Non-destructive inspection apparatus and non-destructive inspection method

Abstract

This non-destructive inspection apparatus for inspecting the state of a pipe including a bending part comprises: a guided wave sensor which includes a plurality of elements capable of propagating guided waves through the pipe and receiving reflected waves of the guided waves; and an analysis device which analyzes a defect of the pipe on the basis of the reflected waves. The analysis device comprises: a grid creation unit for creating virtual grids including a plurality of grids by dividing the pipe along the axial direction and the circumferential direction; a propagation path calculation unit for calculating, on the basis of the virtual grids, a propagation path in which the guided waves are propagated through the pipe; a delay time calculation unit for calculating, for each of the plurality of elements, a delay time of the timing at which a reflected wave is received; a synthesis wave generation unit for generating a synthesis wave by correcting, on the basis of the delay time and the propagation path, the reflected waves received by each of the plurality of elements, and synthesizing the reflected waves; and an image generation unit for generating an image on the basis of the synthesis wave.

Description

Non-destructive testing device and non-destructive testing method

[0001] This disclosure relates to a non-destructive inspection device and a non-destructive inspection method for inspecting the condition of piping, including bends. This application claims priority to application Ser. No. 63 / 605,325, filed with the U.S. Patent and Trademark Office on Dec. 1, 2023, the contents of which are incorporated herein by reference.

[0002] Conventionally, non-destructive testing devices have been known that inspect the condition of a pipe by propagating a guided wave through the pipe. This non-destructive testing device analyzes guided waves (reflected waves) reflected from portions of the pipe where the thickness or shape changes, i.e., defects in the pipe, to calculate the position and size of the defects. However, this non-destructive testing device has difficulty analyzing the reflected waves because the propagation of guided waves is complicated in bent portions of the pipe, resulting in low accuracy in the condition inspection.

[0003] In response to this, Patent Document 1 discloses a non-destructive inspection method in which actual data measured on the basis of previously obtained inspection data of a bent portion of a pipe is corrected to calculate defective portions of the pipe.

[0004] JP 2013-164361 A

[0005] However, the nondestructive inspection method described in Patent Document 1 requires inspection data of the bend in the pipe before a defect occurs. For this reason, it is difficult to apply the nondestructive inspection method described in Patent Document 1 to pipes that are already in operation. Furthermore, it is not easy to reproduce the bend in the pipe to be inspected in order to obtain the inspection data.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a non-destructive inspection device and a non-destructive inspection method that can inspect piping including bends with high accuracy.

[0007] In order to achieve the above object, a non-destructive inspection device according to the present disclosure is a non-destructive inspection device for inspecting a state of a pipe including a bend, the non-destructive inspection device comprising: a guided wave sensor including a plurality of elements capable of propagating a guided wave through the pipe and receiving a reflected wave of the guided wave; and an analysis device that analyzes defects in the pipe based on the reflected wave, wherein the analysis device comprises: a grid creation unit that creates a virtual grid including a plurality of grids obtained by dividing the pipe along each of an axial direction and a circumferential direction; a propagation path calculation unit that calculates a propagation path along which the guided wave propagates through the pipe based on the virtual grid; a delay time calculation unit that calculates a delay time between timings at which the reflected wave is received for each of the plurality of elements; a composite wave generation unit that generates a composite wave by correcting the reflected waves received by each of the plurality of elements based on the delay time and the propagation path and then combining the reflected waves; and an image generation unit that generates an image based on the composite wave.

[0008] In order to achieve the above object, a non-destructive inspection method according to the present disclosure is a non-destructive inspection method for inspecting a state of a pipe including a bend, the non-destructive inspection method comprising the steps of: preparing a guided wave sensor including a plurality of elements capable of propagating a guided wave through the pipe and receiving a reflected wave of the guided wave; creating a virtual grid including a plurality of grids obtained by dividing the pipe along both an axial direction and a circumferential direction; calculating a propagation path of the guided wave propagating through the pipe based on the virtual grid; calculating a delay time for receiving the reflected wave for each of the plurality of elements; generating a composite wave by correcting the reflected waves received by each of the plurality of elements based on the delay time and the propagation path and then combining the reflected waves; and generating an image based on the composite wave.

[0009] According to the non-destructive inspection device and non-destructive inspection method disclosed herein, the condition of a bent portion of a pipe can be inspected with high precision.

