JP2009042173A - Device and method for ultrasonic inspection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems, wherein an ultrasonic sensor using SH waves needs a contact medium, with high viscosity and physical scanning thereof takes a considerable time, and the adhesiveness between an oscillator and a flaw detection surface and the uniformity of a contact medium film cannot be obtained, when a flaw detection surface shape has a curvature, even though electronic scanning can be scanned by phased array technique in the prior phased array technique. <P>SOLUTION: The method for ultrasonic detection includes the steps of improving the adhesiveness and the uniformity of the contact medium film using a sensor 1 formed by connecting vibrators V1 to V8 each other generating SH waves with an elastic body 5 and by reading relative positional relation information of adjacent oscillators with strain gauges G1a to G7a, and G1b to G7b; calculating the drive timing of the oscillators, by using the incident angle of ultrasonic beams and the relative position relationship information of adjacent oscillators; and preventing an error in oscillators' drive timing due to the deformation of the sensor 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an ultrasonic flaw detection apparatus and an ultrasonic flaw detection method for detecting a crack or the like generated in an inspection object using a phased array probe.

  In general, an ultrasonic flaw detector detects a crack or the like of an inspection object by transmitting an ultrasonic wave to an inspection object and receiving and analyzing an ultrasonic signal reflected from the crack or the like.

  As such an ultrasonic apparatus, those using a shear vertical wave (hereinafter referred to as an SV wave) and a shear horizontal wave (hereinafter referred to as an SH wave) are well known. Since SH waves do not cause mode conversion, it is known that attenuation due to interference and generation of pseudo echoes are less than those of SV waves, and the flaw detection accuracy is higher than that of SV waves. However, since the SV wave is easier to handle, in fact, many flaw detection devices using the SV wave are used.

  Since the SH wave cannot enter the inspection object using mode conversion, it is necessary to use a contact medium such as a liquid with high viscosity when the sensor is arranged on the inspection object. Since the contact medium has a higher ultrasonic energy attenuation rate than the structure to be inspected and the sound velocity is different from that of the inspection object, it is desirable that the contact medium be formed as thin and uniform as possible. Further, when such a contact medium having a high viscosity is used, it takes a time from several minutes to several tens of minutes until the reflection echo is stabilized after the sensor is arranged. For this reason, scanning by moving the sensor is very time consuming and inefficient.

  To solve this problem, it is possible to scan the inside of the inspection object without performing physical scanning of the sensor by using phased array technology that electronically scans the ultrasonic beam to detect flaws at various angles. be able to.

  The outline of the phased array technology will be described with reference to FIG. A sensor 107 including a plurality of vibrators 102 is arranged on the inspection object 108 via a contact medium 106. Each of the vibrators 102 generates ultrasonic waves 109 by sequentially driving the plurality of vibrators at different driving timings. By synthesizing the ultrasonic wave 109, an ultrasonic beam 110 having a desired incident angle θ is generated. By calculating and controlling the drive timing of each transducer, an ultrasonic beam of various angles is synthesized, and electronic scanning of the ultrasonic beam is realized.

  The drive timing of the plurality of transducers for obtaining the ultrasonic beam 110 having the incident angle θ will be described below using the equation (1). When the distance between the transducers is d (mm), the flaw detection angle is θ (degrees), and the sound velocity of the ultrasonic waves is v (m / s), the drive timing between the transducers is expressed by Δt ( The oblique flaw detection can be realized by transmitting ultrasonic waves with a delay of ms).

Δt = d · sin θ / v (1)
However, in such a phased array probe, when the flaw detection surface to be arranged is not horizontal, an error occurs between the calculation result of the drive timing of each transducer and the actual ultrasonic wave, so the ultrasonic beam is the target to be inspected. The accuracy of flaw detection is reduced. When the SH wave is used, it is inefficient to search for a flaw detection surface suitable for inspection by repeating the rearrangement of the sensor because it takes time until the reflected echo is stabilized each time the sensor is rearranged.

  As a technique for eliminating the decrease in accuracy caused by the shape of the flaw detection surface, for example, there is an apparatus disclosed in Patent Document 1.

