CN109374682B - Monitoring device for cracking time of brittle material - Google Patents
Monitoring device for cracking time of brittle material Download PDFInfo
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- CN109374682B CN109374682B CN201811419418.0A CN201811419418A CN109374682B CN 109374682 B CN109374682 B CN 109374682B CN 201811419418 A CN201811419418 A CN 201811419418A CN 109374682 B CN109374682 B CN 109374682B
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- brittle material
- acoustic emission
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/72—Investigating presence of flaws
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
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- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
Abstract
The application discloses a device for monitoring the cracking time of a brittle material, which comprises an acoustic emission monitoring device, a strain monitoring device and a temperature monitoring device. The device is a device for jointly monitoring three parameters, namely acoustic emission, strain and temperature, and accurately judges the failure time of the damage of the brittle material by utilizing the impact strength, strain and temperature curve of the acoustic emission.
Description
Technical Field
The application belongs to the field of test technical devices, and particularly relates to a device for monitoring cracking time of a brittle material.
Background
The acoustic emission monitoring system can be used for obtaining damage, destruction or failure information of the brittle material, but in a complex field environment where other electromechanical devices operate, the electromechanical devices, the illuminating lamps or other testing devices generally generate electromagnetic interference to the acoustic emission monitoring system, and the interference signals influence analysis and judgment on damage, destruction or failure of the brittle material.
Aiming at the problem that the cracking and damage of the brittle material are difficult to accurately judge based on a single acoustic emission monitoring technology caused by a complex electromagnetic interference environment, a monitoring device capable of accurately judging the cracking time of the brittle material is needed.
Disclosure of Invention
The application aims to provide a monitoring device capable of accurately judging the cracking time of a brittle material.
The application adopts the following technical scheme:
the monitoring device comprises an acoustic emission monitoring device, a strain monitoring device and a temperature monitoring device, wherein the acoustic emission monitoring device comprises an acoustic emission sensor, a preamplifier and an acoustic emission collector, the acoustic emission sensor is connected to the surface of the brittle material, and the preamplifier and the acoustic emission collector are sequentially connected with the acoustic emission sensor; the strain monitoring device comprises a strain gauge and a strain collector, wherein the strain gauge is connected to the surface of the brittle material, and the strain collector is connected with the strain gauge; the temperature monitoring device comprises a thermocouple and a temperature collector, wherein the thermocouple is connected to the surface of the brittle material, and the temperature collector is connected with the thermocouple; the strain gauge and the thermocouple do not overlap.
In some embodiments of the application, the acoustic emission sensor, strain gauge or thermocouple is adhered to the surface of the brittle material by using an adhesive consistent with the deformation of the surface of the brittle material.
In some embodiments of the application, the adhesive is selected from the group consisting of a flash adhesive and an epoxy adhesive.
In some embodiments of the application, the lateral center-to-center spacing of the strain gauge and thermocouple is less than 1% of the lateral length of the brittle material; the vertical center-to-center spacing of the strain gauge and the thermocouple is less than 5% of the vertical length of the brittle material.
In some embodiments of the application, the acoustic emission collector has a sampling rate of not less than 5MHz and an A/D accuracy of not less than 16 bits.
In some embodiments of the application, the effective filter bandwidth of the pre-amplifier is 20-1000 KHz.
In some embodiments of the application, the strain gauge is attached to a strain gauge using a 1/4 bridge "tri-wire" approach.
In some embodiments of the application, the sampling rates of the strain and temperature collectors are the same, and the sampling rate is not lower than 1Hz.
In some embodiments of the application, the methods of the application are useful for detecting the initiation time of a brittle material, including nonmetallic composite materials, such as polymer-bonded explosives.
Compared with the prior art, the application has the following beneficial effects:
the device comprises an acoustic emission monitoring device, a strain monitoring device and a temperature monitoring device, is a device for jointly monitoring three parameters of acoustic emission, strain and temperature, and can accurately judge the damage failure time of the brittle material by utilizing the impact strength of acoustic emission, the strain and the temperature curve.
The device is provided with the thermocouple near the strain gauge, so that misjudgment of severe shaking of a strain curve caused by rapid temperature change of the measured brittle material is eliminated.