[0010] FIG. 1 is a diagram schematically illustrating a configuration of a non-destructive inspection device according to an embodiment. FIG. 2 is a diagram schematically illustrating a configuration of a guided wave sensor according to an embodiment. FIG. 3 is a diagram schematically illustrating a functional block diagram of an analysis device according to an embodiment. FIG. 4 is a diagram for explaining a virtual grid according to an embodiment. FIG. 5 is a diagram for explaining an example of a method for calculating a propagation path according to an embodiment. FIG. 6 is a diagram illustrating a state in which each of a plurality of elements according to an embodiment receives a reflected wave. FIG. 7 is a diagram illustrating waveform data of a reflected wave according to an embodiment. FIG. 8 is a diagram illustrating a method for combining waveform data of a reflected wave according to an embodiment. FIG. 9 is a diagram illustrating an image according to an embodiment. FIG. 10 is a cross-sectional view of a pipe cut along an axial direction according to an embodiment. FIG. 11 is a flowchart of a non-destructive inspection method according to an embodiment.

[0011] Hereinafter, a conveying device according to an embodiment of the present disclosure will be described with reference to the drawings. The embodiment shows one aspect of the present disclosure, and is not intended to limit the present disclosure. Any modification can be made within the scope of the technical concept of the present disclosure.

[0012] A non-destructive inspection device according to the present disclosure inspects the condition of a pipe including a bent portion. Fig. 1 is a diagram schematically illustrating the configuration of a non-destructive inspection device 1 according to one embodiment. An example of the configuration of a pipe 100 that is an object of inspection by the non-destructive inspection device 1 according to one embodiment will be described with reference to Fig. 1 .

[0013] In the present disclosure, the direction in which the axis O of the pipe 100 extends is referred to as the axial direction D1. The direction in which a circular path traced by rotation around the axis O extends is referred to as the circumferential direction D2. The axis O is located at the center of a flow path formed within the pipe 100 when the pipe 100 is viewed cut in a direction (radial direction) perpendicular to the axial direction D1.

[0014] As illustrated in FIG. 1 , the pipe 100 includes, in order from one side in the axial direction D1, an upstream portion 102, a bending portion 104, and a downstream portion 106. The upstream portion 102 extends linearly on one side in the axial direction D1 of the bending portion 104. As will be described later, a guided wave sensor is attached to the upstream portion 102. The downstream portion 106 extends linearly in a direction different from that of the upstream portion 102 on the other side in the axial direction D1 of the bending portion 104 (opposite to the one side in the axial direction D1). Hereinafter, the one side in the axial direction D1 will be referred to as the upstream side in the axial direction D1, and the other side in the axial direction D1 will be referred to as the downstream side in the axial direction D1.

[0015] The bending portion 104 extends in an arc shape, with an upstream end portion 108 on the upstream side in the axial direction D1 connected to the downstream end of the upstream portion 102, and a downstream end portion 110 on the downstream side in the axial direction D1 connected to the upstream end of the downstream portion 106. The bending portion 104 is connected to each of the upstream portion 102 and the downstream portion 106 by, for example, welding. Note that the bending portion 104 is not limited to the form illustrated in FIG. 1 as long as it connects the upstream portion 102 and the downstream portion 106, which extend in different directions.

[0016] (Configuration) The configuration of a non-destructive testing device 1 according to one embodiment will be described. As shown in Fig. 1 , the non-destructive testing device 1 includes a guided wave sensor 50 and an analysis device 60. In the embodiment illustrated in Fig. 1 , the non-destructive testing device 1 further includes a guided wave flaw detector 70.

[0017] The guided wave sensor 50 includes a plurality of elements 52 (a plurality of channels) that propagate a guided wave W through the pipe 100. When the pipe 100 includes a defect Dm (a portion where the thickness or shape of the pipe 100 changes), each of the plurality of elements 52 is configured to receive a reflected wave Wr, which is the guided wave W reflected from the defect Dm. In one embodiment, each of the plurality of elements 52 is configured to emit the guided wave W by the magnetostrictive effect. The magnetostrictive effect is a phenomenon in which application of a magnetic field to the pipe 100 changes the shape of the pipe 100. As illustrated in FIG. 1 , the guided wave sensor 50 is attached to the upstream portion 102 of the pipe 100. In some embodiments, some of the plurality of elements 52 are configured to receive the reflected wave Wr. In some embodiments, each of the plurality of elements 52 is configured to emit the guided wave W by the piezoelectric effect.

[0018] In one embodiment, the guided wave sensor 50 employs so-called full matrix capture (FMC), which is a data collection method in which a guided wave W emitted from one element 52 is received by all elements 52, and a reflected wave Wr is received by all elements 52.

[0019] FIG. 2 is a diagram schematically illustrating a configuration of a guided wave sensor 50 according to an embodiment. As illustrated in FIG. 2 , the guided wave sensor 50 includes a holder 54 that holds a plurality of elements 52. The holder 54 is made of a metal such as Ni and has a ring shape. The holder 54 is configured to be able to cover the upstream portion 102 of the pipe 100 from the outside. The plurality of elements 52 are arranged along the circumferential direction of the holder 54. When such a guided wave sensor 50 is attached to the upstream portion 102 of the pipe 100, the plurality of elements 52 are arranged side by side along the circumferential direction D2 in the upstream portion 102 of the pipe 100. Note that the number of elements 52 is not limited to the example illustrated in FIG. 2 and may be any number.

