Method and system for non-contact measurement of longitudinal wave sound velocity of solid material

Abstract

The invention provides a method and a system for non-contact measurement of longitudinal wave sound velocity of a solid material. The system comprises an ultrasonic transmitting probe; an ultrasonic receiving probe; the guide rail is provided with scales, the ultrasonic transmitting probe is fixed on the guide rail, and the ultrasonic receiving probe can slide on the guide rail; the clamp is arranged on the guide rail and is used for fixing a solid material to be detected; the signal acquisition and processing unit is connected with the ultrasonic transmitting probe and the ultrasonic receiving probe and is used for receiving probe signals and transmitting the signals according to the relative position between the ultrasonic transmitting probe and the ultrasonic receiving probe and the phase relation of the received signals; and determining the longitudinal wave sound velocity of the solid material. The non-contact measurement device and the measurement method for the longitudinal wave sound velocity in the solid are realized, the longitudinal wave sound velocity in a material which is not suitable for being contacted can be measured, and compared with a traditional contact type solid sound velocity measurement method, the non-contact measurement device and the measurement method have great advantages.

Description

Technical Field

[0001] The present invention relates to the technical field of longitudinal wave sound velocity measurement of solid materials, and particularly relates to a method and a system for non-contact measurement of the longitudinal wave sound velocity of solid materials. Background Art

[0002] At present, in actual engineering, the time difference method for measuring the sound velocity of solids has been widely used. Its basic principle is based on velocity = distance / time. By knowing the thickness of the material and the propagation time of ultrasonic waves in it, the sound velocity in the solid material can be obtained. This method requires the ultrasonic probe to be in close contact with the surface of the solid material. Usually, a coupling agent is needed between the ultrasonic probe and the material to be measured. These coupling agents usually make the experimental site dirty and messy and need to be cleaned up in time after measurement, which makes it difficult to automate the measurement of the solid sound velocity and results in low measurement efficiency. Moreover, in actual measurement, there are many materials that are not suitable to be in contact with the ultrasonic probe. For example, materials at high temperatures cannot be in contact with the probe; materials with strong corrosiveness are likely to damage the probe when in contact with it, and materials that are easily deformed will have their measurement accuracy reduced when compressed by the probe. In addition, it is very difficult to obtain the acoustic wave time difference when the contact method is used to measure the longitudinal wave sound velocity of materials that are too thin, which makes it very difficult to accurately measure the sound velocity in thin film materials by the contact method.

[0003] Therefore, it is necessary to study a method and a system for non-contact measurement of the longitudinal wave sound velocity of solid materials to address the deficiencies of the existing technology and solve or alleviate one or more of the above problems. Summary of the Invention

[0004] In view of this, the present invention provides a method and a system for non-contact measurement of the longitudinal wave sound velocity of solid materials, realizing a non-contact measurement device and method for the longitudinal wave sound velocity in solids, capable of measuring the longitudinal wave sound velocity in materials that are not suitable for contact, and at the same time, capable of measuring the longitudinal wave sound velocity in solids without contact and without using a coupling agent for coupling, making it easy to automate the measurement of the longitudinal wave sound velocity and improving the measurement efficiency; it has great advantages compared with the traditional contact method for measuring the sound velocity of solids.

[0005] On the one hand, the present invention provides a system for non-contact measurement of the longitudinal wave sound velocity of solid materials, and the system for non-contact measurement of the longitudinal wave sound velocity of solid materials includes: An ultrasonic transmitting probe; An ultrasonic receiving probe; A scale-equipped guide rail, where the ultrasonic transmitting probe is fixed on the guide rail, and the ultrasonic receiving probe can slide on the guide rail; A fixture, arranged on the guide rail for fixing the solid material to be measured; and a signal acquisition and processing unit, which is connected to the ultrasonic transmitting probe and the ultrasonic receiving probe, and is configured to receive the probe signals, and determine the longitudinal wave sound velocity of the solid material according to the relative position between the ultrasonic transmitting probe and the ultrasonic receiving probe and the phase relationship of the received signals.

