techniques usually require a model of actual structure, plus tedious calculations to separate the values of principal stresses, and expensive equipment. The limitation of non-interferometric techniques lies in the requirements for a random gray intensity distribution or speckle pattern distribution and heavy dependence on the quality of the imaging system. Over the past twenty years, Raman spectroscopy has also been investigated for strain sensing applications by many researchers.[8– 12] However, Raman-based strain sensing methods are hampered by the low intensity of Raman scattering signals. A more promising approach for non-contact strain sensing technology uses carbon nanotube fluorescence.
 Yong Y. A novel piezoelectric strain sensor for simultaneous damping and tracking control of a highspeed
nanopositioner. IEEE/ASME Transactions, (2013) 18(3), 1113–1121.
 Azevedo RG, Jones DG, Jog A V, et al. A SiC MEMS Resonant Strain Sensor for Harsh Environment
Applications. IEEE Sensors Journal, (2007) 7(4), 568–576.
 Dharap P, Li Z, Nagarajaiah S, Barrera E V. Nanotube film based on single-wall carbon nanotubes for
strain sensing. Nanotechnology, (2004) 15(3), 379–382.
 Ajovalasit A, Petrucci G, Scafidi M. RGB photoelasticity: review and improvements. Strain, (2010)
 Goldrein H, Palmer S, Huntley J. Automated fine grid technique for measurement of large-strain
deformation maps. Optics and Lasers in Engineering, (1995) 23(195), 305–318.
 Pan B. Full-field strain measurement using a two-dimensional Savitzky-Golay digital differentiator in
digital image correlation. Optical Engineering, (2007) 46(3), 033601.
 Hamada S, Fujisawa T, Koyama M, Koga N, Nakada N, Tsuchiyama T, Ueda M, Noguchi H. Strain
mapping with high spatial resolution across a wide observation range by digital image correlation on
plastic replicas. Materials Characterization, (2014) 98, 140–146.
 Zhao Q, Frogley MD, Wagner HD. Direction-sensitive strain-mapping with carbon nanotube sensors.
Composites Science and Technology, (2002) 62(1), 147–150.
 Li Z, Dharap P, Nagarajaiah S, Barrera EV, Kim JD. Carbon Nanotube Film Sensors. Advanced
Materials, (2004) 16(7), 640–643.
 Mu M, Osswald S, Gogotsi Y, Winey KI. An in situ Raman spectroscopy study of stress transfer
between carbon nanotubes and polymer. Nanotechnology, (2009) 20(33), 335703.
 de la Vega A, Kinloch IA, Young RJ, Bauhofer W, Schulte K. Simultaneous global and local strain
sensing in SWCNT–epoxy composites by Raman and impedance spectroscopy. Composites Science and
Technology, (2011) 71(2), 160–166.
 Raju APA, Lewis A, Derby B, Young RJ, Kinloch I a., Zan R, Novoselov KS. Wide-Area Strain Sensors
based upon Graphene-Polymer Composite Coatings Probed by Raman Spectroscopy. Advanced
Functional Materials, (2014) 24(19), 2865–2874.
 Nagarajaiah S, Weisman RB, Sun P, Bachilo SM, Yang Y. Strain-sensing smart skin: A noncontact
optical strain sensor using single-walled carbon nanotubes. In: Loh KJ, Nagarajaiah S, editors.
Innovative Developments of Advanced Multifunctional Nanocomposites in Civil and Structural
Engineering. Oxford: Woodhead Publishing; 2016. p. 353–375.
 Reich S, Thomsen C, Maultzsch J. Carbon nanotubes: basic concepts and physical properties. John
Wiley & Sons; 2008.
 O’Connell MJ, Bachilo SM, Huffman CB, et al. Band gap fluorescence from individual single-walled
carbon nanotubes. Science, (2002) 297(5581), 593–596.
 Weisman R, Bachilo S. Dependence of optical transition energies on structure for single-walled carbon
nanotubes in aqueous suspension: an empirical Kataura plot. Nano Letters, (2003) 3(9), 1235–1238.
 Yang L, Han J. Electronic structure of deformed carbon nanotubes. Physical Review Letters, (2000)
 Minot ED, Yaish Y, Sazonova V, Park J-Y, Brink M, McEuen PL. Tuning carbon nanotube band gaps
with strain. Physical review letters, (2003) 90(April), 156401.
 Li L-J, Nicholas RJ, Deacon RS, Shields P a. Chirality Assignment of Single-Walled Carbon Nanotubes
with Strain. Physical Review Letters, (2004) 93(October), 6–9.
 Maki H, Sato T, Ishibashi K. Direct observation of the deformation and the band gap change from an
individual single-walled carbon nanotube under uniaxial strain. Nano Letters, (2007) 7, 890–895.
 Leeuw TK, Tsyboulski D a, Nikolaev PN, Bachilo SM, Arepalli S, Weisman RB. Strain measurements
on individual single-walled carbon nanotubes in a polymer host: structure-dependent spectral shifts and
load transfer. Nano letters, (2008) 8(3), 826–831.
 Huang M, Wu Y, Chandra B, Yan H, Shan Y, Heinz TF, Hone J. Direct measurement of strain-induced
changes in the band structure of carbon nanotubes. Physical Review Letters, (2008) 100(April), 1–4.
 Valavala PK, Banyai D, Seel M, Pati R. Self-consistent calculations of strain-induced band gap changes
in semiconducting (n,0) carbon nanotubes. Physical Review B - Condensed Matter and Materials
Physics, (2008) 78, 1–6.
 Withey PA, Vemuru VSM, Bachilo SM, Nagarajaiah S, Weisman RB. Strain paint: noncontact strain
measurement using single-walled carbon nanotube composite coatings. Nano letters, (2012) 12(7),
 Sun P, Kim J-H, Bachilo SM, Weisman RB, Nagarajaiah S. “Smart Skin” optical strain sensor using
single wall carbon nanotubes. In: SPIE Smart Structures and Materials+ Nondestructive Evaluation and
Health Monitoring. 2014. p. 906120.
 Sun P, Bachilo SM, Weisman RB, Nagarajaiah S. Carbon nanotubes as non-contact optical strain sensors
in smart skins. The Journal of Strain Analysis for Engineering Design, (2015) , 1–8.
 Sun P, Bachilo SM, Nagarajaiah S, Weisman RB. Toward Practical Non-Contact Optical Strain Sensing
Using Single-Walled Carbon Nanotubes. ECS Journal of Solid State Science and Technology, (2016)
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