KR101328061B1 - Magnetostrictive transducer for omni-directional shear horizontal wave transduction - Google Patents

Abstract

The present invention relates to a magnetostrictive transducer for forward shear horizontal wave conversion, and more particularly, a cylindrical wave guide having a circular cross section and a contact end in contact with the specimen; Magnetostrictive patches of ferromagnetic material attached along the circumferential surface of the waveguide; A coil wound on the waveguide to form a magnetic field passing through the waveguide; And a magnet which forms a static magnetic field in the circumferential direction of the waveguide. It provides a magnetostrictive transducer.

Description

Magnetostrictive transducer for omni-directional shear horizontal wave transduction

The present invention relates to a magnetostrictive transducer for forward shear horizontal wave transformation, and more particularly, to a magnetostrictive strain that performs the transformation of shear horizontal wave so that it can be easily used for non-destructive testing of plate-shaped specimens. It is about a transducer.

Guided ultrasonic waves are elastic ultrasonic waves that propagate along the boundaries of the specimen, which can usually propagate over long distances. Due to such long-distance propagation characteristics, guided ultrasound has recently attracted much attention as a method for nondestructive evaluation of various objects. Ultrasonic waves can travel farther within the specimen, allowing high-speed imaging of large areas, as well as remote sensing even when direct access to the inspection site is difficult. On the other hand, the guided ultrasonic wave is difficult to measure and interpret the signal because its type and mode vary according to the shape of the specimen and the propagation pattern of each mode is complicated. In particular, transducers, measuring instruments, and signal analysis methods for wave excitation and measurement vary according to the mode, frequency band, and shape and material of the ultrasonic wave to be used. get affected. Therefore, it is very important to select an appropriate mode and to select a transducer suitable for the inspection using the guided ultrasound in consideration of the characteristics of the inspection object.

Unlike bulk ultrasonic waves, which are generally divided into longitudinal waves and shear waves, there are various types and modes according to the shape of the waveguide structure. In the case of plate specimens or structures, there are two types of guided ultrasonic waves according to the direction of the displacement of the medium, a lamb wave and a shear horizontal wave (SH wave), each having an infinite mode. FIG. 10 shows the relationship between the frequency and group velocity of the lamb wave and the shear horizontal wave in the aluminum plate having a thickness of 1 mm, respectively. In the case of lamb wave, A0 mode and S0 mode exist in a frequency band below the cut off frequency of A1 mode. As the frequency increases, more and more modes begin to appear, and as shown in FIG. 12 (a), their dispersion curves cross each other in a complicated manner. Therefore, when using a lamb wave in a high frequency band, it may be very difficult to isolate the mode when multiple modes are measured. On the contrary, in the shear horizontal wave of FIG. 12 (b), since the dispersion curves of the modes do not cross each other, the mode is easy to be separated from the measurement signal and the mode speed is sequential, so that the operation of identifying the mode is relatively easy. In addition, in the case of shear horizontal waves, only one mode SH0 may exist below the disconnection frequency of the mode SH1, so that the influence of other modes may be excluded. Best of all, the SH0 mode is the only nondispersive wave whose speed does not change with frequency, so the waveform does not change as the wave travels. For these reasons, it can be said that it is preferable to use the shear horizontal wave, especially SH0 mode, for the induced ultrasound-based nondestructive testing.

On the other hand, a method for measuring shear shear waves in the plate is a piezoelectric transducer (wedge) using a wedge (electromagnetic transducer), electromagnetic acoustic transducer (EMAT), magnetostrictive transducer (magnetostrictive transducer), etc. This is used.

Among these, the magnetostrictive transducer uses the principle of magnetostriction, a phenomenon in which ferromagnetic materials are deformed by magnetic fields, and are very efficient for measuring and measuring shear horizontal waves in plates and torsional waves in pipes or axes. .

Magnetic deformation (magnetostriction) is a ductility phenomenon between magnetic field and mechanical deformation, and occurs mainly in ferromagnetic materials including iron, nickel and cobalt.

