Numerical Simulation of Fiber Bragg Grating Spectrum for Mode-І Delamination Detection

Fiber Bragg optic sensor is embedded in composite
material to detect and monitor the damage that occurs in composite
structures. In this paper, we deal with the mode-Ι delamination to
determine the material strength to crack propagation, using the
coupling mode theory and T-matrix method to simulate the FBGs
spectrum for both uniform and non-uniform strain distribution. The
double cantilever beam test is modeled in FEM to determine the
longitudinal strain. Two models are implemented, the first is the
global half model, and the second is the sub-model to represent the
FBGs with higher refined mesh. This method can simulate damage in
composite structures and converting strain to a wavelength shifting in
the FBG spectrum.





References:
[1] L.Sorensen, The response of embedded FBG sensors to nonuniform
strains in CFRP composites during processing and delamination, 2006.
[2] Measures, Raymod M., "Smart Composite Structure with Embedded
Sensors," composite Engineering, vol. 2, no. 5-7, pp. 597-618, 1992.
[3] Hang-Yin Ling , Kin-Tak Lau , Wei Jin b, and Kok-Cheung Chan,
"Characterization of dynamic strain measurement using reflection
spectrum from a fiber Bragg grating," Optics Communications, vol. 270,
pp. 25-30, 2007.
[4] S. Takeda, Y. Okabe, and N. Takeda, "Delamination detection in CFRP
laminates with embedded small-diameter fiber Bragg grating sensors,"
Composites: Part A, vol. 33, pp. 971-980, 2002.
[5] L. Sorensen, J. Botsis, T. Gmu¨r, and J.¨l Cugnoni, "Delamination
detection and characterisation of bridging tractionsusing long FBG
optical sensors," Composites: Part A, vol. 38, pp. 2087-2096, 2007.
[6] B. D. Manshadi, A. P. Vassilopoulos, and J. Botsis, "A combined
experimental/numerical study of the scaling effects on mode I
delamination of GFRP," Composites Science and Technology, vol. 83,
pp. 32-39, 2013.
[7] C.Schizas, S.Stutz, J. Botsis, and D.Coric, "Monitoring of nonhomageneous
strains in composites with embedded wavelength
multiplexed fiber Bragg gratings: A methodological study," Composite
Structures, vol. 94, pp. 987-994, 2012.
[8] D.H. Kang, S.O. Park, C.S. Hong, and C.G. Kim, "The signal
characteristics of reflected spectra of fiber Bragg grating sensors with
strain gradients and grating lengths," NDT&E International, vol. 38, pp.
712-718, 2005.
[9] C. M. Lawrence, D. V. Nelson, E. Udd, and T. Bennett, "A fiber optic
sensor for transverse strain measurement" Experiment Mech, vol. 39, pp.
202-209, 1999.
[10] Othonos A., Kalli K, Fiber Bragg Gratings: Fundamentals and
Applications in Telecommunications and Sensing, Artech House;
Norwood, MA, USA, 1999.
[11] K. Peters, M. Studer, J. Botsis, A. Iocco, H. Limberger, and R. Salath,
"Embedded Optical Fiber Bragg Grating Sensor in a Nonuniform Strain
Field: Measurements and Simulations," Experimental Mechanics, vol.
41, no. 1, pp. 19-28, March 2001.