[0020] The analysis device 60 analyzes defects in the piping 100 based on the reflected wave Wr. The analysis device 60 is connected to the guided wave sensor 50 via a communication network 80. The analysis device 60 is, for example, a computer, and includes a processor such as a CPU or a GPU (not shown), a memory such as a ROM or a RAM, and an I / O interface. The analysis device 60 realizes each functional unit of the analysis device 60 by the processor operating (calculating, etc.) according to instructions of a program loaded into the memory. The functional units of the analysis device 60 will be described below with reference to FIG. 3 . In some embodiments, the analysis device 60 is a cloud server provided in a cloud environment.

[0021] The guided wave flaw detector 70 is electrically connected to the guided wave sensor 50 via the communication network 80, and acquires the detection value of the guided wave sensor 50. The guided wave flaw detector 70 is located between the guided wave sensor 50 and the analysis device 60 on the communication network 80, and converts the detection value of the guided wave sensor 50 and transmits it to the analysis device 60.

[0022] The communication network 80 is, for example, the Internet, and the guided wave sensor 50 and the analysis device 60 can exchange information with each other via the Internet. The guided wave sensor 50 transmits the detection value as data of the reflected wave Wr to the analysis device 60. Note that the communication network 80 is not limited to the Internet as long as the guided wave sensor 50 and the analysis device 60 can exchange information with each other. The communication network 80 may be wired or wireless.

[0023] 3 is a schematic functional block diagram of an analysis device 60 according to an embodiment. As shown in FIG. 3, the analysis device 60 includes a grid creation unit 2, a propagation path calculation unit 4, a delay time calculation unit 6, a composite wave generation unit 7, and an image generation unit 8. In one embodiment, the analysis device 60 further includes a cross-section defect rate calculation unit 20.

[0024] FIG. 4 is a diagram illustrating a virtual grid 12 (a TFM grid used in the TFM described later) according to an embodiment. As shown in FIG. 4 , the grid creation unit 2 creates the virtual grid 12 (a collection of grids 11) including a plurality of grids 11 obtained by dividing the pipe 100 along the axial direction D1 and the circumferential direction D2. In the embodiment illustrated in FIG. 4 , the grid creation unit 2 acquires shape data for an upstream section 102 in which a plurality of elements 52 are arranged, a bent section 104 downstream of the upstream section 102 in the axial direction D1, and a downstream section 106 downstream of the bent section 104 in the axial direction D1, and forms a rectangular grid 11 based on the acquired shape data. A short side 13 of the rectangular grid 11 is shorter than the wavelength of the guided wave W (see FIG. 5 ). In some embodiments, the grid 11 has a square shape. In some embodiments, one side of the square grid 11 is shorter than the wavelength of the guided wave W.

[0025] As shown in Fig. 4 , the propagation path calculation unit 4 calculates the propagation path 14 of the guided wave W propagating through the pipe 100 based on the virtual grid 12. Fig. 4 illustrates the propagation path 14 of a portion of the guided wave W emitted from the element 52 that enters the upstream portion 102 at a certain angle, but the propagation path calculation unit 4 also calculates the propagation path 14 of a portion that enters the upstream portion 102 at a different angle. That is, the propagation path calculation unit 4 calculates the propagation paths 14 of multiple guided waves W that are incident on one element 52 at different angles (incident angles) into the upstream portion 102 (the propagation path calculation unit 4 calculates the propagation path 14 for each incident angle). Furthermore, the propagation path calculation unit 4 calculates the propagation path 14 of the guided wave W for each of the multiple elements 52 arranged side by side along the circumferential direction D2.

[0026] FIG. 5 is a diagram illustrating an example of a method for calculating the propagation path 14. FIG. 5 illustrates four bend grids 11a, 11b, 11c, and 11d among the multiple grids 11, which correspond to the bend 104. The four bend grids 11a, 11b, 11c, and 11d are defined by three vertical lines extending along the circumferential direction D2 and three horizontal lines extending along the axial direction D1. The three vertical lines include, in order from one side of the axial direction D1, a first vertical line Lv1, a second vertical line Lv2, and a third vertical line Lv3. The three horizontal lines include, in order from one side of the circumferential direction D2, a first horizontal line Lh1, a second horizontal line Lh2, and a third horizontal line Lh3. The lower side of FIG. 5 is defined as one side of the circumferential direction D2, and the upper side of FIG. 5 is defined as the other side of the circumferential direction D2.

