An instrument and method for measuring the attenuation coefficient of ultrasonic shear waves

Abstract

This invention provides a device and method for measuring the ultrasonic shear wave attenuation coefficient. The device includes: an ultrasonic detector for exciting an ultrasonic shear wave probe to generate ultrasonic shear waves, recording the echo amplitudes of the shear waves on the reflective surfaces of a test block and a workpiece under test, and sequentially calculating the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test based on the amplitudes; an ultrasonic shear wave probe for fixing to the coupling surface of the test block or the workpiece under test, emitting and receiving ultrasonic shear waves; and a test block designed according to the material properties of the workpiece under test and the attenuation characteristics of the ultrasonic shear waves, used to receive the ultrasonic shear waves and form an echo on the reflective surface. This invention eliminates the influence of diffusion attenuation in the attenuation coefficient measurement by using a pre-designed test block, sequentially calculating the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test, obtaining a diffusion attenuation coefficient that matches the shape and size of the workpiece under test, and improving the accuracy of ultrasonic shear wave attenuation coefficient measurement.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic shear wave attenuation coefficient measurement technology, specifically to an ultrasonic shear wave attenuation coefficient measurement device and its working method. Background Technology

[0002] When ultrasound propagates in a medium, the energy of the ultrasound decreases due to diffusion attenuation caused by the diffusion of the ultrasound beam itself, absorption attenuation caused by the absorption of ultrasound energy by the medium, and scattering attenuation caused by the scattering of ultrasound by grain boundaries between medium grains. Generally, the attenuation coefficient of ultrasound is the sum of the diffusion attenuation coefficient, absorption attenuation coefficient, and scattering attenuation coefficient. Obtaining the attenuation coefficient of ultrasound is crucial for understanding the attenuation law of the ultrasound sound field in a medium and for the qualitative and quantitative identification of defects in the medium.

[0003] Currently, the ultrasonic shear wave attenuation coefficient is generally obtained using a thin plate specimen made of the same or similar material as the workpiece under test. The ultrasonic shear wave is obliquely incident into the thin plate specimen and reflects back and forth between the bottom surface and the coupling surface. A receiving probe is placed at a distance n times (n = 1, 2, 3, ...) across the coupling surface to obtain the sound pressure of the ultrasonic shear wave after n reflections, thus yielding the attenuation coefficient of the ultrasonic shear wave in the thin plate. However, this method measures the sum of the diffusion attenuation coefficient, absorption attenuation coefficient, and scattering attenuation coefficient, and cannot measure the numerical values ​​of each attenuation coefficient. In particular, the diffusion attenuation coefficient is significantly affected by the shape and size of the workpiece under test, and the diffusion attenuation coefficient measured on the thin plate specimen often cannot represent the diffusion attenuation coefficient within the workpiece under test. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of inaccurate measurement of ultrasonic shear wave attenuation coefficient in the prior art, thereby providing a device and working method for measuring ultrasonic shear wave attenuation coefficient, which can measure the diffusion attenuation coefficient, scattering attenuation coefficient and absorption attenuation coefficient of ultrasonic shear waves of workpieces of different shapes and sizes, thereby improving the accuracy of attenuation coefficient measurement of the workpiece being tested.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] In a first aspect, the present invention provides a measuring device for ultrasonic shear wave attenuation coefficient, the system comprising: an ultrasonic detector, an ultrasonic shear wave probe, and a preset number of test blocks;

[0007] The ultrasonic testing instrument is used to excite the ultrasonic transverse wave transmitting probe to generate an ultrasonic transverse wave of a preset frequency, and to record the echo amplitude of the ultrasonic transverse wave received by the ultrasonic transverse wave receiving probe on the reflecting surfaces of the test block and the workpiece under test. Based on the amplitude, the absorption attenuation coefficient, scattering attenuation coefficient and diffusion attenuation coefficient of the workpiece under test are calculated in sequence.

[0008] The ultrasonic shear wave probe includes an ultrasonic shear wave emitting probe and an ultrasonic shear wave receiving probe, which are used to fix the coupling surface of the test block or the workpiece to be tested. The ultrasonic shear wave emitting probe generates and emits ultrasonic shear waves through the ultrasonic detector, and the ultrasonic shear wave receiving probe receives the echo of the ultrasonic shear wave and returns it to the ultrasonic detector.

[0009] The test block is designed according to the material properties of the workpiece under test and the attenuation characteristics of ultrasonic shear waves, so that the ultrasonic shear waves propagate inside it and form an echo on the reflecting surface. The echo is used to calculate the absorption attenuation coefficient, scattering attenuation coefficient and diffusion attenuation coefficient of the workpiece under test.

[0010] The test block includes: a preset number of semi-cylindrical test blocks or a preset number of isosceles trapezoidal test blocks, wherein the surface roughness, acoustic impedance, and material of the semi-cylindrical test blocks or isosceles trapezoidal test blocks are the same as those of the workpiece to be tested.

[0011] The cylindrical surface radii of each of the semi-cylindrical test blocks are the same and are set to be greater than a preset multiple of the near field region of the ultrasonic shear wave probe. The surface roughness is set to be less than a first preset proportion of the shear wave wavelength. The average grain size of each of the semi-cylindrical test blocks is different and is set to be less than a second preset proportion of the shear wave wavelength.

[0012] The distance between the isosceles trapezoidal surface of each of the isosceles trapezoidal test blocks and the incident point of the ultrasonic shear wave is the same and is set to be greater than a preset multiple of the near field region of the ultrasonic shear wave probe. The surface roughness is set to be less than a first preset proportion of the shear wave wavelength. The average grain size of each of the isosceles trapezoidal test blocks is different and is set to be less than a second preset proportion of the shear wave wavelength.

[0013] The ultrasonic shear wave attenuation coefficient measuring device provided in this invention uses pre-designed semi-cylindrical and isosceles trapezoidal test blocks, based on the material properties of the workpiece under test and the attenuation characteristics of ultrasonic shear waves, as test blocks. An ultrasonic testing instrument excites ultrasonic shear wave transmitting probes fixed to the coupling surfaces of each test block or workpiece under test to generate ultrasonic shear waves of a preset frequency. These ultrasonic shear waves are then emitted to corresponding reflecting surfaces, forming echoes between the coupling and reflecting surfaces. An ultrasonic shear wave receiving probe receives a preset number of echoes, and the ultrasonic testing instrument records the amplitude of each echo. Based on the amplitude, the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test are calculated. This invention eliminates the influence of diffusion attenuation in attenuation coefficient measurement by using pre-designed test blocks, sequentially calculating the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test, and obtaining a diffusion attenuation coefficient that matches the shape and size of the workpiece under test, thereby improving the accuracy of ultrasonic shear wave attenuation coefficient measurement.

[0014] Optionally, the ultrasonic shear wave probe is equipped with a magnetic attraction or clamping device to ensure that the coupling force of the ultrasonic shear wave probe remains consistent when measuring different test blocks or workpieces.

