A prediction method of SH0 guided wave periodic permanent magnet electro-magnetic ultrasonic transducer received signal

Abstract

The application discloses a kind of SH0 waveguide periodic permanent magnet electromagnetic ultrasonic transducer received signal prediction method, the method comprises the following steps: step one: according to the time domain waveform of excitation signal, calculate excitation signal spectrum;Step two: according to the parameter of excitation SH0 waveguide periodic permanent magnet electromagnetic ultrasonic transducer, calculate excitation transducer spectrum;Step three: according to the parameter of received SH0 waveguide periodic permanent magnet electromagnetic ultrasonic transducer, calculate receiving transducer spectrum;Step four: according to the material parameters and structural parameters of measured plate, calculate measured plate spectrum;Step five: according to excitation signal spectrum, excitation transducer spectrum, receiving transducer spectrum and measured plate spectrum calculate received signal spectrum;Step six: according to received signal spectrum, calculate received signal time domain waveform.The method can quickly obtain the received signal of SH0 waveguide periodic permanent magnet electromagnetic ultrasonic transducer by simple mathematical calculation.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic guided wave nondestructive testing technology, and relates to a method for predicting the received signal of an ultrasonic transducer, specifically a method for predicting the received signal of an SHO guided wave periodic permanent magnet electromagnetic ultrasonic transducer. Background Technology

[0002] Metallic materials and structures, as important components of modern engineering, inevitably suffer various forms of damage during manufacturing and service. Ultrasonic non-destructive testing and evaluation techniques, due to their non-destructive nature, have become an effective means of assessing the condition of materials and structures. Among them, ultrasonic guided wave technology, with its advantages of long propagation distance and large detection range, has been widely used in the non-destructive testing of thin-walled plates and pipe structures.

[0003] In sheet metal inspection, the vibration displacement of SH guided waves exists only in the direction parallel to the sheet surface, exhibiting simpler vibration characteristics compared to Lamb waves. Low-order modes (SH0 guided waves) possess non-dispersion characteristics, thus the waveform remains undistorted during propagation, preserving the original signal characteristics. This facilitates accurate identification and analysis of defect echoes, improving inspection reliability. Furthermore, the energy of SH0 guided waves is uniformly distributed along the sheet thickness, giving them excellent detection sensitivity for defects at any depth in the sheet metal.

[0004] The SHO guided wave periodic permanent magnet electromagnetic ultrasonic transducer utilizes an electromagnetic coupling mechanism, allowing for direct excitation and reception of SHO guided waves within a metal plate without contact with the test object. Figure 1 As shown. Commonly used detection configurations are as follows. Figure 2 As shown, the excitation signal drives the SHO guided wave periodic permanent magnet electromagnetic ultrasonic transducer to generate SHO guided waves in the tested material. These SHO guided waves propagate within the material and are collected by the receiving SHO guided wave periodic permanent magnet electromagnetic ultrasonic transducer, yielding the received signal. In practical testing applications, to meet different testing requirements, the periodic permanent magnet array configuration of both the excitation and receiving transducers typically needs to be specifically designed and optimized. Traditional verification methods include experimental testing and numerical simulation. These methods are used to obtain the received signal from the SHO guided wave periodic permanent magnet electromagnetic ultrasonic transducer to evaluate its performance. If the expected results are not achieved, the transducer parameters need to be repeatedly optimized and re-verified until the testing requirements are met.

[0005] However, traditional experimental and numerical simulation verification processes are time-consuming and laborious. Therefore, developing a new method that can quickly and accurately predict the received signal of an SHO guided wave periodic permanent magnet electromagnetic ultrasonic transducer has become a key technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0006] This invention provides a method for predicting the received signal of an SHO guided periodic permanent magnet electromagnetic ultrasonic transducer. This method can quickly obtain the received signal of the SHO guided periodic permanent magnet electromagnetic ultrasonic transducer through simple mathematical calculations.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for predicting the received signal of an SHO guided periodic permanent magnet electromagnetic ultrasonic transducer includes the following steps:

[0009] Step 1: Calculate the excitation signal spectrum based on the time-domain waveform of the excitation signal. The excitation signal spectrum is calculated using the following formula:

[0010]

[0011] in, For the excitation signal spectrum, This represents the time-domain waveform of the excitation signal. The imaginary unit, For time, ω is the angular frequency.

