V-like defect angle detection method based on surface acoustic waves

Abstract

The invention discloses a surface acoustic wave-based V-shaped defect angle detection method. The method comprises the following steps: constructing a first simulation model and a second simulation model; wherein the first simulation model is a simulation model with similar V-shaped groove defects on the surface, and the second simulation model is a simulation model of a laser light source; acting light generated by the second simulation model on the surface of the first simulation model to obtain sound waves; wherein the sound waves propagate along the near surface of the first simulation model in a surface acoustic wave form, and after being concentrated at the bottom of the first simulation model, the sound waves propagate towards the two sides along the bottom of the first simulation model; sound wave waveforms are obtained at equal intervals in the sound wave propagation direction of the bottom of the first simulation model, and a B-scan graph is drawn according to the sound wave waveforms; according to the B-scan graph, carrying out information extraction on the sound waves to obtain propagation rates of the sound waves in different modes; and calculating the defect angle of the V-like groove according to the physical attributes and propagation rates of the sound waves in different modes.

Description

Technical Field

[0001] The invention relates to the technical field of laser ultrasonic testing, and in particular to a method for detecting angles of quasi-V-shaped defects based on surface acoustic waves. Background Art

[0002] As the trend of industrial high-processing becomes increasingly obvious, the requirements for equipment and product processing and maintenance in social production technology are becoming more and more stringent. As the service time of equipment increases, defects of various shapes will inevitably form on its surface, which will affect the service life of the equipment and pose safety hazards if they are not detected and repaired in time. The production status of non-destructive testing and acoustic testing is becoming more and more important, and there are still deficiencies in the relevant detection of defect parameters.

[0003] Laser ultrasonic testing is also an emerging research field of non-destructive testing. The acoustic wave component that is converted into acoustic waves by laser ultrasonic defect research mainly refers to elastic acoustic waves, that is, surface acoustic waves. Surface acoustic waves mainly appear near the surface where the laser interacts with the material. They propagate along the free surface of the solid. The energy amplitude will decay rapidly with the energy depth or internal structural vacancies. However, they are the waveforms excited by the laser source that mainly rely on surface propagation and are highly efficient and undistorted. Therefore, they are very useful detection waveforms in laser ultrasonic testing. To a certain extent, their characteristics can be used to characterize defect information.

[0004] In recent times, the research at home and abroad has been mainly promoted from three aspects: the excitation mechanism of laser ultrasound, the sound wave receiving method and instrument improvement of laser ultrasound echo, and the application expansion of laser ultrasound technology (including the research on the structural performance of the material to be tested, the location of the defect to be tested, and other specific parameters). In the actual engineering integrated production process, the most widely used device equipment is actually metal materials, and aluminum materials are more representative. The research on its defects has a relatively broad representative significance in the application of material defect detection.

[0005] Domestic and foreign research on material defects is still mainly focused on methodology, defect location and depth. However, in actual production, it is known that defects are often complex and often not rectangular. The fact that cracks generally present a V-shape makes the study of defect angles necessary and representative, but it is rarely studied at home and abroad. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a V-type defect angle detection method based on surface acoustic waves, which can realize non-contact and non-destructive testing. The propagation rates of different modal sound waves can be used to deduce the information of the V-type defect angle, and the angle of the V-type defect can be better determined.

[0007] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0008] In one aspect, the present invention provides a method for detecting a V-shaped defect angle based on a surface acoustic wave, comprising:

[0009] Constructing a first simulation model and a second simulation model; wherein the first simulation model is a simulation model having a V-groove-like defect on the surface, and the second simulation model is a simulation model of a laser light source;

[0010] Applying light generated by the second simulation model to the surface of the first simulation model to obtain an acoustic wave; wherein the acoustic wave propagates along the near surface of the first simulation model in the form of a surface acoustic wave, and after being concentrated at the bottom of the first simulation model, propagates in both directions along the bottom of the first simulation model;

[0011] Acquire the acoustic waveforms at equal intervals along the acoustic wave propagation direction at the bottom of the first simulation model, and draw a B-scan diagram based on the acoustic waveforms;

[0012] According to the B-scan image, information is extracted from the sound wave to obtain the propagation rates of the sound waves in different modes;

[0013] The defect angle of the V-shaped groove is calculated based on the physical properties and propagation speed of the sound waves in different modes.

[0014] Optionally, the second simulation model is expressed as:

[0015] ;

[0016] ;

[0017] In the formula, is the time distribution of the laser light source; is the spatial distribution of the laser light source; For time; is the pulse rise time; is an exponential function; is the ratio of the length of the major axis to the minor axis of the laser source line source; is the incident laser center point position in the xz horizontal plane; is the radius of the laser source.

