close

Вход

Забыли?

вход по аккаунту

?

JP2002095088

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2002095088
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
ultrasonic transmitting / receiving element and a nondestructive inspection method of an object
using the same, and more specifically, an ultrasonic wave can be transmitted / received utilizing
a magnetostrictive effect. The present invention relates to a novel magnetostrictive ultrasonic
element and a nondestructive inspection method for inspecting an internal abnormality of an
object using the same.
[0002]
2. Description of the Related Art In recent years, a nondestructive inspection method using
ultrasonic waves is known as one of nondestructive inspection methods for diagnosing
deterioration of the internal structure of an object made of metal, concrete or the like.
Piezoelectric ultrasonic sensors are generally and widely used as elements for transmitting or
receiving the ultrasonic waves.
[0003]
However, ultrasonic sensors with relatively low resolution, such as conventional piezoelectric
sensors, can not efficiently detect the position and size of defects inside the object under test or
material deterioration with high accuracy. was there. In particular, in the case of a non-testing
04-05-2019
1
object made of a metal having coarse crystal grains and uneven distribution, the attenuation of
ultrasonic waves and the echo as background noise occur, and the SN ratio is significantly
reduced.
[0004]
As a solution to the problems associated with such ultrasonic sensors, the present inventors have
already developed an electromagnetic ultrasonic element, which is disclosed in Japanese Patent
Application Nos. 10-363453 and 10-363454. Has been published.
[0005]
The transmission system of this electromagnetic ultrasonic element generates an eddy current in
the metal, generates an oscillating Lorentz force in the metal by the interaction between the eddy
current and the applied magnetic field, and the oscillating Lorentz force It generates and
propagates ultrasonic waves.
Further, in this reception method, an eddy current is generated by ultrasonic vibration of a metal,
and a change in magnetic flux due to the eddy current is detected by a high performance
magnetic head. That is, it can be said that the electromagnetic ultrasonic method is a method of
transmitting and receiving ultrasonic waves via eddy currents in metal.
[0006]
As described above, the electromagnetic ultrasonic element is a unique method, and research and
development for practical use in various applications are continued, particularly in
nondestructive testing. It has been found to be effective. However, as described above, the
electromagnetic ultrasonic wave system is limited to a metal to be inspected, and has a limitation
that it can not be applied to a nonconductive non-inspection body such as concrete.
[0007]
[0007] On the other hand, as reported in recent years, there are frequent occurrences of
concrete fragments falling off in a railway tunnel. This incident is not a problem limited to
04-05-2019
2
railway tunnels, but a problem of the entire concrete structure. Concrete structures such as
tunnels, buildings, dams, and highways will surely have fatigue failure. Technology development
to prevent this accident by detecting this fatigue failure in advance is an urgent issue.
[0008]
As described above, there is awaited the emergence of a new technology capable of precisely
realizing nondestructive inspection of non-conductive objects which can not be detected by the
electromagnetic ultrasonic method, including nondestructive inspection of concrete structures.
Therefore, an object of the present invention is to provide a novel ultrasonic element capable of
transmitting and receiving ultrasonic waves not only to a conductive test object but also to a nonconductive test object, and at the same time using this ultrasonic element. The purpose is to
realize the nondestructive inspection method.
[0009]
SUMMARY OF THE INVENTION According to the first aspect of the present invention, there is
provided a magnetostrictive ring body in which a magnetostrictive material is annularly formed,
and a magnetostrictive ring body for forming a DC bias magnetic field inside the magnetostrictive
ring body. And a signal coil wound around the magnetostrictive ring body to detect a fluctuating
magnetic field generated through the magnetostrictive effect of the magnetostrictive ring body
through ultrasonic vibration of the magnetostrictive ring body, and ultrasonic waves generated
by the signal coil The reception sensitivity is adjusted by the DC bias magnetic field, and the
magnetostrictive ring body is brought into contact with the surface of the test object to transmit
ultrasonic vibration of the surface of the test object to the magnetostrictive ring body and occur
inside the magnetostrictive ring body. The magnetostrictive ultrasonic element is characterized in
that the vibrational distortion is converted into a variable magnetic field by the magnetostrictive
effect, and the variable magnetic field is detected by the signal coil to receive an ultrasonic wave.
