JP2011252708A - Method and apparatus for estimating thinning depth of long member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for estimating a thinning depth of a long member capable of estimating the thinning depth even if no direct reflected signal is acquired from a wall-thinned portion.SOLUTION: In an image generated from a received signal, a short line segment X is determined from a delay signal F to be displayed. An upper end Q of a missing part Z in which the reflected signal from a side face R1 of the long member is missing is specified using the image or an intersection of a scanline SE' of a probe passing through the outside end E' of the short line segment X and a lateral line R1 of the long member. The other face side intersection P where an extension of the short line segment X crosses the other face R2 side facing the side face R1 is determined. A first line segment PQ connecting the other face side intersection P to the upper end Q of the missing portion Z is determined. A second line segment SE which connects a inner end E of the short line segment X to the scanning position S of the probe and/or passes the inner end E of the short line segment X and is inclined at an ultrasonic transmission angle is determined. An intersection U where the first line segment PQ crosses the second line segment SE is determined, and the thinning depth D is estimated by the intersection U.

Description

  The present invention relates to a thinning depth estimation method and a thinning depth estimation device for a long member. More specifically, a thinning depth estimation method for a long member, in which a probe is placed on the end face of the long member, ultrasonic waves are transmitted, and the depth of thinning is estimated by a received signal from the long member. And a thinning depth estimation apparatus.

  Conventionally, for example, a thinning evaluation method for a long member as described in Patent Document 1 is known. Reference 1 paragraph 0035 describes a point to be measured as a thinning width W, a thinning length L, and a thinning depth D. However, in the description, when a direct reflection signal from the thinned portion is obtained, each dimension is measured from a plurality of types of images generated as shown in FIG. The thickness reduction could not be measured when no reflected signal was obtained.

  The ultrasonic flaw detector described in Patent Document 2 also detects a defect by a reflected echo from the defect, and does not assume a case where a direct reflection signal cannot be obtained.

JP 2009-281731 A JP 2002-5903 A

  In view of such a conventional situation, the present invention estimates the thinning depth of a long member capable of estimating the thinning depth even when a direct reflection signal from the thinning portion cannot be obtained. It is an object to provide a method and a thinning depth estimation apparatus.

  In order to achieve the above object, the feature of the thinning depth estimation method for a long member according to the present invention is that an ultrasonic wave is transmitted by placing a probe on the end surface of the long member, In the method for estimating the depth of thinning by the received signal, an image is generated from the received signal obtained by scanning the end face, and in this image, a short line segment is obtained from the displayed delay signal, and the long The upper end of the missing portion where the reflected signal from the side surface of the member is missing is specified by using an image or by the intersection of the scanning line of the probe passing through the outer end of the short line and the outer line of the long member. The other surface side intersection where the extension line of the short line segment and the other surface opposite to the side surface intersect is obtained, a first line segment connecting the other surface side intersection point and the upper end of the missing portion is obtained, and the short line The inner end of the minute and the scanning position of the probe and / or the ultrasonic wave passing through the inner end of the short line Obtains a second segment inclined at transmission angles, to obtain the intersection of said first segment and said second segment intersects, is to estimate the depth of the thinning this intersection.

  Here, a part of the ultrasonic wave incident on the long member is reflected by the thinned portion. As shown in FIG. 8, on the generated image, the intersection of the scanning line SE ′ of the probe using the image or the outer end E ′ of the short line segment X and the outer line R1 of the long member. The upper end Q of the missing part Z specified by the above indicates the upper end of the thinning B. The first connecting the other surface side intersection P where the extended line of the short line segment X obtained from the displayed delay signal F and the other surface R2 facing the side surface R1 of the long member intersect the upper end Q of the missing portion Z. The line segment PQ indicates the inclination of the thinning B that becomes the ultrasonic wave reflection source. Then, the second line segment SE connecting the inner end E of the short line segment X and the scanning position S of the probe and / or passing through the inner end E of the short line segment X and inclined at the transmission angle of the ultrasonic wave is the first line segment SE. Intersects the line segment PQ. The intersection U between the first line segment PQ and the second line segment SE is the farthest point from the side surface R1 of the long member, and indicates the reflection position of the deepest portion in the thinning B. Therefore, it is possible to estimate the thinning depth D by obtaining this intersection point U.

  The probe is rotatably attached to one end of the elongate member, the probe is rotated on the end face, and the end face is scanned at each rotation position. Thereby, the thickness reduction thickness can be estimated over the perimeter of a long member.

