CN-121977685-A - Bending shear type vibration-acoustic emission composite sensor and device

CN121977685ACN 121977685 ACN121977685 ACN 121977685ACN-121977685-A

Abstract

The embodiment of the specification provides a bending shear type vibration-acoustic emission composite sensor and a measuring device, wherein the bending shear type vibration-acoustic emission composite sensor comprises a shell, a low-frequency signal detection part, a high-frequency signal detection part, a signal processing circuit and a sensor, wherein the shell comprises an upper shell and a lower shell, the upper shell and the lower shell are connected through threads to form a closed cavity, the low-frequency signal detection part is clamped at the joint part of the upper shell and the lower shell and comprises a piezoelectric element and a mass block of a bending-shearing coupling type structure and used for detecting a low-frequency vibration signal, the high-frequency signal detection part is arranged at the bottom of the lower shell and comprises a piezoelectric element and a matching layer of a compression type structure and used for detecting a high-frequency acoustic emission signal, the signal processing circuit is arranged inside the lower shell and is electrically connected with the low-frequency signal detection part and the high-frequency signal detection part, so that the mechanical isolation of vibration and the acoustic emission signal detection part is realized, the sensitivity, the bandwidth and the stability of the sensor are improved, and the detection precision is improved.

Inventors

SUN LU
GAO SHUGUO
LI TIANRAN
YAN YONGKE
Li Yumen
HU LIQING

Assignees

国网河北省电力有限公司电力科学研究院
国家电网有限公司

Dates

Publication Date: 20260505
Application Date: 20251210

Claims (10)

1. A bending shear type vibration-acoustic emission composite sensor, comprising: the shell comprises an upper shell and a lower shell, and the upper shell and the lower shell are connected through threads to form a closed cavity; A low frequency signal detection part clamped at a joint portion of the upper case and the lower case, the low frequency signal detection part including a piezoelectric element and a mass block of a bending-shearing coupling structure for detecting a low frequency vibration signal; The high-frequency signal detection part is arranged at the bottom of the lower shell and comprises a piezoelectric element with a compression structure and a matching layer, and is used for detecting high-frequency acoustic emission signals; A signal processing circuit provided inside the lower case, electrically connected to the low frequency signal detecting section and the high frequency signal detecting section; The wiring female seat is arranged on the side face of the lower shell and is electrically connected with the signal processing circuit.
2. The bending shear vibration-acoustic emission composite sensor of claim 1, wherein the low frequency signal detection section comprises a first piezoelectric element, a second piezoelectric element, an electrode pad, a first mass, a second mass, and a screw; The first piezoelectric element and the second piezoelectric element are circular ring-shaped piezoelectric ceramic plates, electrode plates are clamped between the first piezoelectric element and the second piezoelectric element, the first mass block and the second mass block are arranged symmetrically up and down, and the screw rod penetrates through the first piezoelectric element, the electrode plates and the second piezoelectric element and is in threaded connection with the first mass block and the second mass block so as to clamp and fix the first piezoelectric element and the second piezoelectric element.
3. The bending shear vibration-acoustic emission composite sensor of claim 2, wherein the first piezoelectric element and the second piezoelectric element are both radially polarized annular piezoelectric ceramic plates and are oppositely polarized to achieve parallel connection.
4. The bending shear vibration-acoustic emission composite sensor of claim 2, wherein an area of the first and second masses in contact with the piezoelectric element is configured to avoid reducing an effective bending length of the piezoelectric element.
5. The bending shear vibration-acoustic emission composite sensor of claim 1, wherein the high frequency signal detection section comprises a matching layer, a third piezoelectric element, and a backing layer; The matching layer, the third piezoelectric element and the backing layer are bonded through conductive adhesive in a pressurized mode, the matching layer is located at the bottommost part of the sensor and is in direct contact with a tested body, and the backing layer is used for absorbing reflected sound waves.
6. The bending shear vibration-acoustic emission composite sensor of claim 5, wherein the acoustic impedance of the matching layer is a geometric average of the acoustic impedance of the object and the acoustic impedance of the third piezoelectric element.
7. The bending shear vibration-acoustic emission composite sensor of claim 5, wherein the third piezoelectric element is a cylindrical piezoelectric ceramic sheet with a thickness polarization direction.
8. The bending shear type vibration-acoustic emission composite sensor according to claim 1, wherein a step is provided inside the upper housing for supporting the low frequency signal detecting portion, two steps are provided inside the lower housing, a bottom step is provided for adhesively fixing a matching layer in the high frequency signal detecting portion, and a middle step is provided for adhesively fixing the signal processing circuit.
9. The bending shear type vibration-acoustic emission composite sensor according to claim 1, wherein the signal processing circuit is electrically connected to the low frequency signal detecting section and the high frequency signal detecting section through a welding wire, and is connected to the connection base through a welding wire; the wiring female seat is fixed on the side face of the lower shell in a threaded screwing and bonding mode.
10. A measuring device comprising a bending shear vibration-acoustic emission composite sensor as claimed in any one of claims 1 to 9.