In this regard, the applicant of the present invention has been previously registered in the contents disclosed in Korea Patent Registration No. 10-1052800. Using the magnetostriction of the ferromagnetic thin plate 110 made of a ferromagnetic material, as shown in FIG. 13, shear horizontal waves can be generated by properly placing the bias magnetic field direction by the magnet 120 and the magnetic field direction of the coil 130. Has applied for a magnetostrictive transducer.

However, since the magnetostrictive transducer of FIG. 13 only generates shear horizontal waves in the set direction (indicated by the arrow), at least three to ten, as many as 20, are used for measurement such as non-destructive testing of specimens. There was a problem in that more than one transducer was installed on a specimen to be measured and defects were detected by analyzing signals collected from them.

The present invention has been made to solve the above problems, in the present invention, in the magnetostrictive transducer, the forward shear horizontal wave conversion implemented so that the shear horizontal wave can be transformed over the entire direction of the contacting specimen To provide a magnetostrictive transducer for the purpose.

As an embodiment of the present invention for achieving the above object, a cylindrical wave guide having a circular cross section and a contact end in contact with the specimen; A magnetostrictive patch of ferromagnetic material attached along the circumferential surface of the waveguide; A coil wound on the wave guide to form a magnetic field passing through the wave guide; And a magnet forming a static magnetic field in the circumferential direction of the waveguide.

As another embodiment of the present invention for achieving the above object, a cylindrical magnetostrictive patch made of a ferromagnetic material having a circular cross section and a contact end in contact with the specimen; A coil wound on the magnetostrictive patch to form a magnetic field passing through the magnetostrictive patch; And a magnet forming a static magnetic field in a circumferential direction of the magnetostrictive patch.

As described above, the magnetostrictive transducer for forward shear horizontal wave transformation according to the present invention has a static magnetic field formed in the circumferential direction of the wave guide and a dynamic magnetic field passing through the inside of the wave guide. By forming a torsional vibration of the waveguide has the effect of generating a shear horizontal wave over the entire direction of the contacted specimen.

In addition, since the shear horizontal wave is generated in the entire direction of the specimen to be measured in the present invention, there is an effect that can effectively detect defects at various points even with a small number of sensors.

In addition, by using the present invention by adjusting the lambda (λ) value on the pattern structure formed at the contact end of the waveguide or the magnetostrictive patch and the spacing between the coils, the user can generate a shear horizontal wave of the desired frequency have.

In addition, the magnetostrictive transducer for the forward shear horizontal wave conversion according to another embodiment of the present invention can reduce the waveform by the reflected wave, it may be helpful in cost reduction because no separate waveguide is required.

In addition, when the sawtooth-shaped bent portion is formed in the present invention or the rear surface material is further included, unwanted signals such as reflected waves can be removed.

1 is a perspective view of a magnetostrictive transducer for forward shear horizontal wave conversion according to an embodiment of the present invention,
2 is an exploded perspective view of a magnetostrictive transducer for forward shear horizontal wave conversion according to an embodiment of the present invention;
3 is a perspective view showing various forms of the wave guide included in the magnetostrictive transducer according to the present invention,
4 illustrates a pattern structure formed at a contact end of a wave guide included in a magnetostrictive transducer according to the present invention.
5 is a cross-sectional view of a magnetostrictive transducer for forward shear horizontal wave conversion according to an embodiment of the present invention,
FIG. 6 is a conceptual diagram illustrating propagation of shear horizontal waves in all directions of a structure in a magnetostrictive transducer for forward shear horizontal wave transformation according to an embodiment of the present invention.
7 is a photographic photograph of an example of a magnetostrictive transducer for omnidirectional shear horizontal wave transformation actually manufactured according to the present invention, and an experimental measurement example using such a magnetostrictive transducer.
8 to 10 are experimental data obtained according to the experimental example of FIG.
11 is a perspective view of a magnetostrictive transducer for forward shear horizontal wave conversion according to another embodiment of the present invention,
12 is a graph showing the relationship between the frequency and group speed of the lamb wave and the shear horizontal wave,
13 is a block diagram of a magnetostrictive transducer according to the prior art.