[0006] In the aspect and any possible implementation manner as described above, a further implementation manner is provided. The non-contact system for measuring the longitudinal wave sound velocity of a solid material further includes a low-frequency signal generator, which is configured to output a low-frequency signal with a known frequency. The low-frequency signal is used to drive the ultrasonic transmitting probe, and the ultrasonic transmitting probe is configured to transmit ultrasonic waves according to the low-frequency signal.

[0007] In the aspect and any possible implementation manner as described above, a further implementation manner is provided. The signal acquisition and processing unit is configured to amplify the signals received by the ultrasonic receiving probe, and process the signals of the sound waves transmitted by the ultrasonic transmitting probe and the signals of the sound waves received by the ultrasonic receiving probe. The signal acquisition and processing unit is configured to display a Lissajous figure synthesized by the signals at the ultrasonic transmitting probe and the signals at the ultrasonic receiving probe. The horizontal and vertical coordinates in the Lissajous figure respectively represent the instantaneous displacement values of two mutually perpendicular simple harmonic vibration signals.

[0008] In the aspect and any possible implementation manner as described above, a further implementation manner is provided. The signal acquisition and processing unit is configured to, when no solid material is installed on the fixture, change the position of the ultrasonic receiving probe on the guide rail, observe the shape of the Lissajous figure displayed by the signal acquisition and processing unit, record multiple positions of the ultrasonic receiving probe on the guide rail when the Lissajous figure presents a specific phase relationship, and determine the propagation speed of sound in air according to the multiple positions and the frequency output by the low-frequency signal generator.

[0009] In the aspect and any possible implementation manner as described above, a further implementation manner is provided. The fixture is configured to fix the solid material to be measured between the ultrasonic transmitting probe and the ultrasonic receiving probe. The solid material to be measured has a thickness. The non-contact system for measuring the longitudinal wave sound velocity of a solid material is configured to obtain the thickness of the solid material. After the solid material is fixed by the fixture, the ultrasonic waves transmitted by the ultrasonic transmitting probe penetrate the solid material and reach the ultrasonic receiving probe. At this time, the shape of the Lissajous figure displayed by the signal acquisition and processing unit is no longer a straight line.

[0010] For the aspects and any possible implementation manners described above, a further implementation manner is provided. The signal acquisition and processing unit is configured to, when the fixture fixes the solid material, adjust the position of the ultrasonic receiving probe on the guide rail so that the Lissajous figure displayed by the signal acquisition and processing unit presents a specific phase relationship that is the same as when no solid material is installed, and record the multiple positions of the ultrasonic receiving probe on the guide rail at this time.

[0011] For the aspects and any possible implementation manners described above, a further implementation manner is provided. The signal acquisition and processing unit is configured to calculate the longitudinal wave sound velocity in the solid material according to the sound propagation velocity in air determined when no solid material is installed on the fixture, the thickness of the solid material, and the multiple positions of the ultrasonic receiving probe on the guide rail recorded when the fixture fixes the solid material.

[0012] For the aspects and any possible implementation manners described above, a further implementation manner is provided. The specific phase relationship includes: the phase difference between the signal at the ultrasonic transmitting probe and the signal at the ultrasonic receiving probe is zero or an integer multiple of π. When the phase difference is zero or an integer multiple of π, the Lissajous figure displayed by the signal acquisition and processing unit presents a straight line. The recording of the multiple positions of the ultrasonic receiving probe on the guide rail at this time includes recording the position of the ultrasonic receiving probe when the Lissajous figure changes from an ellipse to a straight line, and the position of the ultrasonic receiving probe when the Lissajous figure becomes a straight line again.

