Vibration dynamic monitoring system and method based on birefringent fiber optic loop mirror

Abstract

The invention discloses a birefringence optical fiber environment based vibration dynamic monitoring system and method which can satisfy dynamic monitoring of vibration signals, is high in sensitivity and can solve the problems of the vibration sensing amount and the temperature cross sensitivity of the birefringence optical fiber environment. The birefringence optical fiber environment based vibration dynamic monitoring system comprises steps of constructing birefringence optical fiber environment through an optical fiber coupler, birefringence optical fibers and an optical fiber polarization controller; sticking the birefringence optical fibers on a measured object and fixing the birefringence optical fiber environment on the measured object; constructing a dynamic monitoring system of the vibration signals through the birefringence optical fiber environment, a light source, a photoelectric transducer, a signal amplifier, a data collection card and a computer; collecting birefringence optical fiber environment voltage data along with time variation through the computer when the measured object is in a vibrating state, removing direct components in the obtained data, performing fast fourier transform and obtaining the vibrational frequency and vibrational amplitude of the measured object.

Description

technical field [0001] The invention relates to a vibration dynamic monitoring system and method based on a double refraction optical fiber loop mirror. Specifically, it is a system and method for dynamically monitoring the vibration signal of an object by using a birefringent fiber optic loop mirror sensor. Background technique [0002] Vibration is a problem often encountered in actual production and life, and vibration is ubiquitous in engineering practice. Large-scale systems with huge benefits and high costs, such as space shuttles, offshore platforms, bridges, and buildings, often operate under harsh conditions such as high temperature, high pressure, and heavy loads. Their destruction has serious consequences for the national economy and the safety of people's lives and property. According to statistics, more than 60% of the faults come from environmental factors, and among the environmental factors, the faults caused by vibration account for almost 30%. [0003] Th...

AI Technical Summary

Problems solved by technology

[0005] Due to the intense vibration process, any fiber in the fiber optic loop mirror may move irregularly, causing the optical path difference of the fiber optic loop mirror to change, which interferes with the measurement of real physical quantities. Therefore, the birefringent fiber optic loop mirror sensor with high sensitivity is mainly It is still applied to the measurement of relatively static physical quantities, and the birefringent fiber optic loop mirror sensor is rarely used in severe vibration measurement

[0006] Since the birefringent optical fiber forms birefringence through the asymmetric stress generated by the difference in the thermal expansion coefficient of the material, the temperature has a great influence on the birefringence, so the birefringent fiber optic loop mirror has a serious problem of cross-sensitivity between sensing volume and temperature.

The sensor itself cannot distinguish the changes caused by the measured physical quantity and other physical quantities, which greatly reduces the sensing accuracy or even fails

Although some scholars have proposed a lot of schemes for differentiating measurement of sensing quantity and temperature, these schemes increase the complexity of the system while improving the sensing quantity and temperature cross-sensitivity of the birefringent fiber optic loop mirror.

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