JP2010197377A - Infrared method and apparatus for detecting crack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crack detecting apparatus and method capable of detecting cracks in a structure, in a period which is similar to that of visual inspection, and moreover with higher accuracy than in visual inspection. <P>SOLUTION: The apparatus includes an ultrasonic vibration generating device that makes contact with an outer surface of a structure and imparts ultrasonic vibration to the structure; and a surface temperature detecting means for, by the use of an infrared thermographic device and measuring changes in the temperature on a surface to be measured inside the structure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a crack detection device and a detection method for detecting an abnormality such as a crack generated in a structure, and in particular, a crack temperature generated when ultrasonic vibration is applied to a crack generated in a structure. The present invention relates to an infrared crack detection device and a detection method for detecting a change with an infrared thermography device.

  For example, various structures (mechanical structures) such as converters, rolling mills, and conveying table rollers are used in steel manufacturing plants. However, in recent years, fatigue cracks resulting from long-term use have occurred inside these structures, and structural failures have occurred.

  Therefore, various crack detection methods have been proposed in order to prevent such a failure (for example, refer to Patent Documents 1 and 2).

  However, a crack detection method that is often used at present is a visual detection method in which an inspector directly detects a crack by visual recognition. This visual detection method has an advantage that a crack can be detected in a short time without requiring a special device.

JP 7-333196 A JP 2008-8705 A

  However, in the visual detection method described above, the detection accuracy varies depending on the surface condition such as dirt and rust on the surface of the structure, the work skill level of the inspector and the physical condition of the work day. There is a possibility of oversight. Further, the visual detection method cannot detect a crack that is smaller than the visible level or a closed crack that is completely closed. These are major problems in the maintenance of structures.

  The present invention has been made in view of the above situation, and provides a crack detection device and a detection method capable of performing crack detection on a structure in a short time similar to the visual detection method and with higher accuracy than the visual detection method. The purpose is to provide.

  In order to solve the above problems, the present invention has the following features.

  [1] A crack detection device for detecting a crack in a structure in a nondestructive manner, an ultrasonic vibration generator for applying ultrasonic vibration to the structure by contacting the outer surface of the structure, and the structure An infrared crack detection apparatus comprising surface temperature detection means for measuring a temperature change occurring on a surface to be measured with an infrared thermography apparatus.

  [2] The ultrasonic vibration generating device includes an ultrasonic transducer that generates sound waves and an ultrasonic horn that amplifies the ultrasonic amplitude, and the ultrasonic horn is brought into contact with the surface of the structure to make the structure. The infrared crack detection apparatus according to [1], wherein the object is subjected to ultrasonic vibration.

  [3] The infrared crack detection device according to [2], wherein the ultrasonic horn is processed so that a tip thereof matches a surface shape of the structure.

  [4] The infrared crack detection device according to any one of [1] to [3], wherein the ultrasonic vibration generation device is a handy type.

  [5] The infrared thermography apparatus includes an infrared camera mounted on a helmet mounted on an examiner's head, and a goggle worn in front of the examiner's eyes to display an infrared image measured by the infrared camera. The infrared crack detection device according to any one of [1] to [4], further comprising: an image display device.

  [6] The infrared crack detecting device according to [5], wherein the goggles are translucent and have a function of allowing an inspector to simultaneously view an infrared image and a visible image.

  [7] A crack detection method for nondestructively detecting a crack in a structure, wherein an ultrasonic vibration is applied to the structure by bringing the ultrasonic vibration generator into contact with the outer surface of the structure, and the structure An excitation step for giving a temperature change to a crack in the object, and a measurement step for measuring the temperature change generated on the measurement target surface in the structure with an infrared camera mounted on the helmet and displaying it on goggles in front of the eyes An infrared crack detection method characterized by the above.

  In the present invention, it is possible to detect a crack in a structure in a short time similar to the visual detection method and with higher accuracy than the visual detection method.