[0013] For the aspects and any possible implementation manners described above, a further implementation manner is provided for a non-contact method for measuring the longitudinal wave sound velocity of a solid material. The measurement is performed through the system described above. The method specifically includes the following steps: Step S1: Obtain the low-frequency sine and cosine signals with known frequencies output by the low-frequency signal generator. The low-frequency signals are used to drive the ultrasonic transmitting probe to emit ultrasonic waves. Step S2: Use the ultrasonic transmitting probe to convert the low-frequency signal into ultrasonic waves and emit them. The ultrasonic waves propagate through air or the solid material. Step S3: When no solid material is installed on the fixture, the ultrasonic waves propagate through air to the ultrasonic receiving probe, and the receiving probe receives the ultrasonic waves and outputs a received signal. Step S4: Use the signal acquisition and processing unit to collect the transmitting probe signal and the receiving probe signal, and display the Lissajous figure at the initial position x0 based on the transmitting probe signal and the receiving probe signal. Step S5: Move the position x of the ultrasonic receiving probe on the scaled rail. k , and determine and record the position x of the receiving probe when the Lissajous figure displayed on the signal acquisition and processing unit is in a specific shape by observing the Lissajous figure shape. k Set; Step S6: Obtain the thickness of the solid material, install the solid material on the fixture, and the ultrasonic wave emitted by the ultrasonic transmitting probe penetrates the solid material and propagates to the ultrasonic receiving probe. Step S7: Use the signal acquisition and processing unit to collect the transmitting probe signal and the receiving probe signal, and display the Lissajous figure at the initial position y0 based on the transmitting probe signal and the receiving probe signal. Step S8: Move the position y of the ultrasonic receiving probe on the scaled rail. k , and determine and record the new position y of the receiving probe when the Lissajous figure shape reappears in the specific shape by observing the Lissajous figure shape displayed on the signal acquisition and processing unit. k Set; Step S9: Use the signal acquisition and processing unit to calculate the longitudinal wave speed in the solid material according to the low-frequency signal frequency, the initial position x0, the set of positions x of the receiving probe k , the initial position y0, the set of new positions y of the receiving probe k , and the thickness of the solid material. Step S10: Output the calculated longitudinal wave speed value in the solid material.

[0014] In the above aspects and any possible implementation manners, a further implementation manner is provided. The method is used to measure high-temperature, strongly corrosive, and / or thin-film materials.

[0015] Compared with the prior art, the present invention can obtain the following technical effects: 1) The present invention uses the Lissajous figure to measure the longitudinal wave speed of solid materials. The ultrasonic transmitting probe is driven by a low-frequency signal, and the ultrasonic wave is received and the Lissajous figure is displayed in air and solid materials respectively. The position of the receiving probe is moved, and the set of positions when a specific Lissajous figure appears is recorded. According to the position difference of the receiving probe in the two media, the signal frequency, and the material thickness, the longitudinal wave speed in the solid material is calculated. 2) The present invention cleverly uses the change characteristics of the Lissajous figure, and can accurately obtain the sound speed data through simple position measurement, avoiding complex time measurement, improving the measurement accuracy and efficiency. The method is simple to operate and is applicable to the acoustic property measurement of various solid materials, and has important application value in the fields of material detection and acoustic research.

[0016] Of course, it is not necessary for any product implementing the present invention to achieve all the above-described technical effects simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 is a schematic diagram of a non-contact longitudinal wave sound velocity measurement system for solid materials provided by an embodiment of the present invention; Figure 2 is a schematic diagram of the change of the Lissajous figure when the position of the mobile receiving probe is changed provided by an embodiment of the present invention; Figure 3 is a schematic diagram of the Lissajous figure after inserting the material to be measured provided by an embodiment of the present invention; Among them, in the figure: 1 - graduated guide rail, 2 - signal acquisition and processing unit, 3 - low-frequency signal generator, 4 - ultrasonic receiving probe, 5 - ultrasonic transmitting probe, 6 - fixture. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] In order to better understand the technical solutions of the present invention, the embodiments of the present invention will be described in detail below with reference to the drawings.

