JP2008209283A - Apparatus and method for monitoring structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for monitoring a structure, which complements the inspections conducted by humans, and effectively carries out maintenances and efficiently, in order to solve the problems related to fatigue in the structure. <P>SOLUTION: The apparatus includes a power generating means for generating an electric power, in response to a vibration caused by a vehicle which travels on the structure which is an object to be monitored; a conducting wire made of a conductive material and formed on the surface of the structure; a detecting means for detecting the conduction state of the conducting wire by using the electric power generated by the power generating means; a transmitting means for transmitting information that represents the conduction state of the conducting wire, detected by the detecting means by using the electric power generated by the power generating means; and a receiving means which is installed at the vehicle and receives the information representing the conduction state of the conducting wire which is transmitted by the transmitting means. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a monitoring device and a monitoring method for monitoring the occurrence of fatigue cracks in railway structures and the like.

  The main deformations in steel bridges are fatigue and corrosion, and in order to keep the steel bridge in service on the order of 100 years, it is necessary to cope with these deformations appropriately. For steel railway bridges, the occurrence of deformation such as fatigue and corrosion is captured or progressed through general inspections set forth in the “Maintenance and Management Standards for Railroad Structures / Description” (structure knitting steel / synthetic structures). I know the degree. If abnormalities are found in the general inspection, further individual inspections will be conducted to find out the details of the degree of deformation, investigate the cause of the deformation, and examine repair / reinforcement methods. General inspection here is classified into normal general inspection and special general inspection, and normal general inspection is inspection performed by visual inspection from the bridge sidewalk or under the girder, and special general inspection is in close proximity using scaffolding etc. This is an inspection in which a visual check is performed in a state. Although it is obliged to carry out a general inspection once every two years, generally a general inspection is usually performed, and a special general inspection is performed using the scaffold when repainting.

  In the inspection for corrosion, the site of occurrence is captured, and the state of corrosion is grasped by the corrosion area and the thickness loss. The detection of the occurrence site and the grasp of the corrosion area can be sufficiently grasped by visual observation, and the thickness loss can be grasped by a simple measuring instrument such as a caliper or an ultrasonic thickness gauge. In addition, it is possible to perform sufficiently effective maintenance management by judging the degree of progress of corrosion from the transition of results obtained by a general inspection once every two years. On the other hand, with regard to fatigue, the fatigue cracks that have occurred are found by general inspection. Although the fatigue crack is fine, it may be missed, but the inspection period is set so that it does not progress to a serious state that impedes train travel with a single oversight.

As a prior art, there is known a crack risk diagnosis method using a piezoelectric material that obtains the stress at the crack tip, detects the fatigue level, and diagnoses the risk of fracture (for example, see Patent Document 1). A power generation device using a piezoelectric element is also known (see, for example, Patent Document 2).
JP 2002-098626 A JP 2006-129602 A

  By the way, the progress of fatigue cracks is generally faster than the progress of corrosion, etc. In order to achieve effective maintenance management such as simple repairs and reinforcements, the cracks generated are caught earlier. From the viewpoint of preventive maintenance, it is also desirable to capture fatigue accumulated due to repeated stress, predict the occurrence of fatigue cracks, and take measures in advance. Then, there is a problem that it is difficult to grasp the accumulated fatigue.

  The present invention has been made in view of such circumstances, and for monitoring the structure capable of performing effective and efficient maintenance management by complementing the inspection performed by humans for the above-mentioned problem in fatigue. An object is to provide an apparatus and a monitoring method.

  The present invention provides a power generation means for generating power in response to vibration generated by a vehicle traveling on a structure to be monitored, a conductive wire formed of a conductive material on the surface of the structure, and power generation by the power generation means. Detecting means for detecting an energization state of the conductor using the generated electric power, and transmitting information indicating the energization state of the conductor detected by the detection means using the electric power generated by the power generation means. It is characterized by comprising transmitting means and receiving means provided in the vehicle for receiving information indicating the energization state of the conducting wire transmitted by the transmitting means.

  The present invention is characterized in that the power generation means includes a piezoelectric element that converts kinetic energy generated by the vibration into electric energy.