[0015] The test blocks designed in this invention have the same material properties as the workpiece under test, and their shapes are regular and their sizes are relatively large. This ensures that the absorption attenuation constant and scattering attenuation constant of the test blocks and the workpiece under test are the same, and the diffusion attenuation coefficient conforms to the attenuation formula. By performing ultrasonic shear wave tests on test blocks with different grain sizes, the absorption attenuation constant and scattering attenuation constant of the test blocks can be calculated, thereby obtaining the absorption attenuation coefficient and scattering attenuation coefficient of the workpiece under test. In order to obtain different equations for solving different attenuation constants, ultrasonic shear wave measurements need to be performed on different test blocks and workpieces under test. By configuring magnetic suction or clamping devices, it is possible to ensure that the coupling force of the ultrasonic shear wave probe is the same when it is fixed on different test blocks or workpieces under test, which makes the measured echo amplitude more accurate, thereby further improving the accuracy of the calculated attenuation coefficients.

[0016] Optionally, an ultrasonic transverse wave probe that combines ultrasonic emission and ultrasonic reception functions is fixed on the coupling surface of the test block according to the ultrasonic transverse wave propagation characteristics; the ultrasonic transverse wave emission probe and the ultrasonic transverse wave reception probe are respectively fixed at different positions on the coupling surface of the workpiece under test, separated by a preset multiple span.

[0017] Optionally, if the workpiece to be tested does not have a reflective surface that is approximately parallel to the coupling surface, a test block with the same beam diffusion cross-sectional area as the ultrasonic transverse wave probe is fabricated, and the thickness, material, and surface roughness of the test block are the same as those of the workpiece to be tested.

[0018] If the workpiece tested by this invention does not have a reflective surface that is approximately parallel to the coupling surface, it is impossible to form the conditions for multiple reflections. Directly performing ultrasonic transverse wave measurement will affect the formation of echoes, resulting in inaccurate calculation of the attenuation coefficient. Therefore, a test block with the same material properties as the workpiece to be tested can be processed to replace the workpiece to be tested for measurement, which can ensure the accuracy of the attenuation coefficient measurement.

[0019] Secondly, embodiments of the present invention provide a method for operating a device for measuring the ultrasonic shear wave attenuation coefficient, comprising the following steps:

[0020] Determine the coupling surface and reflecting surface of the test block. Select the rectangular surface of the semi-cylindrical test block as the coupling surface and the semi-cylindrical curved surface as the reflecting surface, or select the opposite upper surfaces of the isosceles trapezoidal test block as the coupling surface and the two isosceles trapezoidal surfaces as the reflecting surfaces.

[0021] An ultrasonic transverse wave probe of a preset frequency is fixed on the coupling surface of a preset number of test blocks, and an ultrasonic detector is used to excite the ultrasonic transverse wave probe to emit ultrasonic transverse waves to the corresponding reflection surface of each test block.

[0022] The ultrasonic shear wave forms an echo between the coupling surface and the reflecting surface of each test block. The ultrasonic shear wave probe receives the echoes reflected back by each test block a preset number of times by the reflecting surface, and the ultrasonic detector records the amplitude of different echoes. The absorption attenuation constant and the scattering attenuation constant are obtained based on the amplitude, and the absorption attenuation coefficient and the scattering attenuation coefficient of the workpiece under test are calculated based on the absorption attenuation constant and the scattering attenuation constant.

[0023] Two relatively parallel surfaces of the workpiece to be tested are selected as its coupling surface and reflecting surface, respectively. An ultrasonic transverse wave emitting probe of a preset frequency is fixed on the coupling surface of the workpiece to be tested. An ultrasonic detector is used to excite the ultrasonic transverse wave emitting probe to emit ultrasonic transverse waves to the reflecting surface of the workpiece to be tested.

[0024] The ultrasonic shear wave forms an echo between the coupling surface and the reflecting surface of the workpiece under test. The ultrasonic shear wave receiving probe is fixed at a preset multiple span distance to receive the echo reflected back from the reflecting surface at the preset multiple span distance. The amplitude of different echoes is recorded by the ultrasonic detector, and the diffusion attenuation coefficient of the workpiece under test is calculated based on the amplitude, the absorption attenuation coefficient, and the scattering attenuation coefficient.

[0025] The working method of the ultrasonic shear wave attenuation coefficient measuring device provided in this invention involves designing semi-cylindrical and isosceles trapezoidal test blocks as test blocks based on the material properties of the workpiece under test and the attenuation characteristics of ultrasonic shear waves. An ultrasonic detector excites ultrasonic shear wave emitting probes fixed to the coupling surface of each test block or workpiece under test to generate ultrasonic shear waves of a preset frequency, which are then emitted to the corresponding reflecting surface. The ultrasonic shear waves form echoes between the coupling surface and the reflecting surface. An ultrasonic shear wave receiving probe receives a preset number of echoes, and the ultrasonic detector records the amplitude of each echo. The absorption attenuation constant and scattering attenuation constant of the workpiece under test for ultrasonic shear waves are calculated based on the echo amplitude of the test block, and then the absorption attenuation coefficient and scattering attenuation coefficient of the workpiece under test are calculated. Finally, the diffusion attenuation coefficient of the workpiece under test for ultrasonic shear waves is calculated based on the absorption attenuation coefficient, scattering attenuation coefficient, and echo amplitude of the workpiece under test. This invention eliminates the influence of diffusion attenuation in attenuation coefficient measurement by using a pre-designed test block, and sequentially calculates the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test, thereby obtaining a diffusion attenuation coefficient that matches the shape and size of the workpiece under test, and improving the accuracy of ultrasonic shear wave attenuation coefficient measurement.

[0026] Optionally, on the test block, the incident point and receiving point of the ultrasonic transverse wave are both at the center of the coupling surface of the test block. The ultrasonic transverse wave passes through the axis of the semi-cylindrical test block and is emitted along the radial direction of the cross-section of the semi-cylindrical test block, or is emitted parallel to the normal direction of the trapezoidal surface of the isosceles trapezoidal test block. On the workpiece to be tested, the incident point of the ultrasonic transverse wave is the fixed position of the ultrasonic transverse wave emitting probe, and the receiving point is the fixed position of the ultrasonic transverse wave receiving probe. The ultrasonic transverse wave is emitted toward the reflecting surface of the workpiece to be tested according to a preset refraction angle.

[0027] This invention pre-designs test blocks with different average grain sizes. Ultrasonic shear waves form echoes on the coupling and reflecting surfaces of the test blocks. Based on the frequency of the ultrasonic shear waves, the preset refraction angle, and the crystal size, semi-cylindrical or trapezoidal test blocks are designed so that after the ultrasonic shear wave probe is coupled to the upper surface of the test block, the emitted shear waves can be reflected back and forth on the semi-cylindrical surface or on the two waist surfaces of the trapezoidal test block, thereby obtaining the ultrasonic shear wave sound pressure after multiple reflections.

[0028] Optionally, the diffusion attenuation coefficients of the semi-cylindrical test block and the isosceles trapezoidal test block satisfy the attenuation formula.

