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Research On Vibration And Temperature Sensing Technology Based On FBG

Posted on:2009-06-11Degree:MasterType:Thesis
Country:ChinaCandidate:Y L JiaFull Text:PDF
GTID:2178360245980080Subject:Measuring and Testing Technology and Instruments
Abstract/Summary:PDF Full Text Request
Aiming at the purpose of analyzing equipment's vibration parameters such as frequency and acceleration during mechanical vibration fault diagnosis, in this paper one kind of vibration/temperature two-parameter fiber grating sensor with the merits EMI (Electromagnetic interference) resistance, high sensitivity, wide dynamic range, small size, etc, was designed and the problems of multi factors' interaction and cross-sensitivity in engineering structure were effectively solved.Vibration sensing text of constant strength cantilever was employed in this paper, and a novel demodulating system was designed based on long period fiber grating to demodulate the temperature and vibration, which could effectively minimize the effect of fluctuation of optical source and decrease the interference of external environment. System measurement range could be as follows: dynamic signal range, 20Hz~160Hz, acceleration measurement range, 0~140g with the sensitivity 0.1g, temperature measurement range, 0℃~100℃with the sensitivity 0.1℃. Following were the main contents in this paper:Firstly, the application and the present development of fiber grating sensor and multi parameter sensor were introduced, and then the basic sensing principle and characters of fiber grating, vibration sensor's fundamental principle was briefly discussed, besides, temperature /vibration sensing and the composition of fiber grating sensing system was studied.Secondly, the principle, merits and faults of several general fiber grating demodulation scheme was analyzed, a novel demodulation scheme was presented based on edge filter effect of long period fiber grating. Then we discussed intensively its' working principle, beam path design, and did the theoretical calculation of resonant wavelength sensitivity of sensing optical intensity and FBG.Thirdly, the structure of constant strength cantilever vibration sensor was designed, static and dynamic characteristic, natural frequency of cantilever analyzed. According to the requirement of system, the size of cantilever was optimized, and simulation about natural frequency of vibration cantilever via ANSY software was realized, which verified the results of theoretical calculation.Forth, system circuits including photoelectric conversion, filtration, differential, data acquisition, dynamic display, etc, were designed, and the test and display of sensing signal was fulfilled by system software.Finally, some experiments were finished to study the temperature sensing character, strain sensing character, vibration sensing character, and the result analysis of experiment was make.
Keywords/Search Tags:fiber Bragg grating, vibration sensing, temperature sensing, long period fiber grating
PDF Full Text Request
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