Ultrasonic transverse wave enhanced focusing type electromagnetic ultrasonic measurement sensor and measurement method

Abstract

The invention discloses an ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measurement sensor and a measurement method. The sensor comprises a probe shell, a focused magnet and a circular coil, wherein the focused magnet is fixed in the probe shell, multiple layers of focused magnets are axially arranged in the probe shell, and each layer of focused magnet is nested inside and outside; and the circular coil is positioned at the bottom of the focused magnet. The focusing type magnet forms a vertical strong magnetic field below the circular coil, and under the combined action of the strong magnetic field and strong current in the coil, ultrasonic body waves are excited in the tested piece. In the process that ultrasonic body waves are propagated in the material, material mass points generate shear vibration perpendicular to the propagation direction, and transverse wave vibration components are formed. During transverse wave propagation, shearing vibration cuts a vertical strong magnetic field, periodic eddy current corresponding to transverse wave vibration is excited near the surface layer of the tested piece, and the periodic eddy current is inducted and received by the circular coil to form a transverse wave signal. As transverse waves have high sensitivity to material interface changes and defects, the technical effects of high magnetic field focusing performance, high defect sensitivity, non-contact and rapid measurement are achieved.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic ultrasonic nondestructive testing technology, specifically to an ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measurement sensor and method, which can be used for high-sensitivity detection of transverse waves. Background Technology

[0002] As a shear wave mode, ultrasonic shear waves exhibit higher detection sensitivity for minute defects, interface discontinuities, and internal deformation features when propagating within metallic materials, thus finding widespread application in nondestructive testing. Compared to traditional contact piezoelectric ultrasonic methods, electromagnetic acoustic transducers (EMATs) generate and receive shear waves non-contactly in conductive metals through electromagnetic induction and Lorentz force mechanisms. This avoids the use of coupling agents and is adaptable to complex industrial environments such as high temperatures and high speeds, offering significant advantages in engineering applications. However, most current shear wave EMAT probes still employ simple permanent magnets or unoptimized magnetic circuit structures, limiting their magnetic field strength and flux density. This results in low shear wave excitation and reception efficiency under conditions of high lift-off height, wide-bandwidth excitation, and strong noise. To obtain high-quality shear wave detection signals, high-voltage pulse amplifiers, large-size magnets, or complex coil structures are often required. This increases the sensor's size and power requirements, while also limiting the portability and efficiency of on-site testing. Summary of the Invention

[0003] In order to solve the problems existing in the prior art, the present invention aims to provide an ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measurement sensor and measurement method, which improves the strength of the magnetic field of the electromagnetic ultrasonic sensor and the transverse wave detection signal.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: An ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measurement sensor includes a probe housing 1, a multi-layered focused magnet 2 arranged axially with each layer nested inside and outside the probe housing 1, and a circular coil 6 located at the bottom of the focused magnet 2. During measurement, the sensor is located above the test piece.

[0005] The focusing magnet 2 is composed of multiple central cylindrical vertically distributed magnets 3, multiple outer annular vertically distributed magnets 5, and multiple transversely distributed magnets 4 arranged in the gaps between the central cylindrical vertically distributed magnets 3 and the outer annular vertically distributed magnets 5. There is no gap between the central cylindrical vertically distributed magnets 3 and the outer annular vertically distributed magnets 5 in the top layer, while there are gaps in the other layers, and transversely distributed magnets 4 are arranged in the gaps.

[0006] The focusing magnet 2 is arranged in three nested layers inside the probe housing 1.

[0007] The three central cylindrical vertically distributed magnets 3 are composed of three cylindrical magnets, each with a height of 15 mm and diameters of Ø22 mm, Ø17 mm and Ø12 mm from top to bottom, respectively.

[0008] The three outer ring-shaped vertically distributed magnets 5 are ring structures. The outer diameter of the upper layer is Ø30 mm and the inner diameter is Ø22 mm. The outer diameter of the middle layer is Ø30 mm and the inner diameter is Ø21 mm. The outer diameter of the lower layer is Ø30 mm and the inner diameter is Ø16 mm. The height of each is 15 mm.

[0009] The horizontally distributed magnet 4 is a circle composed of fan-shaped structures with a central angle of 90-180 degrees. The outer diameter of the middle layer is Ø21 mm and the inner diameter is Ø17 mm. The outer diameter of the lower layer is Ø16 mm and the inner diameter is Ø12 mm. The height of each layer is 15 mm.

[0010] The circular coil 6 is wound with fine copper wire, the spacing of which is the wavelength of the transverse wave, the coil diameter is 10 mm, and the number of turns is 50.

[0011] The vertical magnetic field strength generated by the focusing magnet 2 below the circular coil 6 is 6 times that of the horizontal magnetic field strength, which enables the circular coil 6 to receive a purer ultrasonic transverse wave velocity component.