  The present invention is characterized in that the power generation means moves a coil or a magnet by kinetic energy due to the vibration, and generates an electromotive force in the coil by a magnetic flux change intersecting the coil.

  The present invention is characterized in that the detection means detects an energization state of the conducting wire based on a change in resistance value of the conducting wire.

  The present invention is characterized in that the power generation means is fixed to the structure so as to resonate with vibration generated when a vehicle travels on the structure.

  The present invention uses power generation means for generating electric power in response to vibration generated when a vehicle travels on a structure to be monitored, a sensor provided in the structure, and electric power generated by the power generation means. Detection means for reading the output of the sensor, transmission means for transmitting the sensor output information detected by the detection means using the power generated by the power generation means, and provided in the vehicle, the transmission Receiving means for receiving the sensor output information transmitted by the means.

  The present invention relates to a monitoring device comprising a power generation means for generating electric power in response to vibration generated when a vehicle travels on a structure to be monitored, and a conductive wire formed of a conductive material on the surface of the structure. A detection method for detecting an energization state of the conductor using the electric power generated by the power generation means, and using the electric power generated by the power generation means, It has a transmission step which transmits the information which shows an energized state, and the receiving step which receives the information which shows the energized state of the transmitted said conducting wire in the vehicle.

  The present invention is a monitoring method in a monitoring device comprising a power generation means for generating electric power in response to vibration generated when a vehicle travels on a structure to be monitored, and a sensor provided in the structure, In the vehicle, a detection step of reading the output information of the sensor using the power generated by the power generation means, a transmission step of transmitting the sensor output information using the power generated by the power generation means, And a receiving step of receiving the transmitted sensor output information.

  According to the present invention, the conductive wire formed of the conductive surface material is provided on the surface where the fatigue crack is likely to occur, and the fatigue crack is detected based on the current-carrying state of the conductive wire. It is possible to detect the occurrence of a crack even when the site where the fatigue crack has occurred is a position that cannot be directly viewed from the sidewalk or under the girder. In addition, the piezoelectric element is used to generate power by vibration of the structure, and this generated power is used to detect cracks and transmit information indicating the detection status of cracks. It is possible to detect cracks even in structures in areas where commercial power sources such as electrified sections cannot be used. In addition, since information indicating the detection status of cracks is received by railway vehicles that run on the structure, it is not necessary for the inspector to visit the structure to be inspected, greatly reducing inspection costs. The effect that it can do is acquired. In addition, since the detection data can be collected when the vehicle passes, it is possible to omit a device such as installing a wired or wireless device on the structure and transmitting the detection result to a remote office or the like. The configuration of the monitoring device can be simplified. For this reason, it is possible to reduce the cost of the monitoring device.

  Hereinafter, a monitoring device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment. In this figure, the code | symbol 1 is a girder of a railway steel bridge. Reference numeral 2 is a rail laid on the beam 1 of the railway steel bridge. Reference numeral 3 denotes a railway vehicle (hereinafter referred to as a vehicle) that travels on the rail 2. Reference numeral 11 denotes a power generation unit including a piezo element that generates electricity by applying vibration. Reference numeral 12 denotes a conductive wire formed by applying a conductive surface material having conductivity while having performance as a coating film on the surface of the beam 1. Reference numeral 13 denotes a detection unit that detects an energized state of the conducting wire 12. Reference numerals 14 and 15 are connection terminals for connecting the power generation unit 11 and the detection unit 13 to the conductor 12. Reference numeral 16 denotes a transmission unit that wirelessly transmits information on the energization state of the conducting wire 12 detected by the detection unit 13. Reference numeral 31 is a wireless receiver that is provided in the vehicle 3 and receives the energization state information transmitted by the transmitter 16. Reference numeral 32 denotes a display unit that includes a display device or the like and displays energization state information received by the receiving unit 31. Reference numeral 33 denotes a storage unit that is configured by a flash memory or the like and stores the energization state information received by the receiving unit 31.

