CN117537964A - Oblique polarization piezoelectric ultrasonic transducer for measuring axial stress of bolt and application method thereof - Google Patents
Oblique polarization piezoelectric ultrasonic transducer for measuring axial stress of bolt and application method thereof Download PDFInfo
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- CN117537964A CN117537964A CN202311495943.1A CN202311495943A CN117537964A CN 117537964 A CN117537964 A CN 117537964A CN 202311495943 A CN202311495943 A CN 202311495943A CN 117537964 A CN117537964 A CN 117537964A
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 230000010287 polarization Effects 0.000 title claims abstract description 14
- 239000013078 crystal Substances 0.000 claims abstract description 26
- 238000005259 measurement Methods 0.000 claims abstract description 17
- 238000004806 packaging method and process Methods 0.000 claims abstract description 8
- 238000001914 filtration Methods 0.000 claims abstract description 5
- 230000005284 excitation Effects 0.000 claims description 7
- 238000004458 analytical method Methods 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 5
- 238000012360 testing method Methods 0.000 claims description 5
- 238000011088 calibration curve Methods 0.000 claims description 3
- 230000007613 environmental effect Effects 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/25—Measuring force or stress, in general using wave or particle radiation, e.g. X-rays, microwaves, neutrons
- G01L1/255—Measuring force or stress, in general using wave or particle radiation, e.g. X-rays, microwaves, neutrons using acoustic waves, or acoustic emission
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/24—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed
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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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- General Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Abstract
The invention discloses a obliquely polarized piezoelectric ultrasonic transducer for measuring axial stress of a bolt and a use method thereof, wherein the obliquely polarized piezoelectric ultrasonic transducer comprises an obliquely polarized piezoelectric crystal, a positive electrode, a connecting wire and a packaging shell; the obliquely polarized piezoelectric ultrasonic transducer can excite ultrasonic transverse waves and longitudinal waves simultaneously, and can realize the component proportion of exciting transverse ultrasonic waves and longitudinal ultrasonic waves by adjusting the polarization direction of the piezoelectric crystal according to specific application working conditions, has the advantages of simple equipment, convenient use, easy realization and the like, and can be widely used for measuring the axial stress of the connecting bolts of key structural components in various fields; the use method of the oblique polarization piezoelectric ultrasonic transducer adopts the technical schemes of filtering, automatically intercepting ultrasonic waveforms, accurately identifying transverse and longitudinal wave echo peak signals by using a cross-correlation method, and the like, and obtains the axial stress of the bolt by calculation by using a transverse and longitudinal wave combining method, so that the application is wide, the efficiency is high, and the accuracy of a measurement result is ensured.
Description
Technical Field
The invention relates to the technical field of electric ultrasonic transducers, in particular to an oblique polarization piezoelectric ultrasonic transducer for measuring axial stress of a bolt and a use method thereof.
Background
The bolt is used as a typical connecting piece in industry, is widely applied to the connecting parts of key structural components in the fields of aerospace, ship turbines, bridge construction, petrochemical industry, new energy and the like, plays roles of strengthening, sealing and the like, and the service quality of the bolt is important for safe production. The axial stress of the bolts is becoming more important as an important factor directly affecting the performance, service life and use state of the bolts. Therefore, bolt stress measurement is a key for ensuring that the bolts play a role in connection, evaluating the performance of the bolts and monitoring the integrity of the bolts.
Currently, ultrasonic testing is one of the main methods for quantitatively measuring bolt stress. In the bolt stress measurement technology based on ultrasonic detection, detection technologies such as a pulse echo reflection method, a transit time method, a phase method and the like are commonly used, but the bolt body with unknown original length such as an installed bolt or a buried anchor bolt cannot be effectively applied. The method for measuring the longitudinal and transverse wave combination in the bolt is used for measuring the stress through the change of ultrasonic propagation characteristics, and the influence of the length of the bolt on the stress measurement result can be eliminated, so that the method has great advantages. However, in the measurement process, ultrasonic transverse waves and longitudinal waves are required to be excited simultaneously, the traditional ultrasonic transducer adopts vertical polarization treatment on the piezoelectric crystal, only transverse waves or longitudinal waves can be excited, and two types of waveforms of transverse waves and longitudinal waves cannot be excited simultaneously, so that only two different ultrasonic transducers can be used for respectively exciting/receiving ultrasonic transverse waves and ultrasonic longitudinal waves, the detection sensor and the test system are complex, and the engineering application of the method in actual bolt stress measurement is greatly limited.
