Abstract
This paper investigates the use of embedded optical fiber Bragg gratings to measure strain near a stress concentration within a solid structure. Due to the nature of a stress concentration (i.e., the strong nonuniformity of the strain field), the assumption that the grating spectrum in reflection remains a single peak with a constant bandwidth is not valid. Compact tension specimens including a controlled notch shape are fabricated, and optical fiber Bragg gratings with different gage lengths are embedded near the notch tip. The form of the spectra in transmission varies between gages that are at different distances from the notch tip under given loading conditions. This variation is shown to be due to the difference in the distribution of strain along the gage length. By using the strain field measured using electronic speckle pattern interferometry on the specimen surface and a discretized model of the grating, the spectra in transmission are then calculated analytically. For a known strain distribution, it is then shown that one can determine the magnitude of the applied force on the specimen. Thus, by considering the nonuniformity of the strain field, the optical fiber Bragg gage functions well as an embedded strain gage near the stress concentration.
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References
Measures, R., “Smart Composite Structures with Embedded Sensors,”Composites Eng.,2,597–618 (1992).
Butter, C.D. andHocker, G.B., “Fiber Optic Strain Gauge,”Appl. Opt.,17,2867–2869 (1978).
Miller, M., Case, S., Carmen, G., Schmid, C.A., May, R.G., andClaus, R.D., “Validation of Axial Strain Transfer from a Composite Laminate to Embedded Optical Fiber Sensors,”Proc. SPIE,1798,19–29 (1992).
Pak, Y., “Longitudinal Shear Transfer in Fiber Optic Sensors,”Smart Mat. Struct.,1,57–62 (1992).
Piggott, M.R., “Interface Properties of Fiber-reinforced Polymers,”Composite Applications: The Role of Matrix, Fiber, and Interface, T. Vigo andB. Kinzig, eds. VCH, New York, 230–251 (1992).
Sirkis, J. andLu, I., “On Interphase Modeling for Optical Fiber Sensors Embedded in Unidirectional Composite Systems,”Adapt. Struct. Mat. Sys.,35,419–426 (1993).
Huang, S., Ohn, M., LeBlanc, M., andMeasures, R., “Continuous Arbitrary Strain Profile Measurements with Fiber Bragg Gratings,”Smart Mat. Struct.,7,248–256 (1998).
Limberger, H.G., Fonjallaz, P.Y., andSalathé, R.P., “Spectral Characterization of Photoinduced High Efficient Bragg Gratings in Standard Telecommunication Fibers,”Electr. Lett.,29,47–48 (1993).
Volanthen, M., Geiger, H., Cole, M.J., andDakin, J.P., “Measurement of Arbitrary Strain Profiles within Fibre Gratings,”Electr. Lett.,32,1028–1029 (1996).
Bennion, I., Williams, J.A.R., Zhang, L., Sugden, K., andDoran, N.J., “UV-written In-fibre Bragg Gratings,”Opt. Quant. Electr.,28,93–135 (1996).
Davis, M., Bellemore, D., Putnam, M., andKersey, A., “High Strain Monitoring in Composite-wrapped Concrete Cylinders Using Embedded Fiber Bragg Grating Arrays,”Proc. SPIE,2721,114–123 (1996).
Simonsen, H., Paetsch, R., and Dunphy, J., “Fiber Bragg Grating Sensor Demonstration in Glass-fiber Reinforced Polyester Composite,” Proceedings of the First European Conference on Smart Structures And Materials, 73–76 (1992).
Erdogan, T., “Fiber Grating Spectra,”J. Lightwave Tech.,15,1277–1294 (1997).
Yamada, M. andSakuda, K., “Analysis of Almost-periodic Distributed Feedback Slab Waveguides via a Fundamental Matrix Approach,”Appl. Opt.,26,3474–3478 (1987).
Carmen, G. andSendeckyj, G., “Review of the Mechanics of Embedded Optical Sensors,”J. Composites Tech. Res.,17,183–193 (1995).
Jones, R. andWykes, C., Holographic and Speckle Interferometry, Cambridge University Press, New York (1989).
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Peters, K., Studer, M., Botsis, J. et al. Embedded optical fiber Bragg grating sensor in a nonuniform strain field: Measurements and simulations. Experimental Mechanics 41, 19–28 (2001). https://doi.org/10.1007/BF02323100
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DOI: https://doi.org/10.1007/BF02323100