Manufacturing method and testing method of piezoelectric ceramic sensor for concrete ERT imaging

Abstract

The invention discloses a manufacturing method and a testing method of a piezoelectric ceramic sensor for concrete ERT imaging. The manufacturing method comprises following steps: fixing A, B wires ona positive pole and a negative pole to form an emitting terminal; fixing C,D wires on the positive pole and the negative pole to form a receiving terminal; covering the wires by glue, painting glue on the positive pole, fixing a shielding wire E on the positive pole of the receiving terminal, smearing the conductive layer, painting glue again to cover the shielding wire; connecting the other endsof the wires of the emitting terminal and the receiving terminal to two sensor joints; preparing a mould, smearing a release agent, fixing a piezoelectric ceramic sheet in the center of the mould ina suspension state; evenly mixing cement and epoxy resin according to a mass ratio of 1:(1-2) to prepare an encapsulation material, pouring the encapsulation material into the mould with the fixed piezoelectric ceramic sheet to form a filled block; completely drying the filled block, and removing the mould to obtain the piezoelectric ceramic sensor. During the construction process, the sensor is buried in concrete to online real-time monitoring the corrosion of steel bars in a long term.

Description

technical field [0001] The invention belongs to the technical field of concrete structure health monitoring, and in particular relates to a manufacturing method and a testing method of a concrete ERT imaging piezoelectric ceramic sensor. technical background [0002] Sensing technology is a multidisciplinary modern science and engineering technology about obtaining information from natural sources, processing, transforming and identifying it. A sensor is a device with monitoring functions that is widely used in the fields of industry, agriculture, national defense, and medicine. It is called "electrical five senses", that is, by simulating the functions of human five senses, it monitors various non-electrical quantities. Piezoelectric ceramic sensors are devices that use the piezoelectric effect of piezoelectric ceramic sheets to convert stress or strain into voltage or charge, and then amplify and output through an amplifier. The piezoelectric ceramic sensor is composed of...

AI Technical Summary

Problems solved by technology

The welding point of the piezoelectric ceramic sheet in the piezoelectric ceramic sensor will affect the sensitivity of the piezoelectric ceramic sensor due to the difference in geometric position. In the past, the method of fixing the welding point or randomly selecting the welding point has no basis for positioning the position of the welding point, resulting in The sensitivity of the sensor is not guaranteed, which limits the application range of piezoelectric ceramic sensors

[0004] In the existing ceramic sensor, the matching layer is bonded on the chip. Since the installed matching layer is easily tilted during operation, the outer end surface of the matching layer is not parallel to the electrode surface of the chip (the end surface at the end of the bonding matching layer), which affects the transmission and reception. Angle; the sensor vibrates when it works, which affects its life and is easy to fall off; the choice of adhesive for bonding has an impact on the effect of sending and receiving ultrasonic waves; the two wires are respectively connected to the two electrodes of the piezoelectric ceramic chip, and the matching layer is connected to the piezoelectric ceramic chip. One electrode (usually the negative pole) of the ceramic chip is connected. The setting of the wire on the negative end further leads to the inclination of the matching layer, which is also difficult to avoid even if a thin wire is used; Influence, generally do not weld but use bonding process, low strength, easy to fall off, damage the firmness and service life of the sensor, and the conductivity is also affected to a certain extent; the wire is installed between the matching layer and the sensor electrode, which is inconvenient for production and installation; frequency The adjustment is realized by changing the thickness of the matching layer, which is inconvenient to adjust; when the sensor is used, the overall installation is inconvenient

[0005] In buildings, steel bars play a key role in supporting and bearing pressure, but as time goes by, steel bars are easily corroded and damaged by substances such as oxygen, water, and chlorine salts, which bring certain dangers to people's safety, so , real-time monitoring of steel corrosion is very important, but in reality, the sensor for monitoring steel corrosion has low sensitivity and is easily damaged, requiring frequent replacement, which brings unnecessary trouble to the monitoring work

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