  The probe may be a phased array probe, and the ultrasonic wave may be transmitted and received within a predetermined transmission angle range, and an image may be generated from the obtained reception signal. In such a case, the phased array probe is attached to the one end with the center of transmission / reception in the phased array probe coincident with the center of the end face, and the phased array probe is rotated with reference to the coincident center. It is good to let them. Thereby, an ultrasonic wave can be transmitted uniformly to the circumferential surface of the long member, and the thinning depth can be estimated with higher accuracy.

  In the method according to any one of the above, scanning may be performed with a constant transmission angle of the ultrasonic wave, or may be performed by changing the transmission angle of the ultrasonic wave within a predetermined transmission angle range.

  The long member is a foundation bolt with the end face exposed to the outside, and the foundation bolt may have a threaded portion and a cylindrical portion. It is possible to estimate the thinning depth even in the long member having such a configuration.

  In order to achieve the above object, the feature of the thinning depth estimation device for a long member according to the present invention is that an ultrasonic wave is transmitted by placing a probe on the end surface of the long member, In the configuration in which the depth of thinning is estimated based on a received signal, a scanner that attaches the probe onto the end face and rotates and scans, a control device that controls transmission / reception of the ultrasonic wave, and an image obtained from the obtained received signal And an image processing device that analyzes the generated image and a display device that displays the image. The image processing device generates an image from the received signal, and in this image, from the displayed delay signal The short line is obtained, and the upper end of the missing portion where the reflection signal from the side surface of the long member is missing is used for the image, or the scanning line of the probe passing through the outer end of the short line and the long member Specified by the intersection with the outside line, The other line side intersection where the extension line of the minute and the other surface opposite to the side surface intersect is obtained, a first line segment connecting the other surface side intersection and the upper end of the missing part is obtained, and the inside of the short line segment A second line segment connecting the end and the scanning position of the probe and / or passing through the inner end of the short line segment and tilting at the transmission angle of the ultrasonic wave, and determining the first line segment and the second line segment It is to obtain an intersection where the line segment intersects and to estimate the depth of the thinning by this intersection.

  According to the characteristics of the thinning depth estimation method and thinning depth estimation device for a long member according to the present invention, the thinning depth is obtained even when a direct reflection signal from the thinning portion cannot be obtained. It became possible to estimate.

  Other objects, configurations, and effects of the present invention will become apparent from the following embodiments of the present invention.

It is the schematic of the whole foundation bolt used as the candidate for evaluation of the defect evaluation method concerning the present invention. It is the elements on larger scale near the head of a foundation bolt. It is a block diagram of the defect evaluation apparatus which concerns on this invention. It is the schematic of a scanner. It is a figure explaining electronic scanning of a phased array probe. It is a figure explaining rotation scanning of a phased array probe. It is a figure which shows typically the delay signal from the thinning part in a linear scan. It is a figure explaining the principle of estimation of thickness reduction. It is a figure which shows typically the delay signal from the thinning part in a sector scan. (A)-(c) is a figure which shows the 1st-3rd test body which formed simulated thinning, (d) is a figure which shows the processing shape of simulated thinning. It is a figure which shows the depth estimation result of the simulation partial thinning in the S-scan image of a 1st test body. It is a figure which shows the depth estimation result of the 1st simulation partial thinning in the S-scan image of a 2nd test body. It is a figure which shows the depth estimation result of the 2nd simulation partial thinning in the S-scan image of a 2nd test body. It is a figure which shows the depth estimation result of the simulation whole circumference thinning in the S-scan image of a 3rd test body. It is a figure which shows other embodiment of this invention.

Next, the first embodiment of the present invention will be described in detail with reference to FIGS.
As a long member which is an object of the thickness reduction estimation method according to the present invention, for example, a foundation bolt 101 in a structure 100 such as a chemical plant, a petroleum plant, or a power plant as shown in FIG. The structure of the foundation bolt 101 will be described below as an example.

  As shown in FIGS. 1 and 2, the foundation bolt 101 has a substantially cylindrical shape and includes a screw portion 101 b having a screw thread and a cylindrical portion 101 c having no screw thread. The foundation bolt 101 is installed so that one end of the foundation bolt 101 is exposed through the grout 104 through the sleeve 103 provided on the foundation table 102. Then, the base plate 105 and the seat plate 106 are attached and fixed to the grout 104 by the nut 107. In the present invention, ultrasonic waves are transmitted and received from the end face 101a of the foundation bolt 101 exposed to the outside, and the depths D1 and D2 of the thinned portions B1 and B2 formed in the screw portion 101b and the cylindrical portion 101c embedded in the grout 104 are set. presume.