[0010]
According to a second aspect of the present invention, there is provided a magnetostrictive ring
body in which a magnetostrictive material is annularly formed, a bias coil wound around the
magnetostrictive ring body to form a DC bias magnetic field inside the magnetostrictive ring
body, and A signal coil is wound around the magnetostrictive ring body to ultrasonically vibrate
the magnetostrictive ring body by applying a variable magnetic field to the magnetostrictive ring
body, and the ultrasonic wave transmission sensitivity by the signal coil is set to the DC bias
magnetic field The alternating current is flowed through the signal coil to generate a fluctuating
magnetic field inside the magnetostrictive ring body, ultrasonic vibration is caused to occur in
04-05-2019
3
the magnetostrictive ring body through the magnetostrictive effect by the fluctuating magnetic
field, and the magnetostrictive ring body is inspected This magnetostrictive ultrasonic element is
characterized in that ultrasonic waves are emitted while being in contact with the body surface.
[0011]
The invention of claim 3 is the magnetostrictive ultrasonic element according to claim 1 or 2,
wherein the average circumference of the magnetostrictive ring body is set shorter than the
wavelength of ultrasonic waves to be received or transmitted.
[0012]
The magnetostrictive ring according to claim 1 or 2, wherein the fixing means is provided on the
outer peripheral surface of the magnetostrictive ring body, and the fixing means is engaged with
the surface of the test object to fix the magnetostrictive ring body. It is an ultrasonic element.
[0013]
According to the fifth aspect of the present invention, a free rotation mechanism is provided on
the inner peripheral portion of the magnetostrictive ring so that the magnetostrictive ring is in
rolling contact when brought into contact with the surface of the test object traveling the
magnetostrictive ring. It is a magnetostrictive ultrasonic element according to claim 1 or 2
disposed.
[0014]
According to the sixth aspect of the present invention, ultrasonic waves are made to enter the
inside of the object to be inspected, and ultrasonic waves propagating reflecting the internal
structure of the object to be inspected are received on the surface of the object to be inspected.
In a nondestructive inspection method for inspecting an internal abnormality, a magnetostrictive
ring body formed by annularly forming a magnetostrictive material is disposed in contact with
the surface of an inspection object, a bias coil is wound around the magnetostrictive ring body,
and the inside of the magnetostrictive ring body At the same time, a direct current bias magnetic
field is formed, and at the same time, a signal coil is wound around the magnetostrictive ring
body, the ultrasonic wave receiving sensitivity by this signal coil is adjusted by the direct current
bias magnetic field, and the magnetostrictive ring body is ultrasonically vibrated The ultrasonic
vibration generates a fluctuating magnetic field through the magnetostrictive effect of the
magnetostrictive ring body by the ultrasonic vibration, and the fluctuating magnetic field is
detected by the signal coil to receive the ultrasonic wave, and the ultrasonic wave is received by
the reception ultrasonic wave It is a non-destructive inspection method using a magnetostrictive
ultrasonic device characterized by inspecting the parts abnormality.
04-05-2019
4
[0015]
According to the seventh aspect of the present invention, ultrasonic waves are made to enter the
inside of the object to be inspected, and ultrasonic waves propagating reflecting the internal
structure of the object to be inspected are received on the surface of the object to be inspected.
In a nondestructive inspection method for inspecting an internal abnormality, a magnetostrictive
ring body formed by annularly forming a magnetostrictive material is disposed in contact with
the surface of an inspection object, a bias coil is wound around the magnetostrictive ring body,
and the inside of the magnetostrictive ring body At the same time, a signal coil is wound around
the magnetostrictive ring body, and the ultrasonic wave transmission sensitivity by this signal
coil is adjusted by the DC bias magnetic field, and the ultrasonic wave region is formed inside the
magnetostrictive ring body by this signal coil. A fluctuating magnetic field is generated, and the
fluctuating magnetic field causes the magnetostrictive ring to ultrasonically vibrate through the
magnetostrictive effect of the magnetostrictive ring, and the ultrasonic vibration propagates an
ultrasonic wave to the inside of the subject to be inspected. It is a non-destructive inspection
method using a magnetostrictive ultrasonic element, characterized in that to inspect the internal
abnormalities.