  A conventional phased array type ultrasonic flaw detector disclosed in Patent Document 1 will be described below with reference to FIG. FIG. 7A is a block diagram showing an outline of a conventional apparatus, and FIG. 7B is a block diagram showing an outline of a state in which the conventional apparatus is arranged on the flaw detection surface 105.

  A configuration of a conventional apparatus will be described with reference to FIG. A plurality of transducers 102 are arranged in a row within the frame body 101 of the flaw detection probe 111, and each of the transducers 102 is pressed downward by an elastic body 103 and supported so as to be movable in the vertical direction. Each elastic body 103 that supports each of the vibrators 102 is connected to a vibrator movement amount detector 104 disposed on the upper side.

The operation of this apparatus will be described with reference to FIG. As shown in FIG. 7B, the flaw detection probe 111 is arranged on the flaw detection surface 105 through the contact medium 106. Here, the flaw detection surface 105 has a curved surface, and each of the vibrators 102 is pressed against the flaw detection surface 105 by the elastic body 103. By pressing each transducer 102 against the flaw detection surface 105, the elastic body 103 is compressed according to the surface shape of the flaw detection surface 105, and this is detected by the transducer movement amount detector 104 to detect the vertical direction of each transducer 102. Get phase information. By correcting the drive timing of each transducer 102 using this phase information, the convergence error to the target due to the surface shape of the flaw detection surface is eliminated, and the flaw detection accuracy is improved.
JP 2001-305115 A

  In the apparatus described above, each vibrator is movable only in the vertical direction. Therefore, when the flaw detection surface has a large curvature, the ultrasonic sensor cannot obtain sufficient adhesion to the flaw detection surface. An example in which an ultrasonic sensor is arranged on a flaw detection surface having a large curvature is shown in FIG. In FIG. 8, the structure to be inspected has a circular cross section, and the flaw detection surface has a large curvature. In the inspection object shown in FIG. 8, a part of the vibrator 102 arranged on the flaw detection surface 105 is greatly inclined with respect to the flaw detection surface 105. For this reason, the adhesion is poor, and the ultrasonic waves output from the transducers 102 to the flaw detection surface 105 may not converge, and an ultrasonic beam having a desired angle may not be synthesized. Further, since the film of the contact medium 106 is not uniformly formed between the vibrator 102 and the flaw detection surface 106, there is a possibility that the flaw detection accuracy may be lowered.

  The present invention has been made to solve the above-described problems, and in ultrasonic flaw detection using SH waves, prevents the uneven distribution of the contact medium and the vibrator drive timing error caused by the surface shape of the inspection object. An object of the present invention is to provide an ultrasonic flaw detector capable of improving flaw detection accuracy.

  In order to achieve the above object, an ultrasonic flaw detector according to the present invention includes a plurality of transducers that generate SH waves arranged in a one-dimensional array or a two-dimensional array, and the adjacent transducers are elastically formed. An ultrasonic sensor that is connected to each other, and a flaw detection surface of the ultrasonic sensor and a surface that faces the flaw detection surface are provided between adjacent vibrators among the plurality of vibrators, and are arranged on an inspection target. A plurality of strain detectors that output strain amounts according to the deformation of the ultrasonic sensor, and the relative positional relationship information between adjacent transducers using the strain amounts output from each of the strain detectors. And a second computing unit that calculates driving timings of the plurality of transducers by using an incident angle of the ultrasonic beam incident on the inspection target and relative positional relationship information between adjacent transducers. When The second on the basis of the drive timing calculating unit has calculated, characterized in that it comprises a flaw detector to drive the plurality of vibrators.

In the ultrasonic flaw detection method according to the present invention, a plurality of transducers that generate SH waves are arranged in a one-dimensional array or a two-dimensional array, and the adjacent transducers are connected to each other by an elastic body. A sensor placement step for placing an ultrasonic sensor on a test object, an adjacent transducer relative positional relationship measurement step for measuring a relative positional relationship between the plurality of adjacent transducers, and an adjacent transducer relative positional relationship measurement A transducer drive timing calculation step of calculating drive timings of the plurality of transducers using the relative positional relationship between adjacent transducers measured in steps and incident angle information of an ultrasonic beam incident on the inspection object from the ultrasonic sensor; ,
A vibrator driving step of driving the plurality of vibrators based on the plurality of vibrator driving timing information obtained by the vibrator driving timing calculation step.