[0018] Optionally, the sound wave propagates along the near surface of the first simulation model in the form of a surface acoustic wave, concentrates at the bottom of the first simulation model, and then propagates in both directions along the bottom of the first simulation model, including:

[0019] Changing the distance between the first simulation model and the second simulation model to obtain the attenuation characteristics of the surface acoustic wave;

[0020] Changing the defect angle of the first simulation model to obtain surface acoustic wave graphs of surface acoustic waves propagating to the bottom of the first simulation model at different defect angles;

[0021] According to the surface acoustic wave diagram, the surface acoustic wave propagated to the bottom of the first simulation model is used as a diffraction source to reflect and propagate to both sides.

[0022] Optionally, the B-scan image is an acoustic wave displacement-time image;

[0023] The concentrated area of ​​the acoustic wave displacement-time diagram represents the energy concentration area of ​​the surface acoustic wave propagating to the bottom of the first simulation model, and the diffusion wave lines around the energy concentration area represent the mode of the acoustic wave.

[0024] Optionally, in a single mode, the propagation velocity of the sound wave is calculated as:

[0025] ;

[0026] In the formula, is the displacement distance between two points of the sound wave; is the propagation time of a sound wave between two points.

[0027] Optionally, the defect angle calculation formula of the V-shaped groove is:

[0028] ;

[0029] In the formula, For the The propagation velocity of the sound wave in each mode; is the propagation velocity of surface acoustic waves; is the modal number.

[0030] Optionally, the least square method is used to reduce the propagation velocity error of the sound wave and the defect angle error of the V-shaped groove.

[0031] In a second aspect, the present invention provides a computer system, comprising:

[0032] Memory, for storing computer instructions;

[0033] A processor is used to execute the computer instructions to implement the steps of the V-type defect angle detection method based on surface acoustic wave described in the first aspect.

[0034] The third invention, the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the V-type defect angle detection method based on surface acoustic wave described in the first aspect are implemented.

[0035] Beneficial Effects

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention can realize contactless nondestructive testing by exciting sound waves with pulsed lasers. When the sound waves propagate near the surface of the material to be tested in the form of surface acoustic waves, the surface acoustic wave layer attenuation is small, so that the detection direction can be correct and the defect information can be carried the most. The propagation rates of different modes of sound waves can be used to deduce the information of the angle of V-type defects, and the angle of V-type defects can be better determined. It has wider applicability and higher accuracy in terms of angle smoothness, and can be used for comprehensive detection of defect angles of workpieces corresponding to actual industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 FIG. 1 is a schematic flow chart of a method for detecting angles of V-shaped defects based on surface acoustic waves according to an embodiment of the present invention;

[0039] Figure 2 The figure shows an acoustic wave cloud diagram of a method for detecting angles of V-shaped defects based on surface acoustic waves in one embodiment of the present invention;

[0040] Figure 3 It is a schematic diagram showing the arrangement of the detection points at the bottom of the V-shaped groove defect in one embodiment of the present invention;

[0041] Figure 4 Shown is a schematic diagram of the propagation path of the sound wave at the bottom of the V-shaped groove defect in one embodiment of the present invention. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0043] The term "and / or" is only a description of the association relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " generally indicates that the related objects are in an "or" relationship.

[0044] Example 1

[0045] like Figure 1 As shown, this embodiment introduces a method for detecting angles of V-shaped defects based on surface acoustic waves, which specifically includes the following steps:

[0046] Construct a first simulation model and a second simulation model; wherein the first simulation model is a surface with an angle of The first simulation model is a simulation model of a V-groove defect, and the second simulation model is a simulation model of a laser light source.

[0047] The light generated by the second simulation model acts on the surface of the first simulation model to obtain sound waves. Figure 2 The figure shows a sound wave cloud diagram. In metal materials, sound waves mainly propagate their energy in the form of surface acoustic waves, and attenuate slowly during the process. Surface acoustic waves mainly propagate near the surface of the material. After encountering defects, they gather at the bottom of the defective groove and then reflect with the top as the diffraction source. That is, after encountering defects, the main energy of the surface acoustic wave propagates along the lateral groove direction.

