CN219532323U - Cement-based piezoelectric sensor - Google Patents

Abstract

The utility model discloses a cement-based piezoelectric sensor, which comprises a piezoelectric element, a concrete upper cushion block and a concrete lower cushion block, wherein the piezoelectric element is fixed between the concrete upper cushion block and the concrete lower cushion block, an encapsulation layer is poured outside the piezoelectric element, the piezoelectric element comprises a piezoelectric composite layer, a pair of L-shaped electrode plates which are oppositely arranged and positioned on the upper surface and the lower surface of the piezoelectric composite layer, and a signal wire connected with the L-shaped electrode plates, the L-shaped electrode plates comprise a functional part and a welding part which are integrally connected and mutually perpendicular, the functional part is fixedly attached to a pressed surface of the piezoelectric composite layer in the vertical polarization direction, the welding part is fixedly attached to a non-vertical polarization surface of the piezoelectric composite layer, one end of the signal wire is fixedly welded to the welding parts of the two L-shaped electrode plates, and the other end of the signal wire is connected with a BNC joint; the piezoelectric sensor has the advantages that the welding point can be prevented from being concentrated on the stress surface of the piezoelectric element, the flatness of the stress surface of the electrode plate is ensured, the measurement accuracy of the piezoelectric sensor is improved, and the piezoelectric sensor is simple in structure and easy for mass production.

Description

Cement-based piezoelectric sensor

Technical Field

The utility model relates to the technical field of piezoelectric sensors, in particular to a cement-based piezoelectric sensor.

Background

Piezoelectric sensors are various in variety, such as piezoelectric acoustic emission sensors, impedance sensors, stress-strain sensors and the like, and have good application space in the health monitoring of concrete engineering structures. Currently, there are studies and practices that have applied various piezoelectric sensors to health monitoring of engineering structures, but there are still some problems:

(1) Commercial piezoelectric sensors generally use metal shells, so that the problem of mismatching of concrete interfaces exists in the using process, and the sensors are easy to corrode after being embedded into a concrete structure, so that the durability is poor; and surface mount sensors are susceptible to external environmental conditions because they are disposed outside the structure. Meanwhile, the thickness of the adhesive layer, the manual difference of constructors, human damage and other factors can influence the accuracy of health detection, so that the health evaluation result is deviated, and cost factors such as complex manufacturing process and high price of the sensor are considered in engineering application, so that the sensor is not easy to popularize and use in a large amount in a concrete structure.

(2) When the cement-based piezoelectric sensor is prepared, the traditional wire welding process adopts a bonding method or a welding method, the bonding method generally enables the wire to be in direct contact with the pressed plane of the piezoelectric element, and then the bonding method is fixed by adopting an insulating tape, and the bonding effect is influenced by the insulating tape, so that the wire is easy to shift in the preparation process; the soldering method uses an electric soldering iron to solder the lead wire to the surface of the functional element, and the local temperature of the soldering point is easily overhigh in the soldering process due to the higher melting point of the soldering tin wire, so that the piezoelectric ceramic is at risk of depolarization due to overhigh temperature. And the two wiring methods lead wires or welding spots to exist on the working surface of the piezoelectric functional element, so that the problem of stress concentration and uneven stress are generated in the use process of the sensor, and the accuracy of the sensor is affected.

Disclosure of Invention

The technical problem to be solved by the utility model is to provide the cement-based piezoelectric sensor, which can avoid the concentration of welding points on the stress surface of the piezoelectric element, ensure the flatness of the stress surface of the electrode plate, improve the measurement precision of the piezoelectric sensor, and has the advantages of simple structure, small volume and easy mass production.

The technical scheme adopted for solving the technical problems is as follows:

the utility model provides a cement-based piezoelectric sensor, includes piezoelectric element, concrete upper cushion and concrete lower cushion, piezoelectric element centre gripping is fixed between concrete upper cushion and the concrete lower cushion, the encapsulation layer has been pour outward to piezoelectric element, piezoelectric element includes piezoelectricity composite layer, a pair of relative setting and is located the L type electrode slice of piezoelectricity composite layer upper and lower surface and with the signal wire that L type electrode slice links to each other, L type electrode slice includes an organic whole connection and mutually perpendicular's functional part and welded part, the functional part with the laminating of the epaxial pressurized surface of perpendicular polarization of piezoelectricity composite layer is fixed, welded part with the laminating of the non-perpendicular polarization of piezoelectricity composite layer is fixed, signal wire's one end and two the welded part welded fastening of L type electrode slice, the other end are connected with BNC and connect.

