CN111103355A - Device and method for detecting compactness of carbon fiber plate reinforced colloid - Google Patents
Device and method for detecting compactness of carbon fiber plate reinforced colloid Download PDFInfo
- Publication number
- CN111103355A CN111103355A CN201911338534.4A CN201911338534A CN111103355A CN 111103355 A CN111103355 A CN 111103355A CN 201911338534 A CN201911338534 A CN 201911338534A CN 111103355 A CN111103355 A CN 111103355A
- Authority
- CN
- China
- Prior art keywords
- carbon fiber
- audio
- fiber plate
- colloid
- computer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/045—Analysing solids by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
- G01N29/46—Processing the detected response signal, e.g. electronic circuits specially adapted therefor by spectral analysis, e.g. Fourier analysis or wavelet analysis
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/023—Solids
- G01N2291/0235—Plastics; polymers; soft materials, e.g. rubber
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/26—Scanned objects
- G01N2291/263—Surfaces
- G01N2291/2632—Surfaces flat
Abstract
The invention discloses a device and a method for detecting the compactness of a carbon fiber plate reinforced colloid, which comprises an audio acquisition instrument, an impact hammer and a computer; the impact hammer is an audio signal excitation device and is used for striking a detection part measuring point during detection; the audio acquisition instrument acquires an audio signal generated by impact of the impact hammer, performs preliminary analysis and transmits the signal of the preliminary analysis to the computer; the computer is used for analyzing and processing the acquired audio signals to obtain a cavity cloud picture of the detection part, and the device effectively ensures the construction quality of the carbon fiber plate reinforced colloid.
Description
Technical Field
The invention relates to the field of carbon fiber plate reinforcement, in particular to a device and a method for audio frequency real-time detection of compactness of a carbon fiber plate reinforcement colloid.
Background
Carbon fiber composite materials have been gradually applied to various fields due to their small specific gravity, high material strength, and good corrosion resistance. Particularly, the prestress carbon fiber plate reinforcing technology in an engineering structure can exert the material performance of the carbon fiber plate to the maximum extent, so that the bearing limit of the carbon fiber plate is increased. According to the results of the present investigation, the construction and supervision of the present carbon fiber plate pasting construction are not strict, the carbon fiber plate pasting is easy to be incompact, and the guide is not provided with a clear standard specification, so that once the quality of the carbon fiber plate does not reach the standard, the carbon fiber plate is not adhered compactly, and finally the carbon fiber plate is subject to diseases such as falling off. At present, the carbon fiber plate colloid void detection technology only uses an impact hammer to knock the surface of a carbon plate, and determines the colloid compactness through the vibration sound feedback, and only can carry out qualitative analysis but not quantitative analysis, and has larger artificial influence factors. Therefore, the problem of the adhesion quality of the carbon fiber plate is paid high attention to engineering construction, and necessary detection and control technology is adopted to ensure the adhesion quality of the carbon fiber plate.
Aiming at the problems of the carbon fiber plate in the aspect of adhesion, the research on the aspect is blank so far, and a uniform compactness detection method is not formed at home and abroad. Therefore, develop the closely knit nature detection device research of carbon fiber plate reinforcement colloid, it is crucial to the construction quality who guarantees the carbon fiber plate reinforcement colloid.
Disclosure of Invention
The invention aims to solve the problem of insufficient construction compactness of the conventional carbon fiber plate reinforcing colloid, and provides an audio frequency detection device and method for the compactness of the carbon fiber plate reinforcing colloid, which are applied to detection of construction quality of the carbon fiber plate reinforcing colloid in a construction period so as to ensure the compactness of pasting of the carbon fiber plate in the construction period.
In order to achieve the purpose, the invention adopts the following technical measures:
in a first aspect, the invention provides a device for detecting the compactness of a carbon fiber plate reinforced colloid, which comprises an audio acquisition instrument, an impact hammer and a computer;
the impact hammer is an audio signal excitation device and is used for striking a detection part measuring point during detection;
the audio acquisition instrument acquires an audio signal generated by impact of the impact hammer, performs preliminary analysis and transmits the signal of the preliminary analysis to the computer;
the computer is used for analyzing and processing the collected audio signals to obtain a cavity cloud picture of the detection part.
As a further technical solution, the audio acquisition instrument should approach the microphone to the impact position of the impact hammer during acquisition.