  According to the present invention, in ultrasonic flaw detection using SH waves, an error between the drive timing calculation result of each vibrator and the actual ultrasonic wave caused by the surface shape of the flaw detection surface is eliminated, and each vibrator is inspected. The flaw detection surface can be arranged in good contact with each other, and the flaw detection accuracy can be improved by forming a thin film of the contact medium uniformly.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIGS. 1 to 3 are cross-sectional views each showing an outline of a state in which the sensor 1 of the ultrasonic flaw detector 10 according to the present embodiment is disposed on an inspection target. In FIG. 1, when the flaw detection surface on which the sensor 1 is arranged is a flat surface, in FIG. 2, when the flaw detection surface is included, in FIG. 3, the sensor 1 is moved along the circumferential direction of the structure 52c having a circular cross section. Each case is shown. FIG. 4 is a flowchart showing the operation of the ultrasonic flaw detector 10 of this embodiment.

  The configuration of the ultrasonic flaw detector 10 of this embodiment will be described below with reference to FIGS.

  The ultrasonic flaw detector 10 according to this embodiment includes a sensor 1, a calculator 3, and a flaw detector 4.

  The sensor 1 includes vibrators V1 to V8 that generate SH waves arranged in a one-dimensional array, an elastic body 5 made of a synthetic resin that connects each of the adjacent vibrators V1 to V8, and adjacent vibrators V1 to V1. It is comprised from the strain gauges G1a-G7a and G1b-G7b which are the strain detectors which output the distortion amount attached between each of V8. The strain gauges G1a to G7a are respectively provided on the upper side of the sensor 1, and the strain gauges G1b to G7b are respectively provided on the lower side of the sensor 1.

  The broken lines connecting the computing unit 3 and each of the strain gauges G1a to G7a, G1b to G7b indicate that the computing unit 3 and each of the strain gauges G1a to G7a, G1b to G7b are communicably connected. In FIG. 1 to FIG. The computing unit 3 is communicably connected to the flaw detector 4 and is based on output information of each of the strain gauges G1a to G7a and G1b to G7b and information such as an incident angle of an ultrasonic beam incident on an inspection object. The drive timing of each of the vibrators V1 to V8 is calculated.

  A broken line connecting the flaw detector 4 and each transducer V1 to V8 indicates that the flaw detector 4 and each transducer V1 to V8 are connected so as to be communicable, and a part of them is omitted in FIGS. It is shown. Flaw detector 4 Each vibrator V1-V8 is driven based on the drive timing calculated by the calculator 3.

  The sensor 1 is arranged via the contact medium 2 on the structures 51a to 51c to be inspected. A crack 52 is generated in each of the structures 51a to 51c.

  The operation of the ultrasonic flaw detector according to this embodiment will be described below.

  The sensor 1 can be installed flexibly with respect to the shape of the flaw detection surface even when the flaw detection surface has a curved surface as shown in FIGS. 2 and 3 by the expansion and contraction of the elastic body 5 made of a synthetic resin having an elastic function. Yes, good adhesion can be obtained. Moreover, since each vibrator V1-V8 is arrange | positioned along the surface of the structures 51a-51c, the film | membrane of the contact medium 2 can be formed thinly and uniformly (FIG. 4, step S1).

  When the sensor 1 is arranged on the flaw detection surface, if the sensor 1 is deformed according to the flaw detection surface shape, each of the strain gauges G1a to G7a and G1b to G7b is deformed and outputs a strain amount. Output values of the strain gauges G1a to G7a and G1b to G7b are transmitted to the calculator 3 (FIG. 4, step S2).

  The output values of the strain gauges G1a to G7a and G1b to G7b will be described below.

  When the flaw detection surface is a flat surface as shown in FIG. 1, the sensor 1 is not deformed, and the output values of the strain gauges G1a to G7a and 1b to G7b are all zero.

