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Sub-Microscale Speckle Pattern Creation on Single Carbon Fibers for In-Situ DIC Experiments



High performance carbon and glass fibers are widely used as reinforcements in composite material systems for aerospace, automotive, and defense applications. Modifications to fiber surface treatment (sizing) is one of the ways to improve the strength of fibers and hence the overall longitudinal tensile strength of the composite. Single fiber tensile tests at the millimeter scale are typically used to characterize the effect of sizing on fiber strength. However, the characteristic length-scale governing the composite failure due to a cluster of fiber breaks is in the micro-scales. To access such micro-scale gage-lengths, we aim to employ indenters of varying radii to transversely load fibers and use scanning electron microscope (SEM) with digital image correlation (DIC) to measure strains at these lengthscales. The use of DIC technique requires creation of a uniform, random, and high contrast speckle pattern on the fiber surface such as that shown in Figure 1. In this work, we investigate the formation of sub-microscale speckle pattern on carbon fiber surface via sputter deposition and pulsed laser deposition techniques (PLD) using Gold-Palladium (Au-Pd) and Niobium-doped SrTiO3 (Nb:STO) targets respectively. Different processing conditions are investigated for both sputter deposition: sputtering current and coating duration, and PLD: number of pulses respectively to create sub-micron scale patterns viable for micro-DIC on both sized and unsized carbon fibers. By varying the deposition conditions and SEM-imaging the deposited patterns on fibers, successful pattern formation at sub-micron scale is demonstrated for both as-received sized and unsized IM7 carbon fibers of average diameter 5.2 μm via sputter deposition and PLD respectively.


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Aroush DR Ben, Maire E, Gauthier C, Youssef S, Cloetens P, Wagner HD.

A study of fracture of unidirectional composites using in situ high-resolution

synchrotron X-ray microtomography. Compos Sci Technol 2006;66:1348–


Swolfs Y, Morton H, Scott AE, Gorbatikh L, Reed PAS, Sinclair I, et al.

Synchrotron radiation computed tomography for experimental validation of a

tensile strength model for unidirectional fibre-reinforced composites.

Compos Part A Appl Sci Manuf 2015;77:106–13.


Rosen-Tensile-failure-of-fibrous-comp-1964.pdf n.d.

Phoenix SL, Sexsmith RG. Clamp Effects in Fiber Testing. J Compos Mater

;6:322–37. doi:10.1177/002199837200600311.

Watanabe J, Tanaka F, Okuda H, Okabe T. Tensile strength distribution of

carbon fibers at short gauge lengths. Adv Compos Mater 2014;23:535–50.


Okuda H, Young RJ, Tanaka F, Watanabe J, Okabe T. Tensile failure

phenomena in carbon fibres. Carbon N Y 2016;107:474–81.


Shioya M, Inoue H, Sugimoto Y. Reduction in tensile strength of

polyacrylonitrile-based carbon fibers in liquids and its application to defect

analysis. Carbon N Y 2013;65:63–70. doi:10.1016/j.carbon.2013.07.102.

Sugimoto Y, Shioya M, Kageyama K. Determination of intrinsic strength of

carbon fibers. Carbon N Y 2016;100:208–13.


Sutton MA, Li N, Joy DC, Reynolds AP, Li X. Scanning electron

microscopy for quantitative small and large deformation measurements Part

I: SEM imaging at magnifications from 200 to 10,000. Exp Mech

;47:775–87. doi:10.1007/s11340-007-9042-z.

Sutton MA, Li N, Garcia D, Cornille N, Orteu JJ, McNeill SR, et al.

Scanning electron microscopy for quantitative small and large deformation

measurements Part II: Experimental validation for magnifications from 200

to 10,000. Exp Mech 2007;47:789–804. doi:10.1007/s11340-007-9041-0.

Sockalingam S, Gillespie JW, Keefe M. Influence of multiaxial loading on

the failure of Kevlar KM2 single fiber. Text Res J 2018;88:483–98.


