JP2018179854A - Method and apparatus for evaluating crack closure processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crack closure processing evaluation method capable of accurately evaluating whether or not crack development delay effects can be sufficiently acquired by the crack closure processing such as ICR processing.SOLUTION: A crack closure processing evaluation method such as an ICR processing includes: a measuring step before the processing of measuring a temperature change before the processing, the temperature change generated by a thermoelastic effect at a tip end of a crack 106 of a structure part 102, while applying a fluctuating load to the structure part 102 before performing the ICR processing; a measuring step after the processing of measuring a temperature change after the processing, the temperature change generated by the thermoelastic effect at the tip end of the crack 106 of the structure part 102 subjected to the closure processing, while applying the fluctuating load to the structure part 102, after the ICR processing has been performed; and an evaluation step of evaluating a development delay effect of the ICR processing on the crack 106 on the basis of the temperature change before the processing and the temperature change after the processing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a crack closure processing evaluation method and evaluation apparatus.

  In a steel structure such as a bridge or a large crane, when used for a long time, a crack may occur on the surface of the structure due to a cause such as fatigue. Since the crack develops and spreads when it is left, it is necessary to apply a treatment to slow the growth of the crack and extend the fatigue life of the structure.

  Therefore, as a technique for slowing down the crack growth, a crack closing treatment, for example, an impact crack closing treatment, that is, an ICR (Impact Crack Closure Retrofit Treatment) is known as a technique for closing a crack opening. The ICR process is a technology that reduces the stress intensity factor range and delays crack propagation by partially impacting the crack periphery on the surface of the structure to close the crack opening.

  After ICR treatment of the structure, the opening of the crack in the surface of the structure is closed. Therefore, it is difficult to evaluate the effect of delaying the crack growth by the ICR treatment, that is, the crack growth delay effect, only by visually recognizing the structure after the ICR treatment from the outside.

  Therefore, as a method of evaluating whether or not the crack growth delay effect is obtained after the ICR treatment, a method of confirming the crack closure by the nondestructive test after the ICR treatment can be considered.

  Non-Patent Document 1 discloses a magnetic particle flaw test and a penetration flaw test as representative nondestructive tests.

  In the magnetic particle flaw detection test, a leakage flux is generated in the vicinity of the crack by magnetizing the test object. By applying iron powder to the surface of the test object in this state, the iron powder is attracted to the leakage flux generated by the crack, and it is possible to investigate the presence or absence of the crack by the distribution of the iron powder in the test object.

  In the penetrant test, a red liquid called penetrant is applied to the surface of the test object, so that the penetrant is penetrated into the test object through the crack by the action of capillary action. Thereafter, the penetrant adhering to the surface of the test body is removed and a white fine powder called a developer is applied, whereby the penetrant remaining inside the crack is sucked out to make the crack shape appear red. This makes it possible to check the presence or absence of micro cracks.

Japan Non-Destructive Inspection Association Issue "Magnetic Particle Testing II"

  Although the above-mentioned magnetic particle flaw test and penetration flaw test can both detect the presence or absence of cracks on the surface of the test object, the crack growth delay in the test object after the crack on the surface of the test object is closed by the ICR process There is a problem that it is not possible to accurately evaluate whether an effect is obtained.

  That is, in the above-described magnetic particle flaw detection test, it is possible to detect the presence or absence of a crack generated not only on the surface of the test object but also inside the test object immediately below the surface. Therefore, even in the state where the opening of the surface of the test object is closed by the ICR process, if the micro crack remains inside the test object, it is possible to detect the micro internal crack. However, since ICR treatment is a method for obtaining a crack growth delay effect by closing the opening of a crack, there is a problem that accurate evaluation can not be performed even if magnetic particle flaw testing is used for evaluation of the crack growth delay effect after ICR treatment.

