Composites Research

The Korean Society for Composite Materials (한국복합재료학회)
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Mechanical Strength Characteristics of Fiber Bragg Gratings with Fabrication Process

광섬유 브래그 격자의 제작 방법에 따른 기계적 강도 특성

  • 박상오 (한국과학기술원 기계공학과 항공우주공학전공) ;
  • 김천곤 (한국과학기술원 기계공학과 항공우주공학전공) ;
  • 강동훈 (한국철도기술연구원 남북철도기술개발사업단)
  • Published : 2005.02.01
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Abstract

Application fields on structural health monitoring of fiber Bragg gratings (FBGs) are gradually expanded even to a primary structure as well as a secondary structure and a specimen. For the reason, verification for the reliability of FBGs such as signal characteristics and mechanical strength becomes much more important. In this study, mechanical strength characteristics of FBGs with their fabrication process and reflectivity are investigated with various grating lengths. From the results of tension tests, it is shown that the mechanical strength of optical fibers decreases about $50\%$ just by jacket stripping and the amount of decrease is dependent on stripping methods. About $55\%$ of mechanical strength of stripped optical fibers decreases if gratings are formed in the core and it is regardless of grating lengths and reflectivity. However, the width of strength distribution increases relative to increases in reflectivity.

광섬유 브래그 격자를 이용한 모니터링 연구는 시편 단위의 연구뿐만 아니라 최근 2차 구조물을 비롯하여 주 구조물로까지 그 적용 영역이 점차 확대되고 있어 신뢰성에 대한 검증이 더욱 중요해지고 있다. 본 연구에서는 광섬유 브래그 격자의 제작 방법과 반사율에 따른 기계적 강도 특성을 다양한 격자의 길이에 대해 고찰하였다. 인장 시험을 통해 광섬유는 피복 제거만으로도 약 $50\%$ 정도의 강도 저하가 발생하며 피복 제거 방법에 따라 감소량이 달라짐을 확인하였다. 피복이 제거된 광섬유에 브래그 격자를 형성하게 될 경우 반사율과 격자의 길이와는 무관하게 약 $55\%$ 정도의 강도 저하가 발생하였다. 반면, 반사율이 증가할수록 강도의 분산도는 상대적으로 증가하였다.

Keywords

References

  1. H. K. Kang, D. H. Kang, C. S. Hong and C. G. Kim, 'Simultaneous monitoring of strain and temperature during and after cure of unsymmetric composite laminate using fiber optic sensors,' Smart Materials and Structures, Vol. 12, No. 1, 2003, pp. 29-35 https://doi.org/10.1088/0964-1726/12/1/304
  2. J. A. Guemes, J. M. Menendez, 'Response of Bragg grating fiber-optic sensors when embedded in composite laminates,' Composites Science and Technology, Vol. 62, 2002, pp. 959-966 https://doi.org/10.1016/S0266-3538(02)00010-6
  3. Y. Okabe, S. Yashiro, R. Tsuji, T. Mizutani and N. Takeda, 'Effect of thermal residual stress on the reflection spectrum from fiber Bragg grating sensors embedded in CFRP laminates,' Composites - Part A, Vol. 33, 2002, pp. 991-999 https://doi.org/10.1016/S1359-835X(02)00038-6
  4. S. Huang, M. M. Ohn, M. LeBlanc and R. M. Measures, 'Continuous arbitrary strain profile measurements with fiber Bragg gratings,' Smart Materials and Structures, Vol. 7, 1998, pp. 248-256 https://doi.org/10.1088/0964-1726/7/2/012
  5. S. Huang, M. M. Ohn, M. LeBlanc and R. M. Measures, 'Continuous arbitrary strain profile measurements with fiber Bragg gratings,' Smart Materials and Structures, Vol. 7, pp. 248-256, 1998 https://doi.org/10.1088/0964-1726/7/2/012
  6. D. H. Kang, C. S. Hong and C. G. Kim, 'Fabrication of fiber Bragg grating sensors with various grating lengths and signal characteristics of reflected spectra,' Composites Science and Technology, 2004, submitted
  7. C. Y, Wei, C. C. Ye, S. W. James, R. P. Tatam and P. E. Irving, 'The influence of hydrogen loading and the fabrication process on the mechanical strength of optical fibre Bragg gratings,' Optical Materials. Vol. 20, 2002, pp. 241-251 https://doi.org/10.1016/S0925-3467(02)00069-1
  8. C. G. Askins, M. A. Putnam, H. J. Patrick and E. J. Friebele, 'Fibre strength unaffected by on-line writing of single-pulse Bragg gratings,' Electronics Letters, Vol. 33, No. 15, 1997, pp, 1333-1334
  9. D. S. Starodubov, V. Grubsky and J. Feinberg, 'Efficient Bragg grating fabrication in a fibre through its polymer jacket using near-UV light,' Electronic Letters, Vol. 33, No. 15, 1997, pp. 1331-1333 https://doi.org/10.1049/el:19970874
  10. R. P. Espindola, R. M. Atkins, N. P. Wang, et al., 'Highly reflective fiber Bragg gratings written through a vinyl ether fiber coating,' IEEE Photonics Technology Letters. Vol. 11, No. 7, 1999, pp. 833-835 https://doi.org/10.1109/68.769723
  11. K. O. Hill, B. Malo and F. Bilodeau, et al., 'Bragg gratings fabricated in monomode photosensitive optical fiber by UV exposure through a phase mask,' Applied Physics Letters, Vol. 62, No. 10, 1993, pp. 1035-1037 https://doi.org/10.1063/1.108786
  12. M. J. Mattewson, C. R. Kurkjian and J. R. Hamblin, 'Acid stripping of fused silica optical fibers without strength degradation,' Journal of Lightwave Technology, Vol. 15, No.3, 1997, pp, 490-497 https://doi.org/10.1109/50.557565
  13. C. W. Wei, S. W. James, C. C. Ye, R. P. Tatam, P. E. Irving, in: Proc. of the 6th Annual Inter. Symposium on Smart Materials and Structures, SPIE3670, 1999