Sensitivity-variable fiber grating sensor for monitoring fracture failure process under action of static load and using method of sensitivity-variable fiber grating sensor

Abstract

The invention provides a variable-sensitivity fiber grating sensor for monitoring a fracture failure process under the action of a static load and a using method of the variable-sensitivity fiber grating sensor, belonging to the technical field of structural health monitoring. The sensor comprises a steel pipe, a spring, a piston, a fiber bragg grating and a fixed support. The variable-sensitivity fiber grating sensor is used for monitoring the complete process of the structural fracture failure, namely sudden amplification of strain (displacement) caused by fracture in an elastic stage before failure and in a stage after limit load is exceeded; the above monitoring purpose is achieved through the combination relation among the piston, the steel pipe and the spring; complete measurement of the fracture failure process of a structure under static load effect is achieved through one sensor, strain sensitivity is amplified when strain is small, and a measuring range is amplified when fracture is caused by large strain; and the variable-sensitivity fiber grating sensor is simple in structural design, convenient to use and high in applicability, and has a good application prospect in the field of structural health monitoring.

Description

technical field [0001] The invention relates to a variable-sensitivity optical fiber grating sensor for monitoring the fracture failure process under static load, and belongs to the technical field of structural health monitoring. Background technique [0002] Under the action of static load, structures generally undergo elastic deformation first. When the static load exceeds the critical value of the structure, they are prone to fracture and damage, that is, cracks are generated. Crack propagation is a common form of damage in the field of engineering structural health monitoring. Crack growth It will reduce the stability of the building structure, and in severe cases, it will cause the collapse of the structure. Therefore, it should not be underestimated. The ability to judge the deformation stage and state of the structure in real time creates conditions for analyzing the safety of the structure and for subsequent maintenance. [0003] Due to the suddenness of the fractur...

AI Technical Summary

Problems solved by technology

[0003] Due to the suddenness of the fracture under the static load, the current problem of monitoring structural fracture failure under the static load is that the structure is elastically deformed before the fracture fails, and the deformation caused by the tensile force of the structure is small and difficult to detect

However, as the static load continues to increase to a certain extent, its structure will suddenly break, and ordinary sensors may break and cannot monitor

[0004] Some traditional optical fiber grating sensors based on optical fiber sensing technology have limitations in solving such problems. Therefore, in order to solve the sudden amplification of strain (displacement) caused by the elastic stage before the structural failure and the fracture after exceeding the limit load and To meet the monitoring requirements of this function, it is necessary to design a sensing technology that can meet the large deformation measurement of structural fracture induced displacement and has high strain sensitivity in the small deformation stage in the elastic range

Images