[0012] Step 2: Based on the parameters of the excitation SH0 guided periodic permanent magnet electromagnetic ultrasonic transducer, calculate the excitation transducer spectrum. The excitation transducer spectrum is calculated according to the following formula:

[0013]

[0014] in, This indicates the frequency spectrum of the excitation transducer. This represents the remanent magnetization of the permanent magnet in the excitation transducer. This indicates the propagation speed of the SH0 guided wave in the tested material. This indicates the distance between the lower surface of the permanent magnet in the excitation transducer and the upper surface of the plate being tested. This indicates the height of the permanent magnet in the excitation transducer. The imaginary unit, Angular frequency, The spatial distribution function of the periodic permanent magnets in the excitation transducer satisfies: , The coordinate system is defined with the leftmost end of the periodic permanent magnet in the excitation transducer as the origin, and the direction of the SH0 guided wave propagating towards the receiving transducer as... coordinate system in the positive direction of the axis Axis coordinates.

[0015] Step 3: Based on the parameters of the receiving SHO guided wave periodic permanent magnet electromagnetic ultrasonic transducer, calculate the receiving transducer spectrum. The receiving transducer spectrum is calculated using the following formula:

[0016]

[0017] in, This indicates the received transducer spectrum. This indicates the remanent magnetization of the permanent magnet in the receiving transducer. This indicates the propagation speed of the SH0 guided wave in the tested material. This indicates the distance between the lower surface of the permanent magnet in the receiving transducer and the upper surface of the plate being measured. This indicates the height of the permanent magnet in the receiving transducer. The imaginary unit, Angular frequency, The spatial distribution function of the periodic permanent magnets in the receiving transducer is expressed as follows: superscript This indicates taking the conjugate complex number.

[0018] Step 4: Calculate the spectrum of the tested material based on its material and structural parameters. The spectrum is calculated using the following formula:

[0019]

[0020] in, This indicates the spectrum of the tested board material. This indicates the electrical conductivity of the tested material. The magnetic permeability of the tested material is given by [the value of the material]. The shear modulus of the tested sheet material. The thickness of the material being tested. This indicates the propagation speed of the SH0 guided wave in the tested material. It is an intermediate variable and satisfies The real part is less than 0 and , The imaginary unit, ω is the angular frequency.

[0021] Step 5: Calculate the received signal spectrum based on the excitation signal spectrum, the excitation transducer spectrum, the receiving transducer spectrum, and the spectrum of the tested material. The received signal spectrum is calculated using the following formula:

[0022]

[0023] in, Indicates the received signal spectrum. For the excitation signal spectrum, This indicates the frequency spectrum of the excitation transducer. This indicates the received transducer spectrum. This represents the spectrum of the tested material.

[0024] Step Six: Calculate the time-domain waveform of the received signal based on the received signal spectrum. The time-domain waveform of the received signal is calculated according to the following formula:

[0025]

[0026] in, This represents the time-domain waveform of the received signal. Indicates the received signal spectrum. The imaginary unit, ω is the angular frequency.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] This invention provides a highly efficient and accurate method for predicting received signals from SHO guided wave periodic permanent magnet electromagnetic ultrasonic transducers. Compared to traditional numerical methods such as finite element and finite difference methods, this method significantly improves computational efficiency, making it particularly suitable for large-scale or real-time computational scenarios. Compared to experimental methods, this invention does not rely on physical equipment or repetitive testing, greatly saving manpower, material resources, and time costs. Furthermore, the prediction method of this invention has a clear process and is easy to implement and integrate into software. Attached Figure Description

[0029] Figure 1 A schematic diagram of the structure of an SH0 guided periodic permanent magnet electromagnetic ultrasonic transducer.

[0030] Figure 2 This is a common testing configuration for SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducers;

[0031] Figure 3 This is the commonly used detection configuration when using an SHO guided wave periodic permanent magnet electromagnetic ultrasonic transducer for detection in Example 1;

[0032] Figure 4 A flowchart for calculating the time-domain waveform of the received signal from an SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer.

[0033] Figure 5 The time-domain waveform of the excitation signal;

[0034] Figure 6 To excite the periodic permanent magnet spatial distribution function of the SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer;

[0035] Figure 7 The spatial distribution function of the periodic permanent magnet in the SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer;

[0036] Figure 8The normalized result of the received signal time-domain waveform obtained by the experimental method, the finite element simulation method, and the method of the present invention. Detailed Implementation

[0037] The technical solution of the present invention will be further described below with reference to the accompanying drawings, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0038] When using an SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer to inspect aluminum plates, the commonly used inspection configuration is as follows: Figure 3 As shown, the excitation signal drives the periodic permanent magnet electromagnetic ultrasonic transducer of the SH0 guided wave to generate SH0 guided waves in the aluminum plate under test. The SH0 guided waves propagate in the plate and are collected by the periodic permanent magnet electromagnetic ultrasonic transducer of the SH0 guided wave, thus obtaining the received signal. Figure 4 As shown, the specific prediction steps for the received signal of the SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer are as follows:

[0039] Step 1: Calculate the spectrum of the excitation signal based on the time-domain waveform of the excitation signal.

