Ultrasonic nondestructive testing method and nondestructive detector based on directional shear wave

Abstract

The present invention discloses an ultrasonic nondestructive testing method and nondestructive detector based on directional shear waves, which belongs to the field of nondestructive testing of materials, and includes the following steps: S1, determining the material to be tested; S2, exciting directional shear waves based on the material to be tested: S21, applying multiple longitudinal excitations to the material to be tested in half space; S22, fixing the spacing between multiple longitudinal excitations, and optimizing the phase of the longitudinal excitations; S23, using the phase optimization result obtained in step S22 as a fixed value, optimizing the spacing between multiple longitudinal excitations; S24, using the optimization result obtained in step S23 as the excitation result, at which time the shear wave energy accounts for no less than 90%; S3, determining the parameters of the metasurface based on the phase and spacing obtained in step S2. The present invention adopts the above-mentioned ultrasonic nondestructive testing method and nondestructive detector based on directional shear waves, which have the advantages of long propagation distance, strong anti-interference ability, no need for coupling agent, and light equipment.

Description

Technical Field

[0001] The invention relates to the field of nondestructive testing of materials, and in particular to an ultrasonic nondestructive testing method and a nondestructive detector based on directional shear waves. Background Art

[0002] Nondestructive testing refers to a method that does not damage or affect the performance of the object being tested when inspecting the inside of mechanical materials. It uses changes in heat, sound, light, electricity, magnetism and other reactions caused by abnormal internal structure or defects in materials, and uses physical or chemical methods, with the help of modern technology and equipment, to inspect and test the structure, state and type, quantity, shape, nature, location, size, distribution and changes of defects inside and on the surface of the test piece.

[0003] Nowadays, non-destructive testing (NDT) technology has been widely used in various industries. It can not only identify hidden defects in materials and components, but also monitor product quality in real time during the manufacturing process to ensure safety and reliability of use. At the same time, with the rapid development of modern industry and technology, the importance of non-destructive testing has become increasingly prominent due to the rising demand for product quality, safety and medical diagnosis.

[0004] Existing nondestructive testing mainly includes the following methods: ultrasonic testing (UT), radiographic testing (RT), magnetic particle testing (MT) and penetrant testing (PT). In addition, many optical-based nondestructive testing methods have emerged in recent years, such as infrared testing (IRT), terahertz testing (THz), shear speckle testing (ST) and digital image correlation (DIC). Each method has its own unique applicability and advantages, making it suitable for testing different materials and structures.

[0005] Among them, ultrasonic testing (UT) is one of the most powerful non-destructive testing (NDT) methods for detecting surface and internal defects of objects. Compared with other non-destructive testing methods, ultrasonic testing has the advantages of wide application range, fast detection speed, convenience, and high cost-effectiveness, so it is widely used in the detection of aerospace composite structures and mechanical processing. Among the existing ultrasonic testing products, most of them require specific coupling agents to achieve impedance matching with the sample, and the performance of the coupling agent directly affects the accuracy of the detection.

[0006] The existing engineering nondestructive testing technology based on stress waves, called the impact echo method, has the following defects:

[0007] 1. The impact echo method produces low-frequency waves, and its results are usually difficult to interpret;

[0008] 2. Artifacts may arise from the geometry of the structure being studied, wave scattering, or simply from the presence of multiple resonance modes;

[0009] 3. Since the excitation waves often diverge or undergo multiple reflections and refractions, the effective use of the excitation energy in the required detection area is hindered;

[0010] 4. Longitudinal waves are used as detection waves, and the detection accuracy is low. Summary of the invention

[0011] In order to solve the above problems, the present invention provides an ultrasonic nondestructive testing method and a nondestructive detector based on directional shear waves, which have the advantages of long propagation distance, strong anti-interference ability, no need for coupling agent, and light equipment.