Therefore, there is a need to develop a obliquely polarized piezoelectric ultrasonic transducer for bolt axial stress measurement and a method of using the same to solve the above-mentioned problems.
Disclosure of Invention
The invention aims to solve the problems and designs an oblique polarization piezoelectric ultrasonic transducer for measuring axial stress of a bolt and a using method thereof.
The invention realizes the above purpose through the following technical scheme:
a diagonally polarized piezoelectric ultrasonic transducer for bolt axial stress measurement, comprising:
a diagonally polarized piezoelectric crystal; the obliquely polarized piezoelectric crystal is obtained by obliquely polarizing the piezoelectric crystal;
a positive electrode; the positive electrode is arranged on the upper end face of the obliquely polarized piezoelectric crystal;
a connecting wire; the first end of the connecting wire is connected with the positive electrode, and the second end of the connecting wire penetrates out of the packaging shell;
a package housing; the obliquely polarized piezoelectric crystal is packaged in the packaging shell; the package can acts as a negative electrode.
The application method of the obliquely polarized piezoelectric ultrasonic transducer for measuring the axial stress of the bolt comprises the following steps:
s1, sticking the lower end face of an obliquely polarized piezoelectric ultrasonic transducer to the head of a bolt to ensure that excited ultrasonic energy is directly transmitted into the bolt;
s2, screwing the bolt on a processed device, applying a certain pretightening force by using a torque wrench, generating a pulse excitation signal by using a signal generator, applying the pulse excitation signal to an obliquely polarized piezoelectric crystal to generate ultrasonic transverse and longitudinal waves and transmitting the ultrasonic transverse and longitudinal waves in the bolt body, reflecting the ultrasonic waves after the ultrasonic waves touch a bottom section of the bolt, transmitting the ultrasonic waves to the end part of the bolt, receiving the ultrasonic waves, displaying the ultrasonic waves on an oscilloscope, and recording the ultrasonic waves by using a signal acquisition device;
s3, filtering the ultrasonic echo signals recorded by the signal acquisition device by using a signal analysis processing system, automatically intercepting ultrasonic waveforms, accurately identifying transverse and longitudinal wave echo signals by using a cross-correlation method, measuring the transit time of the transverse and longitudinal wave echo signals, and calculating and obtaining the axial stress of the bolt by using a formula (1) based on a transverse and longitudinal wave combination method:
in the aboveLongitudinal wave sound velocity in zero stress state, +.>Is the transverse wave sound velocity under the zero stress state, K L For measuring stress coefficient, K S For measuring the stress coefficient of transverse waves, the four ultrasonic parameters are obtained through a calibration test under the zero stress state, sigma is the axial stress of the bolt, T L For the transition time of the longitudinal wave of the tested bolt, T S The transverse wave transit time of the bolt to be tested.
The invention has the beneficial effects that:
the obliquely polarized piezoelectric ultrasonic transducer provided by the invention can excite ultrasonic transverse waves and longitudinal waves simultaneously, can realize the component proportion of exciting transverse ultrasonic waves and longitudinal ultrasonic waves by adjusting the polarization direction of the piezoelectric crystal according to specific application working conditions, has the advantages of simple equipment, convenience in use, easiness in realization and the like, and can be widely used for measuring the axial stress of connecting bolts of key structural components in various fields.
The method for using the obliquely polarized piezoelectric ultrasonic transducer for measuring the axial stress of the bolt adopts the technical schemes of filtering, automatically intercepting ultrasonic waveforms, accurately identifying the echo peak signals of transverse and longitudinal waves by using a cross-correlation method, and the like, compensates the influence of factors such as environmental temperature, fatigue and the like on a measurement result by using a calibration curve method, calculates and obtains the axial stress of the bolt by using a transverse and longitudinal wave combined method, has wide applicability and high efficiency, and simultaneously ensures the accuracy of the measurement result.
Drawings
FIG. 1 is a schematic structural diagram of a diagonally polarized piezoelectric ultrasonic transducer of the present application;
FIG. 2 is a schematic diagram of a typical ultrasonic transverse-longitudinal wave signal generated by a diagonally-polarized piezoelectric ultrasonic transducer;
fig. 3 is a graph of the results of the cross-correlation algorithm.