[0029] The pre-designed test block of this invention, due to its special shape or relatively large sound beam propagation cross section, ensures that the diffusion attenuation coefficient of the test block satisfies the attenuation formula, thus eliminating the influence of diffusion attenuation in attenuation coefficient measurement. Calculating the diffusion attenuation coefficient using the attenuation formula allows the diffusion attenuation coefficient to be used as a known quantity during ultrasonic shear wave attenuation coefficient measurement, simplifying the calculation process.

[0030] Optionally, the number of the semi-cylindrical test blocks or isosceles trapezoidal test blocks is at least two.

[0031] This invention obtains the absorption attenuation constant and scattering attenuation constant by testing test blocks. Since there are two unknowns, at least one set of two linear equations must be generated during the measurement of the ultrasonic shear wave attenuation coefficient to ensure that the absorption attenuation constant and scattering attenuation constant can be calculated. Therefore, during the testing process, two semi-cylindrical or isosceles trapezoidal test blocks are selected. The two test blocks are identical in all material properties except for the average grain size. This allows two sets of two linear equations to be generated during the measurement process. By solving the equations simultaneously, a set of two linear equations is generated, which ensures that the equations have a solution, and that the absorption attenuation constant and scattering attenuation constant can be calculated.

[0032] Optionally, the process of receiving a preset number of echoes reflected back from the reflective surfaces of each test block by the ultrasonic shear wave probe, recording the amplitude of different echoes by the ultrasonic detector, obtaining the absorption attenuation constant and the scattering attenuation constant based on the amplitude, and calculating the absorption attenuation coefficient and the scattering attenuation coefficient of the workpiece under test based on the absorption attenuation constant and the scattering attenuation constant, includes: the ultrasonic shear wave forming echoes on the reflective surfaces of the first test block and the second test block; the ultrasonic shear wave probe receiving the m-th and n-th echoes formed on the reflective surfaces of the first test block, and recording the first amplitude of the m-th echo and the second amplitude of the n-th echo by the ultrasonic detector; calculating the first measurement coefficient based on the first amplitude and the second amplitude; and calculating the absorption attenuation coefficient and the scattering attenuation coefficient of the workpiece under test. The first attenuation coefficient of the test block is calculated, and a first equation is constructed between the first attenuation coefficient and the absorption attenuation constant and the scattering attenuation constant. The ultrasonic transverse wave probe receives the m-th and n-th echoes formed on the reflecting surface of the second test block, and the ultrasonic detector records the third amplitude of the m-th echo and the fourth amplitude of the n-th echo. The second attenuation coefficient of the second test block is calculated based on the third and fourth amplitudes, and a second equation is constructed between the second attenuation coefficient and the absorption attenuation constant and the scattering attenuation constant. The first and second equations are combined to calculate the absorption attenuation constant and the scattering attenuation constant. The absorption attenuation coefficient and the scattering attenuation coefficient of the workpiece under test are calculated based on the absorption attenuation constant and the scattering attenuation constant.

[0033] This invention employs two identical ultrasonic shear wave measurements, with ultrasonic shear waves of the same frequency generating echoes at both the coupling and reflecting surfaces of different test blocks. By selecting a preset number of echoes, the attenuation coefficients of the two test blocks can be obtained through the echo amplitude. The attenuation coefficient is the sum of the absorption attenuation coefficient, the scattering attenuation coefficient, and the diffusion attenuation coefficient. The absorption and scattering attenuation coefficients have fixed relationships with their corresponding absorption and scattering attenuation constants, respectively, and the diffusion attenuation coefficient can be calculated using the attenuation formula. Therefore, two sets of relationships between the attenuation coefficient and the absorption and scattering attenuation constants can be obtained. Solving these two linear equations in two variables yields a system of linear equations in two variables. Therefore, the two constants can be solved using this system of linear equations. Substituting these constants into the fixed relationships corresponding to the workpiece under test allows for the calculation of the absorption and scattering attenuation coefficients of the workpiece under test.

[0034] Optionally, the process of fixing the ultrasonic shear wave receiving probe at a preset multiple span distance, receiving the echo reflected back from the reflecting surface at a preset multiple span distance, recording the amplitude of different echoes using the ultrasonic detector, and calculating the diffusion attenuation coefficient of the workpiece under test based on the amplitude, the absorption attenuation coefficient, and the scattering attenuation coefficient includes: the ultrasonic shear wave forming an echo on the reflecting surface of the workpiece under test; fixing the ultrasonic shear wave receiving probe at a first position m times the span distance and a second position n times the span distance from the ultrasonic shear wave transmitting probe within the coupling surface; the ultrasonic shear wave receiving probe receiving the echo m times the span distance at the first position and the echo n times the span distance at the second position, respectively, and recording the fifth amplitude of the echo m times the span distance and the sixth amplitude of the echo n times the span distance using the ultrasonic detector; calculating the third attenuation coefficient of the workpiece under test based on the fifth amplitude and the sixth amplitude; and calculating the diffusion attenuation coefficient based on the third attenuation coefficient, the absorption attenuation coefficient, and the scattering attenuation coefficient of the workpiece under test.

[0035] This invention applies ultrasonic shear waves of the same frequency to the workpiece under test. The ultrasonic shear waves form echoes at the coupling and reflecting surfaces of the workpiece. By selecting echoes at different preset multiples of the span, the total attenuation coefficient of the workpiece can be obtained from the echo amplitude. Subtracting the previously calculated absorption and scattering attenuation coefficients, the diffusion attenuation coefficient of the workpiece can be obtained. For workpieces of different shapes and sizes, since absorption and scattering attenuation are independent of the workpiece's shape and size, but diffusion attenuation is affected, measuring the diffusion attenuation using the actual workpiece under test can obtain the diffusion attenuation coefficient for workpieces of different shapes and sizes, improving the accuracy of attenuation coefficient measurement. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 A schematic diagram of the structure of an ultrasonic shear wave attenuation coefficient measuring device provided in an embodiment of the present invention;

[0038] Figure 2 A schematic flowchart illustrating the working method of an ultrasonic shear wave attenuation coefficient measuring device provided in an embodiment of the present invention.

[0039] Figure 3 A schematic diagram of a semi-cylindrical test block structure for a device for measuring the attenuation coefficient of ultrasonic shear waves provided in an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of the workpiece structure to be tested for an ultrasonic transverse wave attenuation coefficient measuring device provided in an embodiment of the present invention;

[0041] Figure 5 This is a schematic diagram of an isosceles trapezoidal test block structure for a device for measuring the attenuation coefficient of ultrasonic transverse waves, provided in an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] Example 1

[0045] This invention provides a device for measuring the ultrasonic shear wave attenuation coefficient, such as... Figure 1 As shown, the system includes: an ultrasonic testing instrument, an ultrasonic transverse wave probe, and a preset number of test blocks;

[0046] The ultrasonic testing instrument is used to excite the ultrasonic transverse wave transmitting probe to generate an ultrasonic transverse wave of a preset frequency, and to record the echo amplitude of the ultrasonic transverse wave received by the ultrasonic transverse wave receiving probe on the reflecting surfaces of the test block and the workpiece under test. Based on the amplitude, the absorption attenuation coefficient, scattering attenuation coefficient and diffusion attenuation coefficient of the workpiece under test are calculated in sequence.