[0020] It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0021] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms of "a", "the" and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0022] The present invention provides a non-contact system for measuring the longitudinal wave sound velocity of solid materials, and the non-contact system for measuring the longitudinal wave sound velocity of solid materials includes: an ultrasonic transmitting probe; an ultrasonic receiving probe; a graduated guide rail, the ultrasonic transmitting probe is fixed on the guide rail, and the ultrasonic receiving probe can slide on the guide rail; A fixture, which is arranged on the guide rail and used to fix the solid material to be measured; And a signal acquisition and processing unit, which is connected to the ultrasonic transmitting probe and the ultrasonic receiving probe, and is used to receive the probe signals, and determine the longitudinal wave sound velocity of the solid material according to the relative position between the ultrasonic transmitting probe and the ultrasonic receiving probe and the phase relationship of the received signals.

[0023] The non-contact measurement system for the longitudinal wave sound velocity of a solid material further includes a low-frequency signal generator, which is configured to output a low-frequency signal with a known frequency, and the low-frequency signal is used to drive the ultrasonic transmitting probe, and the ultrasonic transmitting probe is configured to transmit ultrasonic waves according to the low-frequency signal.

[0024] The signal acquisition and processing unit is configured to amplify the signals received by the ultrasonic receiving probe, and process the signals of the sound waves emitted by the ultrasonic transmitting probe and the signals of the sound waves received by the ultrasonic receiving probe. The signal acquisition and processing unit is configured to display the Lissajous figure synthesized by the signals at the ultrasonic transmitting probe and the signals at the ultrasonic receiving probe. The Lissajous figure can measure the frequency ratio and phase difference of the two signals. Therefore, an oscilloscope is used to observe the Lissajous figure and measure the frequency or phase difference. The sinusoidal signal to be measured and a standard signal with a known frequency are respectively applied to the Y-axis input terminal and the X-axis input terminal of the oscilloscope. The frequency and phase-related information of the sinusoidal signal to be measured can be obtained through the Lissajous figure displayed on the oscilloscope screen. In the present invention, the horizontal and vertical coordinates in the Lissajous figure respectively represent the instantaneous displacement values of two mutually perpendicular simple harmonic vibration signals, which is equivalent to a harmonic oscillator performing simple harmonic vibration along the vertical direction (Y signal) and a simple harmonic vibration along the horizontal direction (X signal). The synthesis of the two vibrations forms the Lissajous figure. When the frequencies and phases of the two oscillators are different, the movement trajectories are different, and the trajectory of this combined movement is the Lissajous figure.

[0025] The signal acquisition and processing unit is configured to, when no solid material is installed on the fixture, change the position of the ultrasonic receiving probe on the guide rail, observe the shape of the Lissajous figure displayed by the signal acquisition and processing unit, record multiple positions of the ultrasonic receiving probe on the guide rail when the shape of the Lissajous figure presents a specific phase relationship, and determine the propagation speed of sound in air according to the multiple positions and the frequency output by the low-frequency signal generator.

[0026] The fixture is configured to fix the solid material to be measured between the ultrasonic transmitting probe and the ultrasonic receiving probe. The solid material to be measured has a thickness. The non-contact system for measuring the longitudinal wave sound velocity of the solid material is configured to obtain the thickness of the solid material. After the solid material is fixed by the fixture, the ultrasonic wave emitted by the ultrasonic transmitting probe penetrates the solid material and reaches the ultrasonic receiving probe. At this time, the Lissajous figure displayed by the signal acquisition and processing unit is no longer a straight line.

[0027] The signal acquisition and processing unit is configured to, when the fixture fixes the solid material, adjust the position of the ultrasonic receiving probe on the guide rail so that the Lissajous figure displayed by the signal acquisition and processing unit presents a specific phase relationship that is the same as when no solid material is installed, and record multiple positions of the ultrasonic receiving probe on the guide rail at this time.

