Fiber bragg grating vibration acceleration sensor for monitoring low-frequency earthquake waves

Abstract

The invention discloses a fiber bragg grating vibration acceleration sensor for monitoring low-frequency earthquake waves. In the sensor, a slot a is formed on the side wall of the upper part of a hollow rod, an upper gasket is arranged on the lower end of the hollow rod and a lower gasket on the outer edge of which 3 to 8 slots are formed at equal intervals, the hollow rod below the slot a is provided with an upper braking block and a lower braking block positioned below the upper braking block; the hollow rod between the upper braking bock and the lower braking block is provided with a mass block moving along the hollow rod; the distance between the upper surface of the mass block and the bottom surface of the upper braking block is 4 millimeters, and the distance between the lower surface of the mass block and the upper surface of the lower braking block is 8 millimeters; the hollow rod below the mass block is provided with an elastic beam formed by connecting the upper ends of 3 to 8 elastic arms and a wafer and mounting the free ends of the 3 to 8 elastic arms on the lower gasket; a vibration sensing fiber grating is arranged on the outer face of any one of the elastic arms; and the input and output ends of the vibration sensing fiber grating are inserted into the hollow rod from the slot a and come out from the upper end of the hollow rod.

Description

technical field [0001] The invention belongs to the technical field of fiber grating sensors, and in particular relates to a fiber Bragg grating vibration acceleration sensor used for detecting low-frequency seismic wave signals below 10 Hz. technical background [0002] Seismic exploration is to vibrate the earth's crust by means of artificial seismic source excitation, and then analyze the signals monitored by the seismometer, so as to determine the geological structure and carry out a fine description of underground resources such as oil and gas reservoirs. Seismic detectors are widely used in fine exploration fields such as petroleum, metal deposits, coal, and engineering geology. As a new type of passive sensing element, Fiber Bragg Grating has the advantages of good reliability, small size, simple structure, high sensitivity, anti-electromagnetic interference, anti-corrosion, etc. Outstanding advantages, especially suitable for making seismic wave detectors. In the d...

AI Technical Summary

Problems solved by technology

In this way, the rich geological information contained in low-frequency earthquakes may be lost, thereby affecting the accuracy of seismic information acquisition.

Therefore, the low-frequency seismic wave monitoring below 10HZ is the weak point of current seismic exploration, which restricts the high-precision acquisition of seismic waves. In view of this situation, it is urgent to develop a fiber Bragg grating vibration acceleration sensor for low-frequency seismic wave monitoring.

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