  Further, in the case of the penetrant flaw detection test, the penetrant may remain in the uneven portion on the surface of the test object caused by the impact of the ICR treatment, and a pseudo pattern similar to a crack may occur. In addition, if cleaning is performed many times in order to remove the penetrant from this uneven part, the penetrant that has penetrated into the open crack will also be sucked out, resulting in an over-cleaned state, and even if a developer is applied, no instruction may be obtained. . Therefore, there is a problem that accurate evaluation can not be performed even when the penetration flaw test is used to evaluate the crack growth delay effect after ICR treatment.

  The present invention has been made in view of the circumstances as described above, and it is possible to accurately evaluate whether the crack propagation delay effect such as ICR treatment can sufficiently obtain the crack propagation delay effect. The purpose is to provide a process evaluation method.

  In order to solve the above problems, the crack closure treatment evaluation method of the present invention is a method for evaluating a crack closure treatment for closing the opening of a crack generated on the surface of a structure, and before performing the crack closure treatment And a measurement step of measuring the temperature change before treatment which is a temperature change caused by the thermoelastic effect at the tip of the crack of the structure while applying a variable load to the structure, and after performing the crack closing treatment A post-processing measurement step of measuring a post-treatment temperature change which is a temperature change caused by the thermoelastic effect at the tip of the crack of the closed structure of the structure while applying the variable load to the structure; And evaluating the crack propagation delay effect by the crack closing process based on the change and the post-treatment temperature change.

  According to this feature, before performing the crack closing treatment for closing the crack generated on the surface of the structure, in the measurement step before the treatment, the differential stress is applied to the tip of the crack by applying a variable load to the structure. As it occurs, the specific stress field is measured as a pre-treatment temperature change at the tip of the crack caused by the thermoelastic effect. Furthermore, after the crack closing treatment, the post-treatment measurement process measures the post-treatment temperature change caused by the thermoelastic effect at the tip of the crack by applying a variable load to the structure. Thereafter, in the evaluation step, it is evaluated whether the specific stress field disappears by the crack closing treatment and the crack growth delay effect is obtained based on the pre-processing temperature change and the post-processing temperature change. Thereby, it is possible to accurately evaluate whether the crack propagation delay effect by the crack closing process is obtained without being affected by the state of the surface of the structure.

  Preferably, the pre-treatment temperature change and the post-treatment temperature change are relative temperature changes of the temperature change of the tip of the crack to the temperature change of the place away from the crack.

  Since the tip of the crack is affected by the thermoelastic effect when subjected to a fluctuating load as compared to the other parts of the structure, the temperature change at a location away from the crack as the pre-treatment temperature change and the post-treatment temperature change By using the relative temperature change of the temperature change of the tip of the crack with respect to, it is possible to measure a minute temperature change.

  In the evaluation step, when the peak in the time series graph of the temperature change before processing disappears in the time series graph of the temperature change after processing, it is preferable to evaluate that the crack progress delay effect is present.

  According to this feature, since the crack growth delay effect is evaluated using the time series graph of the pre-treatment temperature change and the time series graph of the post-treatment temperature change, the evaluation can be performed quickly and easily.

  In the pre-treatment measurement step, a pre-treatment thermal image which is a temperature distribution at the tip of the crack is measured as the pre-treatment temperature change, and in the post-treatment measurement step, the tip of the crack as the post-treatment temperature change The post-processing thermal image which is the temperature distribution in the part is measured, and in the evaluation step, the pre-processing thermal image and the post-processing thermal image are compared to evaluate the crack growth delay effect by the crack closing process. preferable.

  According to this feature, if the pre-processing thermal image and the post-processing thermal image, which are the temperature distribution at the tip of the crack, are measured before and after the crack closing processing, the pre-processing thermal image and the post-processing thermal image are evaluated in the evaluation step. By comparing with the image, it is possible to easily evaluate the crack propagation delay effect by the crack closing process.

  The crack closing process is an impact crack closing process for closing the opening of the crack by applying an impact to the periphery of the crack in the structure, and the evaluation process is performed after the impact crack closing process. Is preferred.