[0012] To achieve the above object, the present invention provides an ultrasonic nondestructive testing method based on directional shear waves, comprising the following steps:

[0013] S1. Determine the material to be tested;

[0014] S2, based on the excitation of directional shear waves by the material under test:

[0015] S21, based on the finite element software COMSOL, multiple longitudinal excitations are applied to the material under test in half space;

[0016] S22, fixing the spacing between the multiple longitudinal excitations and optimizing the phase of the longitudinal excitations;

[0017] S23, optimizing the spacing between multiple longitudinal excitations using the phase optimization result obtained in step S22 as a fixed value;

[0018] S24, taking the optimization result obtained in step S23 as the excitation result, at which point the shear wave energy accounts for no less than 90%;

[0019] S3. Based on the phase and spacing obtained in step S2, determine the parameters of the metasurface:

[0020] S31, adjusting phase and spacing: changing the spacing of the metasurface by changing the height and length of the metasurface;

[0021] S32, using a sweeping algorithm to select metasurface parameters for setting transmittance and phase;

[0022] S33. Launch a plane longitudinal wave that propagates parallel to the metasurface to verify whether the plane longitudinal wave can generate longitudinal excitations with different phases after passing through the metasurface.

[0023] Preferably, step S22 specifically includes the following steps:

[0024] S221, initial value setting: set the number of shear wave excitations to 10, multiple excitation phases to be periodically arranged along 0 and π, and the spacing between multiple excitations to 0.018m;

[0025] S222, for each longitudinal excitation, introduce a linearly increasing phase ,in For the incentive sequence, is the increasing phase;

[0026] S223, scan at intervals of 0.1pi The proportion of surface waves, longitudinal waves and shear waves in the range of 0-2pi;

[0027] S224: Based on the scanning result described in step S223, the incremental phase is determined based on the highest energy proportion of the shear wave. .

[0028] Preferably, in step S224, the incremental phase is determined is 0.4pi.

[0029] Preferably, step S23 specifically includes the following steps:

[0030] S231, taking the increment phase determined in step S224 as a fixed value, Optimize downwards at intervals of 0.001m and export the scan results;

[0031] S232: Based on the scanning result described in step S231, the spacing is determined based on the highest proportion of shear wave energy. .

[0032] Preferably, in step S232, the spacing is determined It is 0.012m.

[0033] Preferably, in step S32, the sweep calculation is performed using the joint simulation function of COMSOL Multiphysics software version 6.0 and MATLAB.

[0034] Preferably, in step S32, the sweep height range is set to 3 mm-8 mm, the sweep length range is set to 0.5 mm-3 mm, the transmittance is set to be greater than 0.7, and the number is set to ten.

[0035] The nondestructive detector of the ultrasonic nondestructive testing method based on directional shear waves includes a signal generator, a power amplifier, a magnetostrictive longitudinal wave exciter and a metastructure exciter connected in series in sequence, wherein the magnetostrictive longitudinal wave exciter is used to generate a guided wave of the S0 mode in the aluminum plate, and the metastructure exciter includes a metasurface for changing the phase, so as to achieve the magnetostrictive longitudinal wave exciter to generate ten longitudinal excitations with different phases after passing through the metasurface.

[0036] The present invention has the following beneficial effects:

[0037] 1. The non-destructive testing using the excited directional shear wave has the advantages of long propagation distance, strong anti-interference ability, no need for coupling agent, light equipment and high detection accuracy compared with other non-destructive testing technologies;

[0038] 2. Use multiple longitudinal exciters to stimulate shear waves. The wavelength of shear waves is smaller, so smaller defects can be detected, thereby improving detection accuracy;

[0039] 3. The excited shear waves are propagated in a directional manner, so that the energy is more concentrated and the energy utilization rate is improved.

[0040] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of an ultrasonic nondestructive testing method based on directional shear waves of the present invention;

[0042] Figure 2 It is a simulation result diagram of the simulation experiment 1 of the present invention, wherein Figure 2 (a) is the result diagram of surface wave proportion; Figure 2 (b) is the result diagram of longitudinal wave proportion; Figure 2 (c) is the shear wave ratio result diagram;

[0043] Figure 3 The wavelength diagram after phase optimization of the simulation experiment 1 of the present invention;

[0044] Figure 4 It is a simulation result diagram of the simulation experiment 2 of the present invention, wherein Figure 4 (a) is the result diagram of surface wave proportion; Figure 4 (b) is the result diagram of longitudinal wave proportion; Figure 4 (c) is the shear wave ratio result diagram;

[0045] Figure 5 The wavelength diagram after the spacing optimization of the simulation experiment 2 of the present invention;

[0046] Figure 6 This is the energy distribution diagram after the spacing optimization of the simulation experiment 2 of the present invention;

[0047] Figure 7 Schematic diagram of the structure of the super surface unit of the present invention;

[0048] Figure 8 is a schematic diagram of a metasurface array of the present invention;

[0049] Fig. 9 It is a simulation diagram of the present invention, wherein Fig. 9(a) is the transmittance simulation diagram of the metasurface unit under different parameters; Fig. 9 (b) is a simulation diagram of the phase change of the metasurface unit under different parameters;

[0050] Fig.10 A simulation diagram of the phase change effect of the metasurface of the parameters of the present invention;

[0051] Fig.11 Schematic diagram of directional shear waves excited by the use of a metasurface according to the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical scheme and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

[0053] It should be noted that the terms "include", "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or devices.

