Method and device for detecting fiber buckling of composite laminate, terminal and medium

Abstract

The present application relates to the technical field of ultrasonic nondestructive testing, and particularly relates to a composite material laminate fiber buckling detection method, device, terminal and medium. The detection method comprises the following steps: performing ultrasonic A-scan detection on the composite material laminate to obtain an ultrasonic A-display radio frequency signal; selecting a wavelet base function ψ(t) with tight support characteristics according to the ultrasonic A-display radio frequency signal, and performing stretching and translation on the wavelet base function ψ(t) to obtain ψ ab (t); performing convolution operation on the wavelet base function ψ ab (t) and the ultrasonic A-display radio frequency signal to obtain wavelet coefficients; determining an intrinsic scale corresponding to the composite material laminate layer distribution rule according to a two-dimensional time-frequency distribution graph of the wavelet coefficients; and performing detection analysis on the fiber buckling of the composite material laminate according to the intrinsic scale. The composite material laminate fiber buckling detection method, device, terminal and medium aim to solve the problem that weak signals are difficult to identify in the fiber buckling detection of the layers of the composite material laminate.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic nondestructive testing technology, specifically to a method, device, terminal, and medium for detecting fiber buckling in composite laminates. Background Technology

[0002] Carbon fiber reinforced resin matrix composites have been widely used in the aerospace field, and the layup structure and fiber orientation are important design parameters for composite laminates. During the manufacturing stage, process deviations can lead to defects related to fiber buckling, such as layup bridging, thickness deviations, and incorrect lamination sequence, which severely affect the mechanical properties of composite laminates. Therefore, it is necessary to establish a non-destructive testing method for fiber buckling defects in composite laminates, capable of effectively detecting information such as the thickness distribution and lamination orientation of the internal layups. This is of great significance for understanding the internal layup structure of composite materials, optimizing process parameters, and improving the inspection and characterization of laminates.

[0003] Therefore, the inventors provide a method, device, terminal, and medium for detecting fiber buckling in composite laminates. Summary of the Invention

[0004] (1) Technical problems to be solved

[0005] Currently, the main methods used to characterize the internal layup structure of composite laminates are ultrasonic B-scan and ultrasonic tomography. Existing technologies have certain shortcomings and limitations in specific areas: (a) Ultrasonic B-scan requires a full-waveform imaging gate to cover the ultrasonic A-display radio frequency signal of the composite laminate along its thickness direction. The internal characteristics of the composite laminate are obtained by analyzing the time-domain information (mainly signal amplitude and time-domain position) of the interlayer waveforms. Since ultrasound reflection at the solid-gas interface is significant, this method has a good detection effect on defects such as delamination, debonding, and porosity. However, because the acoustic impedance difference between layers within the composite laminate is small, the reflected signals from between layers are very weak and are usually submerged in noise signals, making it difficult to judge the layup-related ultrasonic signals visually. On the other hand, due to the attenuation effect of the composite material on ultrasound, the interlayer reflection signals near the test surface are more obvious than those of the lower layers, i.e., the "upper layer obvious" rule. This leads to a gradual weakening of the characterization ability of conventional ultrasonic testing methods for the layup structure of composite laminates, resulting in insufficient detection capability for fiber buckling defects. (b) Ultrasonic tomography is a process of imaging composite materials layer by layer by setting different imaging gates along the time domain. The width and position of the imaging gates determine the quality of the ply representation structure, and the width of the imaging gates determines the resolution of the ply. At the same time, the images of ultrasonic tomography may be affected by adjacent ply or background noise, and it is difficult to obtain ply structure information of composite laminates by visual inspection alone.

[0006] This invention provides a method, device, terminal, and medium for detecting fiber buckling in composite laminates, which solves the technical problem of difficulty in identifying weak signals of fiber buckling in composite laminate layups.