It is a side view which shows the infrared crack detection apparatus and infrared crack detection method which concern on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the infrared crack detection apparatus which concerns on Embodiment 1 of this invention. It is a side view which shows the infrared crack detection apparatus and infrared crack detection method which concern on Embodiment 2 of this invention.

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

[Embodiment 1]
As an infrared crack detection apparatus and infrared crack detection method according to Embodiment 1 of the present invention, a case where the present invention is applied to crack detection on a wall surface of a structure will be described. A side view of the first embodiment is shown in FIG. FIG. 2 shows an operation flowchart according to the first embodiment.

  First, FIG. 1 will be described. Reference numeral 1 denotes a wall surface portion of a structure to be inspected. An ultrasonic vibration generator 7 is pressed against the wall portion 1 by the hand of the examiner.

  The ultrasonic vibration generator 7 includes an ultrasonic transducer 7a that generates a sound wave and an ultrasonic horn 7b that amplifies the ultrasonic amplitude, and the wall surface portion 1 is brought into contact with the surface of the wall surface portion 1 by bringing the ultrasonic horn 7b into contact with the surface. It is designed to give ultrasonic vibration.

  A helmet 2 is worn on the examiner's head, and an infrared camera 3 is attached to the front of the helmet 2 via an attachment 4. The helmet 2 and the infrared camera 3 can be separated, and the helmet 2 can be used in accordance with the size of the head of each inspector.

  The infrared camera 3 is installed in order to measure infrared rays radiated from the wall surface portion 1 to be inspected. The surface temperature distribution measured by the infrared camera 3 is displayed as a two-dimensional image on the goggle type display 5 via the cable 6. More preferably, the image measured by the infrared camera 3 is received by the goggle type display 5 wirelessly without going through the cable 6.

  Next, the operation of the infrared crack detection apparatus according to the first embodiment configured as described above will be described based on the flowchart shown in FIG.

  First, the ultrasonic vibration generator 7 is brought into contact with the surface of the wall surface portion 1 to apply ultrasonic vibration to the wall surface portion 1 (S100). Specifically, an ultrasonic signal is generated by applying an electrical signal to the ultrasonic transducer 7a, the vibration is amplified by the ultrasonic horn 7b, and the ultrasonic horn 7b is brought into contact with the surface of the wall surface portion 1; Ultrasonic vibration is transmitted to the wall portion 1. The tip of the ultrasonic horn 7b is processed so as to follow the shape of the surface of the wall surface portion 1, and the contact area between the ultrasonic horn 7b and the surface of the wall surface portion 1 is maximized. This enables efficient incidence of ultrasonic waves.

  Next, the temperature distribution of the wall surface portion 1 is acquired (S101). Specifically, the infrared rays emitted from the surface of the wall surface 1 are measured by the infrared camera 3 installed on the front surface of the helmet 2.

  Finally, the surface temperature distribution of the wall surface portion 1 measured by the infrared camera 3 is two-dimensionally displayed on the monitor type display 5, and a crack is detected as a temperature variation portion (S102).

  As described above, the infrared crack diagnostic apparatus according to the first embodiment includes the ultrasonic vibration generator 7 that applies ultrasonic vibration to the structure surface (the wall surface 1 surface), and the structure inside (the wall surface 1 inside). Is formed by surface temperature detecting means (monitor type display 5) for measuring the temperature change generated in the through the infrared camera 3 mounted on the helmet 2. The ultrasonic vibration generating device 7 is a handy type, and an ultrasonic wave can be incident on the structure by bringing the ultrasonic vibration generating device 7 into contact with an arbitrary inspection point on the outer surface of the structure by an inspector. It became.

  In addition, by mounting the infrared camera 3 on the helmet 2 and displaying the temperature distribution on the goggle type display 5, the crack portion can be visually recognized as a high temperature portion in the same manner as the visual detection method, and a crack detection method with high detection efficiency is possible. It became. Furthermore, since heat is generated at the cracks only when vibration is applied, the cracks can be detected with very good visibility and little individual difference in detectability.