The terms and words used in the present specification and claims are to be construed in accordance with the technical idea of the present invention based on the principle that the inventor can properly define the concept of a term in order to explain its invention in the best way It should be interpreted as meaning and concept.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the magnetostrictive transducer for forward shear horizontal wave conversion according to the present invention.

1 is a perspective view of a magnetostrictive transducer for forward shear horizontal wave conversion according to an embodiment of the present invention, Figure 2 is a magnetostrictive transducer for forward shear horizontal wave conversion according to an embodiment of the present invention Is a perspective view of the separation.

Magnetostrictive transducer for forward shear horizontal wave conversion according to an embodiment of the present invention, the cylindrical wave guide having a circular cross section and the contact end in contact with the specimen; A magnetostrictive patch 20 of ferromagnetic material attached along the circumferential surface of the waveguide; A coil 30 wound on the wave guide to form a magnetic field passing through the wave guide; And a magnet 40 forming a static magnetic field in the circumferential direction of the waveguide.

As shown in FIG. 2 of the exploded perspective view, the waveguide 10 is a cylindrical member having a circular cross section and a contact end in contact with the specimen, and on the waveguide 10 a magnetostrictive material, which will be described later, made of a ferromagnetic material. Patch 20 is attached. The waveguide 10 is configured to have a circular cross section so that a circular static magnetic field can be formed by a magnet 40 to be described later, which is installed along its circumference. The contact end of the waveguide 10 may guide the shear horizontal wave generated by contact with the specimen toward the specimen or structure.

The waveguide 10 used in the present invention is a cylindrical member having a circular cross-sectional structure, which can be modified in various ways, and will be described with reference to FIG. 3. 3 is a perspective view showing various forms of the wave guide included in the magnetostrictive transducer according to the present invention.

As shown in Figure 3, the waveguide 10 in the present invention is configured to have a circular cross-sectional structure, the hollow as shown in (b) or a bar shape filled with the inside as shown in Figure 3 (a) It can be configured in a cylindrical shape.

In addition, as shown in (c) of FIG. 3, the waveguide 10 may be configured as a cylindrical member having a rod shape and a circular cross-section structure, and having a conical shape where the contact end with the specimen is narrowed down. . This may also be applied to the hollow cylinder shape as shown in (b) of FIG. In the case of the wave guide 10 including the conical structure, the contact end with the structure to be inspected can be more easily produced in a uniform symmetrical form, it can effectively generate a uniform shear horizontal wave over the entire direction.

Further, although not shown, the wave guide 10 may be formed with a sawtooth-shaped bent portion cut to diffusely reflect the reflected wave. Specifically, it is preferable that the rod-shaped waveguide 10 is cut such that the opposite end of the contact end in contact with the structure or the inner surface of the cylindrical waveguide 10 forms a serrated bent portion, Such a structure can reduce noise by inducing diffuse reflection and injection of the reflected wave.

In addition, although not shown, the waveguide 10 may further include a backing material configuration, and the backing material may damp the unnecessary reflection waves generated in the waveguide 10, thereby shearing horizontally. It can be configured to reduce the noise of the wave.

Additionally, the waveguide 10 may be contacted with the specimen by a liquid shear couplant. That is, in positioning the magnetostrictive transducer on the specimen, the contact end of the waveguide 10 may be configured to be in contact with the structure by a liquid shear couplant, and in some cases a coupler It may be configured to contact the specimen by a dry contact method that does not use.

The contact end of the wave guide 10 may have a shape other than the flat shape. In this regard, Figure 4 shows a pattern structure formed at the contact end of the wave guide included in the magnetostrictive transducer according to the present invention.