In a second aspect, aiming at the detection device, the invention further provides a method for detecting the compactness of the carbon fiber plate reinforced colloid, which comprises the following steps:
step 1: acquiring a dense section audio signal and a void section signal of a carbon plate with the same model as a site actually measured part by using an audio acquisition instrument in advance, and taking the acquired dense section audio signal and void section signal as calibration data;
step 2: measuring points are divided at the actually measured part of the carbon fiber plate reinforcing colloid, so that the measuring points are uniformly distributed and the whole measuring area surface can be completely reflected;
and 4, step 4: repeating the step 3 according to the measuring point sequence divided in the step 2, and clicking to store and generate a file after the whole measuring area is tested;
and 5: and importing the generated test file into a computer, and generating a superior period cloud picture generated by the point location of the measuring area by the computer according to the measuring point distance of the measured part.
As a further technical scheme, a plurality of groups of dense section audio signals and void section signals in the calibration data are respectively collected, and the plurality of groups of dense section audio signals are processed to obtain the calibration data of the dense section audio signals; and processing the plurality of groups of audio signals of the void section to obtain calibration data of the audio signals of the void section.
As a further technical scheme, the computer converts the voltage signal acquired and stored by the audio acquisition instrument from a time domain to a frequency domain through discrete Fourier conversion; and drawing the converted frequency domain voltage signals into a detection area carbon fiber plate reinforced colloid cavity cloud picture according to the detection point sequence.
As a further technical scheme, the acquisition of the data of the compact section and the void section in the step 1 can directly acquire the compact area and the void area of the known detection member on site; when the dense section and the void section are not known on site, a calibration test piece with the same type of carbon plate and the same colloid thickness of the carbon plate as those of the site actually measured part is manufactured, a percussion hammer is used for knocking the test piece, and data are collected at the dense section and the void section to serve as calibration data.
The carbon fiber plate reinforced colloid compactness detection device has the following detection principle:
when the surface of the structure to be measured is hammered, vibrations are induced in the surface, which also compress/stretch the air to form sound waves. Therefore, the acoustic characteristics of the sound waves are closely related to the induced structural vibration characteristics. In general, at the location where the void occurs, the vibration characteristics change as follows:
(1) the bending rigidity is obviously reduced, and the excellent period is prolonged;
(2) the dissipation of elastic wave energy becomes gentle and the duration of vibration becomes long.
The invention has the beneficial effects that:
according to the device and the method for detecting the compactness of the carbon fiber plate reinforced colloid, the impact hammer is used for striking the carbon plate to be detected to generate the audio signal, the compactness of the carbon plate to be detected is acquired and preliminarily analyzed by adopting the audio acquisition instrument and the audio acquisition software, the audio signal is led in by the computer after the acquisition is finished, and the excellent cloud chart of the measuring point of the detected part is obtained through analysis, so that the construction quality of the carbon fiber plate reinforced colloid is effectively ensured.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.
FIG. 1 is a graph of audio data collected by an audio instrument;
FIG. 2 is a test chart of the carbon fiber plate colloid void;
FIG. 3 is a layout diagram of test points of a carbon fiber plate;
FIG. 4 is a data diagram of waveforms of a gel void section of a carbon fiber plate;
FIG. 5 is a data diagram of a carbon fiber plate colloid compaction section waveform;
FIGS. 6(a) and 6(b) are graphs of discrete Fourier transform of test data;
FIG. 7 is a prominent period cloud image generated from different points of carbon fiber plate colloid.
The device comprises a carbon fiber plate colloid cavitation test piece 1, an audio acquisition instrument 2, an impact hammer 3, a carbon fiber plate colloid 4 and a carbon fiber plate colloid cavitation test point 5.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an", and/or "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof;
as introduced in the background art, in the existing carbon fiber plate colloid void detection technology, the surface of a carbon plate is only knocked by an impact hammer, the compactness of the colloid is judged by the knocking sound feedback, only qualitative analysis can be performed, quantitative analysis cannot be performed, and human influence factors are large. Therefore, the problem of the adhesion quality of the carbon fiber plate is paid high attention to engineering construction, and necessary detection and control technology is adopted to ensure the adhesion quality of the carbon fiber plate. Aiming at the problems of the carbon fiber plate in the aspect of adhesion, the research on the aspect is blank so far, and a uniform compactness detection method is not formed at home and abroad. Therefore, develop the closely knit nature detection device research of carbon fiber plate reinforcement colloid, it is crucial to the construction quality who guarantees the carbon fiber plate reinforcement colloid.