  As shown in FIG. 3, a thinning depth estimation device 1 according to the present invention generally includes a phased array probe 2, a control device 3, an image processing device 4, a display device 5, and an input device 6 as probes. Prepare. The phased array probe 2 is rotatably attached to the end surface 101a of the foundation bolt 101 by aligning the center O1 of ultrasonic transmission / reception with the center O2 of the end surface 101a by the scanner 10 shown in FIG. Thereby, an ultrasonic wave can be uniformly propagated with respect to the surrounding surface of the foundation bolt 101, and the thinning depth D of the thinned portion B can be estimated over the entire circumference of the foundation bolt 101.

  As shown in FIG. 5, the phased array probe 2 has a predetermined transmission angle, for example, within the angle range of + θ ° to −θ ° with respect to the axis A at each rotational position of the probe. Electronic scanning can be performed. By using this phased array probe 2, it is possible to select and perform a linear scan that makes the ultrasonic transmission angle constant and a sector scan that changes the ultrasonic transmission angle within an arbitrary angle range. . As shown in FIG. 6A, the phased array probe 2 is rotated from a predetermined position by a scanner 10 to be described later on the basis of the axis A of the foundation bolt 101 at intervals of φ °, for example. A 360 ° rotational scan is performed.

  As shown in FIG. 3, the control device 3 includes a control unit 3a, a pulsar receiver 3b, and a counter 3c. The control unit 3a controls the pulsar receiver 3b, and transmits and receives ultrasonic waves from the phased array probe 2 at a predetermined transmission angle via the pulsar receiver 3b. The counter 3c receives the rotational position information of the phased array probe 2 from the encoder 13a.

  A reception signal obtained by electronic scanning and rotational scanning is output to the image processing device 4 via the control device 3. The image processing device 4 processes reception signals input from the pulsar receiver 3 b and the counter 3 c, generates a B-scan (Bearing scan) image and an S-scan (Sectorial scan) image, and displays them on the display device 5. . The B-scan image is a cross-sectional image displayed by the scanning position and the propagation time by replacing the amplitude of the received signal for each scanning position at the rotational position of the probe with a color scale. This image is generated in the case of linear scanning. The S-scan image is a cross-sectional image displayed in a fan shape by replacing the amplitude of the received signal for each angle at the rotational position of the probe with a color scale. This image is generated in the case of sector scanning. Further, the image processing device 4 estimates the depth D of the thinned portion B from the delay signal F in the generated image by a procedure described later.

  As shown in FIG. 4, the scanner 10 generally includes a first frame 11, a second frame 12, a rotation extraction mechanism 13 and a holding mechanism 14. The first and second frames 11 and 12 have a substantially cylindrical shape and are fitted to each other so as to be relatively rotatable. The first frame 11 is provided with a through hole 15a, and the pair of fixing knobs 15 and 15 are pressed against the side surface of the nut 107 through the through hole 15a to fix the first frame 11 so as not to rotate. The second frame 12 is provided with a long hole 16b in the axial direction, and the holding frame 14a is fixed inside the second frame 12 by a pair of adjusting knobs 16 and 16 through the long hole 16b.

  The rotation extraction mechanism 13 includes an encoder 13a, a pinion gear 13b, and an annular rack 13c. The encoder 13a is attached to the side surface of the first frame 11, and is connected to a pinion gear 13b. The annular rack 13c is provided at the lower end of the second frame 12 with the tooth row facing the outer surface, and meshes with the pinion gear 13b. The rotation of the second frame 12 is transmitted from the rack 13c to the pinion gear 13b and gives rotation to the encoder 13a. Thereby, rotational position information of the probe is obtained.

  The holding mechanism 14 generally includes a holding frame 14a, an elastic member 14b, and a holding member 14c. The holding frame 14a has a disk shape, and holding members 14c around which springs 14b are wound as elastic members are provided in an annular shape at appropriate intervals. At the lower end of the holding member 14c, a ring-shaped pressing portion 14d that presses the peripheral portion of the phased array probe 2 is provided. The height of the holding frame 14 a can be adjusted by the long hole 16 b of the second frame 12, and the phased array probe 2 can be reliably brought into contact with the end surface 101 a of the foundation bolt 101.

