KR20220026954A - Apparatus and method for nonlinear ultrasonic inspection using phased array - Google Patents

Abstract

A nonlinear ultrasound inspection apparatus comprises: a transducer including one receiving vibrator located in a central region and transmitting vibrators located on the left and right sides of the receiving vibrator, respectively; a controller for controlling a time-delayed ultrasonic signal for the same to be transmitted to each of the transmitting vibrators based on the locations of the transmitting vibrators; and a diagnostic device for quantifying fundamental and secondary harmonic components received from the receiving vibrator in response to the ultrasonic signal applied by the transmitting vibrator to one surface of an object to be tested to diagnose micro-deterioration of the object to be tested, wherein the secondary harmonic component represents only the secondary harmonic component generated by the fundamental component reflected from the bottom surface of the object to be tested. One embodiment of the present invention is to provide a technique for inspecting micro-deterioration of an object to be tested based on a signal reflected by passing an ultrasonic wave of a fundamental frequency through the object to be tested by applying a time delay to a phased array probe.

Description

Nonlinear ultrasound inspection apparatus and method using phased array technique

A nonlinear ultrasound examination technique using a phased array technique is provided.

Ultrasonic non-destructive testing methods generally test by using reflection, diffraction, refraction, etc. due to the difference in acoustic impedance between materials and defects using linear ultrasonic characteristics. However, it is difficult to diagnose a small defect or a micro-deterioration phenomenon due to the detection limit of the defect detection technology using such a linear ultrasonic characteristic. Accordingly, in order to measure cracks, interfaces, and micro-deterioration corresponding to microscopic phenomena of materials, a technology using the non-linear characteristics of ultrasonic waves has been developed and used.

Accordingly, a general nonlinear technique is a method using a property that a fundamental wave component propagating a material is distorted by a nonlinear elastic property in the material and a harmonic component is generated. In detail, it is measured using the transmission method using two probes so that the harmonic components generated while propagating the test object can be measured sensitively.

However, if access to both sides of the object is not possible, the examination itself is difficult. To this end, it was attempted to measure the nonlinear parameter from one side of the test object using one probe, but the harmonic component generated as it is reflected from the base of the test object and returned is out of phase with the harmonic component generated during initial propagation. Accordingly, since the received harmonic component is close to zero, it is difficult to precisely examine the nonlinear characteristics of the material.

Therefore, there is a need for a method capable of inspecting the integrity or micro-deterioration of an object by precisely measuring the amplitude of harmonic components generated in the process of transmitting and propagating ultrasonic waves of a fundamental frequency from one side of the object.

As a related prior document, Korean Patent Registration No. 2116051 discloses "a pulse echo type nonlinear inspection apparatus using an array type ultrasonic sensor".

Korean Patent No. 2116051

One embodiment of the present invention is to provide a technique for examining micro-deterioration of a test object based on a signal reflected by transmitting ultrasonic waves of a fundamental frequency by applying a time delay to a phased array probe.

In addition to the above problems, the embodiment according to the present invention may be used to achieve other problems not specifically mentioned.

A nonlinear ultrasound inspection apparatus according to an embodiment of the present invention provides a transducer including one receiving vibrator positioned in a central region and transmitting vibrators positioned on the left and right sides of the receiving vibrator, respectively, based on the positions of the transmitting vibrators. A controller that controls to transmit time-delayed ultrasonic signals for each, and quantifies the fundamental and second harmonic components received from the receiving vibrator in response to the ultrasonic signal applied by the transmitting vibrator to one surface of the test object a diagnostic device for diagnosing deterioration, wherein the second harmonic component represents only the second harmonic component generated by the fundamental wave component reflected from the bottom surface of the test object

A nonlinear ultrasound inspection method according to an embodiment of the present invention includes, in a nonlinear ultrasound inspection apparatus, arranging a transducer in which one receiving vibrator and one transmitting vibrator are arranged at a predetermined interval on one surface of a test object, based on a preset order Transmitting vibrators sequentially apply an ultrasonic signal toward the bottom of the test object. The applied ultrasonic signal is focused on the bottom of the test object, and the fundamental and second harmonic components that are reflected from the bottom of the test object are received. Receiving from the vibrator, and quantifying the fundamental and second harmonic components as nonlinear parameters, wherein the second harmonic component represents only the second harmonic component generated by the fundamental component reflected from the bottom surface.