Sockalingam S, Thomas FD, Casem D, Gillespie JW, Weerasooriya T.

Failure of Dyneema® SK76 single fiber under multiaxial transverse loading.

Text Res J 2019;89:2659–73. doi:10.1177/0040517518798653.

Kammers AD, Daly S. Small-scale patterning methods for digital image

correlation under scanning electron microscopy. Meas Sci Technol 2011;22.


Hoefnagels JPM, van Maris MPFHL, Vermeij T. One-step deposition of

nano-to-micron-scalable, high-quality digital image correlation patterns for

high-strain in-situ multi-microscopy testing. Strain 2019;55:1–13.


Donnelly T, Krishnamurthy S, Carney K, McEvoy N, Lunney JG. Pulsed

laser deposition of nanoparticle films of Au. Appl Surf Sci 2007;254:1303–6.


Agarwal NR, Neri F, Trusso S, Lucotti A, Ossi PM. Au nanoparticle arrays

produced by Pulsed Laser Deposition for Surface Enhanced Raman

Spectroscopy. Appl Surf Sci 2012;258:9148–52.


Domingo C, Resta V, Sanchez-Cortes S, García-Ramos J V., Gonzalo J.

Pulsed laser deposited au nanoparticles as substrates for surface-enhanced

vibrational spectroscopy. J Phys Chem C 2007;111:8149–52.


Jing Y, Wang H, Chen X, Wang X, Wei H, Guo Z. Pulsed laser deposited Ag

nanoparticles on nickel hydroxide nanosheet arrays for highly sensitive

surface-enhanced Raman scattering spectroscopy. Appl Surf Sci

;316:66–71. doi:10.1016/j.apsusc.2014.07.169.

Zhang RL, Huang YD, Su D, Liu L, Tang YR. Influence of sizing molecular

weight on the properties of carbon fibers and its composites. Mater Des

;34:649–54. doi:10.1016/j.matdes.2011.05.021.

Alfonso E, Olaya J, Cubillos G. Thin Film Growth Through Sputtering

Technique and Its Applications. Cryst - Sci Technol 2012.


Jung YS, Lee DW, Jeon DY. Influence of dc magnetron sputtering

parameters on surface morphology of indium tin oxide thin films. Appl Surf

Sci 2004;221:136–42. doi:10.1016/S0169-4332(03)00862-6.

Tomio T, Miki H, Tabata H, Kawai T, Kawai S. Control of electrical

conductivity in laser deposited SrTiO3 thin films with Nb doping. J Appl

Phys 1994;76:5886–90. doi:10.1063/1.358404.

Morintale E, Constantinescu C, Dinescu M. Thin films development by

pulsed laser-assisted deposition. Ann Univ Craiova, Phys 2010;20:43–56.

Li B, Zhang CR, Cao F, Wang SQ, Chen B, Li JS. Effects of fiber surface

treatments on mechanical properties of T700 carbon fiber reinforced BNSi3N4

composites. Mater Sci Eng A 2007;471:169–73.


Gonzalo J, Perea A, Babonneau D, Afonso CN, Beer N, Barnes JP, et al.

Competing processes during the production of metal nanoparticles by pulsed

laser deposition. Phys Rev B - Condens Matter Mater Phys 2005;71:1–8.


Schreier H, Orteu JJ, Sutton MA. Image correlation for shape, motion and

deformation measurements: Basic concepts, theory and applications. 2009.


Yaofeng S, Pang JHL. Study of optimal subset size in digital image

correlation of speckle pattern images. Opt Lasers Eng 2007;45:967–74.


Crammond G, Boyd SW, Dulieu-Barton JM. Speckle pattern quality

assessment for digital image correlation. Opt Lasers Eng 2013;51:1368–78.


Dong YL, Pan B. A Review of Speckle Pattern Fabrication and Assessment

for Digital Image Correlation. Exp Mech 2017;57:1161–81.



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