[0028] The signal acquisition and processing unit is configured to calculate the longitudinal wave sound velocity in the solid material according to the sound propagation velocity in air determined when no solid material is installed on the fixture, the thickness of the solid material, and the multiple positions of the ultrasonic receiving probe on the guide rail recorded when the fixture fixes the solid material.

[0029] The specific phase relationship includes: the phase difference between the signal at the ultrasonic transmitting probe and the signal at the ultrasonic receiving probe is zero or an integer multiple of π. When the phase difference is zero or an integer multiple of π, the Lissajous figure displayed by the signal acquisition and processing unit presents as a straight line. The recording of the multiple positions of the ultrasonic receiving probe on the guide rail at this time includes recording the position of the ultrasonic receiving probe when the Lissajous figure changes from an ellipse to a straight line, and the position of the ultrasonic receiving probe when the Lissajous figure becomes a straight line again.

[0030] The present invention also provides a method for non-contact measurement of the longitudinal wave sound velocity of a solid material. The measurement is performed through the system described above. The method specifically includes the following steps: Step S1: Obtain the low-frequency sine and cosine signals with known frequencies output by the low-frequency signal generator. The low-frequency signals are used to drive the ultrasonic transmitting probe to emit ultrasonic waves. Step S2: Use the ultrasonic transmitting probe to convert the low-frequency signal into ultrasonic waves and emit them. The ultrasonic waves propagate through air or the solid material. Step S3: When no solid material is installed on the fixture, the ultrasonic waves propagate through air to the ultrasonic receiving probe. The receiving probe receives the ultrasonic waves and outputs a received signal. Step S4: The signal acquisition and processing unit is used to acquire the transmitting probe signal and the receiving probe signal, and display the Lissajous figure at the initial position x0 based on the transmitting probe signal and the receiving probe signal. Step S5: Move the position x of the ultrasonic receiving probe on the scale rail. k , and determine and record the positions x of the receiving probe when the Lissajous figure displayed on the signal acquisition and processing unit is in a specific shape by observing the shape of the Lissajous figure. k set; Step S6: Obtain the thickness of the solid material, and install the solid material on the fixture. The ultrasonic wave emitted by the ultrasonic transmitting probe penetrates the solid material and propagates to the ultrasonic receiving probe. Step S7: The signal acquisition and processing unit is used to acquire the transmitting probe signal and the receiving probe signal, and display the Lissajous figure at the initial position y0 based on the transmitting probe signal and the receiving probe signal. Step S8: Move the position y of the ultrasonic receiving probe on the scale rail. k , and determine and record the new positions y of the receiving probe when the Lissajous figure displayed on the signal acquisition and processing unit reproduces the specific shape by observing the shape of the Lissajous figure. k set; Step S9: The signal acquisition and processing unit is used to calculate the longitudinal wave velocity in the solid material according to the low-frequency signal frequency, the initial position x0, the set of positions x of the receiving probe k , the initial position y0, the set of new positions y of the receiving probe k set, and the thickness of the solid material. Step S10: Output the calculated longitudinal wave velocity value in the solid material.

[0031] The method is used to measure high-temperature, strongly corrosive, and / or thin-film materials.

[0032] Example 1: A non-contact device for measuring the longitudinal wave velocity of a material in the present invention has a structure and connection as Figure 1 shown: including, Low-frequency signal generator: It can output low-frequency sine and cosine signals with known frequencies.

[0033] Ultrasonic transmitting probe: In order to improve the ability to penetrate solid materials, the required probe should have sufficient high power.

[0034] Ultrasonic receiving probe: It is arranged on the side opposite to the above-mentioned transmitting probe to receive the sound wave passing through the object to be measured.

[0035] Scaled guide rail: The transmitting probe is fixed at the zero scale of the guide rail, and the receiving probe can slide on the guide rail. The position of the receiving probe can be read through the scale. A fixture for fixing the material to be measured is provided on the guide rail between the two probes.