According to an embodiment of the present invention, it is possible to quantitatively and precisely measure the nonlinear elastic properties of the material of the test object from one side of the test object, and through this, it is possible to precisely inspect the micro-deterioration of the material.

In addition, according to an embodiment of the present invention, by performing an inspection on one side using a single transducer, field applicability is improved for inspection bodies of various structures, so that quality control of various parts and industrial structures such as nuclear power plant facilities The cost and time required for safety management can be reduced.

1 is an exemplary view illustrating an inspection system including a nonlinear ultrasound inspection apparatus according to an embodiment of the present invention.
2 is an exemplary diagram illustrating a probe of a nonlinear ultrasound examination apparatus according to an embodiment of the present invention.
3 is an exemplary diagram for explaining a time delay according to an embodiment of the present invention.
4 is a graph illustrating a phased array signal according to an embodiment of the present invention.
5A and 5B are graphs illustrating a bottom reflection signal and a bottom reflection post-reception signal according to an embodiment of the present invention.

With reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are used for the same or similar components throughout the specification. In addition, in the case of a well-known known technology, a detailed description thereof will be omitted.

Throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

Throughout the specification, one surface of the test object is a surface on which a transducer is disposed to apply an ultrasonic signal, and the bottom surface refers to the opposite surface of the one surface.

Throughout the specification, an ultrasound signal is an ultrasound signal having a single frequency, a fundamental component indicates an ultrasound signal of a fundamental frequency component, and a harmonic component indicates an ultrasound signal of a harmonic component.

1 is an exemplary diagram illustrating an inspection system including a nonlinear ultrasound inspection apparatus according to an embodiment of the present invention.

As shown in FIG. 1 , the inspection system includes a transducer 100 for applying ultrasound to the inspection object 10 , a controller 200 for controlling ultrasound transmission of the transducer 100 , and a basic received from the transducer 100 . and a diagnostic device 300 that separates and quantifies the wave component and the second harmonic component.

The probe 100 represents a needle-like small tool or device used for the purpose of measuring or exploring a test object, and may be used to connect to an input terminal such as a vacuum tube voltmeter (VTVM) or an oscilloscope to contact a point to be measured.

In addition, the transducer 100 may be mounted on a moving body equipped with a motor in order to change the inspection area of the inspection object. The moving body can be remotely controlled by wire or wirelessly by a separately interlocked terminal, so that the position of the probe 100 can be changed by movement by the moving body.

The transducer 100 applies an ultrasonic wave to the test object 10 by the ultrasonic wave application signal of the controller 200 and receives a signal reflected by the applied ultrasonic wave passing through the test object 10 .

At this time, a plurality of vibrators are arranged at a predetermined interval in the transducer 100 , and the controller 200 transmits an ultrasound application signal to the vibrators of the transducer 100 in a preset order.

Accordingly, the vibrators sequentially apply ultrasonic waves according to the ultrasonic wave application signal, and the applied ultrasonic waves are focused and reflected from the bottom surface.

Accordingly, when the transducer 100 senses the reflected signal and transmits it to the diagnostic device 300 , the diagnostic device 300 separates the received ultrasound into a fundamental frequency component and a harmonic component.

In this case, the diagnostic device 300 may collect changes in the input voltage according to time in conjunction with an oscilloscope that converts the signal received from the receiving vibrator into a voltage and displays it.

The diagnostic device 300 quantifies the fundamental wave component and the second harmonic component received from the vibrator to diagnose micro-deterioration of the test object.

The diagnostic device 300 may quantify the second harmonic component as a nonlinear parameter and confirm the degree of change by comparing it with an initial nonlinear parameter of the test object or a nonlinear parameter measured at a previous time point.

In addition, the diagnostic device 300 may diagnose the micro-deterioration based on the confirmed degree of change.

In detail, the diagnostic device 300 separates the received ultrasound into a fundamental frequency component and a harmonic component. In addition, the diagnostic device 300 may obtain the amplitude of the separated fundamental frequency component and the amplitude of the harmonic component and quantify the nonlinear parameter β through Equation 1 below.

[Equation 1]

Here, A ₁ is the amplitude of the ultrasonic wave having a fundamental frequency component, A ₂ is the amplitude of the ultrasonic wave having the second harmonic component, k is a wave number, and x is the propagation distance.

As such, when the diagnostic device 300 calculates the nonlinear parameter, it may be stored in a separate database together with the test object, the test time, the test location, and the like.