[0007] (2) Technical solution

[0008] The first aspect of the present invention provides a method for detecting fiber buckling in composite laminates, comprising the following steps:

[0009] The composite laminate was subjected to ultrasonic A-scan testing to obtain the ultrasonic A-scan radio frequency signal. Based on the ultrasonic A-scan radio frequency signal, a wavelet basis function ψ(t) with tight support characteristics was selected, and the wavelet basis function ψ(t) was scaled and translated to obtain ψ0. ab (t);

[0010] With ψ ab (t) is used as an analysis factor and convolved with the ultrasound A-display radio frequency signal to obtain wavelet coefficients;

[0011] Based on the two-dimensional time-frequency distribution diagram of the wavelet coefficients, the intrinsic scale corresponding to the layup distribution pattern of the composite laminate is determined;

[0012] The fiber buckling of the composite laminate was detected and analyzed based on the intrinsic dimensions.

[0013] Furthermore, the ultrasonic A-scan detection of the composite laminate to obtain the ultrasonic A-display radio frequency signal is specifically as follows:

[0014] The ultrasonic A-wave radio frequency signal of the composite material laminate was extracted using a high-resolution ultrasonic focusing transducer.

[0015] Further, the two-dimensional time-frequency distribution of the wavelet coefficients is determined, specifically as follows:

[0016] Wavelets of different scales extract the signal components that are most similar to their respective time-frequency characteristics, and obtain a two-dimensional time-frequency distribution map of the wavelet coefficients.

[0017] Furthermore, the aforementioned ψ ab (t) is used as an analysis factor and convolved with the ultrasound A-display radio frequency signal to obtain wavelet coefficients, specifically:

[0018] For ψ ab (t) Perform continuous wavelet transform to obtain the wavelet coefficients.

[0019] Furthermore, determining the intrinsic scale corresponding to the layup distribution pattern of the composite laminate based on the two-dimensional time-frequency distribution diagram of the wavelet coefficients specifically includes the following steps:

[0020] The wavelet coefficients are plotted on a three-dimensional time-frequency space to obtain the extreme value fluctuation characteristics of the interlayer reflected wave signal components.

[0021] The intrinsic scale is defined as the scale at which the wavelet coefficients exhibit a clear periodic extreme oscillation pattern on the two-dimensional time-frequency plane.

[0022] Furthermore, the ultrasound A-display radio frequency signal is the sum of three components in the time domain: background noise random signal, instantaneous change signal, and steady-state periodic oscillation signal.

[0023] Furthermore, the wavelet basis function is the Symlet mother wavelet basis function ψ(t).

[0024] A second aspect of the present invention provides a device for detecting fiber buckling in composite laminates, comprising:

[0025] The scanning and detection module is used to perform ultrasonic A-scan detection on composite material laminates to obtain ultrasonic A-display radio frequency signals.

[0026] The wavelet transform module is used to select a wavelet basis function ψ(t) with compact support characteristics based on the ultrasound A-display radio frequency signal, and to obtain ψ(t) by scaling and translating the wavelet basis function ψ(t). ab (t);

[0027] The convolution operation module is used to perform operations with ψ ab (t) is used as an analysis factor and convolved with the ultrasound A-display radio frequency signal to obtain wavelet coefficients;

[0028] The scale calculation module is used to determine the intrinsic scale corresponding to the ply distribution law of the composite laminate based on the two-dimensional time-frequency distribution diagram of the wavelet coefficients.

[0029] The detection and analysis module is used to detect and analyze the fiber buckling of the composite laminate based on the intrinsic scale.

[0030] A third aspect of the present invention provides a terminal including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the detection method as described above.

[0031] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the detection method described above.

[0032] (3) Beneficial effects

[0033] In summary, this invention utilizes continuous wavelet transform to locate the periodic oscillation components in a signal in both time and frequency and to perform multi-resolution analysis. Since the layup in a composite laminate exhibits periodic oscillation characteristics, fiber buckling-related information can be obtained by detecting the layup information of the composite laminate without being affected by background noise. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic flowchart of a method for detecting fiber buckling in a composite laminate provided by an embodiment of the present invention;

[0036] Figure 2 This is a waveform diagram of the ultrasonic A-display radio frequency signal f(t) extracted from a composite laminate using a high-resolution ultrasonic focusing transducer;

[0037] Figure 3 This is a schematic diagram showing that the radio frequency signal f(t) displayed by ultrasound A is represented as the sum of three components in the time domain: steady-state periodic oscillation signal, background noise random signal, and transient change signal.