[0012] The described method for operating an ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor involves a focusing magnet 2 forming a strong magnetic field perpendicular to the direction of the circular coil 6. Under the combined action of the strong magnetic field and the strong current in the circular coil 6, ultrasonic volume waves are generated in the test piece. The ultrasonic volume waves propagating inside the test piece induce shear vibrations, i.e., transverse wave vibration components, in the particles within the material perpendicular to the propagation direction of the ultrasonic volume waves. As the transverse waves propagate within the material, the particles cut the strong magnetic field perpendicular to the propagation direction along the shear vibration, thereby exciting periodic eddy currents corresponding to the transverse wave vibrations near the surface of the test piece. These periodic eddy currents are induced and received as transverse wave vibration signals in the circular coil 6. Because the transverse waves have a significant shear displacement component, they are highly sensitive to changes and defects at the interface of the test piece material. Therefore, this sensor can achieve the technical effects of strong magnetic field focusing, high-sensitivity defect detection, and non-contact rapid measurement.

[0013] Compared with the prior art, the present invention has the following advantages: This invention is an ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measurement sensor. By directionally arranging the magnets, the magnetic field at the working surface is significantly enhanced and highly concentrated, effectively improving magnetic flux density and magnetic field utilization, thus strengthening the transverse wave excitation region. Through the optimized magnetic circuit configuration of this invention, magnetic flux leakage in traditional magnet structures is reduced, improving the transverse wave transduction efficiency and signal-to-noise ratio. This results in a more compact and lightweight overall sensor structure that is simple and easy to operate. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the sensor in an embodiment of the present invention.

[0015] Figure 2 This is a schematic diagram of the system operation for ultrasonic shear wave detection according to the present invention.

[0016] Figure 3 The following are schematic diagrams of the circular coil in this invention.

[0017] Figure 4a , 4b and Figure 4c These are, respectively, the time-domain signal diagram of the ultrasonic transverse wave velocity received by the sensor in this invention, the magnetic flux density diagram of the vertical magnetic field generated by the focusing magnet 2 below the circular coil 6, and the magnetic flux density diagram of the vertical magnetic field generated by a common cylindrical permanent magnet of the same size at the corresponding position. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] like Figure 1As shown, this embodiment of an ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measurement sensor includes a probe housing 1, a focused magnet 2 fixed inside the probe housing 1 with three axially nested layers, and a circular coil 6 located at the bottom of the focused magnet 2. In a preferred embodiment, the focused magnet 2 is composed of three central cylindrical vertically distributed magnets 3, three outer annular vertically distributed magnets 5, and eight transversely distributed magnets 4 with a central angle of 90 degrees arranged in the gaps between the central cylindrical vertically distributed magnets 3 and the outer annular vertically distributed magnets 5 in the lower two layers. The three central cylindrical vertically distributed magnets 3 are composed of three cylindrical magnets, each with a height of 15 mm and diameters of Ø22 mm, Ø17 mm, and Ø12 mm. The three outer annular vertically distributed magnets 5 have a ring structure: the upper layer has an outer diameter of Ø30 mm and an inner diameter of Ø22 mm; the middle layer has an outer diameter of Ø30 mm and an inner diameter of Ø21 mm; and the lower layer has an outer diameter of Ø30 mm and an inner diameter of Ø16 mm, with a height of 15 mm for each layer. The eight horizontally distributed magnets 4 form a fan-shaped structure. Four of these magnets, with a central angle of 90 degrees, form a circle. The outer diameter of the middle circle is Ø21 mm, and the inner diameter is Ø17 mm. The outer diameter of the lower circle is Ø16 mm, and the inner diameter is Ø12 mm. All three have a height of 15 mm. In this embodiment, the vertical magnetic field strength generated by the focusing magnet 2 below the circular coil 6 is six times that of the horizontal magnetic field strength, enabling the circular coil 6 to receive a purer transverse wave velocity component.

[0020] In the sensor, the focusing magnet 2 generates a strong vertical magnetic field B below the circular coil 6. z Under the combined influence of a strong magnetic field and a strong current in circular coil 6, ultrasonic body waves are generated in the specimen. The ultrasonic body waves propagating inside the specimen cause shear vibrations, i.e., transverse wave vibration components v, to occur in the particles inside the specimen material perpendicular to the direction of ultrasonic body wave propagation. x When a transverse wave propagates inside a material, the particles cut the strong magnetic field perpendicular to the propagation direction with shear vibration, thereby exciting periodic eddy currents corresponding to the transverse wave vibration near the surface of the test piece. These periodic eddy currents are induced and received as transverse wave vibration signals in the circular coil 6. Since the transverse wave has a significant shear displacement component, it is highly sensitive to changes and defects in the interface of the test piece material. Therefore, this sensor can achieve the technical effects of strong magnetic field focusing, high-sensitivity defect detection, and non-contact rapid measurement.