[0016]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a result of intensive research
into a method for generating and propagating ultrasonic waves inside a test object without
distinction between conductive and non-conductive, the present inventors have studied
mechanical ultrasonic waves. It was considered necessary to bring a vibrating object, that is, an
ultrasonic vibrator into contact with the test object, and to introduce ultrasonic waves into the
test object by mechanical transmission of the ultrasonic vibration.
[0017]
Conventionally, there is a piezoelectric element as an ultrasonic vibrator which has been
developed from this point of view.
The piezoelectric element utilizes the property of mechanical expansion and contraction of the
piezoelectric material when an alternating voltage is applied.
However, as mentioned above, it has been found that piezoelectric materials have various
04-05-2019
5
disadvantages in nondestructive testing for accuracy and other reasons.
[0018]
Therefore, as a result of intensive research conducted by the present inventors to construct an
ultrasonic vibrator based on another principle, a material exhibiting a magnetostrictive effect,
that is, a magnetostrictive material is suitable as the ultrasonic vibrator. Came to find out.
[0019]
It has been found that a ferromagnetic material has an infinite number of magnetic domains
inside, and the magnetic domains are distorted in the direction of spontaneous magnetization.
When an external magnetic field is applied to this ferromagnetic material, the direction of
magnetization is rotated by the external magnetic field, and the direction and magnitude of strain
also change.
This is the magnetostrictive effect.
That is, the phenomenon in which the ferromagnetic material is slightly deformed by
magnetization is the magnetostrictive effect, and conversely, it is also a reversible dynamic
magnetic phenomenon in which the magnetic flux changes according to the degree of the
deformation when the ferromagnetic material is deformed.
[0020]
Therefore, the main point of the present invention is that the ultrasonic element is made of a
magnetostrictive material, and the ultrasonic element is transmitted and received by mechanical
transmission while being in contact with the surface of the object to be inspected.
That is, in order to emit an ultrasonic wave, an oscillating magnetic field may be applied to
vibrate the ultrasonic element with the magnetostrictive effect, and the ultrasonic vibration may
be mechanically transmitted to the object to be inspected.
04-05-2019
6
Further, in order to receive an ultrasonic wave, the surface vibration of the object to be inspected
may be mechanically transmitted to the ultrasonic element, and an oscillating magnetic field
generated by the magnetostrictive effect may be converted into an ultrasonic signal.
[0021]
The magnetostrictive material that can be used in the present invention is a material exhibiting a
magnetostrictive effect such as a ferromagnetic material, and is made of, for example, a metal, an
alloy, a metal-containing compound, or the like.
More specifically, it includes iron, cobalt, nickel, their alloys, alferro alloys, ferrites, and other
known magnetostrictive materials.
[0022]
Embodiments of a magnetostrictive ultrasonic element and a nondestructive inspection method
using the same according to the present invention will be described in detail below with
reference to the drawings.
FIG. 1 is a front view showing a first embodiment of a magnetostrictive ultrasonic element
according to the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG.
As shown in FIGS. 1 and 2, the magnetostrictive ultrasonic element 2 includes a magnetostrictive
ring 4 having a magnetostrictive material formed in an annular shape, a support rod 6 for fixing
the magnetostrictive ring 4 in the diameter direction, and the support rod. It is comprised from
the support plate 8 on which 6 is set up stably.
[0023]
The top 4a of the magnetostrictive ring body 4 is configured to project upward from the top 6a
of the support rod 6 by a step ΔH. This is to maintain the transmission / reception sensitivity of
ultrasonic waves well by preventing the support crest 6a from coming into contact with the
04-05-2019
7
surface of the object under inspection when the magnetostrictive ring top 4a is brought into
contact with the surface of the inspection object.
[0024]
On the magnetostrictive ring body 4, a bias coil 10 indicated by a dotted line and a signal coil 12
indicated by a solid line are wound. A direct current voltage is applied to the bias coil 10 to flow
a direct current to generate a direct current bias magnetic field in the magnetostrictive ring body
4. The magnitude of the DC bias magnetic field is adjusted to set the sensitivity of the
magnetostrictive effect well.
[0025]
The signal coil 12 is an application coil 12a for passing an alternating current when transmitting
an ultrasonic wave, and is a detection coil 12b for detecting an AC magnetic field when receiving
an ultrasonic wave. In ultrasonic wave transmission, when an alternating current flows through
the signal coil 12 (that is, the application coil 12a), an alternating magnetic field is generated in
the magnetostrictive ring body 4, and the magnetostrictive ring body 4 ultrasonically vibrates
due to the magnetostrictive effect. In general, a sine wave is used as an alternating current at the
time of application, but a rectangular wave, a triangular wave, a sawtooth wave, another regular
wave, or an irregular wave may be used.