  According to this feature, the impact crack closing treatment for closing the opening of the crack by applying an impact to the periphery of the crack in the structure rapidly exerts the effect of delayed crack propagation in the structure after the treatment. . Therefore, it is possible to quickly evaluate the presence or absence of the crack growth delay effect by performing the evaluation step at the site where the impact crack closing treatment is performed after the impact crack closing treatment.

  It is preferable that the above-mentioned crack closure processing evaluation method further includes a reclosing processing step in which the impact crack closure processing is performed again when it is evaluated that there is no crack propagation delay effect in the above evaluation step.

  According to this feature, when it is evaluated that there is no crack propagation delay effect in the evaluation process immediately after performing the impact crack closing treatment, the crack propagation delaying process is performed by performing the impact crack closing treatment again. It becomes possible to obtain the effect surely.

  The crack closing treatment evaluation apparatus according to the present invention is an evaluation unit for evaluating a crack closing treatment for closing an opening of a crack generated on a surface of a structure, wherein the crack of the structure is given by applying a variable load to the structure. A temperature change measurement unit that measures a temperature change caused by a thermoelastic effect at the tip of the tip, and an evaluation unit that evaluates a crack growth delay effect by the crack closing treatment based on the temperature change before and after the crack closing treatment; It is characterized by having.

  According to this configuration, when evaluating the crack growth delaying effect by the crack closing treatment, first, the structure is given a variable load before and after the crack closing treatment which closes the crack generated on the surface of the structure. The temperature change measuring unit measures the temperature change and the temperature change after processing at the tip of the crack caused by the thermoelastic effect. And an evaluation part evaluates the crack progress delay effect by crack closure processing based on the above-mentioned temperature change before and behind crack closure processing. Thereby, it is possible to accurately evaluate whether or not the crack propagation delay effect by the crack closing process is obtained without being affected by the state of the surface of the structure.

  As described above, according to the crack closure processing evaluation method and evaluation apparatus of the present invention, it can be accurately evaluated whether the crack propagation delay effect such as ICR processing is sufficiently obtained. .

It is a block diagram roughly explaining the composition of the crack closure processing evaluation device concerning the embodiment of the present invention. It is a flowchart which shows the procedure of the crack closing process evaluation method which concerns on embodiment of this invention. It is a flowchart which shows the concrete procedure of temperature change measurement before and behind the ICR process of FIG. It is a figure which shows the thermal image of crack part vicinity of the girder of the overhead crane image | photographed with the infrared camera of FIG. 1 before ICR process. It is a figure which shows the difference image created by carrying out the image processing of the thermal image of FIG. It is a graph which shows the relationship between the frame number before an ICR process, and the temperature change before a process. It is a figure which shows the difference image created by carrying out image processing of the thermal image after ICR processing. It is a graph which shows the relationship between the frame number after an ICR process, and a temperature change after a process.

  Hereinafter, embodiments of the crack closure processing evaluation method and evaluation apparatus of the present invention will be described in more detail with reference to the drawings.

  The structure to be an evaluation target of the crack closure processing evaluation method of the present embodiment is, for example, a large steel steel structure such as a large overhead crane or a bridge.

  FIG. 1 shows a large overhead crane 100 as an example of a structure. The overhead crane 100 has a configuration for suspending and transporting heavy loads such as steel materials inside a building such as a factory. The overhead crane 100 is disposed on the upper surface of a girder (main girder) 102 which is a horizontally extending steel column reinforced with a plurality of reinforcing ribs 101 and the girder 102, and can reciprocate in the longitudinal direction of the girder 102. And a dolly (cart) 103. The carriage 103 has a mechanism for moving the suspended load 104 up and down. The girder 102 is movable in the direction perpendicular to the sheet of FIG. 1 by a movement mechanism (not shown).

  The girder 102 is reinforced by a plurality of reinforcing ribs 101 welded to the surface, but fatigue cracks 106 are generated by long-term fluctuation load generated by movement of the carriage 103 and lifting and lowering of the suspended load 104 and the like. There is a case. The crack 106 is generated so as to surround the lower end 105 of the girder 102 where stress is likely to be concentrated, for example, the lower end 105 of the reinforcing rib 101.