[0036] Signal acquisition and processing unit: Amplify the signal received by the receiving probe and process the sound wave emitted by the transmitting probe and the sound wave received by the receiving probe, display the Lissajous figure synthesized by the signal at the transmitting probe and the signal at the receiving probe, and be able to process the measurement data.

[0037] In the non-contact longitudinal wave sound velocity measurement device of the present invention, the longitudinal wave sound velocity measurement method is realized by the following technical solutions: Step 1: When no solid material is installed on the fixture, the ultrasonic wave generated by the transmitting probe directly propagates through the air to the receiving probe. First, use the traveling wave method to measure the sound velocity of the current sound in the air. The specific operation is as follows: The experimental device is as Figure 1 shown. In the experiment, change the position of the receiving probe on the guide rail and observe the shape of the Lissajous figure on the signal acquisition processor. When the shape of the Lissajous figure changes from an ellipse to a straight line, record the position x1 of the probe. Continue to move the receiving probe, and the figure becomes an ellipse again, and then becomes a straight line again, as Figure 2 shown. Record the position x2 of the probe. Continue to move the receiving probe until the figure becomes a straight line again, and record the position x of the probe at this time 3， And so on, measure the N positions of the probe in the same way. The difference between two adjacent readings should theoretically be half of the wavelength. Then, multiply the wavelength by the output frequency of the low-frequency signal generator to obtain the propagation speed of the ultrasonic wave in the air .

[0038] Step 2: First, adjust the position of the receiving probe so that the Lissajous figure displayed on the signal collector is a straight line. At this time, record the position of the receiving probe as y0. The phase difference between the sound source and the receiving probe is shown in the following formula:

[0039] where f is the frequency of the ultrasonic wave, is the phase difference between the sound source and the receiving probe.

[0040] After measuring the thickness d of the material with a micrometer and fixing the solid material to the fixture (the thickness of the material should be as small as possible, which is beneficial to the penetration of ultrasonic waves through the material), the ultrasonic wave can penetrate the material to be measured and reach the receiving probe. At this time, it can be seen that the Lissajous figure is no longer a straight line (as Figure 3), adjust the position of the receiving probe so that the receiving probe moves away from the transmitting probe. When the Lissajous figure changes from an ellipse to a straight line in the same quadrant as before, record the position y1 of the receiving probe at this time. Continue to move the probe. When a straight line in the same quadrant appears again, record the position y2 of the receiving probe at this time, and so on to record the positions of the receiving probe. If y k is the position of the receiving probe when the straight line appears before the k-th reappearance of the Lissajous figure, then the phase difference between the sound source and the receiving probe satisfies the following relationship: ; Then and The relationship of is as follows: ; Among them, is the phase difference between the sound source and the receiving probe when the Lissajous figure reappears for the k-th time.

[0041] Using the above formulas, the longitudinal wave sound velocity in the solid material can be obtained by the following formula: ; Input the data recorded in the measurement into the signal acquisition and processing unit for processing and calculation, and output the measured value of the longitudinal wave sound velocity.

[0042] The present invention realizes a non-contact measurement device and method for the longitudinal wave sound velocity in a solid, which can measure the longitudinal wave sound velocity in materials that are not suitable for contact. Without contact and without using a coupling agent for coupling, the longitudinal wave sound velocity in a solid can be measured, making it easy to automate the measurement of the longitudinal wave sound velocity and improving the measurement efficiency. Since it is very difficult to obtain the acoustic time difference when the traditional contact time difference method measures materials that are too thin, the present invention is particularly suitable for measuring the longitudinal wave sound velocity of thin materials and has great advantages over the traditional solid sound velocity measurement methods.

[0043] The above has introduced in detail a method and system for non-contact measurement of the longitudinal wave sound velocity of solid materials provided by the embodiments of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

[0044] As used in the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not distinguish components by the difference in names, but by the difference in functions of the components. As used throughout the specification and claims, the terms "comprising" and "including" are open-ended terms and should be interpreted as "comprising / including but not limited to". "Substantially" means within an acceptable error range. Those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The following description in the specification is the preferred embodiment for implementing the present application, but the description is for the purpose of explaining the general principles of the present application and is not used to limit the scope of the present application. The protection scope of the present application shall be subject to that defined by the appended claims.