At least one annular groove having a different size may be formed at the contact end of the wave guide 10 based on the center point of the contact end. At this time, as shown in FIG. 4, a wave guide 11 having a diameter of lambda (lambda) is formed at the center of the contact end, and the annular groove 12 is formed at every lambda / 2 based on the wave guide 11 formed at the center. 14) and wave guides 13 and 15 may be alternately formed. Although not shown, a groove having a diameter of lambda (lambda) is formed at the center of the contact end, and may be alternately formed in the order of the waveguide and the annular groove every λ / 2 based on the groove formed at the center. . Here, the depth of the groove or the annular groove is not limited. However, if the depth is dug too deep, it may interfere with the ultrasonic wave transmission. Therefore, it is preferable to make the maximum depth to be lambda (lambda) and to make it shallower.

The formation of such a pattern structure is closely related to the frequency of the wave propagating in the specimen.

In general, when designing the coil 30, by controlling the distance and the frequency between the coil 30 it can generate a desired mode of ultrasonic waves. Depending on the frequency characteristics, ultrasonic travel distance, attenuation, and sensitivity to defects are different. Therefore, when designing a sensor such as a transducer, in general, an optimal frequency for obtaining a desired result is selected, and the coil spacing is determined accordingly. To design. The formula used at this time is as follows.

Where d is the line spacing of the coil 30, c is the wave velocity, f is the frequency of the wave, and λ is the wavelength of the wave propagated to the specimen.

Specifically, the speed c value is fixed because the speed of a typical shear wave in a metal such as iron is 3000 m / s. Then, this equation shows the relationship between the frequency (f) and the wavelength (λ), it can be seen that in order to select the desired frequency, the user needs to properly adjust the distance d between the coils (30).

At this time, increasing the distance d between coils can achieve the same effect as increasing the lambda (lambda) value, and the frequency to be used is lowered therefrom. Conversely, reducing the distance d between coils has the same effect as designing a smaller lambda (lambda) value, resulting in a higher frequency for use. That is, the lambda value may be adjusted by adjusting the distance d value between the coils, and a shear horizontal wave having a frequency desired by the user may be generated.

Magnetostrictive patch 20 in the present invention is made in the form of a patch to be attached along the circumferential surface of the wave guide 10, it is made of a ferromagnetic material. Here, as the magnetostrictive patch 20 of the ferromagnetic material, it is preferable that iron, nickel, cobalt or an alloy thereof is used.

Since the magnetostrictive patch 20 exhibits excellent magnetostriction, when the current is applied to the coil 30 to be described later to form an induction magnetic field around the magnetostrictive patch 20, the magnetostrictive patch 20 exhibits very deformable properties. In particular, when a static magnetic field and a dynamic magnetic field are vertically applied to the magnetostrictive patch 20 of the ferromagnetic material, forward shear horizontal waves are generated.

Specifically, the magnetostrictive patch 20 in one embodiment of the present invention is configured to be attached along the circumferential surface of the wave guide 10 described above, thereby the circumferential surface of the wave guide 10 by the magnet 40 The magnetic field formed along the coil 30 and the magnetic field formed to pass through the inside of the waveguide 10 may act to be perpendicular to each other. Through this, the magnetostrictive patch 20 is sheared (magnetized) from the excitation signal, and the shear deformation of the magnetostrictive patch 20 causes torsional vibration of the waveguide 10 described above. This torsional vibration causes shear horizontal waves across the structure.

However, the magnetostrictive patch 20 is not limited to the embodiment of FIGS. 1 and 2, but is shear deformation by a magnetic field, and the wave guide 10 may be torsionally vibrated by such shear deformation. The form attached to the guide 10 is sufficient.

In addition, in the present invention, in order to shear deformation the magnetostrictive patch 20, which is a ferromagnetic material, it is configured to include a coil 30 and a magnet 40 to form magnetic fields formed in the direction perpendicular to each other.

Coil 30 in the present invention is formed by winding along the circumferential surface of the wave guide 10 to form a magnetic field passing through the above-described wave guide 10 by the electromagnetic induction phenomenon.