  In FIG. 2, the elastic body 5 is expanded and contracted between the transducers V2 and V3 and between the transducers V6 and V7, and the sensor 1 is deformed. The transducers V3 to V6 are arranged along the inclined flaw detection surface. Yes. As the sensor 1 is deformed, the strain gauges G2a, G2b, G6a, and G6b each output strain amounts. Since the other strain gauges do not expand and contract, the output value is zero.

  In FIG. 3, the elastic body 5 between the transducers V1 to V8 is expanded and contracted to deform the sensor 1, and each of the transducers V1 to V8 is disposed along the flaw detection surface. As the sensor 1 is deformed, the strain gauges G1a to G7a and G1b to G7b output strain amounts.

  The computing unit 3 calculates adjacent transducer relative positional relationship information from the output values of the strain gauges G1a to G7a and G1b to G7b (FIG. 4, step S3).

  The adjacent transducer relative position information will be described below with reference to FIG. FIG. 5 shows an example of a state in which the sensor 1 is deformed by enlarging the vibrator V1 and the vibrator V2 as an example, and the vibrator V2 moves downward and tilts with respect to the vibrator V1.

  The adjacent transducer relative position information is information such as the distance between adjacent transducers and the relative inclination angle. By using the adjacent transducer relative positional information, the position of one of the adjacent transducers can be determined. The position of the other vibrator as a reference can be obtained by calculation.

  The relative inclination angle means the inclination of the other vibrator relative to the reference vibrator. In FIG. 5, θ represents the relative angle of the vibrator V2 with respect to the vibrator V1.

  If the adjacent transducer relative positional relationship information is known for each of the transducers V1 to V8, the positional relationship of each of the transducers V1 to V8 can be calculated. For example, the positional relationship between the vibrator V1 and the vibrator V3 is obtained by adding the calculation result of the position of the vibrator V2 with respect to the vibrator V1 and the calculation result of the position of the vibrator V3 with reference to the vibrator V2. Can be obtained. Further, since the positional relationship between the transducers V1 to V8 is known, the shape of the sensor 1 can be obtained from the adjacent transducer relative positional relationship information.

  Next, the relationship between the output values of the strain gauges G1a to G7a, G1b to G7b and the adjacent transducer relative positional relationship information will be described below.

  For example, the output value of the strain gauge G1a is X, the output value of the strain gauge G1b is Y, and the output value when the sensor 1 is not deformed is X = Y = 0.

  When the output value is X> Y, as shown in FIG. 4, the vibrator V2 is moved and tilted toward the strain gauge G1b from the initial position, and when X <Y, the vibrator V2 is moved from the initial position. Is also inclined to move toward the strain gauge G1a. Further, the greater the difference between X and Y, the greater the relative inclination angle of the vibrator V2 with respect to the vibrator V1.

  As described above, the adjacent transducer relative positional relationship information can be obtained from the output values of the strain gauges G1a to G7a and G1b to G7b.

  Next, the computing unit 3 calculates the drive timing of each of the transducers V1 to V8 using the incident angle of the ultrasonic beam incident on the inspection object and the relative positional relationship information of the adjacent transducers (FIG. 4, step S4).

  Next, the calculator 3 transmits the drive timing information of each of the vibrators V1 to V8 calculated in step S4 to the flaw detector 4 (FIG. 4, step S5).

  The flaw detector 4 drives each of the transducers V1 to V8 based on the drive timing information of each of the transducers V1 to V8, and makes an ultrasonic beam incident (FIG. 4, step S6).

  When the ultrasonic beam incident upon driving of the vibrators V1 to V8 reaches the crack 52, a reflected wave is generated. When each of the transducers V1 to V8 receives this reflected wave, the flaw detector 4 calculates and specifies the crack position based on the time difference between the ultrasonic wave incident timing and the reflected wave reception timing, and the ultrasonic velocity (FIG. 4). Step S7).

  By such a series of operations, even if the flaw detection surface has a large curvature, the sensor 1 is arranged on the flaw detection surface with good adhesion, the contact medium 2 film is formed uniformly, and the shape of the flaw detection surface It is possible to prevent an error in the vibrator drive timing caused by the above-mentioned, and to perform highly accurate ultrasonic flaw detection using SH waves.