[0045] It should also be noted that the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a commodity or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or elements inherent to such commodity or system. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the commodity or system including the said element.

[0046] It should be understood that the term "and / or" used herein is merely an associative relationship describing associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0047] The above description shows and describes several preferred embodiments of the present application. However, as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the application concept described herein through the above teachings or the technology or knowledge in the relevant field. And the changes and variations made by those skilled in the art that do not depart from the spirit and scope of the present application shall fall within the protection scope of the appended claims of the present application.

Claims

1. A non-contact system for measuring the longitudinal wave speed of solid materials, characterized in that The system for non-contact measurement of the longitudinal wave sound velocity of a solid material includes: An ultrasonic transmitting probe; An ultrasonic receiving probe; A scale-equipped guide rail, where the ultrasonic transmitting probe is fixed on the guide rail, and the ultrasonic receiving probe can slide on the guide rail; A fixture, arranged on the guide rail for fixing the solid material to be measured; And a signal acquisition and processing unit, which is connected to the ultrasonic transmitting probe and the ultrasonic receiving probe, and is used to receive the probe signals, and determine the longitudinal wave sound velocity of the solid material according to the relative position between the ultrasonic transmitting probe and the ultrasonic receiving probe and the phase relationship of the received signals.

2. The non-contact system for measuring the longitudinal wave sound velocity of solid materials according to claim 1, wherein The system for non-contact measurement of the longitudinal wave sound velocity of a solid material further includes a low-frequency signal generator, which is configured to output a low-frequency signal with a known frequency, and the low-frequency signal is used to drive the ultrasonic transmitting probe, and the ultrasonic transmitting probe is configured to emit ultrasonic waves according to the low-frequency signal.

3. The non-contact system for measuring the longitudinal wave speed of a solid material according to claim 1, characterized in that, The signal acquisition and processing unit is configured to amplify the signal received by the ultrasonic receiving probe, and process the signal of the sound wave emitted by the ultrasonic transmitting probe and the signal of the sound wave received by the ultrasonic receiving probe. The signal acquisition and processing unit is configured to display a Lissajous figure synthesized by the signals at the ultrasonic transmitting probe and the ultrasonic receiving probe. The horizontal and vertical coordinates in the Lissajous figure respectively represent the instantaneous displacement values of two mutually perpendicular simple harmonic vibration signals.

4. The non-contact system for measuring the longitudinal wave sound velocity of a solid material according to claim 2, characterized in that, The signal acquisition and processing unit is configured to, when no solid material is installed on the fixture, by changing the position of the ultrasonic receiving probe on the guide rail, observing the shape of the Lissajous figure displayed by the signal acquisition and processing unit, recording multiple positions of the ultrasonic receiving probe on the guide rail when the Lissajous figure shape presents a specific phase relationship, and determining the sound propagation speed in air according to the multiple positions and the frequency output by the low-frequency signal generator.

5. The non-contact system for measuring the longitudinal wave sound velocity of a solid material according to claim 1, characterized in that, The fixture is configured to fix the solid material to be measured between the ultrasonic transmitting probe and the ultrasonic receiving probe. The solid material to be measured has a thickness. The system for non-contact measurement of the longitudinal wave sound velocity of a solid material is configured to obtain the thickness of the solid material. After the solid material is fixed by the fixture, the ultrasonic waves emitted by the ultrasonic transmitting probe penetrate the solid material and reach the ultrasonic receiving probe. At this time, the shape of the Lissajous figure displayed by the signal acquisition and processing unit is no longer a straight line.