In particular, the shear horizontal wave oscillation in the present invention is due to the interaction between the magnetic field induced by the coil 30 and the static magnetic field formed by the magnet 40 to the magnetostrictive patch 20, and thus the coil 30 is As shown in FIG. 1, the magnetostrictive patch 20 is preferably formed to match the position on the attached waveguide 10. In addition, the coil 30 may be formed in a shape in which the phase of the coil 30 adjacent to a predetermined interval is reversed so that a shear horizontal wave having a frequency desired by the user is generated. Although not shown here, the coil 30 may be electrically connected to a driving current for inducing a magnetic field, and may be a meander coil.

In addition, the magnet 40 in the present invention is a configuration for forming a magnetic field in the circumferential direction of the wave guide 10 described above for the shear deformation of the magnetostrictive patch 20, preferably in Figures 1 and 2 As in one embodiment, a plurality of rod-shaped permanent magnets may be arranged at regular intervals on the circumferential surface of the waveguide 10 in parallel with the axial direction of the waveguide.

In this regard, Figure 5 shows a cross-sectional view of a magnetostrictive transducer for the forward shear horizontal wave conversion according to an embodiment of the present invention, the static magnetic field formed by the magnet is shown on the cross-sectional view (Fig. Arrow). As shown in FIG. 5, the magnet 40 in one embodiment of the present invention is disposed in the circumferential direction so that the S and N poles face each other, and the magnetic field from each permanent magnet is a magnetostrictive material. Ride through the patch 20 to form a static magnetic field formed in the circumferential direction as indicated by the arrow.

The number and arrangement of the magnets are not limited to the same shape as in the embodiment of the present invention, and the configuration may be sufficient so that a circular magnetic field may be formed along the circumferential surface of the waveguide 10.

In addition, although FIG. 1 shows a magnetostrictive transducer in which the coil 30 is wound on the waveguide 10 and then the magnet 40 is installed, the magnet 40 is not related to this arrangement order. It is also possible to preferentially adopt a structure in which it is preferentially installed and then coiled.

6 is a conceptual diagram schematically illustrating propagation of shear horizontal waves in all directions of a structure in a magnetostrictive transducer for forward shear horizontal wave transformation according to an embodiment of the present invention.

The magnetostrictive transducer according to the present invention has a static magnetic field (arrow A) in the circumferential direction formed by the permanent magnet 40 and a dynamic magnetic field passing through the inside of the waveguide induced by the coil 30 through which the current I flows (arrow B). Shear deformation of the magnetostrictive patch 20, which is a ferromagnetic material. This shear deformation causes the torsional vibration of the waveguide 10 to generate a shear horizontal wave (arrow C) over the entire direction of the structure in contact with the waveguide 10, as shown in FIG.

The actual work of the magnetostrictive transducer for omni-directional shearing horizontal wave conversion according to the present invention manufactured to have such a configuration is as shown in the picture of Figure 7, the shear horizontal wave over the entire direction of the structure by such a magnetostrictive transducer An experiment for confirming whether is generated as in Figure 7 was performed, the data resulting from the experiment is the same as in Figures 8 to 10.

The magnetostrictive transducer for the forward shear horizontal wave transformation of FIG. 7 is manufactured in the same manner as the embodiment of FIG. 1, and the magneto-strained patch of iron-cobalt is attached to the cylindrical waveguide, and the magnetic The coil was wound at the position where the modified patch was attached, and then 4 permanent magnets were placed to form a circular magnetic field.

The experimental apparatus implemented using the magnetostrictive transducer for omni-directional shearing wave transformation has two magnetostrictive transducers for omnidirectional shearing-horizontal wave transformation as shown in FIG. 7, respectively, as a transmitter and a receiver. On the transmitter side, an impulse matching box including a pulser for supplying a desired signal and a passive element circuit for electric impedance matching was connected, and an impedance matching box, an amplifier for signal amplification, and an oscilloscope for signal measurement were connected to the receiver. An aluminum plate was selected as the measurement structure in this experiment, and the distance l _d between two magnetostrictive transducers was set to 133 mm.