In an exemplary embodiment of the present application, as shown in fig. 1, the present invention discloses a device for detecting a compactness of a carbon fiber plate reinforced colloid. The method is characterized in that the surface of the carbon fiber plate is knocked by an impact hammer, sound wave data are collected and preliminarily analyzed by an audio collector, then test data are led into computer-side analysis software to obtain a carbon fiber plate colloid cavitation cloud picture in a test area, the carbon fiber plate colloid cavitation condition in the test area is visually reflected, and finally the compactness of the carbon fiber plate reinforced colloid is effectively guaranteed.
Carbon fiber plate consolidates the closely knit nature detection device of colloid, detects the principle as follows: when the surface of the structure to be measured is hammered, vibrations are induced in the surface, which also compress/stretch the air to form sound waves. Therefore, the acoustic characteristics of the sound waves are closely related to the induced structural vibration characteristics. In general, at the location where the void occurs, the vibration characteristics change as follows: (1) the bending rigidity is obviously reduced, and the excellent period is prolonged; (2) the dissipation of elastic wave energy becomes gentle and the duration of vibration becomes long.
The specific detection device structure includes: audio acquisition appearance 2, jump bit 3 and corresponding computer. The carbon fiber plate colloid void test measuring point 4 is marked above the carbon fiber plate colloid void test piece 1; the impact hammer 3 is knocked on a carbon fiber plate colloid void test measuring point 4; the audio acquisition instrument 3 is placed at the tapping measuring point, and the distance is generally required to be not more than 10 cm.
Referring to the drawings of FIGS. 2-7, assuming that the width of the carbon fiber plate is b and the length of the carbon fiber plate is h, marking the measuring points of the carbon fiber plate according to the size of the carbon fiber plate, wherein the measuring points are divided into m measuring points along the length direction, the distance is (h-2)/(m-1), the measuring points are divided into n measuring points along the width direction, and the distance is (b-2)/(n-1);
as shown in fig. 2-7, the carbon fiber plate colloid void test measuring points 5 are arranged 1cm away from the edge of the carbon fiber plate;
with reference to fig. 2-7, the impact hammer 3 should strike the carbon fiber plate colloid test point at a constant speed;
as shown in fig. 2-7, when the impact hammer 3 strikes a carbon fiber plate colloid test point, the audio detector 2 should be close to the strike point, and the distance should be less than 10 cm;
referring to fig. 2 to fig. 7, the waveform data graph of the void area of carbon fiber plate colloid has a longer acoustic duration and a longer test voltage extreme than the waveform data graph of the dense area of carbon fiber plate colloid;
as shown in fig. 2 to fig. 7, when the waveform data diagram is processed by the audio analysis software, the voltage signal is converted from the time domain to the frequency domain by discrete fourier transform;
as shown in fig. 2-7, the cloud images with excellent periods generated from different point positions of the carbon fiber plate colloid can accurately reflect the void condition of the carbon plate of the test specimen.
The following is a description of specific detection and use methods of the above-described apparatus:
step 1: if the field conditions allow, a known detection component compact area and a known detection component void area exist, and an audio acquisition instrument is started;
step 2: enabling a microphone of the audio acquisition instrument to be close to the knocking part, opening audio acquisition software, and selecting a data calibration function;
and step 3: clicking a data acquisition button, knocking the actually measured part by using an impact hammer, checking the validity of the acquired data, storing the data, and knocking again for acquisition if no valid data exists;
and 4, step 4: respectively acquiring three groups of compact section audio signals and void section signals as calibration data by using an audio acquisition instrument;
and 5: when the dense section and the void section are not known on site, manufacturing a calibration test piece with the same type of carbon plate and the same colloid thickness of the carbon plate as the site actually measured part, knocking the test piece by using an impact hammer, and respectively acquiring three groups of data as calibration data in the dense section and the void section;
step 6: measuring points are divided at the actually measured part by using a marker pen, so that the measuring points are uniformly distributed and the whole measuring area surface can be completely reflected;
and 7: opening audio acquisition software, and selecting calibration data corresponding to the actually measured part;
and 8: knocking a measuring point of a measured part by using an impact hammer, collecting an audio signal by using an audio collector, checking the validity of the audio signal in real time, and storing the audio signal;
and step 9: repeating the step 5 according to the sequence of the measuring points, clicking to store and generating a file after the whole measuring area is tested;
step 10: and importing the generated test file into computer analysis software, and generating a superior period cloud picture generated by the point location of the measured area according to the measured point distance of the measured area.