  In the present embodiment, the sensor 1 is described as having a plurality of transducers V1 to V8 arranged in a one-dimensional array. For example, the sensor 1 is configured by arranging a plurality of transducers in a two-dimensional array. Similar effects can be obtained.

  Moreover, although the elastic body 5 was demonstrated as a synthetic resin in the present Example, the same effect | action will be acquired even if it replaces with a natural resin, a spring, rubber | gum, and a gel-like substance, and the effect of this invention can be acquired in connection with it. Of course.

  Although the embodiments of the present invention have been described with reference to the drawings, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. Those skilled in the art can make various modifications and changes in specific embodiments without departing from the technical idea and scope of the present invention.

The block diagram which shows the outline | summary of the state which has arrange | positioned the sensor of the ultrasonic flaw detector of Example 1 in the horizontal flaw detection surface. The block diagram which shows the outline | summary of the state which has arrange | positioned the sensor of the ultrasonic flaw detector of Example 1 in the flaw detection surface which has the inclined part. The block diagram which shows the outline | summary of the state which has arrange | positioned the sensor of the ultrasonic flaw detector of Example 1 along the circumferential direction of the structure which has a circular cross section. 3 is a flowchart showing the operation of the ultrasonic flaw detector according to Embodiment 1. The block diagram which expanded and showed a part of the state which changed about the sensor of the ultrasonic flaw detector of Example 1. FIG. The block diagram which shows the outline | summary of a phased array technique. (A) is a block diagram which shows the outline | summary of the conventional ultrasonic flaw detector, (b) is a block diagram which shows the state which has arrange | positioned the apparatus shown to (a) on the flaw detection surface. The block diagram which shows the outline of the state which has arrange | positioned the conventional ultrasonic flaw detector to the flaw detection surface with a large curvature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor 2 Contact medium 3 Calculator 4 Flaw detector 5 Elastic body 10 Ultrasonic flaw detector 51a-c Structure 52 Crack V1-V8 Vibrator G1a-G7a, G1b-G7b Strain gauge 101 Frame body 102 Vibrator 103 Elastic body 104 vibrator movement amount detector 105 flaw detection surface 106 contact medium 107 sensor 108 inspection object 109 ultrasonic wave 110 ultrasonic beam 111 flaw detection probe

Claims (3)

An ultrasonic sensor in which a plurality of transducers for generating SH waves are arranged in a one-dimensional array or a two-dimensional array, and the adjacent transducers are connected to each other by an elastic body;
The ultrasonic sensor is provided on each of the flaw detection surface and the surface facing the flaw detection surface between adjacent transducers of the plurality of transducers, and according to the deformation of the ultrasonic sensor due to the arrangement on the inspection object. A plurality of distortion detectors that output distortion amounts,
A first computing unit that calculates relative positional relationship information between adjacent vibrators using a strain amount output from each of the strain detectors;
A second computing unit that calculates drive timings of the plurality of transducers using an incident angle of an ultrasonic beam incident on the inspection target and relative positional relationship information between adjacent transducers;
A flaw detector that drives the plurality of vibrators based on the drive timing calculated by the second arithmetic unit;
An ultrasonic flaw detector characterized by comprising:   2. The ultrasonic flaw detector according to claim 1, wherein the elastic body is one member selected from a synthetic resin, a natural resin, a spring, rubber, and a gel substance. A sensor arrangement in which a plurality of transducers that generate SH waves are arranged in a one-dimensional array or a two-dimensional array, and an ultrasonic sensor formed by connecting adjacent transducers to each other by an elastic body is disposed on an inspection target Steps,
An adjacent transducer relative positional relationship measuring step for measuring a relative positional relationship between the plurality of adjacent transducers;
The drive timing of the plurality of transducers is calculated using the adjacent transducer relative positional relationship measured in the adjacent transducer relative positional relationship measurement step and the incident angle information of the ultrasonic beam incident on the inspection object from the ultrasonic sensor. A vibrator driving timing calculation step,
A vibrator driving step for driving the plurality of vibrators based on the plurality of vibrator driving timing information obtained by the vibrator driving timing calculation step;
An ultrasonic flaw detection method comprising:

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