In addition, the diagnostic device 300 may determine a point of damage or a point of deterioration of the test object in response to a point at which the value of the nonlinear parameter is calculated differently.

Hereinafter, the arrangement of the transducer vibrators and the configuration of applying the ultrasonic wave by applying a time delay will be described in detail with reference to FIGS. 2 and 3 .

2 is an exemplary diagram illustrating a probe of a nonlinear ultrasound examination apparatus according to an embodiment of the present invention, and FIG. 3 is an exemplary diagram for explaining a time delay according to an embodiment of the present invention.

The transducer 100 includes a plurality of transmitting vibrator and receiving vibrator are arranged at predetermined intervals.

In the central region of the transducer 100, the receiving vibrator (2s, 110) is located, based on the receiving vibrator 110, the same number of the transmitting vibrator (s, 120) is located on the left and right.

At this time, when the transmitting vibrator 120 is formed with a predetermined size (s), the receiving vibrator 110 is formed with a larger size (2s) than the transmitting vibrator 120 . This is formed so that the focal spot (A) on which the ultrasonic waves are focused is not formed in the middle of the receiving vibrator 110 , and the receiving amplitude of the reflected and returned signal has a certain size or more.

For example, the size of the receiving vibrator 110 may be changed by an administrator later as an example, although there may be a difference of about two times in size.

By applying an ultrasonic signal by applying a time delay at the positions of the transmitting vibrators of the transducer 100 having a fundamental frequency, the ultrasonic signal is focused on the bottom surface A of the test object, and the focused ultrasonic signal is reflected again.

At this time, a time delay of about π/4 is applied to offset harmonic components generated in the process of propagating from one surface to the bottom.

In other words, the ultrasonic wave to which the time delay is applied is alternately applied to the transmission vibrators 210 - 1 located on the left side of the transducer 100 and the transmission vibrators 210 - 2 located on the right side of the transducer 100 to cancel the harmonic component.

For example, after the transmission vibrator 121 applies the ultrasound, ultrasonic waves are applied through the transmission vibrator 122 at a delayed π/4+α time point, and the phase is π/ at the point where the ultrasound waves oscillated from each vibrator are focused. 4 Make a difference. Here, α is a value generated by the difference between the propagation distance of the ultrasonic wave from the transmitting vibrator 121 to the focusing point on the bottom and the ultrasonic wave propagation distance from the transmitting vibrator 122 to the focusing point on the bottom surface. In addition, the transmitting vibrator 123 applies the ultrasonic wave at a time delayed by π/4 +α' from the time when the transmitting vibrator 122 applies the ultrasonic wave. Here, α' is a value generated by the difference between the propagation distance of the ultrasonic wave from the transmitting vibrator 122 to the focusing point from the bottom and the ultrasonic wave propagation distance from the transmitting vibrator 123 to the focusing point on the bottom.

Here, α or α' may vary depending on the distance between the vibrators and the thickness of the test object.

In this way, the ultrasonic signal is applied by alternately selecting the transmission vibrators from the left and right edges toward the center region and applying the set delay time.

4 is a graph illustrating a phased array signal according to an embodiment of the present invention.

4 is a graph illustrating a phased array signal through transmission vibrators using the nonlinear ultrasound examination apparatus of the present invention, and shows the signals before superimposing each phased array signal.

As shown in FIG. 4 , the ultrasonic wave (fundamental wave, f) applied alternately from the edge of the transmission vibrators to the central region and the second harmonic wave 2f generated by the ultrasonic wave are shown.

The signal on the right and the signal on the left are overlapped with each other in the process of being focused on the bottom surface of the test object by the ultrasonic signals propagated from the right transmitting vibrators and the left transmitting vibrators, respectively.

Accordingly, the fundamental wave f has a size smaller than the amplitude of the excitation ultrasonic wave due to destructive interference, but the secondary harmonics 2f cancel each other out.

5A and 5B are graphs illustrating a bottom reflection signal and a bottom reflection post-reception signal according to an embodiment of the present invention.

FIG. 5A is a graph showing the amplitude of the reflected signal from the focal spot of the test object with respect to time and a graph showing the frequency of the reflected signal from the lower surface of the test object. A graph showing the amplitude of the signal over time and a graph showing the final received frequency.

As shown in Fig. 5a, by applying ultrasonic waves with a time delay through the transducer, the second harmonic generated by the ultrasonic waves transmitted from one surface of the test object to the lower surface is canceled, and the amplitude is reduced due to destructive interference on the actual lower surface. Only the fundamental wave f of magnitude is reflected.