According to the device and the method for detecting the compactness of the carbon fiber plate reinforced colloid, the impact hammer is used for striking the carbon plate to be detected to generate the audio signal, the compactness of the carbon plate to be detected is acquired and preliminarily analyzed by adopting the audio acquisition instrument and the audio acquisition software, the audio signal is led in by the computer after the acquisition is finished, and the excellent cloud chart of the measuring point of the detected part is obtained through analysis, so that the construction quality of the carbon fiber plate reinforced colloid is effectively ensured.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (8)
1. A carbon fiber plate reinforcement colloid compactness detection device is characterized by comprising an audio acquisition instrument, an impact hammer and a computer;
the impact hammer is an audio signal excitation device and is used for striking a detection part measuring point during detection;
the audio acquisition instrument acquires an audio signal generated by impact of the impact hammer, performs preliminary analysis and transmits the signal of the preliminary analysis to the computer;
the computer is used for analyzing and processing the collected audio signals to obtain a cavity cloud picture of the detection part.
2. The device for detecting the compactness of the carbon fiber plate reinforced colloid according to claim 1, wherein the audio acquisition instrument is used for enabling a microphone to be close to the impact position of the impact hammer during acquisition.
3. The device for detecting the compactness of the carbon fiber plate reinforced colloid according to claim 1, wherein audio acquisition software is installed on the audio acquisition instrument.
4. The apparatus for testing the compactness of the carbon fiber plate reinforced colloid according to claim 1, wherein audio analysis software is installed on the computer.
5. The detection method of the carbon fiber plate reinforced colloid compactness detection device according to any one of claims 1 to 4, characterized by comprising the following steps:
step 1: acquiring a dense section audio signal and a void section signal of a carbon plate with the same model as a site actually measured part by using an audio acquisition instrument in advance, and taking the acquired dense section audio signal and void section signal as calibration data;
step 2: measuring points are divided at the actually measured part of the carbon fiber plate reinforcing colloid, so that the measuring points are uniformly distributed and the whole measuring area surface can be completely reflected;
step 3, knocking a measuring point of the actually measured part by using an impact hammer, collecting data by an audio collector close to a knocking part, checking the validity of the collected data, storing the data, and knocking and collecting again if no valid data exists;
and 4, step 4: repeating the step 3 according to the measuring point sequence divided in the step 2, and clicking to store and generate a file after the whole measuring area is tested;
and 5: and importing the generated test file into a computer, and generating a superior period cloud picture generated by the point location of the measuring area by the computer according to the measuring point distance of the measured part.
6. The detection method according to claim 5, wherein a plurality of sets of the dense-segment audio signals and the void-segment signals in the calibration data are respectively collected, and the plurality of sets of the dense-segment audio signals are processed to obtain the calibration data of the dense-segment audio signals; and processing the plurality of groups of audio signals of the void section to obtain calibration data of the audio signals of the void section.
7. The detection method according to claim 5, wherein the computer converts the voltage signal collected and stored by the audio collector from time domain to frequency domain by discrete Fourier transform; and drawing the converted frequency domain voltage signals into a detection area carbon fiber plate reinforced colloid cavity cloud picture according to the detection point sequence.