[0048] In this embodiment, the second simulation model can be expressed as:

[0049] ;

[0050] ;

[0051] In the formula, is the time distribution of the laser light source; is the spatial distribution of the laser light source; For time; is the pulse rise time; is an exponential function; is the ratio of the length of the major axis to the minor axis of the laser source line source, When it is 1, it is a point source. When it is not 1, it is a line source; is the incident laser center point position in the xz horizontal plane; is the radius of the laser source.

[0052] The acoustic wave propagates along the near surface of the first simulation model in the form of surface acoustic waves. The acoustic wave propagation characteristics and related modes are detected and recorded by equidistantly recording waveform information to calculate the rate, and the defect is V-shaped.

[0053] When the surface acoustic wave propagates to the bottom of the V-shaped groove defect, the energy is concentrated at the bottom of the V-shaped groove defect, and the acoustic wave no longer propagates in the form of a surface acoustic wave; the acoustic wave directly propagates in both directions along the bottom of the V-shaped groove defect, specifically:

[0054] The distance between the first simulation model and the second simulation model is changed to obtain the attenuation characteristics of the surface acoustic wave. In this embodiment, the relative distance is reduced as much as possible to avoid energy attenuation.

[0055] The angle of the V-shaped defect in the first simulation model is changed to obtain surface acoustic wave graphs of the surface acoustic wave propagating to the bottom of the first simulation model at different defect angles.

[0056] According to the surface acoustic wave diagram, the surface acoustic wave propagated to the bottom of the first simulation model is used as a diffraction source to reflect and propagate to both sides.

[0057] That is, the surface acoustic wave propagates along the near surface of the first simulation model, and the energy is gathered at the bottom of the V-shaped groove defect. It no longer propagates in the form of a surface acoustic wave, and the acoustic wave directly propagates to both sides of the V-shaped groove defect.

[0058] Along the sound wave propagation direction at the bottom of the V-shaped groove defect, equally spaced detection points are selected to obtain the sound wave waveform at equal intervals. The sound wave propagation data of each detection point is exported, and Origin is used to draw the B-scan diagram to intuitively analyze the propagation characteristics of the sound wave at the bottom of the V-shaped groove.

[0059] like Figure 3 As shown in the figure, the B-scan diagram is a sound wave displacement-time diagram, the horizontal axis is time (ns), and the vertical axis is the instantaneous displacement value of the sound wave in the y direction. According to the propagation characteristics of the sound wave, the detection point setting range is determined, and 100 detection points are set at equal intervals in the bottom direction of the V-shaped groove defect.

[0060] Analyzing the B-scan image, the obvious concentrated part in the middle represents the energy concentration area where the surface acoustic wave propagates to the bottom of the V-shaped groove defect, and the diffuse wave lines around the energy concentration area are the modes of the acoustic wave.

[0061] The waveform of the energy concentration area is relatively coarse, and the propagation velocity V1 of the first mode sound wave along the bottom of the V-shaped groove defect is equal to the propagation velocity of the surface acoustic wave.

[0062] The diffusion wave line is a parallel wave, which is mainly a surface acoustic wave that propagates to the bottom of the V-shaped groove defect. When the surface acoustic wave propagates at the bottom of the V-shaped groove defect, it no longer propagates in the form of a surface acoustic wave, that is, the sound wave is directly a diffraction source and then propagates. Affected by the angle of the V-shaped groove defect, the sound wave propagates along the z-axis direction of the bottom of the V-shaped groove defect. Figure 4 The figure shows a schematic diagram of the propagation path of the sound wave at the bottom of the V-shaped groove defect. The propagation rate of the sound wave at different times varies significantly due to the influence of the defect, and the defect angle can be inferred through the speed of different modes.

[0063] According to the B-scan diagram, information is extracted from the sound waves propagating along the bottom of the V-shaped groove defect to obtain the propagation rates of the sound waves in different modes, specifically:

[0064] By combining space and time, the sound waves of different modes can be separated in the B-sacn diagram (time-longitudinal displacement diagram). Secondly, on a single mode, several equally spaced points are taken to calculate the propagation rate of the sound waves of the single mode. The formula is:

[0065] ;

[0066] In the formula, is the displacement distance between two points of the sound wave; is the propagation time of a sound wave between two points.

[0067] Use the least squares method or other data analysis methods to reduce the propagation rate of sound waves.

[0068] Finally, the propagation velocities of acoustic waves of different modes separated and propagating along the V-groove defect are obtained.

[0069] According to the physical properties and propagation speed of sound waves in different modes, the defect angle of V-shaped groove is inferred, which is widely applicable to the smoothness of defect angle.