Accordingly, when the ultrasonic signal of the fundamental wave component is sensed by passing through the test object from the corresponding bottom surface, it can be represented as shown in FIG. 5B. The fundamental wave component (f) is reflected from the bottom of the test object with a reduced amplitude, and is detected by the receiving vibrator with a smaller amplitude while passing through the test object. And, by detecting the second harmonic component 2f generated while the corresponding fundamental component f is transmitted, it is possible to precisely measure the nonlinear elastic properties of the material because it is generated in the process of propagating the material of the test object.

According to the present invention, it is possible to quantitatively and precisely measure the nonlinear elastic properties of the material of the test object from one side of the test object, and through this, it is possible to precisely inspect the micro-deterioration of the material.

In addition, according to the present invention, by performing the inspection from one side using a single transducer, field applicability is improved for inspection bodies of various structures, so that quality control of various parts and safety of industrial structures such as nuclear power plants are managed. This can reduce the cost and time required.

Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the

Claims (10)

A transducer including one receiving vibrator located in the central region and transmitting vibrators located on the left and right sides of the receiving vibrator, respectively;
a controller for controlling to transmit a time-delayed ultrasonic signal to each of the transmitting vibrators based on the positions of the transmitting vibrators; and
A diagnostic device for quantifying the fundamental and secondary harmonic components received from the receiving vibrator in response to the ultrasonic signal applied by the transmitting vibrator to one surface of the test object to diagnose micro-deterioration of the test object
including,
The second harmonic component represents only a second harmonic component generated by a fundamental component reflected from a bottom surface of the inspection object.
In claim 1,
The probe is
The nonlinear ultrasound examination apparatus in which the receiving vibrator and the transmitting vibrators are arranged at a predetermined interval, and having a receiving vibrator having a larger size than the transmitting vibrators having a predetermined size.
In claim 2,
The controller is
Nonlinear ultrasound examination in which ultrasonic waves are alternately transmitted from the left and right edges of the transducer to one transmitting vibrator in the direction of the central region, and a time delay of π/4 +α is applied to the ultrasonic transmission time of each transmitting vibrator Device.
In claim 3,
A nonlinear ultrasound examination apparatus in which a harmonic component generated by a fundamental component is canceled while ultrasound signals transmitted from the transmitting vibrators are focused on a bottom surface of the test object.
In claim 4,
The diagnostic device,
A nonlinear ultrasound inspection apparatus for quantitatively measuring nonlinear elastic properties of the material of the test object by quantifying the second harmonic component received from the receiving vibrator as a nonlinear parameter.
In the nonlinear ultrasonic inspection apparatus, disposing a transducer in which one receiving vibrator and one transmitting vibrator are arranged at predetermined intervals on one surface of the inspection object;
step of sequentially applying the ultrasonic signal toward the bottom of the test object by the transmitting vibrators based on a preset order;
receiving, from the receiving vibrator, a fundamental component and a second harmonic component in which the applied ultrasonic signal is focused on the bottom surface of the inspection body and returned by being reflected from the bottom surface of the inspection body; and
Quantifying the fundamental component and the second harmonic component as a non-linear parameter
including,
The second harmonic component represents only the second harmonic component generated by the fundamental wave component reflected from the bottom surface.
In claim 6,
The step of disposing the transducer,
A nonlinear ultrasonic inspection method in which a receiving vibrator is formed in a central region, and a single transducer having the same number of transmitting vibrators formed on the left and right sides of the receiving vibrator is disposed in close contact with one surface.
In claim 7,
The step of applying the ultrasonic signal comprises:
A nonlinear ultrasound inspection method in which the ultrasonic signal is alternately applied to a left transmitting vibrator and a right transmitting vibrator in a direction from a left or right edge transmitting vibrator to a transmitting vibrator in the central region.
In claim 8,
The step of applying the ultrasonic signal comprises:
A nonlinear ultrasound examination method in which a second harmonic component generated by the ultrasound signal is canceled while the ultrasound signal is focused on the bottom surface of the inspection object by delaying the time for applying the ultrasound signal to each transmission vibrator by π/4+α.
In claim 9,
The step of quantifying with the non-linear parameter is,
A non-linear ultrasound inspection method for measuring the amplitude of the second harmonic component, quantifying it as the non-linear parameter, and comparing the non-linear parameter with the pre-stored non-linear parameter of the test object to determine the degree of micro degradation of the test object.

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