[0038] Figure 4 This is a waveform diagram of a Symlet wavelet basis function ψ(t) provided in an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram of the scaling and translation of a wavelet basis function ψ(t) provided in an embodiment of the present invention;

[0040] Figure 6 This is a two-dimensional time-domain distribution diagram of wavelet coefficients W(a,b;f(t),ψ(t)) provided in an embodiment of the present invention;

[0041] Figure 7 This is a feature scale a provided in an embodiment of the present invention. e The corresponding wavelet coefficient amplitude W(a) e A schematic diagram of the periodic extreme value oscillation pattern exhibited by f(t), ψ(t));

[0042] Figure 8 This is a schematic diagram of an interlayer reflected wave component provided in an embodiment of the present invention;

[0043] Figure 9(a) is a schematic diagram of the ultrasonic A-display radio frequency signal during signal processing of a composite laminate containing fiber buckling defects according to Embodiment 1 of the present invention;

[0044] Figure 9(b) is a schematic diagram of interlayer reflected waves during signal processing of a composite laminate containing fiber buckling defects, provided in Embodiment 1 of the present invention.

[0045] Figure 9(c) is a two-dimensional time-domain distribution diagram of the ultrasonic A-display radio frequency signal during signal processing of a composite laminate containing fiber buckling defects provided in Embodiment 1 of the present invention;

[0046] Figure 9(d) is a curve of interlayer reflected wave components during signal processing of a composite laminate containing fiber buckling defects, provided in Embodiment 1 of the present invention.

[0047] Figure 10 This is a schematic diagram of the structure of a composite laminate fiber buckling detection device provided in an embodiment of the present invention.

[0048] In the picture:

[0049] 100 - Scanning detection module; 200 - Wavelet transform module; 300 - Convolution operation module; 400 - Scale calculation module; 500 - Detection and analysis module. Detailed Implementation

[0050] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] Figure 1 This is a schematic flowchart of a method for detecting fiber buckling in a composite laminate provided by an embodiment of the present invention, as shown below. Figure 1 As shown, the method may include the following steps:

[0053] S100. Perform ultrasonic A-scan detection on the composite material laminate to obtain the ultrasonic A-display radio frequency signal;

[0054] S200. Based on the radio frequency signal displayed by ultrasound A, select a wavelet basis function ψ(t) with compact support characteristics, and obtain ψ(t) by scaling and translating the wavelet basis function ψ(t). ab (t);

[0055] S300, with ψab (t) is used as an analysis factor and convolved with the ultrasound A-display radio frequency signal to obtain wavelet coefficients;

[0056] S400. Based on the two-dimensional time-frequency distribution diagram of wavelet coefficients, determine the intrinsic scale corresponding to the ply distribution law of composite laminate.

[0057] S500. Based on intrinsic dimensions, fiber buckling of composite laminates is detected and analyzed.

[0058] In the above embodiments, continuous wavelet transform is used to expand the one-dimensional high-resolution ultrasonic A-display radio frequency signal in a two-dimensional time-frequency plane, which can provide more and richer detection information. By utilizing the time-frequency localization capability and multi-resolution analysis capability of the periodic oscillation component in the signal by continuous wavelet transform, the layup information of composite laminate can be effectively detected without being affected by other frequency components. The detection results are clear and reliable, and the layup structure information has high recognition.

[0059] This detection method is particularly suitable for analyzing composite material ply structures with periodic oscillation characteristics. It can eliminate the influence of other non-periodic components in the signal. Based on the characteristics of the composite material ply thickness, different types of wavelet basis functions with tight support characteristics (preferably Symlet wavelet basis functions) can be selected to improve the time-frequency positioning accuracy of the signal.

[0060] As an optional implementation, in step S100, the composite material laminate is subjected to ultrasonic A-scan detection to obtain ultrasonic A-display radio frequency signals. Specifically, a high-resolution ultrasonic focusing transducer is used to extract the ultrasonic A-display radio frequency signals of the composite material laminate.