Drawings
FIG. 1 is a schematic structural diagram of a device for monitoring the cracking time of a brittle material according to the present application;
FIG. 2 is a schematic illustration of the positions of strain gauges and thermocouples;
FIG. 3 is a schematic diagram of signals indicating cracking of a brittle material according to one embodiment of the present application.
1-a brittle material; 11-an acoustic emission sensor; a 12-preamplifier; 13-an acoustic emission collector; 21-strain gauge; 22-strain collectors; 31-thermocouple; 32-temperature collector.
Detailed Description
The application is further illustrated and described below in connection with the drawings and specific embodiments of the application.
Referring to fig. 1, a device for detecting the cracking time of a brittle material comprises an acoustic emission monitoring device, a strain monitoring device and a temperature monitoring device, wherein the acoustic emission monitoring device comprises an acoustic emission sensor 11, a preamplifier 12 and an acoustic emission collector 13, the acoustic emission sensor 11 is connected to the surface of the brittle material 1, and the preamplifier 12 and the acoustic emission collector 13 are sequentially connected with the acoustic emission sensor 11; the strain monitoring device comprises a strain gauge 21 and a strain collector 22, wherein the strain gauge 21 is connected to the surface of the brittle material 1, and the strain collector 22 is connected with the strain gauge 21; the temperature monitoring device comprises a thermocouple 31 and a temperature collector 32, wherein the thermocouple 31 is connected to the surface of the brittle material 1, and the temperature collector 32 is connected with the thermocouple 31; the strain gauge 21 and thermocouple 31 do not overlap.
In some embodiments of the present application, the acoustic emission sensor 11, the strain gauge 21, or the thermocouple 31 are adhered to the surface of the brittle material 1 by using an adhesive that is consistent with the deformation of the surface of the brittle material. The adhesive is selected from instant adhesive or epoxy adhesive, and the adhesive can be selected according to the environment so as to ensure that the acoustic emission sensor 11, the strain gauge 21 or the thermocouple 31 is consistent with the surface deformation of the brittle material 1.
In order to eliminate misjudgment of severe jitter of a strain curve caused by rapid temperature change of the measured brittle material, a thermocouple 31 is arranged near the strain gauge 21; and in order to avoid the thermocouple 31 causing the strain gauge 21 to generate a measurement error, the two cannot overlap. Schematic of the positions of the strain gauge 21 and the thermocouple 31 referring to fig. 2, the lateral center-to-center spacing of the strain gauge 21 and the thermocouple 31 is less than 1% of the lateral length of the brittle material; the gauge 21 and thermocouple 31 have a vertical center-to-center spacing of less than 5% of the vertical length of the brittle material. In some embodiments of the application, the thermocouple is a tiny circle and the strain gauge is a regular rectangle.
In some embodiments of the present application, the sampling rate of the acoustic emission collector 13 is not lower than 5mhz, and the a/D accuracy is not lower than 16 bits. For example, in some embodiments of the present application, an acoustic emission harvester of the Express-8 (American physical Acoustic Co.) model is used.
In some embodiments of the present application, the effective filter bandwidth of the preamplifier 12 is 20-1000 KHz. For example, in some embodiments of the application, a 2/4/6 (physical Acoustic Co., USA) model of preamplifier is used.
In some embodiments of the present application, an acoustic emission sensor 11 of the R15 (american physical acoustic company) model is employed.
In some embodiments of the present application, the strain gauge 21 is attached to the strain gauge 22 using a 1/4 bridge "three wire" method. In some embodiments of the present application, a strain gauge of MX1615B model 22 from HBM, germany and a strain gauge of 2AA model from middle avionics instruments, inc. are used.
In some embodiments of the present application, the sampling rates of the strain gage 22 and the temperature gage 32 are the same, and the sampling rate is not lower than 1Hz. In some embodiments of the present application, a temperature harvester 32 of type 2680A from Fluke, U.S. is used.