In particular, in this experiment, the receiver side magnetostrictive transducers were moved with respect to a total of 12 positions as shown in FIG. The signals were measured sequentially.

In relation to this experiment, the shear wave velocity (vs) in the structural metal material in SH0 mode is 3000 Hz to 3200 Hz, so it is assumed that the median value is 3100 Hz, and the distance between two magnetostrictive transducers (l _d ) Calculating the arrival time (s) of the receiver side from the relationship with

That is, the arrival time s on the receiver side is determined to be about 42.9 ms, and this arrival time is also confirmed in the case of Fig. 8 which is a pattern of the detected result.

That is, the first detected signal in the graph of FIG. 8 is a signal generated by the electrical induction phenomenon of the receiver side by applying the signal to the transmitter side, the second signal is a signal applied from the actual transmitter side, the arrival time of such a signal Considering this is about 45 dB, it can be confirmed that this signal is due to shear horizontal wave.

This type of signal appears almost the same at the 12 points shown in FIG. 7, and the measurement results can be seen in the graph of FIG. 9.

Based on these results, the magnitudes of the signals measured at 12 points for each angle are shown in FIG. 10, and as can be seen from FIG. 10, almost uniform shear horizontal waves are generated in all directions. .

On the other hand, Figure 11 is a perspective view of a magnetostrictive transducer for forward shear horizontal wave conversion according to another embodiment of the present invention.

Magnetostrictive transducer for forward shear horizontal wave conversion according to another embodiment of the present invention, the cylindrical magnetostrictive patch 20 made of a ferromagnetic material and having a contact end in contact with the circular section and the specimen; A coil 30 wound on the magnetostrictive patch 20 to form a magnetic field passing through the magnetostrictive patch 20; And a magnet 40 forming a static magnetic field in the circumferential direction of the magnetostrictive patch 20.

Magnetostrictive patch 20 is a cylindrical member, made of a ferromagnetic material and configured to have a circular cross section and a contact end in contact with the specimen. The magnetostrictive patch 20 in another embodiment of the present invention may serve as a waveguide in one embodiment of the present invention. The magnetostrictive patch 20 can be produced using aluminum or stainless steel, and preferably made of iron cobalt alloy so as to have a thickness of about 0.15 mm.

At least one annular groove having a different size may be formed at the contact end of the magnetostrictive patch 20 based on the center point of the contact patch. 4, a magnetostrictive patch having a diameter of lambda (lambda) is formed at the center of the contact end, and a lambda is formed based on the magnetostrictive patch formed at the center of the contact end. Each (lambda) / 2 can be formed with alternating annular grooves and waveguides. On the contrary, a groove having a diameter of lambda (lambda) is formed at the center of the contact end, and the magnetostrictive patch and the annular groove may be alternately formed at each lambda (lambda) / 2 based on the groove formed at the center. This pattern structure is closely related to the frequency of the wave propagating in the specimen.

The magnetostrictive patch 20 in another embodiment of the present invention may also be configured to have a rod shape filled inside, a hollow cylindrical shape or a conical shape where the contact end with the structure is narrowed down, similar to that shown in FIG. Can be.

Furthermore, the magnetostrictive patch 20 in another embodiment of the present invention may further include a sawtooth-shaped bent portion cut to diffusely reflect the reflected wave or a backing material for damping the reflected wave.

In addition, in another embodiment of the present invention, the contact end side of the magnetostrictive patch 20 may be configured to be in contact with the structure by a liquid shear couplant, and in some cases dry without using a coupler It may be configured to contact the structure by a contact method.

Another configuration of the magnetostrictive transducer for forward shear horizontal wave conversion according to another embodiment of the present invention, the above-described configuration in the magnetostrictive transducer for forward shear horizontal wave conversion according to an embodiment of the present invention It can be easily understood by those skilled in the art that the present invention can be applied in the same manner to the present invention.