[0061] Among them, the radiofrequency signal displayed by ultrasound A is the sum of three components in the time domain: background noise random signal, instantaneous change signal, and steady-state periodic oscillation signal.

[0062] The waveform of the ultrasonic A-wave display radio frequency signal 1 of the composite laminate was extracted using a high-resolution ultrasonic focusing transducer, as shown in Figure 1. Figure 2 As shown.

[0063] like Figure 3 As shown, Figure 2The ultrasonic A-display signal 1 shown is interpreted as a one-dimensional time-domain signal f(t) with respect to time t. It can be considered as the sum of three components in the time domain: background noise random signal 2, transient change signal 3, and steady-state periodic oscillation signal 4. Specifically: a) the background noise random signal 2 may originate from external interference such as environment, equipment, instruments, and transducers; b) the transient change signal 3 is related to the structure of the composite material and may originate from the "gas-solid" interface due to defects such as delamination or debonding within the composite material, or from the "liquid-solid" interface formed by the upper and lower coupling surfaces of the composite material. Because the acoustic impedance of gas, liquid, and solid differs significantly, the acoustic reflectivity is high at the "gas-solid" and "liquid-solid" interfaces, resulting in a large ultrasonic echo amplitude that is easily identifiable by the naked eye; c) the steady-state periodic oscillation signal 4 originates from various components within the composite material. The "solid-solid" interface between layers can be considered as a periodic stacking of two equivalent materials: "in-lay" and "between-lay". The "in-lay" material is a mixture of fiber and resin, while the "between-lay" material is resin. Both equivalent materials are solids with very similar acoustic impedances. Therefore, the acoustic reflectivity of this "solid-solid" interface is small, resulting in a small amplitude of ultrasonic echo, which is not easily visible to the naked eye. It is also affected by background noise random signal 2 and transient change signal 3. The layup information of the composite laminate is hidden in the steady-state periodic oscillation signal 4, which needs to be analyzed.

[0064] As an optional implementation, in step S200, a wavelet basis function with tight support characteristics is selected based on the radio frequency signal displayed by ultrasound A, and the wavelet basis function is scaled and translated to obtain ψ. ab (t), specifically: after selecting the wavelet basis function, it is scaled and translated.

[0065] Specifically, a suitable wavelet basis function ψ(t) is selected based on the characteristics of the ultrasound A-display radio frequency signal f(t). This wavelet basis function ψ(t) has a compact support characteristic, meaning that as t→∞, ψ(t) rapidly converges from a finite value to 0. This invention selects a Symlet wavelet of type sym16 (vanishing moment of 16) to perform wavelet transform on the ultrasound A-display radio frequency signal f(t).

[0066] As an optional implementation, in step S300, ψ ab (t) is used as an analysis factor and convolved with the ultrasound A-display radio frequency signal to obtain wavelet coefficients, specifically: for ψ ab Perform continuous wavelet transform on (t) to obtain wavelet coefficients.

[0067] Among them, such as Figure 5 As shown, by performing convolution operations on wavelets of different scales along the time domain, the wavelets will extract the signal component that is most similar to the time-frequency characteristics, i.e.:

[0068]

[0069] In the formula, a is the scaling factor, b is the translation factor, t is time, and R is a real number.

[0070] Then, a continuous wavelet transform is performed on the radio frequency signal f(t) displayed by ultrasound A, that is:

[0071]

[0072] In the formula, ψ * The complex conjugate of ψ is indicated; W(a,b;f(t),ψ(t)) represents the wavelet coefficients corresponding to the ultrasound A-display radio frequency signal f(t). These wavelet coefficients are a two-dimensional matrix about (a,b), representing the energy distribution of the ultrasound A-display radio frequency signal f(t) in the two-dimensional time-frequency plane.

[0073] As an optional implementation, in step S400, the intrinsic scale corresponding to the ply distribution pattern of the composite material laminate is determined based on the two-dimensional time-frequency distribution diagram of the wavelet coefficients, specifically including the following steps:

[0074] S401. Plot the wavelet coefficients on a three-dimensional time-frequency space to obtain the extreme value fluctuation characteristics of the interlayer reflected wave signal components.