  The position of the crack 106 of the girder 102 is checked in advance by nondestructive inspection such as ultrasonic flaw detection before the ICR treatment.

  The crack 106 produced on the surface of the girder 102 is closed by the above-mentioned ICR process in order to delay the development of the crack 106. In the ICR process, the periphery of the crack 106 is impacted using a tool such as a flux chipper to close the opening of the crack 106 by causing the meat of the periphery to approach the crack 106 by the impact. In order to partially impact the periphery of the crack 106, for example, a rod-like object such as a tag attached to the tip of the flux chipper is brought into contact with the periphery of the crack 106, and the flux chipper to the tagane is continuous. It is done by giving a shock. As described above, the ICR treatment brings the peripheral meat close and the opening of the crack 106 closes, so that the specific stress field at the tip 106a, 106b (see FIG. 5) of the crack 106 disappears, and the development of the crack 106 is delayed. It is possible to

  In the present embodiment, in order to evaluate the development delay effect of the crack 106 by the ICR process, the development delay effect is evaluated using the crack closure processing evaluation apparatus 1 (hereinafter referred to as the evaluation apparatus 1) shown in FIG.

  The evaluation device 1 includes an infrared imaging device 2 and a processing device 3.

  The infrared imaging device 2 has a configuration capable of continuously capturing a thermal image by sensing infrared radiation emitted from an object, and is, for example, an infrared video camera or an infrared thermography device. The infrared imaging device 2 is installed at a position and an angle at which the crack 106 of the girder 102 can be continuously photographed even while the girder 102 and the carriage 103 are moving. Since the infrared imaging device 2 such as an infrared video camera has a size and weight that can be carried by hand by the operator, the installation location of a structure such as a large overhead crane or bridge to be evaluated for the crack closure processing evaluation method Can be easily transported to

  The processing device 3 includes an image recording unit 4, an image processing unit 5, a temperature change measurement unit 6, and an evaluation unit 7.

  The image recording unit 4 records a thermal image (for example, a thermal image of the crack 106 and its periphery shown in FIG. 4) continuously acquired by the infrared imaging device 2.

  The image processing unit 5 performs image processing to make it easy to see the temperature change of the tip portions 106a and 106b of the crack 106 like the differential image of FIG. 5 described later and the thermal image of FIG. 4 recorded in the image recording unit 4 .

  The temperature change measurement unit 6 measures the temperature change caused by the thermoelastic effect at the tip portions 106 a and 106 b of the crack 106 of the structure by giving a variable load to the structure such as the girder 102 of the overhead crane 100. The method of measuring the temperature change will be described in the item of the description of the evaluation method in the later stage.

  The evaluation unit 7 evaluates the crack growth delay effect by the ICR process based on the temperature change before and after the crack closing process such as the ICR process.

(Description of evaluation method)
Next, the evaluation method of the crack closing process using the evaluation apparatus 1 configured as described above will be described according to the procedure shown in the flowchart of FIG.

  First, in step S1 of FIG. 2, before performing the ICR process, while applying a fluctuating load to the girder 102 of the overhead crane 100, measure the pre-treatment temperature change which is the temperature change caused by the thermoelastic effect at the tip of the crack of the girder. Perform (pre-treatment measurement process).

  Specifically, the pre-processing measurement process of step S1 is specifically performed according to the procedure shown in the flowchart of FIG.

  First, in the image recording step of step S11 in FIG. 3, a thermal image is continuously captured by the infrared imaging device 2 (for example, 150 frames or more per second and a thermal image of 1600 frames or more are captured). The image recording unit 4 records the above-mentioned thermal image taken continuously. For example, as shown in FIG. 4, a thermal image of a downwardly projecting semicircular crack 106 generated around the lower end 105 of the reinforcing rib 101 in the surface of the girder 102 and its peripheral portion is shown as shown in FIG. ing. The thermal image shows the temperature distribution in the range of approximately 44.5 to 45 ° C. by shading of pixels.