[0047] Specifically, in this embodiment of the invention, the ultrasonic testing instrument has the function of accurately measuring the amplitude of each echo and has the function of gain compensation. The ultrasonic testing instrument generates and emits ultrasonic shear waves by exciting an ultrasonic shear wave emitting probe fixed on the coupling surface of the test block or the workpiece under test. The emitted ultrasonic shear waves form echoes through multiple reflections between the coupling surface and the reflecting surface of the test block or the workpiece under test, and are received by the ultrasonic shear wave receiving probe. The ultrasonic testing instrument obtains the amplitude of the echo at a preset number of times or a preset multiple of the span through the ultrasonic shear wave receiving probe, and calculates the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test in sequence according to the amplitude.

[0048] The ultrasonic shear wave probe includes an ultrasonic shear wave emitting probe and an ultrasonic shear wave receiving probe, which are used to fix the coupling surface of the test block or the workpiece to be tested. The ultrasonic shear wave emitting probe generates and emits ultrasonic shear waves through the ultrasonic detector, and the ultrasonic shear wave receiving probe receives the echo of the ultrasonic shear wave and returns it to the ultrasonic detector.

[0049] Specifically, in this embodiment of the invention, a magnetic or clamping device is provided around the ultrasonic shear wave probe to ensure that the coupling force of the ultrasonic shear wave probe remains consistent when measured on different test blocks or workpieces. Furthermore, based on the propagation characteristics of ultrasonic shear waves, the ultrasonic shear wave probe, which combines ultrasonic emission and ultrasonic reception functions, is fixed to the coupling surface of the test block; the ultrasonic shear wave emitting probe and the ultrasonic shear wave receiving probe are respectively fixed at different positions on the coupling surface of the workpiece under test, separated by a preset multiple of span, wherein the preset multiple corresponds to a preset number of echo measurements performed on the test block.

[0050] The test block is designed based on the material properties of the workpiece under test and the attenuation characteristics of ultrasonic shear waves, allowing the ultrasonic shear waves to propagate within it and form an echo at the reflecting surface. This echo is used to calculate the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test. The test block includes a predetermined number of semi-cylindrical test blocks or a predetermined number of isosceles trapezoidal test blocks. The surface roughness, acoustic impedance, and material of the semi-cylindrical test blocks or isosceles trapezoidal test blocks are the same as those of the workpiece under test. The cylindrical radius of each semi-cylindrical test block is the same and is set to be greater than that of the ultrasonic shear waves. The near-field region of the ultrasonic shear wave probe is pre-defined by a predetermined factor, wherein the surface roughness is set to a first predetermined proportion less than the shear wave wavelength, and the average grain size of each of the semi-cylindrical test blocks is different and set to a second predetermined proportion less than the shear wave wavelength; the distance between the isosceles trapezoidal surface of each of the isosceles trapezoidal test blocks and the ultrasonic shear wave incident point is the same and set to a factor greater than the predetermined factor of the near-field region of the ultrasonic shear wave probe, wherein the surface roughness is set to a first predetermined proportion less than the shear wave wavelength, and the average grain size of each of the isosceles trapezoidal test blocks is different and set to a second predetermined proportion less than the shear wave wavelength.

[0051] Specifically, in this embodiment of the invention, the test blocks are designed based on the material properties of the workpiece under test and the attenuation characteristics of ultrasonic shear waves. The ultrasonic shear waves are located within approximately twice the near-field region of the probe. The attenuation of the ultrasonic shear waves emitted by the probe is mainly composed of absorption attenuation and scattering attenuation. Therefore, the distance between the cylindrical radius of each semi-cylindrical test block or the isosceles trapezoidal surface of each isosceles trapezoidal test block and the incident point of the ultrasonic shear wave is set to be greater than three times the near-field region of the ultrasonic shear wave probe, but not limited to this. Furthermore, the surface roughness is set to be less than 1 / 3 of the shear wave wavelength, and the average grain size varies, but is set to be less than 1 / 10 of the shear wave wavelength, but not limited to this.

[0052] In this embodiment of the invention, not every workpiece under test can have exactly two parallel coupling surfaces and a reflecting surface, thus creating the conditions for multiple reflections. If the workpiece under test does not have a reflecting surface that is approximately parallel to the coupling surface, a test block with the same beam diffusion cross-sectional area as the ultrasonic shear wave probe is fabricated. The thickness, material, and surface roughness of the test block are the same as those of the workpiece under test. The test block is used to replace the workpiece under test for measuring the attenuation coefficient.

[0053] The ultrasonic shear wave attenuation coefficient measuring device provided in this invention uses pre-designed semi-cylindrical and isosceles trapezoidal test blocks, based on the material properties of the workpiece under test and the attenuation characteristics of ultrasonic shear waves, as test blocks. An ultrasonic transverse wave probe, fixed to the coupling surface of each test block or workpiece under test, generates ultrasonic shear waves of a preset frequency and emits them to the corresponding reflecting surface. The ultrasonic shear waves form echoes between the coupling and reflecting surfaces. The ultrasonic shear wave probe receives a preset number of reflected echoes, and the ultrasonic detector records the amplitude of each echo. Based on the amplitude, the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test are calculated. This invention eliminates the influence of diffusion attenuation in attenuation coefficient measurement by using pre-designed test blocks, sequentially calculating the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test, and obtaining a diffusion attenuation coefficient that matches the shape and size of the workpiece under test, thereby improving the accuracy of ultrasonic shear wave attenuation coefficient measurement.

[0054] Example 2

[0055] This invention provides a method for operating a device for measuring the attenuation coefficient of ultrasonic shear waves, such as... Figure 2 As shown, this method measures the attenuation coefficient based on the device provided in Example 1. Taking a semi-cylindrical test block as an example, the steps include:

[0056] Step S1: Determine the coupling surface and reflecting surface of the test block. Select the rectangular surface of the semi-cylindrical test block as the coupling surface and the semi-cylindrical curved surface as the reflecting surface, or select the upper surface of the isosceles trapezoidal test block as the coupling surface and the two isosceles trapezoidal surfaces as the reflecting surfaces.

[0057] Specifically, in this embodiment of the invention, a semi-cylindrical test block is designed in advance based on the material properties of the workpiece to be tested and the attenuation characteristics of the ultrasonic shear wave. The semi-cylindrical test block is designed according to the frequency of the ultrasonic shear wave, the preset refraction angle, and the crystal size, so that after the ultrasonic shear wave probe is coupled to the rectangular surface of the semi-cylindrical test block, the emitted shear wave can be reflected back and forth on the semi-cylindrical surface. Therefore, by determining the coupling surface and the reflecting surface of the semi-cylindrical test block, the fixed position of the ultrasonic shear wave probe is determined.

[0058] Step S2: Fix the ultrasonic transverse wave probe of the preset frequency to the coupling surface of the preset number of test blocks respectively, and use an ultrasonic detector to excite the ultrasonic transverse wave probe to emit ultrasonic transverse waves to the corresponding reflection surface of each test block.