[0075] S402. Determine a certain scale on which the wavelet coefficients exhibit obvious periodic extreme value oscillations on the two-dimensional time-frequency plane as the intrinsic scale.

[0076] In the above embodiments, such as Figure 6 As shown, the wavelet coefficients W(a,b;f(t),ψ(t)) are plotted on a three-dimensional time-frequency space. Coordinate 8 represents the translation parameter b, coordinate 9 represents the scale parameter a, and coordinate 10 represents the amplitude of W(a,b;f(t),ψ(t)) at coordinate (b,a), i.e., |W(a,b;f(t),ψ(t))|. The extreme value fluctuation characteristics of the interlayer reflected wave signal components can be obtained 11.

[0077] like Figure 7 As shown, the wavelet coefficients W(a,b;f(t),ψ(t)) are plotted on a two-dimensional time-frequency plane, with the horizontal axis representing the translation parameter b and the vertical axis representing the scale parameter a. The amplitude of W(a,b;f(t),ψ(t)) at coordinate (b,a) is represented by color intensity, and the extreme value fluctuation characteristics of the interlayer reflected wave signal components can be obtained.

[0078] like Figure 8 As shown, W(a,b;f(t),ψ(t)) at a certain scale a in the two-dimensional time-frequency plane e The above exhibits a clear periodic extreme value oscillation pattern, and this characteristic scale ae The corresponding wavelet coefficient amplitude W(a) e The unprocessed interlayer reflection wave 12 was extracted separately, and the interlayer reflection wave component curve 13 was extracted after wavelet transformation. The horizontal axis is the translation parameter b (i.e., time t), and the vertical axis is the amplitude of the wavelet coefficient. It can be seen that it exhibits the characteristics of periodic oscillation, which corresponds to the periodic distribution law of the ply in the composite material, that is, the periodic alternation of "in-layer" and "interlayer".

[0079] Figure 10 This is a schematic diagram of the structure of a composite laminate fiber buckling detection device provided in an embodiment of the present invention, as shown below. Figure 10 As shown, the device may include:

[0080] The scanning and detection module 100 is used to perform ultrasonic A-scan detection on the composite material laminate to obtain the ultrasonic A-display radio frequency signal.

[0081] Wavelet transform module 200 is used to select wavelet basis functions with compact support characteristics based on the ultrasound A-wave radio frequency signal, and to obtain ψ by scaling and translating the wavelet basis functions. ab (t);

[0082] Convolution operation module 300, used for ψ ab (t) is used as an analysis factor and convolved with the ultrasound A-display radio frequency signal to obtain wavelet coefficients;

[0083] The scale calculation module 400 is used to determine the intrinsic scale corresponding to the ply distribution law of composite laminate based on the two-dimensional time-frequency distribution map of wavelet coefficients.

[0084] The detection and analysis module 500 is used to detect and analyze the fiber buckling of composite laminates based on intrinsic dimensions.

[0085] The scale calculation module 400 is specifically used for:

[0086] By plotting wavelet coefficients on a three-dimensional time-frequency space, the extreme value fluctuation characteristics of the interlayer reflected wave signal components can be obtained.

[0087] The intrinsic scale is determined by identifying a scale at which the wavelet coefficients exhibit a clear periodic extreme oscillation pattern on the two-dimensional time-frequency plane.

[0088] This invention provides a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the detection method described above.

[0089] This invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the detection method described above.

[0090] Example 1

[0091] The fiber buckling detection method for composite laminates of the present invention was used to detect fiber buckling defects in a composite laminate prepared from a carbon fiber reinforced resin matrix composite material system BA3602. A high-resolution focusing transducer with a frequency of 5MHz was selected. Figures 9(a)-9(b) As shown in Figure 9(c), the ultrasound A-display radio frequency signal f(t)14 was obtained. The interlayer reflected wave 15 was extracted in the time domain. Using the Symlet wavelet basis function ψ(t) of type sym16 selected in this invention, as shown in Figure 9(c), a two-dimensional time-frequency analysis was performed on the ultrasound A-display radio frequency signal f(t)14 to obtain a two-dimensional time-domain distribution map, and the feature scale a was extracted. e The corresponding wavelet coefficient amplitude W(a) e As shown in Figure 9(d), the interlayer reflection wave component curve 17 extracted after wavelet transform exhibits extreme value fluctuations, but at t=1.3×10 -6 At position 's', the interlayer reflected wave represented by the extreme fluctuation disappears. Based on the longitudinal wave velocity of the composite material (3000 m / s) and the single-layer thickness of the laminate (0.187 mm), it can be calculated that a fiber buckling defect exists at the 10th layer. The detection results of this invention are intuitive and reliable, and can provide detailed information on fiber buckling of the composite laminate.