In the above, a specific preferred embodiment according to the present invention has been described. However, it is to be understood that the present invention is not limited to the above-described embodiments, and the above-described embodiments merely represent a part of various embodiments to which the principles of the present invention are applied. Those skilled in the art to which the present invention pertains may make various changes without departing from the spirit of the technical idea of the present invention described in the claims below.

10: waveguide 20: magnetostrictive patch
30: coil 40: magnet

Claims (16)

A cylindrical waveguide having a circular cross section and a contact end in contact with the specimen;
A magnetostrictive patch of ferromagnetic material attached along the circumferential surface of the waveguide;
A coil wound on the wave guide to form a magnetic field passing through the wave guide; And
Magnets to form a static magnetic field in the circumferential direction of the wave guide; magnetostrictive transducer for forward shear horizontal wave conversion comprising a.
The magnetostrictive transducer for forward shear horizontal wave transformation according to claim 1, wherein at least one annular groove is formed at a contact end of the waveguide.
The wave guide having a diameter of lambda (lambda) is formed at the center of the contact end, and the annular groove and the wave guide are alternately formed at each lambda (lambda) / 2 based on the wave guide formed at the center. Magnetostrictive transducer for forward shear horizontal wave conversion, characterized in that.
The method of claim 2, wherein a groove having a diameter of lambda (lambda) is formed at the center of the contact end, and the waveguide and the annular groove are alternately formed at each lambda (lambda) / 2 based on the groove formed at the center. Magnetostrictive transducers for forward shear horizontal wave conversion.
The magnetostrictive transducer for forward shear horizontal wave transformation according to claim 1, wherein the waveguide is formed in a rod shape or a cylinder shape.
The magnetostrictive transducer as claimed in any one of claims 1 to 5, wherein the waveguide is formed in a conical shape in which the contact end is narrowed down.
The magnetostrictive transducer as claimed in any one of claims 1 to 5, wherein the waveguide has a sawtooth-shaped bent portion cut in order to diffusely reflect reflected waves.
A cylindrical magnetostrictive patch made of ferromagnetic material and having a circular end face and a contact end in contact with the specimen;
A coil wound on the magnetostrictive patch to form a magnetic field passing through the magnetostrictive patch; And
Magnets to form a static magnetic field in the circumferential direction of the magnetostrictive patch; magnetostrictive transducer for forward shear horizontal wave conversion comprising a.
9. The magnetostrictive transducer for omni-directional shearing wave transformation according to claim 8, wherein at least one annular groove is formed at the contact end of the magnetostrictive patch.
The method of claim 9, wherein a groove having a diameter of lambda (lambda) is formed at the center of the contact end, and the magnetostrictive patch and the annular groove are alternately formed at each lambda (lambda) / 2 based on the groove formed at the center. A magnetostrictive transducer for omni-directional shearing wave transformation.
The magnetostrictive patch having a diameter of lambda (lambda) is formed at the center of the contact end, and the annular groove and the magnetostrictive patch are alternated every lambda (lambda) / 2 based on the magnetostrictive patch formed at the center. Magnetostrictive transducer for forward shear horizontal wave conversion, characterized in that formed by going.
9. The magnetostrictive transducer for forward shear horizontal wave transformation according to claim 8, wherein the magnetostrictive patch is formed in a rod or cylinder shape.
13. The magnetostrictive transducer of claim 8, wherein the magnetostrictive patch is formed in a conical shape in which the contact end is narrowed down.
The magnetostrictive transducer according to any one of claims 8 to 12, wherein the magnetostrictive patch has a sawtooth-shaped bent portion that is cut to diffusely reflect the reflected wave.
9. The magnetostrictive transducer of claim 1 or 8, wherein the magnet consists of a plurality of permanent magnets arranged with magnetic poles to form a circular magnetic field passing through the magnetostrictive patch.
9. The magnetostrictive transducer of claim 1 or 8, further comprising a backing material for damping treatment.

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