[0026]
In ultrasonic wave reception, when the magnetostrictive ring body 4 is subjected to ultrasonic
vibration, its mechanical vibration is converted to an alternating current by the magnetostrictive
effect of the magnetostrictive ring body 4 and this alternating magnetic field is converted by the
signal coil 12 (that is, the detection coil 12b). Convert to alternating current. The vibration on the
surface of the object under inspection includes not only regular vibration but also irregular
vibration, and the detected alternating current also includes regular current and irregular
current.
[0027]
04-05-2019
8
FIG. 3 is a schematic view showing a desirable condition of the average circumference of the
magnetostrictive ring 4. As shown in FIG. When the magnetostrictive ring body 4 is subjected to
ultrasonic vibration, the magnetostrictive ring body is naturally deformed. At this time, when the
average circumference D of the magnetostrictive ring body 4 indicated by the alternate long and
short dash line is shorter than the wavelength λ of the ultrasonic wave, that is, D <λ, the
deformation of the magnetostrictive ring body 4 remains in local deformation. In the case of local
deformation, the generated magnetic flux is also generated stably without being canceled, and
ultrasonic waves can be reliably received.
[0028]
FIG. 4 is a schematic view showing the case where the magnetostrictive ring body is deformed
symmetrically. When the average circumference D is longer than the wavelength λ (D ≧ λ), a
standing wave may be formed in the circumferential direction of the magnetostrictive ring 4. In
detail, when the condition of D = mλ (m is a natural number) is satisfied, a standing wave is
formed in the magnetostrictive ring body 4 and this standing wave is laterally symmetrical
deformed. Internally cancel each other, and the resultant signal flux becomes zero. FIG. 4 shows a
situation where the left magnetic flux B1 due to the left deformation and the right magnetic flux
B2 due to the right deformation cancel each other. In this case, the resultant magnetic flux
becomes zero and the ultrasonic wave can not be received.
[0029]
The above-mentioned standing wave condition is important when receiving ultrasonic waves, and
does not matter when transmitting. When an alternating current flows in the application coil 12a,
an alternating magnetic field is generated in the magnetostrictive ring body 4, but all of the
alternating magnetic fields are generated in the same direction, and therefore they do not cancel
each other inside the magnetostrictive ring body 4. .
[0030]
FIG. 5 is a schematic block diagram of an ultrasonic wave receiving test by the magnetostrictive
ultrasonic element. The magnetostrictive ultrasonic element 2 is disposed so as to bring the top 4
a of the magnetostrictive ring body 4 into contact with the vibrating plate 14, and this vibrating
04-05-2019
9
plate 14 is forcedly vibrated by the vibration device 16 at the frequency of the ultrasonic region.
A direct current flows from the current control circuit 18 to the bias coil 10, and the signal coil
12 (that is, the detection coil 12 a) is connected to the signal detection circuit 20.
[0031]
FIG. 6 is a time chart of the magnetic flux generated inside the magnetostrictive ring. The DC bias
magnetic field B0 is applied by the DC current of the bias coil 10, and the signal magnetic field
.DELTA.B is a signal magnetic field generated internally by the magnetostrictive effect of the
magnetostrictive ring 4 due to ultrasonic vibration. Depending on the state of vibration, the
signal magnetic field ΔB may be a regular signal or an irregular signal. In FIG. 6, ΔB is depicted
as an irregular signal. A combined magnetic field B of a DC bias magnetic field B0 and a signal
magnetic field ΔB is generated in the magnetostrictive ring 4.
[0032]
FIG. 7 is a time chart of the detected current detected by the signal coil. When the signal
magnetic field ΔB which is the vibration component is generated, the signal current ΔI is
induced in the signal coil 12 by electromagnetic induction. The signal current ΔI is detected by
the signal detection circuit 20 and displayed on a display (not shown).
[0033]
FIG. 8 is a diagram showing the relationship between the DC bias magnetic field B0 and the
signal magnetic field ΔB. As described above, when the magnetostrictive ring 4 is subjected to
ultrasonic vibration, the signal magnetic field ΔB is generated due to the magnetostrictive effect.
