Fiber bragg grating strain sensor for structure surface

Abstract

The invention discloses a fiber bragg grating strain sensor for a structure surface, a metal sheet is composed of sheet branches in three directions, an angle between two adjacent sheet branches is 45 degrees, the three sheet branches are located on the same plane, a fiber bragg grating adopts a double-grating fiber and two single-grating fibers, and the double-grating fiber and the single-grating fiber are arranged on the same plane. The double-grating optical fiber is composed of a large-wavelength grating and a small-wavelength grating, the double-grating optical fiber and the two single-grating optical fibers are arranged in grooves of the slice branches respectively, the metal tube is connected with the outer ends of the slice branches provided with the double-grating optical fiber, and the small-wavelength grating is arranged in the metal tube in a penetrating mode. The sensor is reasonable in structure, strain monitoring of a certain point of the structure in three directions can be achieved, meanwhile, temperature changes of the peripheral environment are obtained, additional arrangement of a temperature sensor is avoided, and the sensor is simple in overall structure, easy to manufacture, simple in installation step and low in cost. The method can be used for pre-monitoring under complex conditions.

Description

technical field [0001] The invention relates to the technical field of optical fiber grating strain sensors, which can be used for two-dimensional strain monitoring on steel structure surfaces of buildings, bridges and other projects, and specifically relates to an optical fiber grating strain sensor for structural surfaces. Background technique [0002] Strain testing is one of the routine testing items for engineering structures such as buildings, bridges, and tunnels. Most of the commonly used strain detection sensors are electrical signal sensors such as resistance strain gauges and vibrating wire strain gauges. The disadvantages are that the measuring instrument needs to be powered to output electrical signals, the transmission distance is limited, and it is susceptible to electromagnetic interference. [0003] As a new type of grating element, fiber Bragg grating is currently being used as a core sensitive element in fiber optic sensors. The principle is that when the ...

AI Technical Summary

Problems solved by technology

However, in special cases, if the force state (deformation state) of the test point is not known, and the test point is relatively complex, there is a risk of unreasonable sensor arrangement, so pre-calibration, multi-point or multi-directional detection is required. Therefore, Desiring an improved technology to solve the above-mentioned problems in the prior art

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