[0092] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0093] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art without departing from the scope of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A method for detecting fiber buckling in composite laminates, characterized in that, The method includes the following steps: The composite laminate was subjected to ultrasonic A-scan testing to obtain the ultrasonic A-scan radio frequency signal. Based on the ultrasound A-wavelength radio frequency signal, a wavelet basis function with tight support characteristics is selected. and the wavelet basis functions Scale and translate to obtain ; by The wavelet coefficients are obtained by convolving the wavelet coefficients with the ultrasound A-display radio frequency signal as analysis factors. Based on the two-dimensional time-frequency distribution diagram of the wavelet coefficients, the intrinsic scale corresponding to the layup distribution pattern of the composite laminate is determined; Based on the intrinsic dimensions, the fiber buckling of the composite laminate was detected and analyzed; The determination of the intrinsic scale corresponding to the ply distribution pattern of the composite laminate based on the two-dimensional time-frequency distribution diagram of the wavelet coefficients specifically includes the following steps: The wavelet coefficients are plotted on a three-dimensional time-frequency space to obtain the extreme value fluctuation characteristics of the interlayer reflected wave signal components. The intrinsic scale is defined as the scale at which the wavelet coefficients exhibit a clear periodic extreme oscillation pattern in the two-dimensional time-frequency plane. The wavelet basis function is the Symlet wavelet basis function. .

2. The method for detecting fiber buckling in composite laminates according to claim 1, characterized in that, The ultrasonic A-scan detection of the composite material laminate to obtain the ultrasonic A-display radio frequency signal is specifically as follows: The ultrasonic A-wave radio frequency signal of the composite material laminate was extracted using a high-resolution ultrasonic focusing transducer.

3. The method for detecting fiber buckling in composite laminates according to claim 1, characterized in that, The two-dimensional time-frequency distribution of the wavelet coefficients is determined as follows: Wavelets of different scales extract the signal components that are most similar to their respective time-frequency characteristics, and obtain a two-dimensional time-frequency distribution map of the wavelet coefficients.

4. The method for detecting fiber buckling in composite laminates according to claim 1, characterized in that, The The wavelet coefficients are obtained by convolving the wavelet coefficients with the ultrasound A-display radio frequency signal as an analysis factor. right Perform a continuous wavelet transform to obtain the wavelet coefficients.

5. The method for detecting fiber buckling in composite laminates according to claim 1, characterized in that, The ultrasound A-display radio frequency signal is the sum of three components in the time domain: background noise random signal, instantaneous change signal, and steady-state periodic oscillation signal.

6. A testing device employing the method for detecting fiber buckling in composite laminates as described in any one of claims 1-5, characterized in that, include: The scanning and detection module is used to perform ultrasonic A-scan detection on composite material laminates to obtain ultrasonic A-display radio frequency signals. The wavelet transform module is used to select a wavelet basis function with compact support characteristics based on the ultrasound A-display radio frequency signal, and to scale and translate the wavelet basis function to obtain... ; The convolution operation module is used to perform operations such as... The wavelet coefficients are obtained by convolving the wavelet coefficients with the ultrasound A-display radio frequency signal as analysis factors. The scale calculation module is used to determine the intrinsic scale corresponding to the ply distribution law of the composite laminate based on the two-dimensional time-frequency distribution diagram of the wavelet coefficients. The detection and analysis module is used to detect and analyze the fiber buckling of the composite laminate based on the intrinsic scale.

7. A terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the detection method as described in any one of claims 1-5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the detection method as described in any one of claims 1-5.

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