In order to detect this signal magnetic field ΔB accurately, the amplitude of the signal magnetic
field ΔB should be large. That is, the magnitude of the amplitude of the signal magnetic field ΔB
depends on the DC bias magnetic field B0, and the relationship between the detection
sensitivities is shown in FIG.
[0034]
04-05-2019
10
This relationship depends on the physical properties of the magnetostrictive material, and FIG. 8
shows only its general tendency. In order to enhance the detection sensitivity of the
magnetostrictive ultrasonic element 2, it is important to find a condition under which the
oscillating magnetic field ΔB becomes maximum while adjusting the magnitude of the DC bias
magnetic field B0.
[0035]
FIG. 9 is a receiving block diagram using a magnetostrictive ultrasonic element as an ultrasonic
wave receiver. The ultrasonic transmitter 22 and the magnetostrictive ultrasonic element 2 are
disposed on the surface of the inspection object 24 separated by a predetermined distance L. The
ultrasonic transmitter 22 is composed of a piezoelectric transmitter or an electromagnetic
ultrasonic transmitter. Although the piezoelectric transmitter acts on either the conductor or the
nonconductor under test, the electromagnetic ultrasonic transmitter acts only in the case of a
conductor. A transmitter 26 is connected to the ultrasonic transmitter 22.
[0036]
On the other hand, the magnetostrictive ultrasonic element 2 is connected to a preamplifier 28, a
receiver 30 and a receiver display 32. When the ultrasonic transmitter 22 is ultrasonically
vibrated by the transmission device 26, the ultrasonic vibration is propagated to the inspection
object 24 in the direction of the arrow a. The ultrasonic vibration is detected by the
magnetostrictive ultrasonic element 2 and preamplified by the preamplifier 28, and then
received by the receiver 30. This signal waveform is displayed on the reception display device
32.
[0037]
FIG. 10 is a waveform diagram of received ultrasonic waves by the receiving display apparatus.
The upper waveform W1 shows the case where the separation distance L is L = 40 mm, and the
lower waveform W2 corresponds to the case where L = 70 mm. The transmission time τ of the
upper waveform W1 is τ = 17 (μs), and that of the lower waveform W2 is τ = 29 (μs). Sound
velocity V = V? When calculated by τ, W = V2 = 2.4 (km / s) is obtained from W1 and V2 is also
obtained = 2.4 (km / s). Therefore, since the same sound velocity was obtained from both, it
became clear that the magnetostrictive ultrasonic element according to the present invention can
04-05-2019
11
be used for precise measurement as an ultrasonic wave receiver.
[0038]
FIG. 11 is a transmission configuration diagram using a magnetostrictive ultrasonic element as
an ultrasonic wave transmitter. A transmitting device 26 is connected to the magnetostrictive
ultrasonic element 2 and is brought into contact with the surface of the inspection object 24
while ultrasonically vibrating the magnetostrictive ultrasonic element 2. The ultrasonic waves
propagate inside the object 24 in the direction of the arrow b and are detected by the ultrasonic
receiver 23. The ultrasonic wave receiver 23 is composed of a piezoelectric receiver or an
electromagnetic ultrasonic wave receiver.
[0039]
The ultrasonic receiver 23 is connected to the preamplifier 28, the receiver 30 and the receiver
display 32. Although the reception waveform obtained by the reception display device 32 is not
shown, a signal waveform with high accuracy is obtained as in FIG. Satisfactory results were also
obtained for the measurement of the propagation velocity of ultrasound. Therefore, it has
become clear that the magnetostrictive ultrasonic element according to the present invention is
also used as an ultrasonic wave transmitter.
[0040]
FIG. 12 is a front view showing a second embodiment of the magnetostrictive ultrasonic element
according to the present invention. The same reference numerals as in FIG. 1 denote the same
parts, and a description thereof will be omitted, and different parts will be described. The feature
of this embodiment is that the fixing means 5 is formed near the top 4 a of the magnetostrictive
ring 4. The fixing means 5 engages with the surface of the inspection object 24 and does not
cause positional deviation even if the magnetostrictive ring body 4 is subjected to ultrasonic
vibration. Therefore, the separation distance between the ultrasonic transmitter and the
ultrasonic receiver does not change, and the accuracy of ultrasonic measurement can be
improved.