  The thermal image in the vicinity of the crack 106 on the surface of the girder 102 is obtained by photographing with the infrared imaging device 2 the temperature distribution generated by the thermoelastic effect generated when a variable load is applied to the crack 106. The fluctuating load that can be applied to the crack 106 is, for example, reciprocating the carriage 103 on the girder 102 linearly with the suspension load 104 having a weight close to the rated load suspended from the carriage 103 in FIG. It can be generated by moving horizontally in the direction perpendicular to the paper surface of 1.

  For example, the thermal image is continuously captured by the infrared imaging device 2 at a speed of 150 frames or more per second, and the thermal image of 1600 frames or more is stored in the image recording unit 4.

  Next, in the image processing step of step S12 in FIG. 3, the image processing unit 5 performs image processing to make it easy to see the temperature change at the tip of the crack 106 in the thermal image recorded in the image recording unit 4.

  In the image processing unit 5, for example, a standard thermal image obtained by averaging the thermal images of the initial stage of recording from the start of recording to several tens of frames is created and measured using the thermal image of the standard By taking the difference between the thermal image of the frame and the reference thermal image for all the frames of the thermal image, a plurality of difference images corresponding to all the frames are created. For example, in the difference image shown in FIG. 5, it is shown that the whiter portion has a larger temperature change.

  Thereafter, in the temperature change measurement step of step S13 in FIG. 3, the temperature change measurement unit 6 derives the temperature change at the tip portions 106 a and 106 b of the crack 106. Specifically, the temperature change is calculated from the difference in color value of the pixel at the position designated by the user. For example, the temperature change is calculated from the difference between the color values of the pixels at any one of the tip portions 106 a and 106 b of the crack 106 and the position 107 where the influence of the crack 106 is small. In the present embodiment, for each of the tip portions 106a and 106b of the crack 106, the temperature change is calculated from the difference in color value of the pixel from the position 107 described above.

  In the difference image (see FIG. 5) generated by the image processing unit 5 described above, the temperature change measuring unit 6 has a portion (whitened portion) where the temperature change of the tip portions 106a and 106b of the crack 106 is large; At positions 107 (non-whitened portions) where the influence of the crack 106 slightly away from the crack 106 is small, respective temperature changes are respectively derived from the plurality of difference images. At a position 107 away from the crack 106, it is not white because the degree of temperature rise caused by the thermoelastic effect is small, and it is gray as in the other parts.

  Further, the temperature change measurement unit 6 calculates, for each frame, the difference in temperature change between the portion where the temperature change of the tip portions 106 a and 106 b of the crack 106 is large and the position 107 where the influence of the crack 106 slightly away from the crack 106 is small. Then, a time-series graph of temperature change at the tip portions 106a and 106b of the crack 106 as shown in FIG. 6 is created. That is, the graph of FIG. 6 shows the pre-processing temperature change which is the temperature change before the ICR process.

  The line P1 in FIG. 6 shows the change in temperature before treatment, which is the temperature difference between one end 106a of the crack 106 and the position 107 where the influence of the crack 106 is small, and the line P2 shows the other end 106b of the crack 106 and The temperature change before processing which is the temperature difference from the position 107 where the influence of the crack 106 is small is shown. It can be seen that in the lines P1 and P2 of FIG. 6, the temperature change shows a peak (maximum value) around 1400 frames.

  After the pre-processing temperature change measurement process of step S1 of FIG. 2 described above, the crack 106 of the overhead crane 100 is subjected to the above-described ICR process in step S2 to close the opening of the crack 106.

  After that, in step S3 of FIG. 2, after performing ICR processing, measure the post-treatment temperature change which is the temperature change caused by the thermoelastic effect at the tip of the crack of the girder while giving a fluctuating load to the girder 102 of the overhead crane 100. (Measurement process after treatment).

  The post-processing measurement step of step S3 is also performed in accordance with the procedure shown in the flowchart of FIG. 3 as in the pre-processing measurement step of step S1 described above.