Next, the principle of estimating the depth of the thinned portion B will be described with reference to FIGS.
FIG. 7 schematically shows a delay signal F obtained from the thinned portion B in the oblique linear scan. A thinned portion B ′ shown in FIG. 4B is an example shallower than the thinned portion B shown in FIG. The delayed signal refers to a signal obtained by delaying from the normal propagation time because the propagation path is different among signals from the same cause (thinning part) or mode conversion from longitudinal wave to transverse wave is performed.

  As exemplified by reference numerals S1 to S10 in FIG. 7, when electronic scanning (linear scanning) is performed from the end face 101a of the foundation bolt 101 at a fixed transmission angle, a part of the ultrasonic wave incident on the foundation bolt 101 is reduced on the side face R1. Reflected by the meat part B, reflected by the other surface R2 of the foundation bolt 101, and propagated to the probe through the same path as the forward path. At this time, on the cross-sectional image, delay signals F1 and F2 appear at the positions of symbols M1 and M2. The delay signal F1 indicates a delay signal when propagating to the other surface R2 by a longitudinal wave, and the delay signal F2 indicates a delay signal when propagating to the other surface R2 by a transverse wave mode-converted from the longitudinal wave. As shown in the figure, each line segment SF that connects each scanning position S of the probe and the delay signal F and is inclined at the transmission angle of the ultrasonic wave converts the propagation time of the ultrasonic wave in which the delay signal F is generated into a distance. It can be seen that the thinned portion B exists on the line segment SF.

  Assuming that the thinned portion B has a certain inclination, as shown in FIGS. 7A and 7B, the inclination of the delay signal F approaches the thinned portion B as the thinning becomes deeper. To change. Further, assuming that the thinned portion B reaches the other surface R2 (penetration), the propagation time of the ultrasonic wave crossing the foundation bolt 101 becomes zero. From these considerations, the line L1 that extends the line segment having the inclination of the thinned portion B to the other surface R2, and the line L2 that extends the line segment having the inclination that the delay signal F is displayed to the other surface R2 are: Intersects at point P on the other surface R2. Based on this geometric positional relationship, the thinning depth D can be estimated from the delay signal F.

Here, a procedure for estimating the thinning depth D from the delay signal F on the image will be described. FIG. 8 schematically shows a received signal such as a delay signal F in the generated image.
First, the short line segment X is obtained from the delay signal F displayed in the image, and the reflection signal Y from the screw portion 101b as a reflection signal from the side surface R1 is lost due to the thinned portion B of the foundation bolt 101. The upper end Q of the missing portion Z of the signal Y is specified. The upper end Q is specified by using, for example, signal strength using the generated image. It is also possible to manually set via the input device 6. This upper end Q shows the upper end part of the thinning part B in side surface R1. Next, the other surface side intersection P where the extended line obtained by extending the obtained short line segment X intersects the other surface R2 of the foundation bolt 101 is obtained. And the 1st line segment PQ which connects this other surface side intersection P and the upper end Q of the missing part Z is calculated | required. The first line segment PQ indicates the reflection source of the transmitted ultrasonic wave, that is, the wall portion (inclination) of the thinned portion.

  Further, a second line segment SE that connects the inner end E of the short line segment X located on the center side of the foundation bolt 101 and the scanning position S of the probe and is inclined at an ultrasonic transmission angle is obtained. The second line segment SE indicates a line segment located on the center side of the foundation bolt 101 in the line segment SF obtained by converting the propagation time of the ultrasonic wave in which the delay signal F is generated into a distance. Therefore, the intersection U between the first line segment PQ and the second line segment SE is the point farthest from the side surface R1 of the foundation bolt 101 and indicates the deepest position of the thinning. Therefore, the depth D of the thinned portion B can be obtained from this intersection point U.

An operation procedure for estimating the thickness of the foundation bolt 101 will be described with reference to FIG.
First, the scanner 10 is fitted to the nut 107, the first frame 11 is fixed to be non-rotatable by the fixing knob 15, and the phased array probe 2 is attached to the end face 101 a of the foundation bolt 101. At this time, the end surface 101a of the foundation bolt 101 is smoothed in advance with a grinder or the like, and a contact medium (glycerin paste or the like) for propagating ultrasonic waves from the phased array probe 2 to the foundation bolt is applied. The pressing force of the spring 14b is adjusted by the adjusting knob 16, and the phased array probe 2 is brought into contact with the end surface 101a by the pressing portion 14d.