  Here, the conducting wire 12 formed on the surface of the beam 1 using a conductive surface material will be described. There are two types of uses of the lead wire 12, one for the purpose of detecting the occurrence of fatigue cracks and another for the purpose of detecting the progress of fatigue cracks. Metallic pigment (silver / silver-coated copper powder) is used as the conductive surface material for the purpose of detecting the occurrence of fatigue cracks, and conductive surface material for the purpose of detecting the growth of fatigue cracks. For this, a carbon pigment (carbon black) is used. Each pigment is made of various materials such as silver, copper, nickel, graphite, carbon black, etc., and the conductive surface materials are prepared, and the film forming property, workability, volume resistivity, etc. are studied as parameters. It is desirable to select. Bridge painting is classified into undercoat, intermediate coat, and topcoat, and consists of multiple layers, but the conductive surface material is applied to the second layer of the intermediate coat or undercoat.

  When conductive surface material is applied to the members constituting the bridge and a fatigue crack is generated or propagates, the conductive surface material on the crack breaks along the generated crack. By detecting changes in electrical resistance of the conductive surface material and detecting the occurrence or progress of fatigue cracks, it is possible to detect the occurrence of fatigue cracks or the detection of fatigue cracks.

  Next, the principle of fatigue crack detection in the monitoring apparatus shown in FIG. 1 will be briefly described. The conductive wire 12 is formed by applying a conductive surface material in a thin line shape with a single stroke (no branching) at a place where fatigue cracks are likely to occur. Then, the occurrence of a fatigue crack is detected by detecting disconnection of the conducting wire 12 (no longer being energized). Since only the disconnection of the conducting wire 12 is detected, there is a feature that it is not necessary to use measuring instruments. In addition, assuming that commercial power cannot be used in mountainous areas or non-electrified sections, power is generated by piezoelectric elements (piezo elements) that generate electricity from the vibration of steel girders when passing through railway vehicles. Use. Further, since the energization state information is transmitted to the vehicle 3 traveling on the beam 1 to which the detection unit 13 is attached, the detection result is sufficiently transmitted with the electric power generated by the piezoelectric element. be able to.

  Next, with reference to FIG. 2, the structure of the electric power generation part 11 shown in FIG. 1 is demonstrated. The power generation unit 11 performs power generation using piezoelectric ceramics (piezo power generation), and can efficiently generate power by efficiently converting kinetic energy applied to the piezoelectric ceramics into electrical energy. For the power generation unit 11, for example, a piezoelectric power generation device described in Patent Document 2 can be used. FIG. 2 is a diagram illustrating a configuration for efficiently transmitting the vibration of the girder 1 to the power generation unit 11. As shown in this figure, the power generation unit 11 is attached to a leaf spring 11a having one end fixed to the beam 1 and the other end having a mass 11b. At this time, the power generation unit 11 is adjusted and attached so as to resonate with the vibration of the beam 1 based on the natural frequency determined from the relationship between the spring constant of the leaf spring 11a and the mass 11b. In this way, by fixing the power generation unit 11 to the leaf spring 11a, the vibration of the beam 1 can be efficiently transmitted to the power generation unit 11, so that it is possible to obtain a sufficient power generation amount in the power generation unit 11. Become.

  Next, the operation of the monitoring device will be described with reference to FIG. First, when the vehicle 3 is not traveling on the beam 1, the power generation unit 11 does not generate power because no vibration is generated in the beam 1. On the other hand, when the vehicle 3 passes over the girder 1, the power generation unit 11 generates power by vibration generated in the girder 1, and a current flows in the conductor 12. The detection unit 13 detects an energized state (presence of disconnection). As shown in FIG. 3, when the fatigue crack has generate | occur | produced in the girder 1, the conducting wire 12 will be disconnected by the crack 1a. The detection unit 13 can detect the occurrence of a crack by detecting the occurrence of this disconnection. The detection unit 13 outputs energization state information obtained as a result of detecting the energization state to the transmission unit 16. The transmission unit 16 uses the power generated by the power generation unit 11 due to the vibration of the digit 1 to transmit the energization state information output from the detection unit 13 by wireless communication. At this time, the reception unit 31 mounted on the vehicle 3 passing over the digit 1 receives the energization state information (1-bit information with / without disconnection) transmitted by the transmission unit 16.