  Further, by using the semi-transparent goggles 5, the visible image and the temperature distribution image can be synthesized, and the crack position can be easily identified.

  In addition, since microscopic cracks and closed cracks also generate heat due to the incidence of ultrasonic vibration, these cracks that cannot be detected by the visual detection method can be detected.

[Embodiment 2]
As an infrared crack detection apparatus and infrared crack detection method according to Embodiment 2 of the present invention, a case where the present invention is applied to crack detection of aluminum piping having a high thermal conductivity will be described. A side view of the second embodiment is shown in FIG. In FIG. 3, the same parts as those in FIG.

  In this second embodiment, the first embodiment is different from the first embodiment, which is intended for aluminum piping that has a high thermal conductivity and is difficult to maintain a temperature difference. After differential processing of the temporal temperature fluctuation curve of the measurement site, Surface flaws and cracks can be detected according to the judgment level.

  In the second embodiment, as shown in FIG. 3, the infrared crack detection device is the same as that of the first embodiment, except that the inspection target is an aluminum pipe 8. The operation flowchart of the second embodiment is the same as the operation flowchart of the first embodiment shown in FIG.

  Operations and effects unique to the second embodiment will be described.

  In (S101) of the operation flowchart, a temporal temperature fluctuation curve is obtained for an arbitrary temperature measurement point, and signal processing (differentiation processing) is performed on the temporal temperature fluctuation curve. If the value after signal processing (differential processing) at each temperature measurement point is equal to or greater than a predetermined threshold value, it is determined that the temperature measurement point is a crack / scratch. On the other hand, if the value after signal processing (differentiation processing) at each temperature measurement point is less than the threshold value, it is determined that the temperature measurement point is a normal part.

  In this way, in the second embodiment, the temporal temperature variation curve of the measurement site is signal-processed (differentiated), and cracks / scratches are evaluated according to the determination level. Detection sensitivity can be improved with respect to an aluminum material in which the singular part easily diffuses.

DESCRIPTION OF SYMBOLS 1 Wall surface part of structure 2 Helmet 3 Infrared camera 4 Attachment 5 Goggle type display 6 Cable 7 Ultrasonic vibration generator 7a Ultrasonic vibrator 7b Ultrasonic horn 8 Aluminum piping

Claims (7)

  A crack detection device for detecting cracks in a structure in a nondestructive manner, an ultrasonic vibration generator for applying ultrasonic vibration to the structure by contacting the outer surface of the structure, and measurement in the structure An infrared crack detection apparatus comprising: a surface temperature detection means for measuring a temperature change generated on a target surface by an infrared thermography apparatus.   The ultrasonic vibration generator includes an ultrasonic vibrator that generates a sound wave and an ultrasonic horn that amplifies the ultrasonic amplitude, and the ultrasonic horn is brought into contact with the surface of the structure so that the structure is supersonic. The infrared crack detection apparatus according to claim 1, wherein sonic vibration is applied.   The infrared crack detection apparatus according to claim 2, wherein the ultrasonic horn is processed so that a tip thereof matches a surface shape of a structure.   The infrared crack detection device according to claim 1, wherein the ultrasonic vibration generation device is a handy type.   The infrared thermography apparatus includes an infrared camera mounted on a helmet mounted on an examiner's head, and an image display on goggles worn in front of the examiner's eyes in order to display an infrared image measured by the infrared camera. The infrared crack detection apparatus according to claim 1, further comprising an apparatus.   6. The infrared crack detection apparatus according to claim 5, wherein the goggles are translucent and have a function of allowing an inspector to simultaneously view an infrared image and a visible image.   A crack detection method for detecting cracks in a structure in a non-destructive manner, wherein an ultrasonic vibration generator is brought into contact with the outer surface of the structure, thereby applying ultrasonic vibration to the structure, It has an excitation step for giving a temperature change to the crack, and a measurement step for measuring the temperature change generated on the measurement target surface in the structure with an infrared camera mounted on the helmet and displaying it on goggles in front of the eyes. Infrared crack detection method.

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