[0040] In this step, since the received signal of the SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer is related to the SH0 guided wave excited by the SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer, and the SH0 guided wave excited by the SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer is related to the excitation signal, it is necessary to determine the excitation signal used to drive the SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer. The spectrum of the excitation signal is calculated according to the following formula:

[0041]

[0042] in, For the excitation signal spectrum, Represents the time-domain waveform of the excitation signal, such as Figure 5 As shown, The imaginary unit, For time, ω is the angular frequency.

[0043] Step 2: Calculate the excitation transducer spectrum based on the parameters of the excitation SH0 guided periodic permanent magnet electromagnetic ultrasonic transducer.

[0044] In this step, the parameters for exciting the SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer include the remanent magnetization of the permanent magnet in the excitation transducer, the distance between the lower surface of the permanent magnet and the upper surface of the aluminum plate being tested, the height of the permanent magnet, and the spatial distribution function of the periodic permanent magnet. The excitation transducer spectrum is calculated according to the following formula:

[0045]

[0046] in, This indicates the frequency spectrum of the excitation transducer. This represents the remanent magnetization of the permanent magnet in the excitation transducer. This indicates the propagation speed of the SH0 guided wave in the aluminum plate being tested. This indicates the distance between the lower surface of the permanent magnet in the excitation transducer and the upper surface of the aluminum plate being measured. This indicates the height of the permanent magnet in the excitation transducer. The imaginary unit, Angular frequency, The spatial distribution function of the periodic permanent magnets in the excitation transducer, such as Figure 6 As shown, the following conditions are met: , The coordinate system is defined with the leftmost end of the periodic permanent magnet in the excitation transducer as the origin, and the direction of the SH0 guided wave propagating towards the receiving transducer as... coordinate system in the positive direction of the axis Axis coordinates.

[0047] Step 3: Calculate the receiving transducer spectrum based on the parameters of the receiving SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer.

[0048] The parameters of the SH0 guided wave periodic permanent magnet electromagnetic ultrasonic transducer include the remanent magnetization of the permanent magnet in the transducer, the distance between the lower surface of the permanent magnet and the upper surface of the aluminum plate being tested, the height of the permanent magnet, and the spatial distribution function of the periodic permanent magnet. The transducer spectrum is calculated according to the following formula:

[0049]

[0050] in, This indicates the received transducer spectrum. This indicates the remanent magnetization of the permanent magnet in the receiving transducer. This indicates the propagation speed of the SH0 guided wave in the aluminum plate being tested. This indicates the distance between the lower surface of the permanent magnet in the receiving transducer and the upper surface of the aluminum plate being measured. This indicates the height of the permanent magnet in the receiving transducer. The imaginary unit, Angular frequency, The spatial distribution function of the periodic permanent magnets in the receiving transducer, such as Figure 7 As shown, it satisfies superscript This indicates taking the conjugate complex number.

[0051] Step 4: Calculate the spectrum of the tested board based on its material and structural parameters.

[0052] In this step, the material and structural parameters of the tested material include its electrical conductivity, magnetic permeability, shear modulus, and aluminum plate thickness. The spectrum of the tested material is calculated using the following formula:

[0053]

[0054] in, This indicates the spectrum of the aluminum plate being measured. This indicates the propagation speed of the SH0 guided wave in the aluminum plate being tested. This indicates the electrical conductivity of the aluminum plate being tested. The permeability of the aluminum plate being measured is... The shear modulus of the aluminum plate being tested. The thickness of the aluminum plate being tested. It is an intermediate variable and satisfies The real part is less than 0 and , The imaginary unit, ω is the angular frequency.

[0055] Step 5: Calculate the received signal spectrum based on the excitation signal spectrum, the excitation transducer spectrum, the receiving transducer spectrum, and the spectrum of the plate under test.

[0056] In this step, the received signal spectrum satisfies:

[0057]

[0058] in, Indicates the received signal spectrum. For the excitation signal spectrum, This indicates the frequency spectrum of the excitation transducer. This indicates the received transducer spectrum. This represents the spectrum of the tested material.

[0059] Step 6: Calculate the time-domain waveform of the received signal based on the received signal spectrum.

[0060] In this step, the time-domain waveform of the received signal satisfies:

[0061]

[0062] in, This represents the time-domain waveform of the received signal. Indicates the received signal spectrum. The imaginary unit, ω is the angular frequency.