  And the receiving part 31 relates and memorize | stores the information which identifies the vehicle 3, the time information, and the received electricity supply state information in the memory | storage part 31. FIG. The receiving unit 31 displays the received energization state information on the display unit 32. This display is confirmed visually by an inspector on the vehicle 3. When the vehicle 3 travels from the starting point to the ending point, the energization state information transmitted from the monitoring device attached to the girder 1 of each bridge on the route from the starting point to the ending point is stored in the storage unit 33. It will be. By analyzing the information stored in the storage unit 33, it is possible to detect the occurrence of cracks in each bridge.

  As shown in FIG. 3, the detection unit 13 may detect the occurrence of a crack by detecting a change in resistance value that changes in accordance with the state of the crack 1b. Further, instead of applying the conductive surface material to the surface of the structure, a conductive wire or the like using the conductive material may be formed on the surface of the structure, and the conduction state of the conductive wire may be detected.

  Also, when fatigue cracks occur and repair / reinforcement is required, in situations where time is required for construction every year, fatigue cracks can cause significant length (for example, brittle fracture is induced It is necessary to confirm frequently that it has not progressed to such a length that would cause it to break. In such a case, the progress of the crack may be detected by newly applying a conductive surface material near the end of the fatigue crack (reference numeral 1c shown in FIG. 3). In addition, when detecting the progress of a fatigue crack, the conductive surface material is applied in a planar shape to the site where the fatigue crack has occurred, and when the cross-sectional area of the conductive surface material is reduced due to the progress of the fatigue crack. The amount of progress of the fatigue crack may be detected by capturing a change in the electrical resistance value.

  In the above description, an example of fatigue crack detection has been described based on the energization state of the conducting wire 12. However, instead of the conducting wire 12, a sensor for detecting strain or the like is attached to the structure, and the output of this sensor is The sensor detection circuit (corresponding to the detection unit 13) may be driven by the power generated by the power generation unit 11, and the output of the sensor detection circuit may be transmitted by the transmission unit 16. By doing in this way, for example, it becomes possible to detect a large strain or the like suffered during an earthquake.

  In addition, it replaces with a piezoelectric element, and the electric power generation part 11 may move a coil or a magnet with the kinetic energy by vibration, and may make it generate required electromotive force by generating an electromotive force in a coil by the magnetic flux change which cross | intersects a coil. Good.

  In the above description, the bridge is taken as an example. However, the crack detection target is not limited to the bridge, and may be a slope, an inner surface of a tunnel, or the like. Further, the vehicle traveling on the structure is not limited to the railroad but may be an automobile or the like.

<Performance confirmation test of conductive surface material>
Next, the performance confirmation test result of the conductive surface material will be described. The required performance of the conductive surface material is that the surface material is destroyed along with the crack generated in the steel (crack visibility), and the conductivity of the surface material changes with long-term outdoor use. Not to be done (durability), the change in resistance value of the conductive surface material destroyed with the progress of the fatigue crack and the amount of progress of the fatigue crack are correlated (crack growth detectability), etc. It is done. Here, the results of tests conducted on durability and detectability of crack growth are shown.

(1) Durability test Durability was confirmed by an accelerated deterioration test. From the standpoint of evaluating durability when actually installing on bridges, the general environment described in “Edition of Railway Technical Research Institute: Steel Structure Coating Design and Construction Guidelines, Kenyusha, 2005” 15 A test piece using a conductive surface material as part of a coating-type intermediate coating that can be expected to have a long-term durability of more than a year was evaluated, and the durability of electrical characteristics was evaluated. As a result, the change rate of the electrical resistance value during the accelerated deterioration test was all within 5%. Because the location environment of steel bridges varies widely, the number of cycles of accelerated tests cannot be matched with the period in the actual environment, but the electrical resistance even when the conductive surface material is used in the actual environment It was suggested that the change of the value was very small.

