Distributed crack sensor based on coaxial cable

Abstract

The invention relates to a distributed crack sensor based on a coaxial cable, belonging to the technical field of an engineering structure safety monitoring. The distributed crack sensor provided by the invention is characterized in that a metal conductor core on the inner layer, an insulating layer in the middle, the metal conductor layer provided with a weak link (such as sunk weak threads, dot mode weak threads and the like) and a surface anticorrosive material are sequentially arranged from inside to outside; the weak threads are machined by applying the rotation advancing traction to the coaxial cable and simultaneously utilizing a drill to carve grooves on an outer conductor layer or utilizing a puncher to continuously punch on the outer conductor layer; the depth and pitch of the weak threads select different numerical values according to the requirements of the structure on the test sensitivity and the space resolution; and when cracks are monitored, the attenuation signals which are generated because of the crack modulation of the coaxial cable are obtained through an electric time domain reflectometer to determine the occurrence position and expansion degree of the cracks. The sensor provided by the invention has the beneficial effects that the sensor is a coaxial cable distributed crack sensor provided with weak threads, the structure is simple, the durability is good, the crack monitoring scale is large, and a structural damage memory function is achieved.

Description

technical field [0001] The invention belongs to the technical field of engineering structure safety monitoring, relates to a damage monitoring sensor for structural behavior, and particularly relates to a distributed crack (or large strain) monitoring sensor for harsh service environments based on coaxial cables. Background technique [0002] Cracks are the most direct indicator of structural damage and safety behavior, and effective means for long-term and reliable monitoring and early warning of them are of great practical significance in the field of structural safety. Crack test methods currently used in engineering applications mainly include: displacement sensor (LVDT), strain test conversion, visual inspection, etc., as well as traditional non-destructive testing techniques, including non-contact testing such as shear flash spot, white light flash spot, and laser CCD. Penetration testing. The above method has fatal shortcomings such as the inability to realize real-t...

AI Technical Summary

Problems solved by technology

However, because the outer conductor layer of the coaxial cable sensor is made by manual spiral winding, there are problems such as poor contact of the wound metal sheet, large medium interference, and large signal attenuation, resulting in short effective test distance, difficult anti-corrosion treatment, and easy damage during the laying process. It is impossible to realize the promotion and application of industrialized production and actual engineering

At present, its achievements have not been applied in practical engineering

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