[0027] The first bend grid 11a (11) is defined by a first vertical line Lv1, a second vertical line Lv2, a first horizontal line Lh1, and a second horizontal line Lh2. The second bend grid 11b (11) is defined by a first vertical line Lv1, a second vertical line Lv2, a second horizontal line Lh2, and a third horizontal line Lh3. The third bend grid 11c (11) is defined by a second vertical line Lv2, a third vertical line Lv3, a first horizontal line Lh1, and a second horizontal line Lh2. The fourth bend grid 11d (11) is defined by a second vertical line Lv2, a third vertical line Lv3, a second horizontal line Lh2, and a third horizontal line Lh3.

[0028] As shown in Fig. 5, the propagation path 14 of the guided wave W extends linearly. The guided wave W incident on the upstream portion 102 at an incident angle θ1 penetrates the first bend portion grid 11a at an entrance angle θ11 with respect to the first vertical line Lv1, penetrates the second bend portion grid 11b at an entrance angle θ12 with respect to the second horizontal line Lh2, and penetrates the fourth bend portion grid 11d at an entrance angle θ13 with respect to the second vertical line Lv2. The propagation path calculation unit 4 calculates the propagation path 14 in the first bend portion grid 11a based on the entrance angle θ1 of the first bend portion grid 11a. Similarly, the propagation path calculation unit 4 calculates the propagation path 14 in the second bend portion grid 11b based on the entrance angle θ12 of the second bend portion grid 11b. The propagation path calculation unit 4 calculates a propagation path 14 in the fourth bend grid 11b based on the penetration angle θ13 of the fourth bend grid 11d. The smaller of the two angles formed by the guided wave W and the vertical line is defined as the penetration angle. Similarly, the smaller of the two angles formed by the guided wave W and the horizontal line is defined as the penetration angle.

[0029] In some embodiments, the propagation path calculation unit 4 calculates an entry position P1 where the guided wave W enters the first bend grid 11a, and calculates the propagation path 14 within the first bend grid 11a based on the entry angle θ11 of the first bend grid 11a and the entry position P1. Similarly, the propagation path calculation unit 4 calculates an entry position P2 where the guided wave W enters the second bend grid 11b, and calculates the propagation path 14 within the second bend grid 11b based on the entry angle θ12 of the second bend grid 11b and the entry position P1. The propagation path calculation unit 4 calculates an entry position P3 where the guided wave W enters the fourth bend grid 11d, and calculates the propagation path 14 within the fourth bend grid 11d based on the entry angle θ13 of the fourth bend grid 11d and the entry position P3. This configuration can improve the calculation accuracy of the propagation path 14.

[0030] The delay time calculation unit 6 calculates a delay time Td between the timings at which the reflected wave Wr is received for each of the plurality of elements 52. The composite wave generation unit 7 generates a composite wave Wc by correcting the reflected waves Wr received by each of the plurality of elements 52 based on the delay time Td and the propagation path 14 and then combining the waves. The image generation unit 8 generates an image Im based on the composite wave Wc.

[0031] In one embodiment, the analysis device 60 applies the so-called total focusing method (TFM). TFM is an image construction method that constructs an image by processing data of reflected waves Wr received by each of the multiple elements 52. As described above, the guided wave sensor 50 applies FMC, and therefore the non-destructive inspection device 1 according to one embodiment inspects the state of the pipe 100 by constructing an image Im of the pipe 100 including the bend 104 by FMC / TFM. The image construction method using FMC / TFM will be described with reference to FIGS. 6 to 8 .

[0032] 6 is a diagram illustrating a state in which each of the plurality of elements 52 according to an embodiment receives a reflected wave Wr. As illustrated in FIG. 6, the first element 521 (52) emits a guided wave W. The first element 521 (52), the second element 522 (52), and the third element 523 (52) each receive a reflected wave Wr that is the guided wave W reflected by the defect Dm. The first element 521, the second element 522, and the third element 523 have different propagation paths 14 of the reflected wave Wr, and therefore receive the reflected wave Wr at different times. In the present disclosure, the propagation path 14 of the reflected wave Wr from the defect Dm to the first element 521 is referred to as the first propagation path 141(14), the propagation path 14 of the reflected wave Wr from the defect Dm to the second element 522 is referred to as the second propagation path 142(14), and the propagation path 14 of the reflected wave Wr from the defect Dm to the third element 523 is referred to as the third propagation path 143(14). For the sake of explanation, it is assumed that the reflected wave Wr is received in the order of the first element 521, the second element 522, and the third element 523. Note that the number of elements 52 is arbitrary. Furthermore, since the guided wave W is also emitted from the second element 522 and the third element 523, one element 52 receives three reflected waves Wr. In other words, nine reflected waves Wr (number of elements × number of elements) are received.