[0054] Like reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0055] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0056] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the detection of plate-like structures, the use of shear wave nondestructive testing technology has advantages over the use of Lamb waves. In plate structures, SHO waves are the only non-dispersive waves, which means that their phase velocity and group velocity are independent of frequency. Therefore, in this case, it is crucial to study stress wave detection technology that can excite directional shear waves. Based on the above analysis, the present invention is designed as follows: Figure 1 As shown, an ultrasonic nondestructive testing method based on directional shear waves comprises the following steps:

[0058] S1. Determine the material to be tested;

[0059] In this embodiment, the material to be tested is, but is not limited to, an aluminum plate;

[0060] S2, based on the excitation of directional shear waves by the material under test:

[0061] S21, based on the finite element software COMSOL, multiple longitudinal excitations are applied to the material under test in half space;

[0062] S22, fixing the spacing between the multiple longitudinal excitations and optimizing the phase of the longitudinal excitations;

[0063] Step S22 specifically includes the following steps:

[0064] S221, initial value setting: set the number of shear wave excitations to 10, multiple excitation phases to be periodically arranged along 0 and π, and the spacing between multiple excitations to 0.018m;

[0065] S222, for each longitudinal excitation, introduce a linearly increasing phase ,in For the incentive sequence, is the increasing phase;

[0066] S223, scan at intervals of 0.1pi The proportion of surface waves, longitudinal waves and shear waves in the range of 0-2pi;

[0067] S224: Based on the scanning result described in step S223, the incremental phase is determined based on the highest energy proportion of the shear wave. .

[0068] like Figure 2 and Figure 3 As shown in 0-pi and pi-2pi are symmetrical. In a process (taking 0-pi as an example), the surface wave ratio first increases and then decreases, the longitudinal wave ratio becomes higher and higher, and the shear wave ratio first decreases, then increases, and then decreases. Another interesting phenomenon is that when As pi approaches, the energy of surface waves and shear waves becomes lower and lower, while the energy of longitudinal waves becomes higher and higher. It can be seen that the phase When the phase is 0.4pi, the ratio of surface waves and longitudinal waves is low, and the ratio of shear waves is high. Therefore, in step S224, the incremental phase is determined. is 0.4pi.

[0069] S23, optimizing the spacing between multiple longitudinal excitations using the phase optimization result obtained in step S22 as a fixed value;

[0070] Step S23 specifically includes the following steps:

[0071] S231, taking the increment phase determined in step S224 as a fixed value, Optimize downwards at intervals of 0.001m and export the scan results;

[0072] S232: Based on the scanning result described in step S231, the spacing is determined based on the highest proportion of shear wave energy. .

[0073] like Figure 4-Figure 6 As shown in the figure, as the spacing increases, the overall trend of the surface wave ratio decreases, the longitudinal wave ratio increases, and the shear wave ratio increases first and then decreases. It can be seen that when the spacing is 0.012m, the surface wave and longitudinal wave ratios are both low, the shear wave ratio is high, and the shear wave ratio can reach more than 90% at this time. Therefore, in step S232, the spacing determined is It is 0.012m.

[0074] S24, taking the optimization result obtained in step S23 as the excitation result, at which point the shear wave energy accounts for no less than 90%;

[0075] S3. Based on the phase and spacing obtained in step S2, determine the parameters of the metasurface:

[0076] S31, adjust the phase and spacing: by changing Figure 8-Figure 9 The parameters of the metasurface shown, vary the spacing of the metasurface;

[0077] S32, using the sweep algorithm to filter out the metasurface parameters for setting transmittance and phase, and obtain the result as follows Fig.10 As shown;

[0078] In step S32 , the sweep calculation is performed using the joint simulation function of COMSOL Multiphysics software version 6.0 and MATLAB.

[0079] In step S32, the sweep height range is set to 3 mm-8 mm, the sweep length range is set to 0.5 mm-3 mm, the transmittance is set to be greater than 0.7, and the number is set to ten.