6. The non-contact system for measuring the longitudinal wave sound velocity of a solid material according to claim 5, characterized in that, The signal acquisition and processing unit is configured to, when the fixture fixes the solid material, by adjusting the position of the ultrasonic receiving probe on the guide rail, make the shape of the Lissajous figure displayed by the signal acquisition and processing unit present the same specific phase relationship as when no solid material is installed, and record multiple positions of the ultrasonic receiving probe on the guide rail at this time.

7. The non-contact system for measuring the longitudinal wave velocity of a solid material according to claim 6, characterized in that, The signal acquisition and processing unit is configured to calculate the longitudinal wave sound velocity in the solid material based on the sound propagation speed in the air determined when no solid material is installed on the fixture, the thickness of the solid material, and the multiple positions of the ultrasonic receiving probe on the guide rail recorded when the fixture fixes the solid material.

8. The non-contact system for measuring the longitudinal wave sound velocity of solid materials according to claim 6, wherein, The specific phase relationship includes: the phase difference between the signal at the ultrasonic transmitting probe and the signal at the ultrasonic receiving probe is zero or an integer multiple of π; when the phase difference is zero or an integer multiple of π, the Lissajous figure displayed by the signal acquisition and processing unit appears as a straight line; and the multiple positions of the ultrasonic receiving probe on the guide rail at this time are recorded, including the position of the ultrasonic receiving probe when the Lissajous figure changes from an ellipse to a straight line, and the position of the ultrasonic receiving probe when the Lissajous figure changes back to a straight line.

9. A method for non-contact measurement of the longitudinal wave sound velocity of a solid material, which is measured by the system according to any one of the above claims 1-8, characterized in that, The method specifically comprises the following steps: Step S1, obtaining a low-frequency sine and cosine signal of a known frequency output by the low-frequency signal generator, wherein the low-frequency signal is used to drive the ultrasonic transmitting probe to transmit ultrasonic waves; Step S2, using the ultrasonic transmitting probe to convert the low-frequency signal into ultrasonic waves and transmit the ultrasonic waves, wherein the ultrasonic waves propagate through the air or the solid material; Step S3, when the fixture is not equipped with the solid material, the ultrasonic wave is transmitted through the air to the ultrasonic receiving probe, and the receiving probe receives the ultrasonic wave and outputs a receiving signal; Step S4, using the signal acquisition processing unit to acquire the transmitting probe signal and the receiving probe signal, and displaying a Lissajous figure of the initial position x0 based on the transmitting probe signal and the receiving probe signal; Step S5, move the position x of the ultrasonic receiving probe on the graduated guide rail k , by observing the Lissajous figure shape displayed on the signal acquisition and processing unit, determine and record the position x of the receiving probe when the Lissajous figure shape is a specific shape k set; Step S6, obtaining the thickness of the solid material, and mounting the solid material on the fixture, wherein the ultrasonic wave emitted by the ultrasonic transmitting probe penetrates the solid material and propagates to the ultrasonic receiving probe; Step S7, using the signal acquisition processing unit to acquire the transmitting probe signal and the receiving probe signal, and displaying a Lissajous figure of the initial position y0 based on the transmitting probe signal and the receiving probe signal; Step S8, move the position y of the ultrasonic receiving probe on the graduated guide rail k , by observing the Lissajous figure shape displayed on the signal acquisition and processing unit, determine and record the new position y of the receiving probe when the Lissajous figure shape reproduces the specific shape k set; Step S9, using the signal acquisition and processing unit, calculate the longitudinal wave sound velocity in the solid material according to the low-frequency signal frequency, the initial position x0, the set of positions x of the receiving probe, the initial position y0, the set of new positions y of the receiving probe, and the thickness of the solid material. k and the set of new positions y of the receiving probe, and the thickness of the solid material. k calculate the longitudinal wave sound velocity in the solid material. Step S10, outputting the calculated value of the longitudinal wave sound velocity in the solid material.

10. The method for non-contact measurement of the longitudinal wave sound velocity of a solid material according to claim 9, characterized in that, The method is useful for measuring high temperature, highly corrosive and / or thin film materials.

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