[0033] The delay time calculation unit 6 calculates the time from when the first element 521 receives the reflected wave Wr until when the second element 522 receives the reflected wave as a second delay time Td2, and calculates the time from when the first element 521 receives the reflected wave Wr until when the third element 523 receives the reflected wave as a third delay time Td3. Note that the first delay time Td1, which is the delay time of the first element 521, is zero.

[0034] 7 is a diagram showing waveform data of the reflected wave Wr according to one embodiment. As shown in FIG. 7, the data of the reflected wave Wr received by the first element 521 includes a first waveform A1. Similarly, the data of the reflected wave Wr received by the second element 522 includes a second waveform A2. The data of the reflected wave Wr received by the third element 523 includes a third waveform A3.

[0035] The composite wave generating unit 7 generates a composite wave Wc based on the first waveform A1, the first delay time Td1, the first propagation path 141, the second waveform A2, the second delay time Td2, the second propagation path 142, the third waveform A3, the third delay time Td3, and the third propagation path 143.

[0036] In one embodiment, the composite wave generating unit 7 generates a corrected waveform by correcting the phase of the waveform of the reflected wave Wr received by each of the multiple elements 52 based on the delay time Td and the propagation path 14. Then, the multiple corrected waveforms are combined to generate a composite wave Wc. The generation of the composite wave Wc will be specifically described with reference to FIG. 8 .

[0037] 8 is a diagram illustrating a method for synthesizing waveform data of a reflected wave Wr according to an embodiment. The composite wave generating unit 7 shifts (corrects) the phase of the first waveform A1 by a first difference Δ1 calculated from the first propagation path 141 and the first delay time Td1 to generate a first correction waveform A11. Similarly, the composite wave generating unit 7 shifts (corrects) the phase of the second waveform A2 by a second difference Δ2 calculated from the second propagation path 142 and the second delay time Td2 to generate a second correction waveform A12. The composite wave generating unit 7 shifts (corrects) the phase of the third waveform A3 by a third difference Δ3 calculated from the third propagation path 143 and the third delay time Td3 to generate a third correction waveform A13. The composite wave generating unit 7 then generates a composite wave Wc of the composite waveform As by combining the first correction waveform A11, the second correction waveform A12, and the third correction waveform A13. Note that the first waveform A1 may be the same as the first correction waveform A11.

[0038] FIG. 9 is a diagram illustrating an image Im according to an embodiment. As illustrated in FIG. 9 , the image Im is a graph in which the horizontal axis represents the position in the axial direction D1 of the pipe 100 and the vertical axis represents the position in the circumferential direction D2 of the pipe 100. X0 is the position where the guided wave sensor 50 is installed. X1 is the position of the upstream end 108 of the bent portion 104. X2 is the position of the downstream end 110 of the bent portion 104. That is, an image of the upstream portion 102 of the pipe 100 is configured in the range from X0 to X1, an image of the bent portion 104 of the pipe 100 is configured in the range from X1 to X2, and an image of the downstream portion 106 of the pipe 100 is configured in the portion opposite to the X1 side from X2. Y0 and Y1 are not particularly limited, but for example, Y0 is the position of the upper end of the pipe 100 and Y1 is the position of the lower end of the pipe 100. As illustrated in FIG. 9 , in one embodiment, the image generating unit 8 generates an image Im of the downstream portion 106 of the pipe 100.

[0039] The image generating unit 8 maps the composite waveform As onto an image Im. For example, the image generating unit 8 applies a color corresponding to the magnitude of the amplitude of the composite waveform As to a position (X3, Y0) on the image Im corresponding to the timing at which the amplitude of the composite waveform As occurs. Therefore, as shown in FIG. 9 , the image generating unit 8 generates an image Im in which the position of the defect Dm is clearly indicated. The output destination of the image Im is not particularly limited, and may be, for example, the monitor of the analysis device 60.

[0040] The cross-sectional defect rate calculation unit 20 calculates the cross-sectional defect rate Sa by dividing the cross-sectional area reduction amount Sd by the pipe cross-sectional area S. The pipe cross-sectional area S and the cross-sectional area reduction amount Sd will be described with reference to FIG. 10 . FIG. 10 is a cross-sectional view of the pipe 100 cut along the axial direction D1. The pipe cross-sectional area S is the area occupied by the thick-walled portion 101 of the pipe 100 when viewed in cross section. The cross-sectional area reduction amount Sd is the area occupied by the defective portion Dm within the thick-walled portion 101 of the pipe 100 when viewed in cross section. The pipe cross-sectional area S and the cross-sectional area reduction amount Sd are each calculated based on, for example, waveform data of the reflected wave Wr.