8. The test method as claimed in claim 5, wherein the collection of the data of the compact section and the void section in step 1 can directly collect the compact area and the void area of the known test member in the field; when the dense section and the void section are not known on site, a calibration test piece with the same type of carbon plate and the same colloid thickness of the carbon plate as those of the site actually measured part is manufactured, a percussion hammer is used for knocking the test piece, and data are collected at the dense section and the void section to serve as calibration data.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911338534.4A CN111103355A (en) | 2019-12-23 | 2019-12-23 | Device and method for detecting compactness of carbon fiber plate reinforced colloid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911338534.4A CN111103355A (en) | 2019-12-23 | 2019-12-23 | Device and method for detecting compactness of carbon fiber plate reinforced colloid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111103355A true CN111103355A (en) | 2020-05-05 |
Family
ID=70423293
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911338534.4A Pending CN111103355A (en) | 2019-12-23 | 2019-12-23 | Device and method for detecting compactness of carbon fiber plate reinforced colloid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111103355A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1712950A (en) * | 2005-07-04 | 2005-12-28 | 上海科鸣建筑工程技术有限公司 | Audio-frequency detection of concrete fault |
| CN102759744A (en) * | 2012-06-20 | 2012-10-31 | 中国水电顾问集团贵阳勘测设计研究院 | Method for detecting grotto steel lining concrete void thickness |
| CN108254440A (en) * | 2018-02-01 | 2018-07-06 | 湖南大学 | It is a kind of to detect robot and the method using detection robot detection concrete filled steel tube pouring quality |
| CN110045016A (en) * | 2019-04-24 | 2019-07-23 | 四川升拓检测技术股份有限公司 | A kind of tunnel-liner lossless detection method based on audio analysis |
-
2019
- 2019-12-23 CN CN201911338534.4A patent/CN111103355A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1712950A (en) * | 2005-07-04 | 2005-12-28 | 上海科鸣建筑工程技术有限公司 | Audio-frequency detection of concrete fault |
| CN102759744A (en) * | 2012-06-20 | 2012-10-31 | 中国水电顾问集团贵阳勘测设计研究院 | Method for detecting grotto steel lining concrete void thickness |
| CN108254440A (en) * | 2018-02-01 | 2018-07-06 | 湖南大学 | It is a kind of to detect robot and the method using detection robot detection concrete filled steel tube pouring quality |
| CN110045016A (en) * | 2019-04-24 | 2019-07-23 | 四川升拓检测技术股份有限公司 | A kind of tunnel-liner lossless detection method based on audio analysis |
Non-Patent Citations (3)
| Title |
|---|
| 刘蒙: ""基于麦克风冲击共振法的钢-混凝土组合结构脱空损伤诊断研究"", 《中国优秀硕士学位论文全文数据库 工程科技II辑》 * |
| 宋福春 等: ""冲击弹性波法检测钢板加固混凝土质量试验研究"", 《建筑结构》 * |
| 格桑泽仁: "基于诱导振动的钢管混凝土脱空无损检测技术的研究及应用", 《四川理工学院学报》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105424802B (en) | A kind of the ultrasonic guided wave detecting system and its detection method of composite insulator defect | |
| CN102636303B (en) | Method for measuring residual stress of thin plating layer based on surface ultrasonic waves | |
| CN100523765C (en) | Vibrating detection method for detecting looseness of large-scale generator rotor slot wedge and apparatus therefor | |
| CN101793873B (en) | Testing method of characteristics of sound vibration and point vibration of piano sound board and special equipment thereof | |
| CN110045016B (en) | Tunnel lining nondestructive testing method based on audio frequency analysis | |
| CN1696686A (en) | System for testing quality of cast in place concrete pile | |
| CN106053597A (en) | Detection method of steel pipe concrete cavity defect extracted on basis of HHT characteristics | |
| CN111487315A (en) | Audio frequency nondestructive testing method for tunnel lining thickness and void | |
| CN109696480A (en) | A kind of glass fiber compound material acoustic emission source positioning and imaging method based on improvement time reversal algorithm | |
| CN109374748A (en) | Antidirection finding imaging method when acoustic emission source | |
| CN103698404A (en) | Damping material loss factor measurement method and device based on impulse response method | |
| CN108519583A (en) | Acoustic emission source locating method suitable for anisotropy two dimensional panel | |
| JP6367506B1 (en) | Grout filling status discrimination system and grout filling status discrimination program | |
| CN102590341B (en) | Method for detecting sonic time and tracking phase wave band of concrete pile shaft by ultrasonic transmission method | |
| CN111103355A (en) | Device and method for detecting compactness of carbon fiber plate reinforced colloid | |
| CN105092709A (en) | Concrete structure nondestructive detection method | |
| CN109115885A (en) | It is a kind of based on without constraint resonance method asphalt damping ratio acquisition device and method | |
| CN106556858B (en) | A kind of ultrasonic signal excitation reception test macro | |
| CN209086205U (en) | It is a kind of based on without constraint resonance method asphalt damping ratio acquisition device | |
| CN106370293A (en) | Measurement system and decomposition method for integral sound vibration and firmware vibration of violin | |
| CN114878684A (en) | Steel pipe concrete arch rib compactness detection method based on piezoelectric ceramic ultrasound | |
| CN101806616A (en) | Test method of vibration characteristic of violin board and special equipment thereof | |
| JP3023508B1 (en) | Evaluation method of physical properties of elasto-plastic body by percussion sound | |
| CN1456884A (en) | Compactness diagnosing method and apparatus for concrete slope surface | |
| CN1257380C (en) | Method for measuring thickness of concrete slab |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |