Intelligent photoelectric composite cable for monitoring local large deformation of structure and monitoring method

Abstract

The invention discloses an intelligent photoelectric composite cable for monitoring local large deformation of a structure and a monitoring method. The intelligent photoelectric composite cable comprises distributed sensing devices capable of working together, wherein the distributed sensing devices are formed by compounding two sensing probes of an optical fiber and a coaxial cable employing silicone rubber as a cohering and filling medium and customizing a strain measurement gauge length in advance; various strains and temperature sensing probes are connected to an ROTOR demodulator, an FBG demodulator, a BOTDA / Rdemodulator and a CCFPI demodulator through transmission cables respectively; and strain data of a strain sensing array after temperature compensation correction is obtained, so that whole-process monitoring of the local large deformation of the structure is achieved. Aiming at the condition that an existing test method cannot easily track damage information of the local large deformation process of the structure, the bottleneck problem of combination of micro high precision and a macro large strain test is solved by the intelligent photoelectric composite cable; and a distributed optical fiber sensing technology and a distributed coaxial cable sensing technology are merged for the first time to construct an intelligent monitoring system.

Description

technical field [0001] The invention belongs to the technical field of structural health monitoring and modern detection, and relates to an intelligent photoelectric composite cable and a monitoring method for monitoring local large deformation of a structure. Background technique [0002] Large local deformation of structures (mainly manifested as localized large strains) is an important cause of structural failure and damage, and its behavior often manifests as strong nonlinearity (geometric or material nonlinearity) and strong coupling effects. The whole process test of the local large deformation of the structure can provide technical support for the scientific understanding of the failure mechanism, the design of the structural behavior and the evaluation of the safety state. [0003] The overall performance monitoring of structures generally adopts displacement sensors such as velocity and accelerometers. When a material or component partially enters the nonlinear lar...

AI Technical Summary

Problems solved by technology

However, the strain caused by the local large deformation of the structure can reach more than 10%, which is far beyond the deformation capacity of the glass optical fiber. At the same time, it is prone to shear brittle fracture. More than 20,000 microstrains

Although plastic optical fiber exhibits good characteristics of high ductility and large strain, up to about 15%, commercialized plastic optical fiber is mainly multimode optical fiber, and dispersion and multimode interference restrict the distributed sensing ability of this technology

In addition, some people have preliminarily realized the real-time monitoring of local cracks in the structure with the help of electrical time domain reflection technology of high-ductility coaxial cables (a distributed crack sensor based on coaxial cables, application number: 201110027121.1), but the damage caused by this method Sensitivity, distributed testing and reuse capabilities need to be verified

[0004] Considering that the spatio-temporal characteristics of the local behavior of the structure (stress state or damage) are constantly changing with the change of the load and damage evolution process, and there will be sudden changes and internal force redistribution at the discontinuous point, which proposes a new approach to the traditional fixed-point monitoring method and technology. However, there is still a lack of suitable means for monitoring large local deformations of structures.

Images