[0041] (Actions and Effects) Actions and effects of the nondestructive inspection device 1 according to one embodiment will be described. In conventional nondestructive inspection devices, propagation of the guided wave W through the bend 104 of the piping 100 is complex, making it difficult to analyze the reflected wave Wr and reducing the accuracy of the state inspection. However, according to one embodiment, in order to analyze defects in the piping 100, an image Im is generated based on a composite wave Wc that includes not only the reflected wave Wr and the delay time Td but also the propagation path 14. This makes it possible to inspect the state of the piping 100, including the bend 104, with high accuracy. Furthermore, according to one embodiment, the image Im is generated by combining multiple correction waveforms (the first correction waveform A11, the second correction waveform A12, and the third correction waveform A13) with each other, so that an image Im that depicts the state of the piping 100 with high accuracy can be generated.

[0042] As described above, the propagation of the guided wave becomes complicated at the bend 104 of the pipe 100. Therefore, the propagation of the guided wave W is also complicated in the downstream portion 106 of the pipe 100, making it difficult to analyze the reflected wave Wr and reducing the accuracy of the state inspection. However, according to one embodiment, an image Im is generated in which the propagation path 14 in the downstream portion 106 of the pipe 100 is taken into consideration, so that the state of the downstream portion 106 of the pipe 100 can be inspected with high accuracy.

[0043] According to one embodiment, since each of the plurality of elements 52 is configured to emit the guided wave W by the magnetostrictive effect, the propagation distance of the guided wave W can be made longer compared to when a piezoelectric element is used to emit the guided wave W. According to one embodiment, the plurality of elements 52 are disposed in the upstream portion 102 of the pipe 100 away from the bend 104 of the pipe 100, so that the state of the bend 104 of the pipe 100 can be inspected with high accuracy. That is, in the non-destructive inspection device 1 according to the one embodiment, interference between the guided wave sensor 50 and the pipe 100 or peripheral members of the pipe 100 is suppressed.

[0044] According to one embodiment, the rectangular short side 13 of the grid 11 is shorter than the wavelength of the guided wave W, so that it is possible to prevent the occurrence of a grid 11 from which waveform information for creating the propagation path 14 cannot be acquired. Therefore, when the image Im is generated by the image generator 8, it is possible to prevent a portion of the image Im from being lost (display omission). Note that, in some embodiments, the rectangular short side 13 of the grid 11 is longer than the wavelength of the guided wave W or has the same length as the wavelength of the guided wave W. In this case, when a grid 11 from which waveform information cannot be acquired occurs, the grid 11 and the surrounding grids 11 (having waveform information) may be combined into one large grid 11 to prevent a portion of the image Im from being lost.

[0045] <Non-destructive inspection method> Fig. 11 is a flowchart of a non-destructive inspection method according to one embodiment. As shown in Fig. 10, the non-destructive inspection method includes a preparation step S1, a virtual grid creation step S2, a propagation path calculation step S3, a delay time calculation step S4, a composite wave generation step S5, and an image generation step S6.

[0046] In the preparation step S1, a guided wave sensor 50 including a plurality of elements 52 capable of propagating a guided wave W through a pipe 100 and receiving a reflected wave Wr of the guided wave W is prepared.

[0047] In the virtual grid creation step S2, a virtual grid 12 including a plurality of grids 11 obtained by dividing the pipe 100 along both the axial direction D1 and the circumferential direction D2 is created.

[0048] In the propagation path calculation step S3, a propagation path 14 along which the guided wave W propagates through the pipe 100 is calculated based on the virtual grid 12.

[0049] In the delay time calculation step S4, a delay time Td between the timing of receiving the reflected wave Wr for each of the plurality of elements 52 is calculated.

[0050] In the composite wave generating step S5, the reflected waves Wr received by each of the plurality of elements 52 are corrected based on the delay time Td and the propagation path 14, and then the corrected waveforms are combined to generate a composite wave Wc. In one embodiment, in the composite wave generating step S5, the phases of the waveforms of the reflected waves Wr received by each of the plurality of elements 52 are corrected based on the delay time Td and the propagation path 14 to generate corrected waveforms, and the plurality of corrected waveforms are combined to generate a composite wave Wc.

[0051] In the image generating step S6, an image Im is generated based on the composite wave Wc.

[0052] The contents described in each of the above embodiments can be understood, for example, as follows.

[0053] [1] A non-destructive inspection device (1) according to the present disclosure is a non-destructive inspection device for inspecting a state of a pipe (100) including a bend (104), comprising: a guided wave sensor (50) including a plurality of elements (52) capable of propagating a guided wave (W) through the pipe and receiving a reflected wave (Wr) of the guided wave; and an analysis device (60) that analyzes defects (Dm) in the pipe based on the reflected wave, wherein the analysis device comprises: a grid creation unit (2) that creates a virtual grid (12) including a plurality of grids (11) that divide the pipe along each of an axial direction (D1) and a circumferential direction (D2); a propagation path calculation unit (4) that calculates a propagation path (14) along which the guided wave propagates through the pipe based on the virtual grid; and a delay time calculation unit (6) that calculates a delay time (Td) between the timing of receiving the reflected wave for each of the plurality of elements. The system includes a composite wave generating unit (7) that generates a composite wave (Wc) by correcting the reflected waves received by each of the plurality of elements based on the delay time and the propagation path and then combining them together, and an image generating unit (8) that generates an image (Im) based on the composite wave.