(2) Confirmation test of crack growth detectability Fatigue crack progress detectability is conducted by conducting a fatigue test using a girder cut out from the removed actual bridge, and conducting surface material at the site of the generated fatigue crack. This was confirmed by coating and measuring the electric resistance value. As a result, a result that the resistance value of the conductive surface material increases as the fatigue crack progresses was obtained, and it was confirmed that the progress of the fatigue crack was detectable using the conductive surface material.
In addition, since the resistance value also changes depending on the film thickness of the conductive surface material, the film thickness of the conductive surface material must be constant in order to accurately grasp the correlation between the fatigue crack growth amount and the resistance value change amount. The result that it was desirable to be obtained was obtained.

  As described above, the conductive wire formed of the conductive surface material is provided on the surface of the portion where the fatigue crack is likely to occur, and the fatigue crack is detected by detecting the disconnection of the conductive wire or the change in the resistance value. Therefore, it is possible to detect the occurrence of a crack even when the site where the fatigue crack has occurred is a position that cannot be directly seen from the bridge sidewalk or under the girder. In addition, the piezoelectric element is used to generate power by vibration of the structure, and this generated power is used to detect cracks and transmit information indicating the detection status of cracks. It is possible to detect cracks even in structures in areas where commercial power sources such as electrified sections cannot be used. In addition, since information indicating the detection status of cracks is received by railway vehicles that run on the structure, it is not necessary for the inspector to visit the structure to be inspected, greatly reducing inspection costs. can do.

It is a block diagram which shows the structure of one Embodiment of this invention. It is explanatory drawing which shows the detailed structure of the electric power generation part 11 shown in FIG. It is explanatory drawing which shows the state of the fatigue crack which generate | occur | produced in the girder 1 shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Digit, 11 ... Power generation part, 12 ... Detection part, 13 ... Transmission part, 14, 15 ... Connection terminal, 16 ... Conductive surface material, 2 ... Rail 3 ... Vehicle, 31 ... Receiver, 32 ... Display, 33 ... Storage

Claims (8)

Power generation means for generating power in response to vibration generated by the vehicle traveling on the structure to be monitored;
A conducting wire formed of a conductive material on the surface of the structure;
Detecting means for detecting an energization state of the conducting wire using electric power generated by the power generating means;
Transmitting means for transmitting information indicating the energization state of the conducting wire detected by the detecting means using the power generated by the power generating means;
A monitoring device, comprising: a receiving unit that is provided in the vehicle and receives information indicating an energization state of the conducting wire transmitted by the transmitting unit.   The monitoring apparatus according to claim 1, wherein the power generation unit includes a piezoelectric element that converts kinetic energy generated by the vibration into electric energy.   The monitoring apparatus according to claim 1, wherein the power generation unit moves a coil or a magnet by kinetic energy due to the vibration and generates an electromotive force in the coil by a magnetic flux change intersecting the coil.   The monitoring device according to claim 1, wherein the detection unit detects an energization state of the conducting wire based on a change in resistance value of the conducting wire.   5. The monitoring device according to claim 1, wherein the power generation unit is fixed to the structure so as to resonate with vibration generated when a vehicle travels on the structure. . Power generation means for generating power in response to vibration generated by the vehicle traveling on the structure to be monitored;
A sensor provided in the structure;
Detection means for reading the output of the sensor using the power generated by the power generation means;
Transmitting means for transmitting the sensor output information detected by the detecting means using the power generated by the power generating means;
A monitoring device, comprising: a receiving unit that is provided in the vehicle and that receives the sensor output information transmitted by the transmitting unit. This is a monitoring method in a monitoring device comprising a power generation means for generating electric power in response to vibration generated when a vehicle travels on a structure to be monitored, and a conductive wire formed of a conductive material on the surface of the structure. And
A detection step of detecting an energization state of the conducting wire using the power generated by the power generation means;
A transmission step of transmitting information indicating the detected energization state of the conductor using the power generated by the power generation means;
The vehicle monitoring method further comprising: a receiving step of receiving the transmitted information indicating the energized state of the conducting wire. A monitoring method in a monitoring device comprising a power generation means for generating electric power in response to vibration generated by a vehicle traveling on a structure to be monitored, and a sensor provided in the structure,
A detection step of reading output information of the sensor using the power generated by the power generation means;
A transmission step of transmitting the sensor output information using the power generated by the power generation means;
A receiving method for receiving the transmitted sensor output information in the vehicle.

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