Further, the L-shaped electrode sheet is adhered to the piezoelectric composite layer through a conductive adhesive.

Further, the adhesive is conductive silver paste.

Further, the L-shaped electrode plate is a copper sheet, and the thickness range is 0.1-0.2 mm.

Further, a welding hole is formed in the welding portion of the L-shaped electrode plate, and one end of the signal wire is fixed to the welding hole in a welding mode.

Furthermore, the piezoelectric element is adhered and fixed to the middle parts of the concrete upper cushion block and the concrete lower cushion block through epoxy resin adhesive.

Furthermore, the packaging layer is made of polyurethane materials.

Compared with the prior art, the utility model has the advantages that as the L-shaped electrode plates are arranged on the upper surface and the lower surface of the piezoelectric composite layer, the lead welding points are concentrated on the non-stress surface of the piezoelectric element, the problem of uneven stress surface of the electrode plates of the cement-based piezoelectric sensor is solved, and the stability and the accuracy of the compression of the electrode plates are ensured; the middle packaging layer is made of polyurethane materials, so that the piezoelectric element is not easily affected by the environment, the electromechanical response of the sensor is stable and reliable, the whole sensor is small in size and simple to manufacture, mass production is easy, and the piezoelectric element can be widely popularized and used in concrete structures.

Drawings

FIG. 1 is a schematic perspective view of the present utility model;

FIG. 2 is an exploded view of the present utility model;

fig. 3 is a schematic structural view of a piezoelectric element according to the present utility model.

In the figure: 1. a piezoelectric composite layer; 2. an L-shaped electrode plate; 21. a functional unit; 22. a welding part; 23. welding holes; 3. a signal wire; 4. a concrete upper cushion block; 5. an encapsulation layer; 6. BNC connector; 7. and a concrete lower cushion block.

Detailed Description

The utility model is described in further detail below with reference to the embodiments of the drawings.

As shown in fig. 1-3, a cement-based piezoelectric sensor comprises a piezoelectric element, a concrete upper cushion block 4 and a concrete lower cushion block 7, wherein the piezoelectric element is fixed between the concrete upper cushion block 4 and the concrete lower cushion block 7 through epoxy resin adhesion, the epoxy resin has waterproof sealing performance, materials of the concrete upper cushion block 4 and the concrete lower cushion block 7 are similar to the surrounding environment embedded by a sensor, the cement-based piezoelectric sensor is suitable for concrete building environments, the sensor is embedded into a concrete structure, the sensor has good phase performance and is not easy to corrode, the piezoelectric element comprises a piezoelectric composite layer 1, a pair of L-shaped electrode plates 2 which are oppositely arranged and are positioned on the upper surface and the lower surface of the piezoelectric composite layer 1, and a signal wire 3 which is connected with the L-shaped electrode plates 2, an encapsulation layer 5 is poured outside the piezoelectric element, the piezoelectric composite layer 1, the concrete upper cushion block 4 and the concrete lower cushion block 7 are in regular hexahedrons, the whole body after encapsulation is in a sandwich shape, the thickness of the encapsulation can be realized, the larger electric displacement output is obtained, the L-shaped electrode plates 2 are attached and kept flat through conductive silver paste and the piezoelectric composite layer 1, the L-shaped electrode plates 2 comprise an integral part 21 and a vertical polarization part 22, and a vertical polarization part 22 are attached to one end of the piezoelectric composite layer and a vertical polarization part 22 and a vertical polarization part is welded with the vertical polarization part and a vertical polarization part is connected with the vertical part and a vertical polarization part and a vertical terminal part is welded with the vertical part and a terminal part and is 23, and is welded with the vertical part and is connected with the vertical part and the vertical part of the vertical part and is 23.

In this embodiment, the connection position of the signal wire 3 and the electrode is not a stress surface of the electrode plate, but an L-shaped electrode plate 2 is arranged, so that welding spots of the signal wire 3 are concentrated on a non-stress surface of the electrode plate, the problems of uneven stress surface and tangential force are solved, and the sensitivity and accuracy of the sensor can be improved.

