Vibration-Monitoring of a Real Bridge by Using a $Moir\'{e}$-Fringe-Based Fiber Optic Accelerometer

  • Kim, Dae-Hyun (Department of Mechanical Engineering, Seoul National University of Technology) ;
  • Lee, Jong-Jae (Department of Civil and Environmental Engineering, Sejong University)
  • 발행 : 2007.12.30

초록

This paper presents the use of a novel fiber optic accelerometer system to monitor ambient vibration (both wind-induced one and vehicle-induced) of a real bridge structure. This sensor system integrates the $Moir\'{e}$ fringe phenomenon with fiber optics to achieve accurate and reliable measurements. A low-cost signal processing unit implements unique algorithms to further enhance the resolution and increase the dynamic bandwidth of the sensors. The fiber optic accelerometer has two major benefits in using this fiber optic accelerometer system for monitoring civil engineering structures. One is its immunity to electromagnetic (EM) interference making it suitable for difficult applications in such environments involving strong EM fields, electrical spark-induced explosion risks, and cabling problems, prohibiting the use of conventional electromagnetic accelerometers. The other is its ability to measure both low- and high-amplitude vibrations with a constantly high resolution without pre-setting a gain level, as usually required in a conventional accelerometer. The second benefit makes the sensor system particularly useful for real-time measurement of both ambient vibration (that is often used for structural health monitoring) and strong motion such as earthquake. Especially, the semi-strong motion and the small ambient one are successfully simulated and measured by using the new fiber optic accelerometer in the experiment of the structural health monitoring of a real bridge.

키워드

참고문헌

  1. Ansari, F. (2005) Fiber Optic Health Monitoring of Civil Structures Using Long Gage and Acoustic Sensors, Smart Mater. Struct., Vol. 14, S1-S7 https://doi.org/10.1088/0964-1726/14/1/001
  2. Feng, M. Q. and Kim, J. M. (1998) Identification of a Dynamic System Using Ambient Vibration Measurements, Journal of Applied Mechanics, ASME, Vol. 65 (2), pp. 1010-1023 https://doi.org/10.1115/1.2791895
  3. Feng, M. Q. and Kim, D. -H. (2006) Novel Fiber Optic Accelerometer System Using Geometric Moire Fringe, Sensors and Actuators A: Physical, Vol. 128, pp. 37-42 https://doi.org/10.1016/j.sna.2005.12.050
  4. Kageyama, K. et al. (2005) Acoustic Emission Monitoring of a Reinforced Concrete Structure by Applying New Fiber-Optic Sensors, Smart Mater. Struct., Vol. 14, S52-S59 https://doi.org/10.1088/0964-1726/14/3/007
  5. Kim, D. -H. at al. (2004) Damage Detection of Composite Structures Using a Stabilized Extrinsic Fabry-Perot Interferometric Sensor System, Smart Mater. Struct., Vol. 13(3), pp. 593-598 https://doi.org/10.1088/0964-1726/13/3/018
  6. Kim, D. -H. and Feng, M. Q. (2005) A Novel Optical Fiber Accelerometer System for Monitoring Civil Infrastructure, In proceedings of the 2005 IEEE Sensors Conference, pp. 1107-1111
  7. Kim, D. -H. and Feng, M. Q. (2007) Real-Time Structural Health Monitoring Using a Novel Fiber Optic Accelerometer System, IEEE Sensors Journal, Vol. 7(4), pp. 536-543 https://doi.org/10.1109/JSEN.2007.891988
  8. Li, H. N., Li, D. S. and Song, G. B. (2004) Recent Applications of Fiber Optic Sensors to Health Monitoring in Civil Engineering, Engineering Structures, Vol. 26, pp. 1647-1657 https://doi.org/10.1016/j.engstruct.2004.05.018
  9. Udd, E. et al. (1995) Fiber Optic Smart Structures (New York: Wiley)
  10. Vi, J. -H., Cho, S, Koo, K. -Y., Yun, C. -B., Kim, J. -T., Lee, C. -G. and Lee, W. -T. (2007) Structural Performance Evaluation of a Steel-Plate Girder Bridge Using Ambient Acceleration Measurements, Smart Structures and Systems 3(3)