Coaxial Cable Bragg Grating Sensors for Structural Health Monitoring

In situ strain monitoring is critical to ensure the continued safe and reliable operation of various civil structures, such as dams, bridges, and buildings. In situ strain monitoring is especially important for structures that may experience large strains. In this project, a new coaxial cable Bragg grating (CCBG) is developed as a strain sensor, and the sensor's capacity for large range strain measurement is demonstrated for the first time. The sensor device is comprised of regularly spaced periodic discontinuities along a coaxial cable. The discontinuities are fabricated using a computer numerical controlled (CNC) machine to drill holes in the cable. Each discontinuity generates a weak reflection to the electromagnetic wave propagating inside the cable. Superposition of these weak reflections produces a strong reflection at discrete frequencies that can be explained by the Bragg grating theory. By monitoring the resonant frequency shift of the sensor's reflection or transmission spectra, strain measurement sensitivity of 20με and a dynamic range of 50000 με (5%) were demonstrated for axial strain measurements. The experimental results show that the CCBG sensors perform well for the large strain measurement needed in structural health monitoring (SHM).

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  • English

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  • Accession Number: 01470475
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 17 2013 2:16PM