In the figure: 1-a diagonally polarized piezoelectric crystal; 2-positive electrode; 3-connecting lines; 4-packaging the shell.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. are based on the directions or positional relationships shown in the drawings, or the directions or positional relationships conventionally put in place when the inventive product is used, or the directions or positional relationships conventionally understood by those skilled in the art are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific direction, be configured and operated in a specific direction, and therefore should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," and the like, are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.
In the description of the present invention, it should also be noted that, unless explicitly specified and limited otherwise, terms such as "disposed," "connected," and the like are to be construed broadly, and for example, "connected" may be either fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The following describes specific embodiments of the present invention in detail with reference to the drawings.
As shown in fig. 1, the obliquely polarized piezoelectric ultrasonic transducer for bolt axial stress measurement comprises:
a diagonally polarized piezoelectric crystal 1; the obliquely polarized piezoelectric crystal 1 is obtained by obliquely polarizing the piezoelectric crystal, and the oblique polarization direction is 45 degrees (the adjustment of the component proportion of ultrasonic transverse wave and longitudinal wave can be realized by adjusting the polarization direction of the piezoelectric crystal according to the actual application requirement);
a positive electrode 2; the positive electrode 2 is arranged on the upper end face of the obliquely polarized piezoelectric crystal 1;
a connecting wire 3; the first end of the connecting wire 3 is connected with the positive electrode 2, and the second end of the connecting wire 3 penetrates out of the packaging shell 4;
a package case 4; the obliquely polarized piezoelectric crystal 1 is encapsulated in the encapsulation shell 4; the package can 4 serves as a negative electrode.
When the obliquely polarized piezoelectric ultrasonic transducer works, excitation voltage is applied to the positive electrode 2 and the packaging shell 4 through the connecting wire 3, so that the obliquely polarized piezoelectric crystal 1 generates an inverse piezoelectric effect, and vibration along the polarization direction of the obliquely polarized piezoelectric crystal 1 is excited, and therefore ultrasonic transverse waves and longitudinal waves are generated simultaneously.
The invention also discloses a using method of the oblique polarization piezoelectric ultrasonic transducer for measuring the axial stress of the bolt, which comprises the following steps:
s1, tightly and firmly adhering the lower end face of an obliquely polarized piezoelectric ultrasonic transducer to the head of a bolt to ensure that excited ultrasonic energy is directly transmitted into the bolt;
s2, screwing the bolt on a processed device, applying a certain pretightening force (such as 10 kN) by using a torque wrench, generating a pulse excitation signal by using a signal generator, applying the pulse excitation signal to an obliquely polarized piezoelectric crystal to generate ultrasonic transverse and longitudinal waves and transmitting the ultrasonic transverse and longitudinal waves in the bolt body, reflecting the ultrasonic waves after the ultrasonic waves touch a bottom section of the bolt, transmitting the ultrasonic waves to the end part of the bolt, receiving the ultrasonic waves, displaying the ultrasonic waves on an oscilloscope, and recording the ultrasonic waves by using a signal acquisition device, wherein the signal acquisition device is shown in figure 2;
s3, filtering an ultrasonic echo signal recorded by a signal acquisition device by using a signal analysis processing system, automatically intercepting an ultrasonic waveform, accurately identifying a transverse and longitudinal wave echo signal by using a cross-correlation method, measuring the transit time (effectively improving the signal to noise ratio of a detected signal), and displaying the stress state of the current bolt on a screen, wherein the cross-correlation method is a typical result diagram as shown in FIG. 3, the influence of environmental temperature, fatigue and other factors on a measurement result is compensated by using a calibration curve method, and the axial stress of the bolt is obtained by using a formula (1) based on the method of combining transverse and longitudinal waves:
in the aboveLongitudinal wave sound velocity in zero stress state, +.>Is the transverse wave sound velocity under the zero stress state, K L For measuring stress coefficient, K S Stress system for transverse wave measurementThe number, sigma is the axial stress of the bolt and T, of the four ultrasonic parameters are obtained through calibration tests under zero stress state L For the transition time of the longitudinal wave of the tested bolt, T S The transverse wave transit time of the bolt to be tested.
In some embodiments, in step S1, the bolt head to which the obliquely polarized piezoelectric ultrasonic transducer is attached is flat and perpendicular to the central axis of the bolt, and the ultrasonic transducer needs to be tightly and firmly attached to the bolt head, so as to ensure that the excited ultrasonic waves are directly transmitted into the interior of the bolt.