[0041]
04-05-2019
12
The specific structure of the fixing means 5 may be, for example, a projection which pierces the
surface, an adhesive substance fixed to the surface, or a known structure such as an engaging
fastener.
[0042]
FIG. 13 is a front view showing a magnetostrictive ultrasonic element according to a third
embodiment of the present invention.
The same reference numerals as in FIG. 1 denote the same parts, and a description thereof will be
omitted, and different parts will be described. A free rotation mechanism 7 is provided at the
central portion of the magnetostrictive ring body 4, and when the test body 24 travels in the
direction of arrow c, the magnetostrictive ring body 4 is rotated on the surface of the test body
24 in the direction of arrow d. It contacts and measures an ultrasonic measurement in this rolling
state. The specific structure of the free rotation mechanism 7 can use a known mechanism such
as a bearing.
[0043]
FIG. 14 is a schematic explanatory view of a nondestructive inspection method of an object to be
inspected using a magnetostrictive ultrasonic element. In this embodiment, magnetostrictive
ultrasonic elements according to the present invention are used for transmitting and receiving
ultrasonic waves. That is, the magnetostrictive ultrasonic transducer element 2a for transmission
is fixed on the surface of the inspection object 24 by the fixing means 5, and the magnetostrictive
ultrasonic transducer element 2b for reception is arranged movably separately from this.
[0044]
There is an abnormal part 24a in the inspection object 24, and in order to detect this position, an
ultrasonic wave is made incident on the inside of the inspection object 24 from the transmitting
magnetostrictive ultrasonic element 2a. Once the material of the inspection object 24 is
determined, the propagation speed of the ultrasonic wave is determined. The transmission paths
of the ultrasonic waves received by the receiving magnetostrictive ultrasonic element 2b are
mainly three paths of a direct arrival path P1, an abnormal part reflection path P2 and a back
04-05-2019
13
surface reflection path P3.
[0045]
Since the distance between the transmitting magnetostrictive ultrasonic element 2a and the
receiving magnetostrictive ultrasonic element 2b and the thickness of the inspection object 24
are fixed, the reception time of the ultrasonic wave passing through the direct delivery path P1
and the back surface reflection path P3. τ1 and τ3 can be calculated in advance. The reception
time is an elapsed time of ultrasonic waves from transmission to reception. If the abnormal
portion 24a is present, the abnormal portion reflection path P2 should be present, and the
reception time τ2 satisfies the relationship of τ1 <τ2 <τ3.
[0046]
While moving the position of the receiving magnetostrictive ultrasonic element 2b, an abnormal
part reflected ultrasonic wave located between τ1 and τ3 is searched. If τ2 satisfying τ1
<τ2 <τ3 can be found, it means that there is an abnormal portion 24a inside the inspected
object 24. Thus, the nondestructive inspection of the inspection object 24 is performed.
[0047]
The present invention is not limited to the above embodiment, and includes various modifications
and design changes within the technical scope without departing from the technical concept of
the present invention.
[0048]
According to the invention of claim 1, a novel and original magnetostrictive ultrasonic receiving
element can be realized, and the magnetostrictive ring is brought into contact with the surface of
the inspection object while adjusting the DC bias magnetic field. The ultrasonic vibration of the
object to be inspected can be detected with high sensitivity as the oscillating magnetic field or
the oscillating current of the magnetostrictive ring body only by making
[0049]
According to the second aspect of the present invention, a novel and unique magnetostrictive
ultrasonic transducer for transmission can be realized, and while the transmission sensitivity is
04-05-2019
14
favorably adjusted by the DC bias magnetic field, an AC current is caused to flow through the
signal coil to generate a magnetostrictive ring. Ultrasonic waves can be emitted simply by
ultrasonically vibrating the body and bringing the magnetostrictive ring body into contact with
the test object.
[0050]
According to the invention of claim 3, by setting the average circumference of the
magnetostrictive ring body shorter than the wavelength of the ultrasonic wave, the
magnetostrictive ring body is prevented from forming a standing wave, and the local oscillation
of the magnetostrictive ring body is achieved. Can be realized to realize a magnetostrictive
ultrasonic element capable of efficiently receiving or transmitting ultrasonic waves.