  That is, in the image recording step of step S11 in FIG. 3, the infrared image pickup device 2 continuously shoots a thermal image in the crack 106 after ICR processing and its peripheral portion, and continuously captures the thermal image as an image recording unit Record in 4.

  Next, in the image processing step of step S12 in FIG. 3, the image processing unit 5 performs the same process as described above in order to make it easy to see temperature changes near the tip portions 106a and 106b of the crack 106 in the thermal image recorded in the image recording unit 4. Perform image processing. That is, using a plurality of thermal images captured and recorded continuously after the ICR process, the ICR processed image is obtained by averaging the thermal images of the initial stage of recording from the recording start to several tens of frames. By creating a reference thermal image and using the reference thermal image to calculate the difference between the thermal image of the frame and the reference thermal image for all the frames after the initial stage of the thermal image measured after the ICR process. A plurality of difference images corresponding to all processed frames are created.

  If the difference image shown in FIG. 7 is viewed on a monitor (not shown) or the like, it can be seen that asperities generated by the impact of the ICR process are formed in the vicinity of the crack 106. Moreover, it is confirmed that the whitened portions (that is, the portions of the temperature change corresponding to the singular stress field) are eliminated at the tip portions 106a and 106b of the crack 106.

  Thereafter, in the temperature change measurement step of step S13 in FIG. 3, the temperature change caused by the thermoelastic effect at the tip portions 106a and 106b of the crack 106 after the ICR process is measured. Specifically, in the difference image after ICR processing (see FIG. 7) created by the image processing unit 5 described above, the temperature change measurement unit 6 includes the portion of the tip portions 106a and 106b of the crack 106 and the crack 106 The respective temperature changes are respectively extracted from the plurality of difference images described above at a position 107 slightly away from.

  The temperature change measurement unit 6 further calculates, for each frame, the difference in temperature change between the portion of the tip portions 106 a and 106 b of the crack 106 after ICR processing and the position 107 where the influence of the crack 106 slightly away from the crack 106 is small. Then, the temperature change caused by the crack 106 as shown in FIG. 8 is extracted.

  FIG. 8 shows the post-processing temperature change which is the temperature change after the ICR process. Line P1 shows the temperature change after processing which is the temperature difference between one tip 106a of crack 106 and position 107 away from crack 106, and line P2 is away from the other tip 106b of crack 106 and crack 106 It shows a temperature change after processing which is a temperature difference from the position 107. In any of the lines P1 and P2 in FIG. 8, no locally elevated peaks as shown by the lines P1 and P2 in FIG. 6 appear, that is, no temperature rise due to a specific stress field occurs. I understand.

  After the pre-processing temperature change measurement step of step S3 of FIG. 2, the pre-processing temperature change shown in the graph of FIG. 6 for the tip portions 106a and 106b of the crack 106 and the post-processing temperature change shown in FIG. Based on the evaluation process to evaluate the crack growth delay effect by ICR treatment. Specifically, the evaluation unit 7 causes the peak of the graph of the temperature change before processing of FIG. 6 (maximum value of 0.1 ° C. appearing in 1400 frames) to disappear in the graph of the temperature change after processing shown in FIG. Determine if it is. Specifically, the difference in temperature between one tip 106 a of the crack 106 and the position 107 away from the crack 106 falls below a predetermined threshold (for example, about 0.02 to 0.03 ° C.), and When the difference in temperature between the other tip 106a of the crack 106 and the position 107 away from the crack 106 falls below the above threshold, the evaluation unit 7 loses the peak in the graph of FIG. Determine that it is. It is evaluated that there exists the crack progress delay effect by ICR process by this.

  On the other hand, either one of the difference in temperature between one tip 106 a of the crack 106 and the position 107 away from the crack 106 and the difference in temperature between the other tip 106 a and the position 107 away from the crack 106 is If the threshold value is exceeded, the evaluation unit 7 determines that the peak has not disappeared in the graph of FIG. In that case, by performing the ICR process again, it is possible to reliably obtain the crack growth delay effect by the ICR process. The present invention is not limited to the evaluation method using both of the tip portions 106a and 106b of the crack 106 as described above, and only one of the tip portions 106a and 106b of the crack 106 may be used for cracking. Progress delay effects may be assessed.

