Application of interpolation algorithm in plate structure detection based on Fiber Bragg grating sensing technology

Abstract

Due to the speed development of the mechanical equipment, it is important to realize the nondestructive evaluation in time to guarantee the safe and reliable operation. Distributed vibration detection is a conventional approach, but it may suffer from the disadvantages that it is complex to arrange a large amount of measuring points. On the other hand, some optimization algorithms are effective for approximate solutions. Taking into these considerations, we proposes a corresponding damage identification method to realize the damage localization by Fiber Bragg grating sensing technology with interpolation algorithm, which can create a simple method to identify the damaged region for the plate structural. In this paper, vibration detection based on some FBG sensors is built up and the optimum parameters are given. On the basis of this, interpolation algorithm is applied into vibration test and the experimental results show that localization method by the interpolation analysis is feasible to damage detection and it has better detection effect for a thin steel plate.

Online monitoring for floating raft structure displacement based on optimal placement of measuring points

“…The error is mainly affected by the number of sensors and the size of the interpolation step. 23 Tables 3-6 show that with the increase of the applied load, the average absolute error and average relative error of the deformation value obtained from the test increase compared with the analysis value. However, the relative error of each point is kept within 5%, and the average relative error is less than 4%.…”

Study on phase shifted fiber Bragg grating spatial sensing properties to ultrasonic wave at arbitrary excitation angle

“…Its basic principle is to excite the mechanical structure by ultrasonic wave and measure the ultrasonic strain with FBG, then analyze the damage state of the mechanical structure [1]. However, in order to avoid the micro bending modulation of ultrasonic strain wave on FBG, the length of the FBG should be less than half of the ultrasonic wave length [2], therefore a shorter FBG is hoped; On the other hand, the center wavelength demodulation is based on optical power detection in ultrasonic excitation-FBG detection technology, namely using the narrow band optical filter to capture FBG spectrum under broadband light source or using laser source to intercept the FBG spectrum directly, and achieving the wavelength change by measuring the variation of the output light intensity [3], and when the light source intensity is certain, the demodulation sensitivity depends on the slope of the FBG spectrum, therefore it requires that the FBG length is as long as possible; in addition, ultrasound with high frequency (such as MHz) is generally chosen in order to improve the damage detection accuracy, and the corresponding strain amplitude is very small (several or dozens of micro-strain) [4], therefore conventional FBG can not measure high-frequency ultrasound effectively.…”

A temperature-independent force transducer using one optical fiber with multiple Bragg gratings

“…However, the measured signals from such electrical transducers are susceptible to be contaminated by the electromagnetic interference (EMI), which is common in the harsh industrial environment. Because the advantages such as anti-electromagnetic interference, anti-oil corrosion and multiple measuring points in one optical fiber, fiber Bragg grating (FBG) based transducer have attracted a lot of interests and been widely investigated by researchers and industrial engineers recently [4,5].…”