[0051]
According to the invention of claim 4, since the fixing means is provided on the outer peripheral
surface of the magnetostrictive ring body, the magnetostrictive ring body can be fixed on the
surface of the inspection object without positional deviation, and as a result, ultrasonic waves
Since the transmission point or the reception point of can be determined at one point, a
magnetostrictive ultrasonic element with high positional accuracy can be realized.
[0052]
According to the fifth aspect of the present invention, since the free rotation mechanism is
provided on the inner peripheral portion of the magnetostrictive ring body, the magnetostrictive
ring body can be brought into rolling contact with the surface of the subject to be inspected. A
magnetostrictive ultrasonic element that can be applied to a test object can be realized.
[0053]
According to the invention of claim 6, the magnetostrictive ring is brought into contact with the
surface of the object to be inspected, the receiving sensitivity is favorably adjusted by the DC bias
magnetic field, and the ultrasonic wave propagating inside the object to be inspected is It is
possible to efficiently detect an abnormal part inside the object under inspection and from the
propagation abnormality of the received ultrasonic signal.
[0054]
According to the seventh aspect of the present invention, the magnetostrictive ring is brought
into contact with the surface of the object to be inspected, the transmission sensitivity is
favorably adjusted by the DC bias magnetic field, and ultrasonic waves are emitted inside the
04-05-2019
15
object to be inspected. This ultrasonic wave can be propagated to the inside of the subject to
efficiently detect the internal abnormality of the subject.
[0055]
Brief description of the drawings
[0056]
1 is a front view showing a first embodiment of the magnetostrictive ultrasonic element
according to the present invention.
[0057]
2 is a cross-sectional view taken along line AA of FIG.
[0058]
3 is a schematic view showing a desirable condition of the average circumference of the
magnetostrictive ring body.
[0059]
4 is a schematic view showing a case where the magnetostrictive ring body is deformed
symmetrically.
[0060]
5 is a schematic configuration diagram of an ultrasonic wave receiving test by the
magnetostrictive ultrasonic element.
[0061]
6 is a time chart of the magnetic flux generated inside the magnetostrictive ring body.
[0062]
7 is a time chart of the detected current detected by the signal coil.
[0063]
04-05-2019
16
8 is a diagram showing the relationship between the DC bias magnetic field B0 and the signal
magnetic field ΔB.
[0064]
9 is a reception configuration diagram using a magnetostrictive ultrasonic element as an
ultrasonic wave receiver.
[0065]
10 is a waveform diagram of the reception ultrasound by the reception display device.
[0066]
11 is a transmission configuration diagram using a magnetostrictive ultrasonic element as an
ultrasonic wave transmitter.
[0067]
12 is a front view showing a second embodiment of the magnetostrictive ultrasonic element
according to the present invention.
[0068]
13 is a modified front view showing a third embodiment of the magnetostrictive ultrasonic
element according to the present invention.
[0069]
14 is a schematic explanatory view of a nondestructive inspection method of the object to be
inspected using the magnetostrictive ultrasonic element.
[0070]
Explanation of sign
[0071]
2 is a magnetostrictive ultrasonic element, 2a is a magnetostrictive ultrasonic element for
transmission, 2b is a magnetostrictive ultrasonic element for reception, 4 is a magnetostrictive
ring body, 4a is a magnetostrictive ring top, 5 is a fixing means, 6 is a support rod, 7 is 6a is a
04-05-2019
17
support crest, 8 is a support plate, 10 is a bias coil, 12 is a signal coil, 12a is an application coil,
12b is a detection coil, 14 is an excitation plate, 16 is an excitation device, 18 is a current Control
circuit, 20: signal detection circuit, 22: ultrasonic transmitter, 23: ultrasonic receiver, 24: test
object, 24a: abnormal part, 26: transmitter, 28: preamplifier, 30: receiver, 32 Reception display
device, B1: left magnetic flux, B2: right magnetic flux, D: average circumference, B0: DC bias
magnetic field, ΔB: fluctuating magnetic field, ΔI: detection current, P1: direct path, P2:
abnormal part reflection path, P3: Back surface reflection path, W1 is an upper waveform, W2 is
a lower waveform.
04-05-2019
18
Документ
Категория
Без категории
Просмотров
0
Размер файла
30 Кб
Теги
jp2002095088
1/--страниц
Пожаловаться на содержимое документа