[0059] Specifically, in this embodiment of the invention, the absorption attenuation constant and scattering attenuation constant are calculated based on the echo amplitude formed in the test block. This involves two unknowns. During the ultrasonic shear wave attenuation coefficient measurement, at least one set of two linear equations must be generated to ensure that the absorption attenuation constant and scattering attenuation constant can be calculated. Therefore, the number of semi-cylindrical test blocks is set to two, but this is not a limitation; in practical applications, multiple numbers can be used, but at least two are required for subsequent attenuation constant calculations. The average grain sizes of the two semi-cylindrical test blocks are d1 and d2, respectively, and the cylindrical surface radius is R. In this embodiment of the invention, as... Figure 3 As shown, an ultrasonic transverse wave probe with frequency f is fixed at the center of the coupling surface of a semi-cylindrical test block 1 with an average grain size of d1 and a cylindrical surface radius of R, so that the probe incident point coincides with the center of the upper surface. An ultrasonic detector is used to excite the ultrasonic transverse wave probe to generate and emit ultrasonic transverse waves. The ultrasonic transverse waves pass through the axis of the semi-cylindrical test block and are emitted along the radial direction of the cross-section of the semi-cylindrical test block.

[0060] Step S3: The ultrasonic shear wave forms an echo between the coupling surface and the reflecting surface of each test block. The ultrasonic shear wave probe receives the echoes reflected back by each test block a preset number of times by the reflecting surface, and the ultrasonic detector records the amplitude of different echoes. The absorption attenuation constant and the scattering attenuation constant are obtained according to the amplitude, and the absorption attenuation coefficient and the scattering attenuation coefficient of the workpiece under test are calculated according to the absorption attenuation constant and the scattering attenuation constant.

[0061] Specifically, in this embodiment of the invention, the ultrasonic transverse wave probe receives the m-th and n-th echoes formed on the reflecting surface of the semi-cylindrical test block 1, and records the first amplitude A of the m-th echo of the ultrasonic transverse wave on the semi-cylindrical curved surface using an ultrasonic testing instrument. m The second amplitude A of the nth echo n (n>m). Based on the relationship between the attenuation coefficient and the echo amplitude, the first attenuation coefficient α1 of the semi-cylindrical test block 1 is calculated. Simultaneously, the first attenuation coefficient and the absorption attenuation constant C are constructed. a and scattering attenuation constant C s The equation between them is given, where the attenuation coefficient is the sum of the absorption attenuation coefficient, the scattering attenuation coefficient, and the diffusion attenuation coefficient. Because the semi-cylindrical sample has a regular shape and large size, its diffusion attenuation coefficient α... d It satisfies the attenuation formula, as described below:

[0062]

[0063] Therefore, the attenuation coefficient of the semi-cylindrical test block 1 is: α1=α a +α s1 + d The resulting equation is shown below:

[0064]

[0065] Where α1 is the first attenuation coefficient of the ultrasonic transverse wave on the semi-cylindrical test block 1, α a α is the absorption attenuation coefficient. s1 C is the scattering attenuation coefficient of the semi-cylindrical test block 1. a C is the absorption attenuation constant. s denoted as the scattering attenuation constant, f as the ultrasonic transverse wave frequency, d1 as the average grain size of the semi-cylindrical specimen 1, R as the cylindrical radius of the semi-cylindrical specimen 1, and δ as the single bottom wave reflection loss of the semi-cylindrical specimen 1.

[0066] Repeat steps S2 and S3, fixing an ultrasonic shear wave probe with frequency f at the center of the coupling surface of a semi-cylindrical specimen 2 with an average grain size of d2 and a cylindrical surface radius of R. Use an ultrasonic testing instrument to excite the ultrasonic shear wave probe to generate and emit ultrasonic shear waves. The ultrasonic shear waves form echoes at the coupling surface and the reflecting surface of the semi-cylindrical specimen 2. The ultrasonic shear wave probe receives the m-th and n-th echoes formed on the reflecting surface of the semi-cylindrical specimen 2, and records the third amplitude B of the m-th echo of the ultrasonic shear wave on the semi-cylindrical surface using an ultrasonic testing instrument. , The fourth amplitude B of the mth echo m (n>m). Based on the relationship between the attenuation coefficient and the echo amplitude, the second attenuation coefficient α2 of the semi-cylindrical test block 2 is calculated, and the relationship between the second attenuation coefficient and the absorption attenuation constant C is constructed. a and scattering attenuation constant C s The equations between them are as follows:

[0067]

[0068] Where α2 is the second attenuation coefficient of the ultrasonic transverse wave on the semi-cylindrical test block 2, α a α is the absorption attenuation coefficient. s2 C is the scattering attenuation coefficient of the semi-cylindrical test block 2. a C is the absorption attenuation constant. s denoted as the scattering attenuation constant, f as the ultrasonic transverse wave frequency, d2 as the average grain size of the semi-cylindrical specimen 2, R as the cylindrical radius of the semi-cylindrical specimen 2, and δ as the single bottom wave reflection loss of the semi-cylindrical specimen 2.

[0069] Combining equations (2) and (3) above, we obtain the absorption attenuation constant C. a and scattering attenuation constant C s :

[0070]

[0071]

[0072] According to α a = a f and α s = s f 4 d 3 Using the fixed relationship, the absorption attenuation coefficient and scattering attenuation coefficient of the workpiece under test are calculated:

[0073]

[0074]

[0075] Where, d c The average grain size of the workpiece under test.

[0076] Step S4: Select two relatively parallel surfaces of the workpiece to be tested as its coupling surface and reflecting surface, respectively, and fix the ultrasonic transverse wave emitting probe of a preset frequency on the coupling surface of the workpiece to be tested. Use an ultrasonic detector to excite the ultrasonic transverse wave emitting probe to emit ultrasonic transverse waves to the reflecting surface of the workpiece to be tested.

[0077] Specifically, in this embodiment of the invention, two relatively parallel surfaces of the workpiece to be tested are selected as the coupling surface and the reflecting surface. If the workpiece to be tested does not have a reflecting surface approximately parallel to the coupling surface, a test workpiece with the same material properties as the workpiece to be tested is designed. An ultrasonic transverse wave emitting probe with frequency f is fixed at a certain position on the coupling surface of the workpiece to be tested or the test workpiece, and an ultrasonic transverse wave receiving probe is fixed at a position where the distance between the receiving probe and the ultrasonic transverse wave emitting probe is a preset multiple of the span. Figure 4 The example shown shows the ultrasonic shear wave receiving probe fixed at a position with a distance of one span from the ultrasonic shear wave transmitting probe. This is merely an example and not a limitation. An ultrasonic transverse wave transmitting probe is excited by an ultrasonic testing instrument to generate ultrasonic shear waves, which are then emitted at a preset refraction angle β.

[0078] Step S5: The ultrasonic transverse wave forms an echo between the coupling surface and the reflecting surface of the workpiece under test. The ultrasonic transverse wave receiving probe is fixed at a preset multiple span distance to receive the echo reflected back from the reflecting surface at the preset multiple span distance. The amplitude of different echoes is recorded by the ultrasonic detector, and the diffusion attenuation coefficient of the workpiece under test is calculated based on the amplitude, the absorption attenuation coefficient, and the scattering attenuation coefficient.