In this embodiment, the encapsulation layer 5 is made of polyurethane, which has good waterproof performance, good insulation, shock resistance, aging resistance and high and low temperature resistance, and can ensure stable electrical performance of the sensor. The polyurethane casting packaging layer 5 wraps the periphery of the piezoelectric element, isolates the piezoelectric element from the outside, plays a role in anti-corrosion protection, minimizes the influence on the performance of the piezoelectric composite layer 1, and simultaneously maintains good electromechanical response performance.

In the embodiment, the L-shaped electrode plate 2 is a copper sheet, and the thickness range is 0.1-0.2 mm; the signal wire 3 is a double-strand copper core wire; the piezoelectric composite layer 1 may be made of piezoelectric ceramics.

The preparation method of the cement-based piezoelectric sensor comprises the following steps: two L-shaped electrode plates 2 are adhered to the upper and lower stress surfaces and one side surface of the piezoelectric composite layer 1 through conductive silver paste, wherein: the functional part 21 of the L-shaped electrode plate 2 is flatly attached to the stress surface of the piezoelectric composite layer 1, the functional part 21 completely covers the whole stress surface, the welding part 22 is attached to the non-stress surface, then the signal wires 3 are respectively welded on the welding holes 23 of the welding parts 22 of the two L-shaped electrode plates 2 by using an electric soldering iron, the assembled piezoelectric element is adhered to the middle parts of the concrete upper cushion block 4 and the concrete lower cushion block 7 by using epoxy resin, the piezoelectric element is placed into a pouring die, polyurethane is poured into the die in a horizontal mode, the polyurethane is wrapped around the piezoelectric element to form the packaging layer 5, the vibration defoaming is carried out by using a concrete compaction table in the process, finally, standing and curing are carried out for 24 hours at normal temperature, and the head of the signal wires 3 is connected with the BNC connector 6, so that the cement-based piezoelectric sensor is obtained.

The scope of the present utility model includes, but is not limited to, the above embodiments, and any alterations, modifications, and improvements made by those skilled in the art are intended to fall within the scope of the utility model.

Claims (7)

1. The utility model provides a cement-based piezoelectric sensor, includes that piezoelectric element, concrete go up cushion and concrete down the cushion, piezoelectric element centre gripping is fixed between cushion and the concrete down the cushion on the concrete, the packaging layer has been pour outward to piezoelectric element, its characterized in that: the piezoelectric element comprises a piezoelectric composite layer, a pair of L-shaped electrode plates which are oppositely arranged and positioned on the upper surface and the lower surface of the piezoelectric composite layer, and a signal wire connected with the L-shaped electrode plates, wherein the L-shaped electrode plates comprise a functional part and a welding part which are integrally connected and mutually perpendicular, the functional part is fixedly attached to a pressed surface on the vertical polarization direction of the piezoelectric composite layer, the welding part is fixedly attached to a non-vertical polarization surface of the piezoelectric composite layer, and one end of the signal wire is fixedly welded to the welding part of the two L-shaped electrode plates, and the other end of the signal wire is connected with a BNC connector.

2. A cement-based piezoelectric sensor as claimed in claim 1, wherein: the L-shaped electrode sheet is adhered to the piezoelectric composite layer through a conductive adhesive.

3. A cement-based piezoelectric sensor as claimed in claim 2, wherein: the adhesive is conductive silver paste.

4. A cement-based piezoelectric sensor as claimed in claim 1, wherein: the L-shaped electrode plate is a copper sheet, and the thickness range is 0.1-0.2 mm.

5. A cement-based piezoelectric sensor as claimed in claim 1, wherein: the welding part of the L-shaped electrode plate is provided with a welding hole, and one end of the signal wire is welded and fixed with the welding hole.

6. A cement-based piezoelectric sensor as claimed in claim 1, wherein: the piezoelectric element is fixed in the middle of the concrete upper cushion block and the concrete lower cushion block through epoxy resin adhesive.

7. A cement-based piezoelectric sensor as claimed in claim 1, wherein: the packaging layer is made of polyurethane materials.