[0021] like Figure 2 As shown, the sensor's circular coil 6 transmits signals via a duplexer to a computer for processing through a pulse ultrasonic transducer / receiver module.

[0022] like Figure 3The diagram shows a schematic of a circular coil 6. In a preferred embodiment of the present invention, the circular coil 6 has a spacing equal to the transverse wave wavelength, is wound with fine copper wire, has a coil diameter of 10 mm, and has 50 turns.

[0023] like Figure 4a The figure shows the time-domain signal of the ultrasonic shear wave velocity received by the sensor. It can be seen from the figure that the sensor of the present invention can receive good shear wave velocity components, and the defective shear wave velocity components are greater than the defective shear wave velocity components.

[0024] like Figure 4b The image shows the magnetic flux density diagram of the strong magnetic field generated in the vertical direction below the circular coil 6 by the focusing magnet 2 of this invention. Figure 4c The comparison shows that the optimized magnet configuration of this invention directionally arranges the magnets, which significantly enhances and highly concentrates the magnetic field on the working surface.

Claims

1. An ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor, characterized in that: The device includes a probe housing (1), a multi-layered focusing magnet (2) arranged axially and nested inside the probe housing (1), a circular coil (6) located at the bottom of the focusing magnet (2), and a sensor located above the test piece during measurement.

2. The ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor according to claim 1, characterized in that: The focusing magnet (2) is composed of multiple central cylindrical vertical distributed magnets (3), multiple outer ring-shaped vertical distributed magnets (5), and horizontal distributed magnets (4) arranged in the gaps between the central cylindrical vertical distributed magnets (3) and the outer ring-shaped vertical distributed magnets (5). There is no gap between the central cylindrical vertical distributed magnets (3) and the outer ring-shaped vertical distributed magnets (5) in the top layer, while there are gaps in the other layers, and horizontal distributed magnets (4) are arranged in the gaps.

3. The ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor according to claim 1, characterized in that: The focusing magnet (2) is arranged in three nested layers inside the probe housing (1).

4. The ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor according to claim 3, characterized in that: The three central cylindrical vertically distributed magnets (3) consist of three cylindrical magnets, each with a height of 15 mm and diameters of Ø22 mm, Ø17 mm and Ø12 mm from top to bottom, respectively.

5. The ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor according to claim 3, characterized in that: The three outer ring-shaped vertically distributed magnets (5) are ring structures. The outer diameter of the upper layer is Ø30 mm and the inner diameter is Ø22 mm. The outer diameter of the middle layer is Ø30 mm and the inner diameter is Ø21 mm. The outer diameter of the lower layer is Ø30 mm and the inner diameter is Ø16 mm. The height of each is 15 mm.

6. The ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor according to claim 3, characterized in that: The horizontally distributed magnet (4) is a circle composed of a fan-shaped structure with a central angle of 90-180 degrees. The outer diameter of the middle layer is Ø21 mm and the inner diameter is Ø17 mm. The outer diameter of the lower layer is Ø16 mm and the inner diameter is Ø12 mm. The height of each layer is 15 mm.

7. The ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor according to claim 1, characterized in that: The circular coil (6) is made of fine copper wire with a spacing equal to the transverse wave wavelength, a coil diameter of 10 mm, and 50 turns.

8. The ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor according to claim 1, characterized in that: The vertical magnetic field strength generated by the focusing magnet (2) below the circular coil (6) is 6 times that of the horizontal magnetic field strength, which enables the circular coil (6) to receive a purer ultrasonic transverse wave velocity component.

9. The operating method of the ultrasonic transverse wave enhanced focused electromagnetic ultrasonic measuring sensor according to any one of claims 1 to 8, characterized in that: In the sensor, the focusing magnet (2) forms a strong magnetic field in the vertical direction below the circular coil (6). Under the combined action of the strong magnetic field and the strong current in the circular coil (6), ultrasonic body waves are generated in the test piece. The ultrasonic body waves propagating inside the test piece cause the particles inside the test piece material to generate shear vibrations perpendicular to the propagation direction of the ultrasonic body waves, i.e., transverse wave vibration components. When the transverse waves propagate inside the material, the particles cut the strong magnetic field in the vertical direction along the shear vibration perpendicular to the propagation direction, thereby exciting periodic eddy currents corresponding to the transverse wave vibrations near the surface of the test piece. The periodic eddy currents are induced and received as transverse wave vibration signals in the circular coil (6). Since the transverse waves have obvious shear displacement components, they are highly sensitive to changes and defects in the interface of the test piece material. Therefore, the sensor can achieve the technical effects of strong magnetic field focusing, high-sensitivity defect detection, and non-contact rapid measurement.

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