  As described above, in the evaluation method and the evaluation apparatus 1 of the present embodiment, before performing the ICR process which is the crack closing process for closing the crack 106 generated on the surface of the girder 102 of the overhead crane 100 which is a structure, measurement before treatment In the process, a singular stress field is generated at the tip portions 106a and 106b of the crack 106 by applying a variable load to the girder 102 of the overhead crane 100. Therefore, the tip of the crack 106 is generated by the thermoelastic effect. The temperature change measuring unit 6 measures the temperature change before processing in the units 106a and 106b. Furthermore, after performing the ICR process, in the post-process measurement step, the post-process temperature change caused by the thermoelastic effect at the tip portions 106 a and 106 b of the crack 106 is given by the fluctuating load to the girder 102. Measured by Thereafter, in the evaluation step, the evaluation unit 7 evaluates whether or not the crack growth delay effect is obtained by the crack closure processing based on the pre-processing temperature change and the post-processing temperature change. Thereby, it is possible to accurately evaluate whether the crack growth retarding effect by the crack closing process is obtained without being affected by the state of the surface of the girder 102.

  Further, in the evaluation method of the present embodiment, the relative temperature change of the temperature change of the tip portions 106a and 106b of the crack 106 to the temperature change of the place away from the crack 106 is used as the pre-processing temperature change and the post-processing temperature change. Be The tip portions 106a and 106b of the crack 106 are separated from the crack 106 as the pre-treatment temperature change and the post-treatment temperature change because the influence of the thermoelastic effect when subjected to the fluctuating load is large as compared with the other parts of the girder 102. By using the relative temperature change of the temperature change of the tip portion 106a, 106b of the crack 106 with respect to the temperature change of the place, it is possible to measure a minute temperature change.

  Further, in the evaluation method of the present embodiment, in the evaluation step, the peak in the time series graph of the temperature change before processing shown in FIG. 6 disappears in the time series graph of the temperature change after processing shown in FIG. It is evaluated that there is a crack progress delay effect. In this evaluation method, since the crack growth delay effect is evaluated using the time series graph of the temperature change before processing and the time series graph of the temperature change after processing, the evaluation can be performed quickly and easily.

  The crack closing process evaluated by the evaluation method of this embodiment is an ICR process (impact crack closing process) for closing the opening of the crack 106 by applying an impact to the periphery of the crack 106 of the girder 102. There is no need to move to a dedicated location for ICR processing. For this reason, it is possible to perform an evaluation process in the field where ICR processing was performed after performing impact crack closing processing. In the ICR process, compared with other crack closing processes (for example, a process of inserting an alumina paste into a crack 106 described later, etc.), the delayed crack propagation effect is rapidly exhibited in the girder 102 after the process. . Therefore, it is possible to quickly evaluate the presence or absence of the crack propagation delay effect by performing the evaluation process at the site where the ICR process is performed after the impact crack closing process.

  In the present invention, in the above embodiment, as the crack closing process, the crack progress delaying effect on the impact crack closing process (ICR process) for closing the opening of the crack 106 by giving an impact to the periphery of the crack 106 of the girder 102. Although the evaluation method to evaluate the is shown, the present invention is not limited thereto. According to the present invention, it is possible to evaluate various crack closing treatments if it is a closing treatment for closing the opening of the crack 106. For example, the evaluation of the present invention also applies to a crack closing treatment in which alumina paste is inserted into the crack 106 It is possible to apply the method.

  The evaluation method of the present embodiment includes the re-closing process step of performing the ICR process (impact crack closing process) again when it is evaluated that there is no crack progress delay effect in the evaluation process. Therefore, if it is evaluated that there is no crack propagation delay effect in the evaluation process at the site where ICR treatment is performed after ICR treatment, crack propagation delay effect can be obtained by performing the re-closing treatment step of performing ICR treatment again. It will be possible to obtain for sure.