[0070] The calculation formula for the defect angle of the V-shaped groove is:

[0071] ;

[0072] In the formula, For the The propagation speed of the sound wave in each mode; is the propagation speed of surface acoustic waves; is the modal number.

[0073] because , , It corresponds to, known , when the modal When it is 1, The propagation speed of the sound wave in the mode is , calculate the unknown quantity ; When the modal When it is 2, The propagation speed of the sound wave in the mode is , calculate the unknown quantity ;…. The least squares method is used to fit and reduce the angle error of the V-shaped groove defect to obtain the final .

[0074] Example 2

[0075] This embodiment introduces a computer system, including:

[0076] Memory, for storing computer instructions;

[0077] A processor is used to execute the computer instructions to implement the steps of the V-type defect angle detection method based on surface acoustic wave described in Example 1.

[0078] Example 3

[0079] This embodiment introduces a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the V-type defect angle detection method based on surface acoustic wave described in Example 1 are implemented.

[0080] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0081] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0082] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0083] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0084] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A method for detecting the angle of a V-shaped defect based on surface acoustic wave, characterized in that: include: Constructing a first simulation model and a second simulation model; wherein the first simulation model is a simulation model having a V-groove-like defect on the surface, and the second simulation model is a simulation model of a laser light source; Applying light generated by the second simulation model to the surface of the first simulation model to obtain an acoustic wave; wherein the acoustic wave propagates along the near surface of the first simulation model in the form of a surface acoustic wave, and after being concentrated at the bottom of the first simulation model, propagates in both directions along the bottom of the first simulation model; Acquire the acoustic waveforms at equal intervals along the acoustic wave propagation direction at the bottom of the first simulation model, and draw a B-scan diagram based on the acoustic waveforms; According to the B-scan image, information is extracted from the sound wave to obtain the propagation rates of the sound waves in different modes; The defect angle of the V-shaped groove is calculated based on the physical properties and propagation speed of the sound waves in different modes.

2. The method for detecting the angle of a V-shaped defect based on surface acoustic wave according to claim 1, characterized in that: The second simulation model is expressed as: ； ； In the formula, is the time distribution of the laser light source; is the spatial distribution of the laser light source; For time; is the pulse rise time; is an exponential function; is the ratio of the length of the major axis to the minor axis of the laser source line source; is the incident laser center point position in the xz horizontal plane; is the radius of the laser source.

3. The method for detecting the angle of a V-shaped defect based on surface acoustic wave according to claim 1, characterized in that: The acoustic wave propagates along the near surface of the first simulation model in the form of a surface acoustic wave, concentrates at the bottom of the first simulation model, and then propagates in both directions along the bottom of the first simulation model, including: Changing the distance between the first simulation model and the second simulation model to obtain the attenuation characteristics of the surface acoustic wave; Changing the defect angle of the first simulation model to obtain surface acoustic wave graphs of surface acoustic waves propagating to the bottom of the first simulation model at different defect angles; According to the surface acoustic wave diagram, the surface acoustic wave propagated to the bottom of the first simulation model is used as a diffraction source to reflect and propagate to both sides.

4. The method for detecting the angle of a V-shaped defect based on surface acoustic wave according to claim 1, characterized in that: The B-scan image is a sound wave displacement-time image; The concentrated area of ​​the acoustic wave displacement-time diagram represents the energy concentration area of ​​the surface acoustic wave propagating to the bottom of the first simulation model, and the diffusion wave lines around the energy concentration area represent the mode of the acoustic wave.

5. The method for detecting the angle of a V-shaped defect based on surface acoustic wave according to claim 1, characterized in that: In a single mode, the propagation velocity of sound waves is calculated as: ； In the formula, is the displacement distance between two points of the sound wave; is the propagation time of a sound wave between two points.

6. The method for detecting angles of V-shaped defects based on surface acoustic waves according to claim 1, characterized in that: The calculation formula for the defect angle of the V-shaped groove is: ； In the formula, For the The propagation velocity of the sound wave in each mode; is the propagation velocity of surface acoustic waves; is the modal number.

7. The method for detecting the angle of a V-shaped defect based on surface acoustic wave according to claim 1, characterized in that: The least square method is used to reduce the error of the propagation velocity of the acoustic wave and the error of the defect angle of the V-shaped groove.

8. A computer system, characterized in that: include: Memory, for storing computer instructions; A processor is used to execute the computer instructions to implement the steps of the V-type defect angle detection method based on surface acoustic wave according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for detecting angles of V-type defects based on surface acoustic waves described in any one of claims 1 to 7 are implemented.

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