[0054] In conventional non-destructive testing devices, the propagation of guided waves around bends in a pipe is complex, making it difficult to analyze reflected waves and resulting in low accuracy in condition inspection. However, according to the configuration described in [1] above, in order to analyze defects in the pipe, an image is generated based on a composite wave that includes not only reflected waves and delay times but also the propagation path. This makes it possible to inspect the condition of pipes, including bends, with high accuracy.

[0055] [2] In some embodiments, in the configuration described in [1] above, the composite wave generating unit generates corrected waveforms (A11, A12, A13) by correcting the phase of the waveforms (A1, A2, A3) of the reflected waves received by each of the plurality of elements based on the delay time and the propagation path, and generates the composite wave by combining the plurality of corrected waveforms with each other.

[0056] According to the configuration described in [2] above, it is possible to generate an image that depicts the state of the piping with high accuracy.

[0057] [3] In some embodiments, in the configuration described in [1] or [2] above, the pipe includes an upstream portion extending linearly upstream of the bent portion in the axial direction and having the guided wave sensor attached thereto, and a downstream portion (106) extending linearly downstream of the bent portion in the axial direction, and the image generating unit generates the image of the downstream portion of the pipe.

[0058] As described above, the propagation of guided waves becomes complicated at bends in a pipe. Therefore, the propagation of guided waves is also complicated in the downstream portion of the pipe, making it difficult to analyze reflected waves and reducing the accuracy of the condition inspection. However, according to the configuration described in [3] above, an image is generated that takes into account the propagation path in the downstream portion of the pipe, so that the condition of the downstream portion of the pipe can be inspected with high accuracy.

[0059] [4] In some embodiments, in the configuration according to any one of [1] to [3] above, each of the plurality of elements is configured to emit the guided wave by a magnetostrictive effect.

[0060] According to the configuration described in [4] above, the distance over which the guided wave can propagate can be increased compared to when the guided wave is generated using a piezoelectric element.

[0061] [5] In some embodiments, in the configuration described in any one of [1] to [4] above, the propagation path calculation unit calculates the propagation path for each incident angle (θ1) at which the guided wave is incident on a bend grid (11a, 11b, 11d) corresponding to the bend of the pipe among the plurality of grids.

[0062] According to the configuration described in [5] above, it is possible to calculate the propagation path required to generate an image.

[0063] [6] In some embodiments, in the configuration described in any one of [1] to [5] above, the pipe includes an upstream portion (102) that extends linearly upstream of the bent portion in the axial direction and to which the guided wave sensor is attached, and each of the plurality of elements is configured to emit the guided wave by magnetostriction effect and is arranged side by side in the circumferential direction in the upstream portion of the pipe.

[0064] According to the configuration described in [6] above, a plurality of elements are arranged in the upstream portion of the pipe, and the state of the bend in the pipe can be inspected with high precision.

[0065] [7] In some embodiments, in the configuration described in any one of [1] to [6] above, the grid has a rectangular shape, and a short side (13) of the rectangle is shorter than the wavelength of the guided wave.

[0066] According to the configuration described in [7] above, it is possible to prevent a part of the image from being lost (display omission).

[0067] [8] A non-destructive inspection method according to the present disclosure is a non-destructive inspection method for inspecting a state of a pipe (100) including a bend (104), the non-destructive inspection method comprising: a step (S1) of preparing a guided wave sensor (50) including a plurality of elements (52) capable of propagating a guided wave (W) through the pipe and receiving a reflected wave (Wr) of the guided wave; a step (S2) of creating a virtual grid (12) including a plurality of grids (11) obtained by dividing the pipe along each of an axial direction (D1) and a circumferential direction (D2); a step (S3) of calculating a propagation path (14) along which the guided wave propagates through the pipe based on the virtual grid; a step (S4) of calculating a delay time (Td) between the timing of receiving the reflected wave for each of the plurality of elements; a step (S5) of generating a composite wave (Wc) by correcting the reflected waves received by each of the plurality of elements based on the delay time and the propagation path and then combining the corrected reflected waves; and a step (S6) of generating an image (Im) based on the composite wave.

[0068] According to the method described in [8] above, the same effect as that described in [1] above can be achieved.

[0069] [9] In some embodiments, in the method described in [8] above, the step of generating the composite wave generates corrected waveforms (A11, A12, A13) by correcting the phase of the waveform of the reflected wave received by each of the plurality of elements based on the delay time and the propagation path, and generates the composite wave by combining the plurality of corrected waveforms with each other.