In some embodiments, in step S3, the signal analysis processing system filters and automatically intercepts the waveform for the first echo to improve the stress measurement accuracy of the instrument.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the scope of the invention.
Claims (6)
1. Oblique polarization piezoelectric ultrasonic transducer for measuring axial stress of bolt, which is characterized by comprising:
a diagonally polarized piezoelectric crystal; the obliquely polarized piezoelectric crystal is obtained by obliquely polarizing the piezoelectric crystal;
a positive electrode; the positive electrode is arranged on the upper end face of the obliquely polarized piezoelectric crystal;
a connecting wire; the first end of the connecting wire is connected with the positive electrode, and the second end of the connecting wire penetrates out of the packaging shell;
a package housing; the obliquely polarized piezoelectric crystal is packaged in the packaging shell; the package can acts as a negative electrode.
2. The obliquely polarized piezoelectric ultrasonic transducer of claim 1, wherein the oblique polarization direction is 35 ° or 45 ° or 55 °.
3. Use of a obliquely polarised piezoelectric ultrasonic transducer for axial stress measurement of bolts according to claim 1 or 2, characterised by the steps of:
s1, pasting a obliquely polarized piezoelectric ultrasonic transducer on the head of a bolt to ensure that excited ultrasonic energy is directly transmitted into the bolt;
s2, screwing the bolt on a processed device, applying a certain pretightening force by using a torque wrench, generating a pulse excitation signal by using a signal generator, applying the pulse excitation signal to an obliquely polarized piezoelectric crystal to generate ultrasonic transverse and longitudinal waves and transmitting the ultrasonic transverse and longitudinal waves in the bolt body, reflecting the ultrasonic waves after the ultrasonic waves touch a bottom section of the bolt, transmitting the ultrasonic waves to the end part of the bolt, receiving the ultrasonic waves, displaying the ultrasonic waves on an oscilloscope, and recording the ultrasonic waves by using a signal acquisition device;
s3, filtering the ultrasonic echo signals recorded by the signal acquisition device by using a signal analysis processing system, automatically intercepting ultrasonic waveforms, accurately identifying transverse and longitudinal wave echo signals by using a cross-correlation method, measuring the transit time of the transverse and longitudinal wave echo signals, and calculating and obtaining the axial stress of the bolt by using a formula (1) based on a transverse and longitudinal wave combination method:
in the aboveLongitudinal wave sound velocity in zero stress state, +.>Is the transverse wave sound velocity under the zero stress state, K L For measuring stress coefficient, K S For measuring the stress coefficient of transverse waves, the four ultrasonic parameters are obtained through a calibration test under the zero stress state, sigma is the axial stress of the bolt, T L For the transition time of the longitudinal wave of the tested bolt, T S The transverse wave transit time of the bolt to be tested.
4. A method of using a obliquely polarized piezoelectric ultrasonic transducer for bolt axial stress measurement according to claim 3, wherein in step S1, the bolt head of the obliquely polarized piezoelectric ultrasonic transducer is stuck flat and perpendicular to the central axis of the bolt.
5. A method of using a obliquely polarised piezoelectric ultrasonic transducer for bolt axial stress measurement according to claim 3, where in step S3 the signal analysis processing system filters and automatically intercepts the waveform for the first echo.
6. The method of using a obliquely polarized piezoelectric ultrasonic transducer for measuring axial stress of a bolt according to claim 3, wherein in step S3, the influence of environmental temperature factors and fatigue factors on the measurement result is compensated by using a calibration curve method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311495943.1A CN117537964A (en) | 2023-11-10 | 2023-11-10 | Oblique polarization piezoelectric ultrasonic transducer for measuring axial stress of bolt and application method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311495943.1A CN117537964A (en) | 2023-11-10 | 2023-11-10 | Oblique polarization piezoelectric ultrasonic transducer for measuring axial stress of bolt and application method thereof |
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| CN117537964A true CN117537964A (en) | 2024-02-09 |
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| CN202311495943.1A Pending CN117537964A (en) | 2023-11-10 | 2023-11-10 | Oblique polarization piezoelectric ultrasonic transducer for measuring axial stress of bolt and application method thereof |
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- 2023-11-10 CN CN202311495943.1A patent/CN117537964A/en active Pending
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