Description

Bending shear type vibration-acoustic emission composite sensor and device Technical Field The embodiment of the specification relates to the technical field of sensors, in particular to a bending shear type vibration-acoustic emission composite sensor. Background In the operation process of large industrial devices such as power equipment (such as transformers, generators, switch cabinets), rotary machines (such as motors, fans, compressors) and pressure vessels, abnormal events such as defects, discharge, impact, friction or crack growth in the equipment usually generate two types of characteristic signals, namely a low-frequency vibration signal reflecting the dynamic response and energy transmission process of the whole structure, and a high-frequency acoustic emission signal reflecting the transient release process of the internal or local micro-damage of materials. In existing monitoring systems, these two types of signals are typically collected by two separate sensors, respectively, the vibration signal being detected by an accelerometer and the acoustic emission signal being detected by an acoustic emission sensor. Because of the different installation positions, coupling modes, sampling channels and the like of the two types of sensors, the measurement results have space and time inconsistency, and the same point and synchronous detection of the same defect event cannot be realized, so that the comprehensive analysis of the running state of the equipment is influenced. In addition, the existing vibration-acoustic emission composite sensor integrates a low-frequency signal detection part and a high-frequency signal detection part, and can realize the same-point and synchronous acquisition of two frequency band signals. However, the low-frequency signal detection part adopts a compression type or shearing type structure, so that the problems of limited sensitivity, uneven frequency band coverage, mutual interference of the structure and the like of the composite sensor exist. Thus, a better solution is needed. Disclosure of Invention In view of this, the present embodiments provide a bending shear type vibration-acoustic emission composite sensor to solve the technical drawbacks existing in the prior art. According to a first aspect of embodiments of the present specification, there is provided a bending shear vibration-acoustic emission composite sensor comprising: The shell comprises an upper shell and a lower shell, and the upper shell and the lower shell are connected through threads to form a closed cavity; A low frequency signal detecting part clamped at a joint portion of the upper and lower cases, the low frequency signal detecting part including a piezoelectric element and a mass block of a bending-shearing coupling structure for detecting a low frequency vibration signal; The high-frequency signal detection part is arranged at the bottom of the lower shell and comprises a piezoelectric element with a compression structure and a matching layer, and is used for detecting high-frequency acoustic emission signals; the signal processing circuit is arranged inside the lower shell and is electrically connected with the low-frequency signal detection part and the high-frequency signal detection part; the wiring mother seat is arranged on the side surface of the lower shell and is electrically connected with the signal processing circuit. In one possible implementation, the low frequency signal detection portion includes a first piezoelectric element, a second piezoelectric element, an electrode pad, a first mass, a second mass, and a screw; the first piezoelectric element and the second piezoelectric element are ring-shaped piezoelectric ceramic plates, electrode plates are clamped between the first piezoelectric element and the second piezoelectric element, the first mass block and the second mass block are arranged symmetrically up and down, and a screw rod penetrates through the first piezoelectric element, the electrode plates and the second piezoelectric element and is in threaded connection with the first mass block and the second mass block so as to clamp and fix the first piezoelectric element and the second piezoelectric element. In one possible implementation, the first piezoelectric element and the second piezoelectric element are both radially polarized annular piezoelectric ceramic plates, and the polarization directions are opposite to realize parallel connection. In one possible implementation, the areas of the first and second masses in contact with the piezoelectric element are configured to avoid reducing the effective bending length of the piezoelectric element. In one possible implementation, the high frequency signal detection portion includes a matching layer, a third piezoelectric element, and a backing layer; The matching layer, the third piezoelectric element and the backing layer are bonded through conductive adhesive in a pressurizing mode, the matching layer is located