(Modification)
(A)
In the above embodiment, the evaluation unit 7 automatically determines whether the peak of the pre-processing temperature change graph of FIG. 6 disappears in the post-processing temperature change graph shown in FIG. The present invention is not limited to this, and a worker may judge these graphs by a worker who looks at a monitor (not shown) or the like.

(B)
As a modification of the evaluation method of the present invention, in the pre-processing measurement step, the pre-processing thermal image (for example, the difference image in FIG. 5) which is the temperature distribution at the tip portions 106a and 106b of the crack 106 as the pre-processing temperature change. In the post-process measurement step, a post-process thermal image (eg, the difference image of FIG. 7), which is a temperature distribution at the tip portions 106a and 106b of the crack 106, is measured as a post-process temperature change. The thermal image and the post-process thermal image may be compared to evaluate the crack growth delay effect by the crack closure process.

  In this case, if the pre-processing thermal image and the post-processing thermal image, which are the temperature distribution at the tip portions 106a and 106b of the crack 106, are measured before and after the crack closing processing, these pre-processing thermal images and the post-processing thermal image By comparing with the thermal image, it is possible to easily evaluate the crack growth delay effect by the crack closing process.

DESCRIPTION OF SYMBOLS 1 crack closing processing evaluation apparatus 2 infrared imaging device 3 processing apparatus 6 temperature change measurement part 7 evaluation part 100 overhead crane 102 girder 106 crack 106a, 106b tip of crack

Claims (7)

A method of evaluating a crack closure process for closing the opening of a crack formed on the surface of a structure, comprising:
A pre-treatment measuring step of measuring a pre-treatment temperature change which is a temperature change caused by a thermoelastic effect at the tip of the crack of the structure while applying a variable load to the structure before performing the crack closing treatment;
After processing the temperature change after processing, which is the temperature change caused by the thermoelastic effect at the tip of the crack subjected to the closing treatment of the structure while applying the variable load to the structure after performing the crack closing treatment Measurement process,
Evaluating the crack growth retarding effect by the crack closing treatment based on the pre-treatment temperature change and the post-treatment temperature change.
Crack closure treatment evaluation method. The pre-treatment temperature change and the post-treatment temperature change are relative temperature changes of the temperature change of the tip of the crack to the temperature change of the place away from the crack,
The crack closure processing evaluation method according to claim 1. In the evaluation step, when the peak in the time series graph of the temperature change before processing disappears in the time series graph of the temperature change after processing, it is evaluated that the crack progress delay effect is present.
The crack closure processing evaluation method according to claim 1 or 2. In the pre-process measurement step, a pre-process thermal image, which is a temperature distribution at the tip of the crack, is measured as the pre-process temperature change,
In the post-process measurement step, a post-process thermal image, which is a temperature distribution at the tip of the crack, is measured as the post-process temperature change,
In the evaluation step, the pre-processing thermal image and the post-processing thermal image are compared to evaluate the crack growth delay effect by the crack closing process.
The crack closure processing evaluation method according to claim 1. The crack closing process is an impact crack closing process which closes the opening of the crack by impacting the periphery of the crack of the structure.
The evaluation process is performed after the impact crack closing process.
The crack closure processing evaluation method according to any one of claims 1 to 4. The method further includes a reclosing process step of performing an impact crack closing process again when it is evaluated in the evaluation process that the crack growth delay effect is not present.
A crack closure processing evaluation method according to claim 5. An evaluation device for evaluating a crack closing process for closing an opening of a crack generated on a surface of a structure, comprising:
A temperature change measurement unit that measures a temperature change caused by a thermoelastic effect at a tip of the crack of the structure by applying a variable load to the structure;
And an evaluation unit that evaluates a crack growth delay effect by the crack closing process based on the temperature change before and after the crack closing process.
Crack closure processing evaluation device.