  Next, an ultrasonic wave is transmitted from the phased array probe 2 within a predetermined angle range and electronically scanned to obtain a reception signal at that position, and the image processing device 4 shown in FIG. A B-scan image is generated. Then, the phased array probe 2 is mechanically rotated and rotated 360 ° at an appropriate angle by the scanner 10 to sequentially generate images at each rotation position of the probe. The position information of the probe by this rotational scanning is obtained by counting the signal of the encoder 13a by the counter 3c. The signal of the encoder 13a is generated when the rotation of the scanner 10 gives rotation to the encoder 13a via the pinion gear 13b and the annular rack 13c in order to transmit the position information of the probe. From the image thus generated, the depth D of the thinned portion B is estimated as described above.

Next, a second embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the same members as those in the above-described embodiments.
In the first embodiment, the linear scan is performed with the ultrasonic transmission angle constant, but in the second embodiment, the sector scan is performed to change the ultrasonic transmission angle within a predetermined angle range.

  In the case of sector scanning, as shown in FIG. 9, the ultrasonic wave transmission position S is one point. In addition, the transmission angle of the ultrasonic wave is variable within an angle range of + θ ° to −θ ° with respect to the axis A as shown in FIG. Therefore, the other surface side intersections indicated by reference numerals P ′ and P ″ are different points on the other surface R2. Thereby, the line segment P′Q and the line segment P ″ Q as the first line segment are displaced from the line segment PQ having the inclination of the thinned portion B. This is different from linear scanning in which the transmission angle is constant.

  However, since the line segment P′Q and the line segment P ″ Q are both based on the upper end Q, the closer to the upper end Q, the smaller the deviation from the line segment PQ. And the intersection U with 2nd line segment SE is normally located in the upper end Q side (side surface R1 side). Therefore, the influence on the estimation of the thinning depth D due to this shift is small. Therefore, also in the case of sector scanning, the depth D of the thinned portion B can be estimated from the intersection point U in the same procedure as described above.

  In the case of sector scanning, ultrasonic waves are transmitted in a fan shape within a predetermined angle range as described above. Therefore, ultrasonic waves can be transmitted to the peripheral surface of the foundation bolt 101 at each rotational position of the probe, and the thinning of both the side surface R1 and the other surface R2 of the foundation bolt 101 is detected by one sector scan. The thinning depth D can be estimated. Further, the generated S-scan image makes it easy to visually grasp the depth D and position of the thinning B. In these respects, the second embodiment is superior.

  Next, a third embodiment of the present invention will be described. In this embodiment, the thinning depth of the thinning formed mainly in the cylindrical portion 101c of the foundation bolt 101 is estimated. In the cylindrical portion 101c, the reflected signal from the side surface may be weak. In such a case, the difference between the weak reflected signal and the missing portion Z in which the reflected signal is lost due to thinning becomes unclear on the image.

  Therefore, in this embodiment, as shown in FIGS. 7 to 9, the missing line is caused by the intersection of the scanning line SE ′ of the probe passing through the outer end E ′ of the short line segment X and the outer line indicating the side surface R 1 of the foundation bolt 101. The upper end Q of the part Z is specified. As described above, each line segment SF is a line segment (scan line) obtained by converting the propagation time of the ultrasonic wave in which the delay signal F is generated by the thinned portion B into a distance, and the scan line passing through the outer end E ′ of the short line segment X. SE ′ represents a scanning line farthest from the center side of the foundation bolt 101 in the line segment SF. That is, the intersection with the side surface R1 as the outer line indicates the upper end of the thinned portion B, and this intersection is the upper end Q of the missing portion Z. Therefore, even if the reflected signal from the cylindrical portion 101c is weak or difficult to detect, the upper end of the thinned portion B can be specified on the image, and the thinning depth D can be estimated. The specification of the upper end Q is also applicable to each of the above embodiments, and may be appropriately performed according to the clarity of the missing portion Z.

  Here, the inventors manufactured first to third specimens T1 to T3 shown in FIGS. 10A to 10C, and performed a sector scan using these specimens T1 to T3 to obtain an S-scan image. We confirmed the effectiveness of this method.