Test example 1:
the acoustic emission sensor, strain gauge and thermocouple were attached to the polymer cement explosive according to the schematic diagram of fig. 1, and the whole was then placed in a temperature control box. And (3) performing temperature impact on the brittle material through the temperature control box to crack and destroy the brittle material. The crack initiation time of the brittle material is detected by adopting the crack initiation time detection device for the brittle material, and three parameter diagrams of acoustic emission, strain and temperature are obtained, and are shown in FIG. 3, wherein the abscissa is time, the ordinate is amplitude of acoustic emission, strain and temperature, and the units are respectively: dB. Mu epsilon and DEG C. As can be seen from fig. 3, the impact event is silently emitted while the material surface temperature remains unchanged; when the test temperature needs to be reduced, a high-power motor in the temperature control box is started, a plurality of acoustic emission impact events caused by electromagnetic interference exist, and if the acoustic emission impact events are taken as the basis for judging the cracking of the material, the time is misjudged to be the cracking time of the material. When the brittle material to be tested actually breaks, a plurality of acoustic emission impact events occur, and meanwhile, the strain curve shakes, so that the time for breaking the material can be accurately considered.
Reference throughout this specification to "one embodiment," "another embodiment," "an embodiment," and so forth, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application as broadly described. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is intended that such feature, structure, or characteristic be implemented within the scope of the application.
Although the application has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope and spirit of the principles of this disclosure. More specifically, various variations and modifications may be made to the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, drawings and claims. In addition to variations and modifications in the component parts and/or arrangements, other uses will be apparent to those skilled in the art.
Claims (6)
1. The device is characterized by comprising an acoustic emission monitoring device, a strain monitoring device and a temperature monitoring device, wherein the acoustic emission monitoring device comprises an acoustic emission sensor (11), a preamplifier (12) and an acoustic emission collector (13), the acoustic emission sensor (11) is connected to the surface of the brittle material (1), and the preamplifier (12) and the acoustic emission collector (13) are sequentially connected with the acoustic emission sensor (11); the strain monitoring device comprises a strain gauge (21) and a strain collector (22), wherein the strain gauge (21) is connected to the surface of the brittle material (1), and the strain collector (22) is connected with the strain gauge (21); the temperature monitoring device comprises a thermocouple (31) and a temperature collector (32), wherein the thermocouple (31) is connected to the surface of the brittle material (1), and the temperature collector (32) is connected with the thermocouple (31); the strain gauge (21) and the thermocouple (31) are not overlapped;
the acoustic emission sensor (11), the strain gauge (21) or the thermocouple (31) are respectively adhered to the surface of the brittle material (1) by adopting adhesive glue which is consistent with the deformation of the surface of the brittle material; the transverse center-to-center distance between the strain gauge (21) and the thermocouple (31) is less than 1% of the transverse length of the brittle material (1);
the vertical center-to-center distance between the strain gauge (21) and the thermocouple (31) is smaller than 5% of the vertical length of the brittle material (1).
2. The apparatus for detecting the cracking time of a brittle material according to claim 1, wherein the adhesive is selected from the group consisting of instant adhesive and epoxy adhesive.
3. The device for detecting the cracking time of the brittle material according to claim 1, wherein the sampling rate of the acoustic emission collector (13) is not lower than 5MHz, and the A/D precision is not lower than 16 bits.
4. The device for detecting the cracking time of a brittle material according to claim 1, wherein the effective filter bandwidth of the preamplifier (12) is 20-1000 khz.
5. The device for detecting the cracking time of a brittle material according to claim 1, wherein the strain gauge (21) is connected to the strain gauge (22) by a 1/4 bridge 'three-wire' method.
6. The device for detecting the cracking time of a brittle material according to claim 1, wherein the sampling rate of the strain collector (22) and the sampling rate of the temperature collector (32) are the same, and the sampling rate is not lower than 1Hz.
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| CN201811419418.0A CN109374682B (en) | 2018-11-26 | 2018-11-26 | Monitoring device for cracking time of brittle material |
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| CN201811419418.0A CN109374682B (en) | 2018-11-26 | 2018-11-26 | Monitoring device for cracking time of brittle material |
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| CN109374682B true CN109374682B (en) | 2023-08-22 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112198193B (en) * | 2020-10-30 | 2024-08-02 | 四川大学 | Concrete structure crack monitoring device and monitoring method thereof |
| CN114813964B (en) * | 2022-04-24 | 2023-08-22 | 中国工程物理研究院化工材料研究所 | Method for deciding cracking damage of brittle material structural member by adopting time domain information |
| CN116539413B (en) * | 2023-06-27 | 2023-11-07 | 中国矿业大学(北京) | Rock characteristic stress determining method based on acoustic emission counting nonlinear evolution |
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