[0079] Specifically, in this embodiment of the invention, ultrasonic shear waves generate echoes at the coupling surface and the reflecting surface of the workpiece under test. An ultrasonic shear wave receiving probe is fixed within the coupling surface at a first position m times the span and a second position n times the span from the ultrasonic shear wave transmitting probe, respectively. The ultrasonic shear wave receiving probe receives the echo at the first position m times the span and the echo at the second position n times the span, respectively, and records the fifth amplitude C of the ultrasonic shear wave echo at the reflecting surface m times the span using an ultrasonic testing instrument. m The sixth amplitude C of the n-fold span echo n (n>m). The third attenuation coefficient α3 of the workpiece under test is calculated based on the echo amplitude, and the diffusion attenuation coefficient is calculated based on the obtained absorption attenuation coefficient and scattering attenuation coefficient of the workpiece under test. The calculation formulas are as follows:

[0080]

[0081] α dc =α3-α ac -α sc (9)

[0082] Where H is the thickness of the workpiece to be measured, β is the preset refraction angle of the ultrasonic transverse wave emitting probe, and δ c This represents the single bottom wave reflection loss of the workpiece under test.

[0083] The working method of the ultrasonic shear wave attenuation coefficient measuring device provided in this invention involves designing semi-cylindrical and isosceles trapezoidal test blocks as test blocks based on the material properties of the workpiece under test and the attenuation characteristics of ultrasonic shear waves. An ultrasonic detector excites an ultrasonic shear wave emitting probe fixed to the coupling surface of each test block or the workpiece under test to generate an ultrasonic shear wave of a preset frequency, which is then emitted to the corresponding reflecting surface. The ultrasonic shear wave forms an echo between the coupling surface and the reflecting surface. An ultrasonic shear wave receiving probe receives the echoes of a preset number of times, and the ultrasonic detector records the amplitude of each echo. Based on the echo amplitude of the test block, the absorption attenuation constant and scattering attenuation constant of the workpiece under test for ultrasonic shear waves are obtained. Then, the absorption attenuation coefficient and scattering attenuation coefficient of the workpiece under test are calculated. Finally, the diffusion attenuation coefficient of the workpiece under test for ultrasonic shear waves is calculated based on the absorption attenuation coefficient, scattering attenuation coefficient, and echo amplitude of the workpiece under test. This invention eliminates the influence of diffusion attenuation in attenuation coefficient measurement by using a pre-designed test block, and sequentially calculates the absorption attenuation coefficient, scattering attenuation coefficient, and diffusion attenuation coefficient of the workpiece under test, thereby obtaining a diffusion attenuation coefficient that matches the shape and size of the workpiece under test, and improving the accuracy of ultrasonic shear wave attenuation coefficient measurement.

[0084] Example 3

[0085] This invention provides a method for operating a device for measuring the attenuation coefficient of ultrasonic shear waves. This method measures the attenuation coefficient based on the device provided in Embodiment 1. Taking an isosceles trapezoidal test block as an example, the steps include:

[0086] Step S1: Determine the coupling surface and the reflecting surface of the test block. Select the rectangular surface of the semi-cylindrical test block as the coupling surface and the semi-cylindrical curved surface as the reflecting surface, or select the upper surface of the isosceles trapezoidal test block as the coupling surface and the two isosceles trapezoidal surfaces as the reflecting surfaces.

[0087] Specifically, in this embodiment of the invention, an isosceles trapezoidal test block is designed in advance based on the material properties of the workpiece to be tested and the attenuation characteristics of the ultrasonic shear wave. The isosceles trapezoidal test block is designed according to the frequency of the ultrasonic shear wave, the preset refraction angle, and the crystal size, so that after the ultrasonic shear wave probe is coupled to the upper surface of the isosceles trapezoidal test block, the emitted shear wave can be reflected back and forth on the two sides of the trapezoidal test block. Therefore, by determining the coupling surface and the reflecting surface of the isosceles trapezoidal test block, the fixed position of the ultrasonic shear wave probe is determined.

[0088] Step S2: Fix the ultrasonic transverse wave probe of the preset frequency to the coupling surface of the preset number of test blocks respectively, and use an ultrasonic detector to excite the ultrasonic transverse wave probe to emit ultrasonic transverse waves to the corresponding reflection surface of each test block.

[0089] Specifically, in this embodiment of the invention, the number of isosceles trapezoidal test blocks is set to two, but is not limited to this. The average grain sizes of the two isosceles trapezoidal test blocks are d1 and d2, respectively, and the distance from the isosceles trapezoidal surface to the ultrasonic incident point is h. In this embodiment of the invention, as... Figure 5 As shown, an ultrasonic transverse wave probe with frequency f is fixed at the center of the coupling surface of an isosceles trapezoidal test block 1 with an average grain size of d1 and a distance of h between the isosceles trapezoidal surface and the ultrasonic incident point. An ultrasonic detector is used to excite the ultrasonic transverse wave probe to generate and emit ultrasonic transverse waves. The ultrasonic transverse waves are emitted parallel to the normal direction of the trapezoidal surface of the isosceles trapezoidal test block to the two isosceles trapezoidal surfaces.

[0090] Step S3: The ultrasonic shear wave forms an echo between the coupling surface and the reflecting surface of each test block. The ultrasonic shear wave probe receives the echoes reflected back by each test block a preset number of times by the reflecting surface, and the ultrasonic detector records the amplitude of different echoes. The absorption attenuation constant and the scattering attenuation constant are obtained according to the amplitude, and the absorption attenuation coefficient and the scattering attenuation coefficient of the workpiece under test are calculated according to the absorption attenuation constant and the scattering attenuation constant.

[0091] Specifically, in this embodiment of the invention, the ultrasonic transverse wave probe receives the m-th and n-th echoes formed on the reflecting surface of the isosceles trapezoidal test block 1, and records the first amplitude A of the m-th echo of the ultrasonic transverse wave on the reflecting surface using an ultrasonic testing instrument. m The second amplitude A of the nth echon (n>m). Based on the relationship between the attenuation coefficient and the echo amplitude, the first attenuation coefficient α1 of the isosceles trapezoidal test block 1 is calculated. Simultaneously, the first attenuation coefficient and the absorption attenuation constant C are constructed. a and scattering attenuation constant C s The first equation between them is given, where the attenuation coefficient is the sum of the absorption attenuation coefficient, the scattering attenuation coefficient, and the diffusion attenuation coefficient. Because the isosceles trapezoidal specimen has a regular shape and large size, its diffusion attenuation coefficient α... d It conforms to the attenuation formula, as shown below:

[0092]

[0093] Therefore, the attenuation coefficient of the isosceles trapezoidal test block 1 is: α1=α a +α s1 +α d The resulting equation is shown below:

[0094]

[0095] Where α1 is the first attenuation coefficient of the ultrasonic transverse wave on the isosceles trapezoidal test block 1, α a α is the absorption attenuation coefficient. s1 Let C be the scattering attenuation coefficient of isosceles trapezoidal specimen 1. a C is the absorption attenuation constant. s denoted as the scattering attenuation constant, f as the ultrasonic transverse wave frequency, d1 as the average grain size of isosceles trapezoidal block 1, h as the distance between the isosceles trapezoidal surface of isosceles trapezoidal block 1 and the ultrasonic incident point, and δ as the single bottom wave reflection loss of isosceles trapezoidal block 1.