[0063] Figure 8Experimental results, finite element simulation results, and prediction results of the normalized received signal time-domain waveform disclosed in this patent are presented. Using the same computer, traditional finite element simulation takes more than 2 hours, while the method of this invention takes less than 3 minutes. Furthermore, the method of this invention has high prediction accuracy, and the predicted received signal time-domain waveform closely matches the experimental results.

Claims

1. A method for predicting the received signal of an SHO guided periodic permanent magnet electromagnetic ultrasonic transducer, characterized in that... The method includes the following steps: Step 1: Calculate the spectrum of the excitation signal based on its time-domain waveform; Step 2: Calculate the spectrum of the excitation transducer based on the parameters of the excitation SH0 guided periodic permanent magnet electromagnetic ultrasonic transducer; Step 3: Calculate the receiving transducer spectrum based on the parameters of the receiving SH0 guided periodic permanent magnet electromagnetic ultrasonic transducer; Step 4: Calculate the spectrum of the tested material based on its material and structural parameters. in, This indicates the spectrum of the tested board material. This indicates the electrical conductivity of the tested material. The magnetic permeability of the tested material is given by [the value of the material]. The shear modulus of the tested sheet material. The thickness of the material being tested. This indicates the propagation speed of the SH0 guided wave in the tested material. It is an intermediate variable and satisfies The real part is less than 0 and , The imaginary unit, Angular frequency; Step 5: Calculate the received signal spectrum based on the excitation signal spectrum, the excitation transducer spectrum, the receiving transducer spectrum, and the spectrum of the tested material. Step 6: Calculate the time-domain waveform of the received signal based on the received signal spectrum.

2. The method for predicting the received signal of the SHO guided periodic permanent magnet electromagnetic ultrasonic transducer according to claim 1, characterized in that... The spectrum of the excitation signal is calculated according to the following formula: in, For the excitation signal spectrum, This represents the time-domain waveform of the excitation signal. The imaginary unit, For time, ω is the angular frequency.

3. The method for predicting the received signal of the SHO guided periodic permanent magnet electromagnetic ultrasonic transducer according to claim 1, characterized in that... The spectrum of the excitation transducer is calculated according to the following formula: in, This indicates the frequency spectrum of the excitation transducer. This represents the remanent magnetization of the permanent magnet in the excitation transducer. This indicates the propagation speed of the SH0 guided wave in the tested material. This indicates the distance between the lower surface of the permanent magnet in the excitation transducer and the upper surface of the plate being tested. This indicates the height of the permanent magnet in the excitation transducer. This represents the spatial distribution function of the periodic permanent magnets in the excitation transducer. The coordinate system is defined with the leftmost end of the periodic permanent magnet in the excitation transducer as the origin, and the direction of the SH0 guided wave propagating towards the receiving transducer as... coordinate system in the positive direction of the axis Axis coordinates The imaginary unit, ω is the angular frequency.

4. The method for predicting the received signal of the SHO guided periodic permanent magnet electromagnetic ultrasonic transducer according to claim 3, characterized in that... The .

5. The method for predicting the received signal of the SHO guided periodic permanent magnet electromagnetic ultrasonic transducer according to claim 1, characterized in that... The spectrum of the receiving transducer is calculated according to the following formula: in, This indicates the received transducer spectrum. This indicates the remanent magnetization of the permanent magnet in the receiving transducer. This indicates the propagation speed of the SH0 guided wave in the tested material. This indicates the distance between the lower surface of the permanent magnet in the receiving transducer and the upper surface of the plate being measured. This indicates the height of the permanent magnet in the receiving transducer. This represents the spatial distribution function of the periodic permanent magnets in the receiving transducer. The coordinate system is defined with the leftmost end of the periodic permanent magnet in the excitation transducer as the origin, and the direction of the SH0 guided wave propagating towards the receiving transducer as... coordinate system in the positive direction of the axis Axis coordinates, superscript This indicates taking the conjugate complex number. The imaginary unit, ω is the angular frequency.

6. The method for predicting the received signal of the SHO guided periodic permanent magnet electromagnetic ultrasonic transducer according to claim 5, characterized in that... The .

7. The method for predicting the received signal of the SHO guided periodic permanent magnet electromagnetic ultrasonic transducer according to claim 1, characterized in that... The received signal spectrum is calculated according to the following formula: in, Indicates the received signal spectrum. For the excitation signal spectrum, This indicates the frequency spectrum of the excitation transducer. This indicates the received transducer spectrum. This represents the spectrum of the tested material.

8. The method for predicting the received signal of the SHO guided periodic permanent magnet electromagnetic ultrasonic transducer according to claim 1, characterized in that... The time-domain waveform of the received signal is calculated according to the following formula: in, This represents the time-domain waveform of the received signal. Indicates the received signal spectrum. The imaginary unit, Angular frequency, For time.

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