[0070] According to the method described in [9] above, the same effect as that described in [2] above can be achieved.

[0071] REFERENCE SIGNS LIST 1 Non-destructive inspection device 2 Grid creation unit 4 Propagation path calculation unit 6 Delay time calculation unit 7 Composite wave generation unit 8 Image generation unit 11 Grid 12 Virtual grid 13 Short side 14 Propagation path 20 Cross-sectional defect rate calculation unit 50 Guided wave sensor 52 Element 54 Holder 60 Analysis device 70 Guided wave flaw detector 80 Communication network 100 Pipe 101 Thick-walled portion of pipe 102 Upstream portion of pipe 104 Bend portion of pipe 106 Downstream portion of pipe 108 Upstream end of bend portion 110 Downstream end of bend portion 141 First propagation path 142 Second propagation path 143 Third propagation path 521 First element 522 Second element 523 Third element A1 First waveform A2 Second waveform A3 Third waveform A11 First corrected waveform A12 Second corrected waveform A13 Third corrected waveform As Composite waveform D1 Axial direction D2 Circumferential direction Dm Defective portion Im Image O Axis S Pipe cross-sectional area Sa Sectional defect rate Sd Sectional reduction amount Td Delay time Td1 First delay time Td2 Second delay time Td3 Third delay time W Guided wave Wr Reflected wave Wc Composite wave S1 Preparation step S2 Virtual grid creation step S3 Propagation path calculation step S4 Delay time calculation step S5 Composite wave generation step S6 Image generation step

Claims

1. A non-destructive inspection device for inspecting a condition of a pipe including a bend, comprising: a guided wave sensor including a plurality of elements capable of propagating a guided wave through the pipe and receiving a reflected wave of the guided wave; and an analysis device for analyzing defects in the pipe based on the reflected wave, the analysis device comprising: a grid creation unit that creates a virtual grid including a plurality of grids obtained by dividing the pipe along each of an axial direction and a circumferential direction; a propagation path calculation unit that calculates a propagation path along which the guided wave propagates through the pipe based on the virtual grid; a delay time calculation unit that calculates a delay time of a timing for receiving the reflected wave for each of the plurality of elements; a composite wave generation unit that generates a composite wave by correcting the reflected waves received by each of the plurality of elements based on the delay time and the propagation path and then combining the reflected waves; and an image generation unit that generates an image based on the composite wave.

2. The non-destructive testing device according to claim 1, wherein the composite wave generating unit generates a corrected waveform by correcting the phase of the waveform of the reflected wave received by each of the plurality of elements based on the delay time and the propagation path, and generates the composite wave by combining the plurality of corrected waveforms together.

3. A non-destructive inspection device as described in claim 1 or 2, wherein the piping includes an upstream portion extending linearly upstream of the bend in the axial direction and to which the guided wave sensor is attached, and a downstream portion extending linearly downstream of the bend in the axial direction, and the image generating unit generates the image of the downstream portion of the piping.

4. The non-destructive inspection device according to claim 1 or 2, wherein each of the plurality of elements is configured to generate the guided wave by magnetostriction effect.

5. The non-destructive inspection device according to claim 1 or 2, wherein the propagation path calculation unit calculates the propagation path for each incident angle at which the guided wave is incident on a bend grid among the plurality of grids that corresponds to the bend in the pipe.

6. The non-destructive inspection device according to claim 1 or 2, wherein the piping includes an upstream portion that extends linearly upstream of the bent portion in the axial direction and to which the guided wave sensor is attached, and each of the plurality of elements is configured to emit the guided wave by magnetostriction effect, and is arranged side by side in the circumferential direction in the upstream portion of the piping.

7. A non-destructive inspection device according to claim 1 or 2, wherein the grid has a rectangular shape, and a short side of the rectangular shape is shorter than the wavelength of the guided wave.

8. A non-destructive inspection method for inspecting a condition of a pipe including a bend, comprising the steps of: preparing a guided wave sensor including a plurality of elements capable of propagating a guided wave through the pipe and receiving a reflected wave of the guided wave; creating a virtual grid including a plurality of grids obtained by dividing the pipe along both the axial direction and the circumferential direction; calculating a propagation path along which the guided wave propagates through the pipe based on the virtual grid; calculating a delay time for the timing at which the reflected wave is received for each of the plurality of elements; generating a composite wave by correcting the reflected waves received by each of the plurality of elements based on the delay time and the propagation path and then combining the reflected waves; and generating an image based on the composite wave.

9. The non-destructive testing method according to claim 8, wherein the step of generating the composite wave comprises generating a corrected waveform by correcting the phase of the waveform of the reflected wave received by each of the plurality of elements based on the delay time and the propagation path, and generating the composite wave by combining the plurality of corrected waveforms with each other.