[0080] like Figure 7 and Fig.11 As shown, S33, a plane longitudinal wave propagating parallel to the metasurface is emitted to verify whether the plane longitudinal wave can generate longitudinal excitations with different phases after passing through the metasurface.

[0081] The nondestructive detector of the ultrasonic nondestructive testing method based on directional shear waves includes a signal generator, a power amplifier, a magnetostrictive longitudinal wave exciter and a metastructure exciter connected in series in sequence, wherein the magnetostrictive longitudinal wave exciter is used to generate a guided wave of the S0 mode in the aluminum plate, and the metastructure exciter includes a metasurface for changing the phase, so as to achieve the magnetostrictive longitudinal wave exciter to generate ten longitudinal excitations with different phases after passing through the metasurface.

[0082] Therefore, the present invention adopts the above-mentioned ultrasonic nondestructive testing method and nondestructive detector based on directional shear waves, which have the advantages of long propagation distance, strong anti-interference ability, no need for coupling agent, and light equipment.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An ultrasonic nondestructive testing method based on directional shear waves, characterized in that: The following steps are involved: S1. Determine the material to be tested; S2, based on the excitation of directional shear waves by the material under test: S21, based on the finite element software COMSOL, multiple longitudinal excitations are applied to the material under test in half space; S22, fixing the spacing between the multiple longitudinal excitations and optimizing the phase of the longitudinal excitations; Step S22 specifically includes the following steps: S221, initial value setting: set the number of shear wave excitations to 10, multiple excitation phases to be periodically arranged along 0 and π, and the spacing between multiple excitations to 0.018m; S222, for each longitudinal excitation, introduce a linearly increasing phase ,in For the incentive sequence, is the increasing phase; S223, scan at intervals of 0.1pi The proportion of surface waves, longitudinal waves and shear waves in the range of 0-2pi; S224: Based on the scanning result described in step S223, the incremental phase is determined based on the highest energy proportion of the shear wave. ; S23, optimizing the spacing between multiple longitudinal excitations using the phase optimization result obtained in step S22 as a fixed value; Step S23 specifically includes the following steps: S231, taking the increment phase determined in step S224 as a fixed value, Optimize downwards at intervals of 0.001m and export the scan results; S232: Based on the scanning result described in step S231, the spacing is determined based on the highest proportion of shear wave energy. ; S24, taking the optimization result obtained in step S23 as the excitation result, at which point the shear wave energy accounts for no less than 90%; S3. Based on the phase and spacing obtained in step S2, determine the parameters of the metasurface: S31, adjusting phase and spacing: changing the spacing of the metasurface by changing the height and length of the metasurface; S32, using a sweeping algorithm to select metasurface parameters for setting transmittance and phase; S33, emitting a plane longitudinal wave propagating in parallel to the metasurface, and verifying whether the plane longitudinal wave can generate longitudinal excitations with different phases after passing through the metasurface; S4. Nondestructive testing using nondestructive detectors: The nondestructive detector includes a signal generator, a power amplifier, a magnetostrictive longitudinal wave exciter and a metastructure exciter connected in series in sequence, wherein the magnetostrictive longitudinal wave exciter is used to generate a guided wave of the S0 mode in an aluminum plate, and the metastructure exciter includes a metasurface for changing the phase, and the metasurface has the metasurface parameters determined in step S3, so that the guided wave excited by the magnetostrictive longitudinal wave exciter generates longitudinal excitations of ten different phases after passing through the metasurface, and the directional shear wave excited by the longitudinal excitation is used for nondestructive testing.

2. The ultrasonic nondestructive testing method based on directional shear waves according to claim 1, characterized in that: In step S224, the incremental phase is determined is 0.4pi.

3. The ultrasonic nondestructive testing method based on directional shear waves according to claim 1, characterized in that: In step S232, the spacing is determined It is 0.012m.

4. The ultrasonic nondestructive testing method based on directional shear waves according to claim 1, characterized in that: In step S32 , the sweep calculation is performed using the joint simulation function of COMSOL Multiphysics software version 6.0 and MATLAB.

5. The ultrasonic nondestructive testing method based on directional shear waves according to claim 4, characterized in that: In step S32, the sweep height range is set to 3 mm-8 mm, the sweep length range is set to 0.5 mm-3 mm, the transmittance is set to be greater than 0.7, and the number is set to ten.

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