  FIG. 10 (a) shows a partial thinning with a distance (depth) of 70 mm from the end face 101′a of the long member 101 ′ to the simulated thinning center (deepest part) and a depth of 5 mm at the deepest part of the simulated thinning. The 1st test body T1 which formed Bt1 in screw part 101'b is shown. FIG. 4B shows a screw portion 101 ′ having a first partial thickness reduction Bt2 having the same distance (depth) of 70 mm and the same depth of 10 mm and a second partial thickness reduction Bt3 having the same distance (depth) of 100 mm and the same depth of 5 mm. The 2nd test body T2 formed in b is shown. FIG. 4C shows a third test body T3 in which the entire circumference thinning Bt4 having the same distance (depth) 140 mm and the same depth 5 mm is formed in the cylindrical portion 101 ′ c. The simulated partial thickness reduction was formed by processing a half circumference of the long member 101 ′ with a grinder, as shown in FIG.

  FIG. 11 shows the estimation result of the thinning depth of the partial thinning Bt1 of the first specimen T1. FIG. 12 shows the depth estimation result of the first partial thinning Bt2 of the second specimen T2. FIG. 13 shows the estimation result of the thinning depth of the second partial thinning Bt3 of the second specimen T2. FIG. 14 shows the estimation result of the thinning depth of the entire circumference thinning Bt4 of the third specimen T3. In addition, the image on the right side of each S-scan image shows the vicinity of the simulated thinning of the specimen. As shown in each figure, it is confirmed that the thinning depth D and the thinning position (distance from the end face) of the simulated thinning Bt1 to Bt4 can be estimated in any of the test bodies T1 to T3. did it.

Finally, reference is made to the possibilities of other embodiments of the invention.
In each of the above embodiments, electronic scanning is performed using the phased array probe 2 as a probe, but the present invention is not limited to this. For example, as shown in FIG. 15A, instead of linear scanning, scanning may be performed by mechanically moving the oblique ultrasonic probe 2 ′ by a moving mechanism that horizontally moves on the end surface 101a. Further, instead of sector scanning, for example, as shown in FIG. 6B, it is also possible to mechanically scan in a fan shape with a variable angle probe 2 ″ whose transmission angle (refraction angle) can be adjusted. Further, it may be scanned electrically like a fan by a switch device or the like.

  In each of the above embodiments, scanning was performed with the transmission / reception center O1 and the center O2 of the end face 101a of the phased array probe 2 aligned with the axis A of the foundation bolt 101. However, in addition to the case where the centers O1 and O2 are made coincident, for example, the center O1 and O2 can be made coincident and rotational scanning can be performed based on a point different from the center O2 of the end face 101a. However, since it becomes difficult to propagate ultrasonic waves uniformly to the peripheral surface of the foundation bolt 101 and the image processing becomes complicated, the above embodiments are excellent.

In each of the embodiments described above, the second line segment SE is obtained as a line segment that connects the inner end E of the short line segment X and the scanning position S of the probe and is inclined at the ultrasonic transmission angle. However, the second line segment SE may be a line segment that satisfies at least one of the following conditions 1 and 2. Each line segment of conditions 1 and 2 indicates a scanning line located on the center side of the foundation bolt 101 among ultrasonic scanning lines that generate the delay signal F. Therefore, the thinning depth D can be estimated using the line segment that satisfies any one of the conditions.
Condition 1: A line segment connecting the inner end E of the short line segment X and the scanning position S of the probe. 2: A line segment that passes through the inner end E of the short line segment X and is inclined at an ultrasonic transmission angle.

  In each of the above-described embodiments, the holding mechanism and the rotation extraction mechanism are merely examples, and are not particularly limited as long as the probe is pressed against the end face to be surely brought into contact with the rotation scanning. Further, the long member is not limited to the embedded foundation bolt, and can be applied as long as an ultrasonic wave can be incident from one end side.

  In each of the above embodiments, the delay signal for obtaining the short line segment X may be either a delay signal F1 due to a longitudinal wave or a delay signal F2 due to a transverse wave that has undergone mode conversion. For example, the short line segment X may be obtained from the delayed signal that appears more clearly on the image, and the thinning depth D may be estimated.

  The present invention relates to a method for estimating a thinning depth of a long member, in which a probe is placed on an end face of the long member, ultrasonic waves are transmitted, and a depth of thinning is estimated based on a received signal from the long member. And it can utilize as a thinning depth estimation apparatus. In addition to a substantially cylindrical foundation bolt, the present invention can also be applied to a long member such as a square or an ellipse.