[0096] Repeat steps S2 and S3, fixing an ultrasonic shear wave probe with frequency f at the center of the coupling surface of an isosceles trapezoidal test block 2 with an average grain size of d2 and a distance h from the ultrasonic incident point. Use an ultrasonic testing instrument to excite the ultrasonic shear wave probe to generate and emit ultrasonic shear waves. The ultrasonic shear waves form echoes at the coupling surface and reflecting surface of the isosceles trapezoidal test block 2. The ultrasonic shear wave probe receives the m-th and n-th echoes formed at the reflecting surface of the isosceles trapezoidal test block 2, and records the third amplitude B of the m-th echo at the reflecting surface using an ultrasonic testing instrument. m The fourth amplitude B of the nth echo n (n>m). Based on the relationship between the attenuation coefficient and the echo amplitude, the second attenuation coefficient α2 of the isosceles trapezoidal test block 2 is calculated. Simultaneously, a relationship between the second attenuation coefficient and the absorption attenuation constant C is constructed. a and scattering attenuation constant C s The equations between them are as follows:

[0097]

[0098] Where α2 is the second attenuation coefficient of the ultrasonic transverse wave on the isosceles trapezoidal test block 2, α a α is the absorption attenuation coefficient. s2 C is the scattering attenuation coefficient of the isosceles trapezoidal specimen 2. a C is the absorption attenuation constant. s denoted as scattering attenuation constant, f as ultrasonic transverse wave frequency, d2 as average grain size of isosceles trapezoidal block 2, h as distance from isosceles trapezoidal surface of isosceles trapezoidal block 2 to ultrasonic incident point, and δ as single bottom wave reflection loss of isosceles trapezoidal block 2.

[0099] Combining equations (11) and (12) above, we obtain the absorption attenuation constant and the scattering attenuation constant:

[0100]

[0101]

[0102] According to α a =C a f and α s =C s f 4 d 3 The absorption attenuation coefficient and scattering attenuation coefficient of the workpiece under test were calculated:

[0103]

[0104]

[0105] Where, d c The average grain size of the workpiece under test.

[0106] Step S4: Select two relatively parallel surfaces of the workpiece to be tested as its coupling surface and reflecting surface, respectively, and fix the ultrasonic transverse wave emitting probe of a preset frequency on the coupling surface of the workpiece to be tested. Use an ultrasonic detector to excite the ultrasonic transverse wave emitting probe to emit ultrasonic transverse waves to the reflecting surface of the workpiece to be tested.

[0107] Specifically, in this embodiment of the invention, an ultrasonic transverse wave emitting probe with a frequency of f is fixed at a certain position on the coupling surface of the workpiece to be tested, and an ultrasonic detector is used to excite the ultrasonic transverse wave emitting probe to generate an ultrasonic transverse wave, which is emitted according to a preset refraction angle β.

[0108] Step S5: The ultrasonic transverse wave forms an echo between the coupling surface and the reflecting surface of the workpiece under test. The ultrasonic transverse wave receiving probe is fixed at a preset multiple span distance to receive the echo reflected back from the reflecting surface at the preset multiple span distance. The amplitude of different echoes is recorded by the ultrasonic detector, and the diffusion attenuation coefficient of the workpiece under test is calculated based on the amplitude, the absorption attenuation coefficient, and the scattering attenuation coefficient.

[0109] Specifically, in this embodiment of the invention, ultrasonic shear waves generate echoes at the coupling surface and the reflecting surface of the workpiece under test. An ultrasonic shear wave receiving probe is fixed within the coupling surface at a first position m times the span and a second position n times the span from the ultrasonic shear wave transmitting probe, respectively. The ultrasonic shear wave receiving probe receives the echo at the first position m times the span and the echo at the second position n times the span, respectively, and records the fifth amplitude C of the ultrasonic shear wave echo at the reflecting surface m times the span using an ultrasonic testing instrument. m The sixth amplitude C of the n-fold span echo n (n>m). The third attenuation coefficient α3 of the workpiece under test is calculated based on the echo amplitude, and the diffusion attenuation coefficient is calculated based on the obtained absorption attenuation coefficient and scattering attenuation coefficient of the workpiece under test. The calculation formulas are as follows:

[0110]

[0111] α dc =α3-α ac -α sc (18)

[0112] Where H is the thickness of the workpiece to be measured, β is the preset refraction angle of the ultrasonic transverse wave emitting probe, and δ c This represents the single bottom wave reflection loss of the workpiece under test.

[0113] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A device for measuring the attenuation coefficient of ultrasonic shear waves, characterized in that, include: An ultrasonic testing instrument, an ultrasonic shear wave probe, and a preset number of test blocks, wherein the ultrasonic shear wave probe includes an ultrasonic shear wave transmitting probe and an ultrasonic shear wave receiving probe. The ultrasonic testing instrument is used to excite the ultrasonic transverse wave transmitting probe to generate an ultrasonic transverse wave of a preset frequency, and to record the echo amplitude of the ultrasonic transverse wave received by the ultrasonic transverse wave receiving probe on the reflecting surfaces of the test block and the workpiece under test. Based on the amplitude, the absorption attenuation coefficient, scattering attenuation coefficient and diffusion attenuation coefficient of the workpiece under test are calculated in sequence. The ultrasonic shear wave probe is used to fix the coupling surface of the test block or the workpiece to be tested. The ultrasonic shear wave emitting probe is excited by the ultrasonic detector to generate and emit ultrasonic shear waves. The ultrasonic shear wave receiving probe receives the echo of the ultrasonic shear wave and returns it to the ultrasonic detector. The test block is designed according to the material properties of the workpiece under test and the attenuation characteristics of ultrasonic shear waves, so that the ultrasonic shear waves propagate inside it and form an echo on the reflecting surface. The echo is used to calculate the absorption attenuation coefficient, scattering attenuation coefficient and diffusion attenuation coefficient of the workpiece under test. The test block includes: a preset number of semi-cylindrical test blocks or a preset number of isosceles trapezoidal test blocks, wherein the number of semi-cylindrical test blocks or isosceles trapezoidal test blocks is at least 2, and the surface roughness, acoustic impedance, and material of the semi-cylindrical test blocks or isosceles trapezoidal test blocks are the same as those of the workpiece to be tested. The cylindrical surface radii of each of the semi-cylindrical test blocks are the same and are set to be greater than a preset multiple of the near field region of the ultrasonic shear wave probe. The surface roughness is set to be less than a first preset proportion of the shear wave wavelength. The average grain size of each of the semi-cylindrical test blocks is different and is set to be less than a second preset proportion of the shear wave wavelength. The distance between the isosceles trapezoidal surface of each of the isosceles trapezoidal test blocks and the incident point of the ultrasonic shear wave is the same and is set to be greater than a preset multiple of the near field region of the ultrasonic shear wave probe. The surface roughness is set to be less than a first preset proportion of the shear wave wavelength. The average grain size of each of the isosceles trapezoidal test blocks is different and is set to be less than a second preset proportion of the shear wave wavelength.

2. The measuring device for ultrasonic shear wave attenuation coefficient according to claim 1, characterized in that, The ultrasonic shear wave probe is equipped with a magnetic attraction or clamping device to ensure that the coupling force of the ultrasonic shear wave probe remains consistent when measuring different test blocks or workpieces.

3. The measuring device for ultrasonic shear wave attenuation coefficient according to claim 2, characterized in that, Based on the propagation characteristics of ultrasonic transverse waves, an ultrasonic transverse wave probe that combines ultrasonic transmission and ultrasonic reception functions is fixed on the coupling surface of the test block. The ultrasonic transverse wave transmitting probe and the ultrasonic transverse wave receiving probe are fixed at different positions on the coupling surface of the workpiece to be tested, separated by a preset multiple of the span.

4. The measuring device for ultrasonic shear wave attenuation coefficient according to claim 1, characterized in that, If the workpiece to be tested does not have a reflective surface parallel to the coupling surface, a test block with the same beam diffusion cross-sectional area as the ultrasonic transverse wave probe is fabricated, and the thickness, material and surface roughness of the test block are the same as those of the workpiece to be tested.

5. A method for operating a device for measuring the attenuation coefficient of ultrasonic shear waves, characterized in that, Measuring the ultrasonic shear wave attenuation coefficient using the device according to any one of claims 1-4, the working method comprising: Determine the coupling surface and the reflecting surface of the test block. Select the rectangular surface of the semi-cylindrical test block as the coupling surface and the semi-cylindrical curved surface as the reflecting surface, or select the upper surface of the isosceles trapezoidal test block as the coupling surface and the two isosceles trapezoidal surfaces as the reflecting surfaces. The number of semi-cylindrical test blocks or isosceles trapezoidal test blocks shall be at least 2. An ultrasonic transverse wave probe of a preset frequency is fixed on the coupling surface of a preset number of test blocks, and an ultrasonic detector is used to excite the ultrasonic transverse wave probe to emit ultrasonic transverse waves to the corresponding reflection surface of each test block. The ultrasonic shear wave forms an echo between the coupling surface and the reflecting surface of each test block. The ultrasonic shear wave probe receives the echoes reflected back by each test block a preset number of times by the reflecting surface, and the ultrasonic detector records the amplitude of different echoes. The absorption attenuation constant and the scattering attenuation constant are obtained based on the amplitude, and the absorption attenuation coefficient and the scattering attenuation coefficient of the workpiece under test are calculated based on the absorption attenuation constant and the scattering attenuation constant. The process of receiving a preset number of echoes reflected from the reflective surfaces of each test block by the ultrasonic shear wave probe, recording the amplitude of different echoes by the ultrasonic detector, obtaining the absorption attenuation constant and scattering attenuation constant based on the amplitude, and calculating the absorption attenuation coefficient and scattering attenuation coefficient of the workpiece under test based on the absorption attenuation constant and scattering attenuation constant, includes: the ultrasonic shear wave forming echoes on the reflective surfaces of the first test block and the second test block; the ultrasonic shear wave probe receiving the m-th and n-th echoes formed on the reflective surfaces of the first test block, and recording the first amplitude of the m-th echo and the second amplitude of the n-th echo by the ultrasonic detector; calculating the absorption attenuation coefficient and scattering attenuation coefficient of the workpiece under test based on the first amplitude and the second amplitude; and calculating the absorption attenuation coefficient and scattering attenuation coefficient of the first test block based on the first amplitude and the second amplitude. The first attenuation coefficient of the test block is calculated, and a first equation is constructed between the first attenuation coefficient and the absorption attenuation constant and the scattering attenuation constant. The ultrasonic transverse wave probe receives the m-th and n-th echoes formed on the reflecting surface of the second test block, and records the third amplitude of the m-th echo and the fourth amplitude of the n-th echo using the ultrasonic detector. The second attenuation coefficient of the second test block is calculated based on the third and fourth amplitudes, and a second equation is constructed between the second attenuation coefficient and the absorption attenuation constant and the scattering attenuation constant. The absorption attenuation constant and the scattering attenuation constant are calculated simultaneously using the first and second equations. The absorption attenuation coefficient and the scattering attenuation coefficient of the workpiece under test are calculated based on the absorption attenuation constant and the scattering attenuation constant. Two relatively parallel surfaces of the workpiece to be tested are selected as its coupling surface and reflecting surface, respectively. An ultrasonic transverse wave emitting probe of a preset frequency is fixed on the coupling surface of the workpiece to be tested. An ultrasonic detector is used to excite the ultrasonic transverse wave emitting probe to emit ultrasonic transverse waves to the reflecting surface of the workpiece to be tested. The ultrasonic shear wave forms an echo between the coupling surface and the reflecting surface of the workpiece under test. The ultrasonic shear wave receiving probe is fixed at a preset multiple span distance to receive the echo reflected back from the reflecting surface at a preset multiple span distance. The amplitude of different echoes is recorded by the ultrasonic detector, and the diffusion attenuation coefficient of the workpiece under test is calculated based on the amplitude, the absorption attenuation coefficient, and the scattering attenuation coefficient. The process of fixing the ultrasonic shear wave receiving probe at a preset multiple span distance, receiving the echo reflected back from the reflecting surface at the preset multiple span distance, recording the amplitude of different echoes using the ultrasonic detector, and calculating the diffusion attenuation coefficient of the workpiece under test based on the amplitude, the absorption attenuation coefficient, and the scattering attenuation coefficient includes: the ultrasonic shear wave forming an echo on the reflecting surface of the workpiece under test; fixing the ultrasonic shear wave receiving probe at a first position m times the span distance and a second position n times the span distance from the ultrasonic shear wave transmitting probe within the coupling surface; the ultrasonic shear wave receiving probe receiving the echo m times the span distance at the first position and the echo n times the span distance at the second position, respectively, and recording the fifth amplitude of the echo m times the span distance and the sixth amplitude of the echo n times the span distance using the ultrasonic detector; calculating the third attenuation coefficient of the workpiece under test based on the fifth amplitude and the sixth amplitude; and calculating the diffusion attenuation coefficient based on the third attenuation coefficient, the absorption attenuation coefficient, and the scattering attenuation coefficient of the workpiece under test.

6. The operating method of the ultrasonic shear wave attenuation coefficient measuring device according to claim 5, characterized in that, On the test block, the incident point and receiving point of the ultrasonic transverse wave are both at the center of the coupling surface of the test block. The ultrasonic transverse wave passes through the axis of the semi-cylindrical test block and is emitted along the radial direction of the cross-section of the semi-cylindrical test block, or is emitted parallel to the normal direction of the isosceles trapezoidal surface of the isosceles trapezoidal test block. On the workpiece to be tested, the incident point of the ultrasonic transverse wave is the fixed position of the ultrasonic transverse wave emitting probe, and the receiving point is the fixed position of the ultrasonic transverse wave receiving probe. The ultrasonic transverse wave is emitted toward the reflecting surface of the workpiece to be tested according to a preset refraction angle.

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