1: thinning depth estimation device, 2: phased array probe (probe), 3: control device, 3a: control unit, 3b: pulser receiver, 3c: counter, 4: image processing device (PC), 5: display device, 6: input device, 10: scanner, 11: first frame, 12: second frame, 13: rotation extraction mechanism, 13a: encoder, 13b: pinion gear, 13c: rack, 14: holding mechanism, 14a: holding frame, 14b: elastic member, 14c: holding member, 14d: pressing portion, 15: fixing knob, 15a: through hole, 16: adjusting knob, 16a: through hole, 16b: long hole, 100: structure Body, 101: foundation bolt (long member), 101a: end face, 101b: screw part, 101c: cylindrical part, 102: foundation platform, 103: sleeve, 104: grout, 105: base plate, 06: seat plate, 107: nut, A: axial center, B: thinning portion, D: thinning depth, F: delay signal, E: inner end, E ′: outer end, O1: transmission / reception center, O2: End surface center, P: intersection on the other surface side, PQ: first line segment, Q: upper end, R1: side surface (outer line), R2: other surface, S: scanning position, SE: second line segment, SE ′ : Scan line, U: Intersection, X: Short line segment, Y: Reflected signal, Z: Missing part

Claims (8)

It is a thinning depth estimation method for a long member that mounts a probe on the end face of a long member, transmits ultrasonic waves, and estimates the depth of thinning by a received signal from the long member,
An image is generated from a received signal obtained by scanning the end face,
In this image,
Find the short line from the displayed delay signal,
Use the image for the upper end of the missing part where the reflected signal from the side surface of the long member is missing, or the intersection of the scanning line of the probe that passes the outer end of the short line and the outer line of the long member Identified by
Finding the other surface side intersection where the extension line of the short line and the other surface facing the side surface intersect,
Find the first line segment connecting this other surface side intersection and the upper end of the missing part,
A second line segment connecting the inner end of the short line segment and the scanning position of the probe and / or passing through the inner end of the short line segment and inclined at the transmission angle of the ultrasonic wave,
Find the intersection where the first line segment and the second line segment intersect,
A method for estimating a thinning depth of a long member, wherein the thinning depth is estimated from the intersection. The reduction of the long member according to claim 1, wherein the probe is rotatably attached to one end of the long member, the probe is rotated on the end surface, and the end surface is scanned at each rotation position. Meat depth estimation method. The thinning depth of the long member according to claim 1 or 2, wherein the probe is a phased array probe, transmits and receives the ultrasonic wave in a predetermined transmission angle range, and generates an image from the obtained reception signal. Estimation method. The phased array probe is attached to the one end with the transmission / reception center of the phased array probe and the center of the end face being coincident, and the phased array probe is rotated with reference to the coincident center. 3. A method for estimating a thinning depth of a long member according to 3. The method for estimating a thinning depth of a long member according to any one of claims 1 to 4, wherein scanning is performed with a constant transmission angle of the ultrasonic wave. The method for estimating a thinning depth of a long member according to claim 1, wherein scanning is performed while changing the transmission angle of the ultrasonic wave within a predetermined transmission angle range. The said long member is a foundation bolt with the said end surface exposed outside, This foundation bolt has a thread part and a cylindrical part, The thinning depth estimation method of the elongated member in any one of Claims 1-6. . A thinning depth estimation device for a long member that mounts a probe on the end face of a long member, transmits ultrasonic waves, and estimates the depth of thinning by a received signal from the long member,
A scanner that mounts the probe on the end face and rotationally scans;
A control device for controlling transmission and reception of the ultrasonic wave;
An image processing device for generating an image from the obtained received signal and analyzing the generated image;
A display device for displaying the image,
The image processing device generates an image from the received signal,
In this image,
Find the short line from the displayed delay signal,
Use the image for the upper end of the missing part where the reflected signal from the side surface of the long member is missing, or the intersection of the scanning line of the probe that passes the outer end of the short line and the outer line of the long member Identified by
Finding the other surface side intersection where the extension line of the short line and the other surface facing the side surface intersect,
Find the first line segment connecting this other surface side intersection and the upper end of the missing part,
A second line segment connecting the inner end of the short line segment and the scanning position of the probe and / or passing through the inner end of the short line segment and inclined at the transmission angle of the ultrasonic wave,
Find the intersection where the first line segment and the second line segment intersect,
A thinning depth estimation device for a long member that estimates the thickness of the thinning based on this intersection.