WO2011071241A2 - Crack detecting system and crack detecting method - Google Patents

Crack detecting system and crack detecting method Download PDF

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Publication number
WO2011071241A2
WO2011071241A2 PCT/KR2010/007421 KR2010007421W WO2011071241A2 WO 2011071241 A2 WO2011071241 A2 WO 2011071241A2 KR 2010007421 W KR2010007421 W KR 2010007421W WO 2011071241 A2 WO2011071241 A2 WO 2011071241A2
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Prior art keywords
ultrasonic wave
crack
ultrasonic
detection information
sensor tag
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PCT/KR2010/007421
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French (fr)
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WO2011071241A3 (en
Inventor
Youngbin Cho
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Lg Innotek Co., Ltd.
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/07—Analysing solids by measuring propagation velocity or propagation time of acoustic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/043—Analysing solids in the interior, e.g. by shear waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G01N29/24—Probes
    • G01N29/2481—Wireless probes, e.g. with transponders or radio links
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G01N29/26—Arrangements for orientation or scanning by relative movement of the head and the sensor
    • G01N29/265—Arrangements for orientation or scanning by relative movement of the head and the sensor by moving the sensor relative to a stationary material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/028—Material parameters
    • G01N2291/0289—Internal structure, e.g. defects, grain size, texture

Definitions

  • the present invention relates to a crack detection system and a method thereof using an ultrasonic sensor and a short-range wireless communication tag.
  • the present invention relates to a method of simultaneously gauging the length and angle of surface opening cracks of a concrete structure, and more particularly, to a method of simultaneously measuring with a nondestructive test method the length and the angle of surface opening cracks in a concrete structure using an ultrasonic method and an impact-echo method.
  • the conventional ultrasonic method measures a transmission time (t) when ultrasonic waves produced from the transmission probe 1 arrives at the reception probe 2 through a vertex point 4 of the crack part 3.
  • the transmission time (t) indicates a time ultrasonic waves from the transmission probe 1 arrives at the reception probe 2 through a shortest range distance.
  • the depth of the crack portion 3 is obtained as shown in the Equation 1.
  • the method disposes an ultrasonic wave transmission probe 1 and an ultrasonic wave reception probe 2 at equal distance from a crack portion 3 at the left and right side of the crack portion 3 (A and B positions in the Figure), and measures a transmission time (t1) through which ultrasonic waves produced from a transmission probe 1 arrives at a reception probe 2.
  • the method places a transmission probe 1 at its original position and shifts a reception probe 2 by distance X again to the outside (C position in the Figure), and repeatedly measures a transmission time (t2) through which ultrasonic waves produced from the transmission probe 1 arrives at a reception probe 2'.
  • the depth D of the crack portion 3 may be calculated by the following Equation 2.
  • a crack detection method by the prior-art technology detects a crack only in a case a crack detection vehicle passes through tunnels, etc. Therefore, it is difficult to perform a continuous management of cracks in a tunnel in terms of a cost and a tunnel use time.
  • the present invention is to provide a crack detection system and a method thereof that can monitor cracks in a tunnel at a cheap cost.
  • a crack detection system comprises an ultrasonic wave sensor tag including a time measurement unit for measuring a current time, an ultrasonic wave detection unit capable of detecting ultrasonic waves applied from the outside, a storage unit storing ultrasonic wave detection information containing a time at which ultrasonic waves are detected by the ultrasonic wave detection unit, a short-range wireless communication module for transmitting the ultrasonic wave detection information to the outside, and a driving electric power supply unit configured to supply driving electric power to said each component; and
  • a crack detection server including a communication module for receiving the ultrasonic wave detection information by forming a communication channel with the short-range wireless communication module, a crack determination unit configured to determine if there occur cracks in a tunnel from the ultrasonic wave detection information.
  • a crack detection method includes detecting ultrasonic waves in a case there occur cracks by an ultrasonic wave sensor tag; storing ultrasonic wave detection information including the ultrasonic wave detected time; determining if a short-range wireless communication signal is detected; transmitting the stored ultrasonic wave detection information from the ultrasonic wave sensor tag to a crack detection server; and determining the occurrence of a crack from the ultrasonic wave detection information by the crack detection server.
  • a crack detection method includes determining if a preset time has elapsed after the sleeping time of an ultrasonic wave sensor tag; emitting ultrasonic waves from the ultrasonic wave sensor tag; detecting the reflective waves of the emitted ultrasonic waves; storing ultrasonic wave detection information containing the intensity and delayed time of the reflective waves; determining if a short-range wireless communication signal is detected; transmitting the ultrasonic wave detection information from the ultrasonic wave sensor tag to a crack detection server; and determining the occurrence of a crack from the ultrasonic wave detection information by the crack detection server.
  • FIG. 1 is a description view schematically showing a method of measuring the depth of cracks vertically taken place on the surface of a concrete structure using a conventional ultrasonic method
  • FIG. 2 is a construction view showing a crack detection system according to one embodiment of the present invention
  • FIG. 3 is a conceptional view showing one example of a crack detection method applicable to the present invention
  • FIG. 4 is a flow chart showing a crack detection method according to one embodiment of the present invention.
  • FIG. 5 is a flowchart showing a crack detection method according to another embodiment of the present invention.
  • FIG. 2 shows a crack detection system according to one embodiment of the present invention.
  • a crack detection system is comprised of an ultrasonic wave sensor tag 100 attached to the inner wall of a tunnel, that is an object for which a crack or not is monitored; and a crack detection server 200 mounted on a transportation means such as tunnel-passing vehicles, receiving a piece of information from the ultrasonic wave sensor tag 100, and determining a crack or not in a tunnel.
  • the ultrasonic wave sensor tag 100 includes a time measurement unit 110 for measuring a current time, an ultrasonic wave detection unit 120 detectable of ultrasonic waves applied from the outside, a storage part 140 storing an ultrasonic wave detection information containing a time at which the ultrasonic wave detection part 120 detects ultrasonic waves, a short-range wireless communication module 160 for transmitting ultrasonic wave detection information stored in the storage part 140 to the following crack detection server 200, and a driving electric power supply unit 180 supplying driving electric power to said each component.
  • the crack detection server 200 includes a communication module 220 for receiving information stored in the storage unit 140 of the ultrasonic wave sensor tag 100; and a crack (fracture) determination unit 260 determining cracks of the tunnel from the received values.
  • the ultrasonic wave detection unit 120 is configured to detect ultrasonic waves, and when ultrasonic waves are detected, it stores a detected value (for example: intensity) and a detected time together in the storage part 140.
  • the ultrasonic wave detection unit 120 can be applicable as one of the following three implementations.
  • the ultrasonic wave detection unit simply detects only whether ultrasonic waves have occurred.
  • Such an implementation may be applicable as a fashion of when a crack takes place at the material of a wall surface of a tunnel (for example: concrete), detecting ultrasonic waves concurrently produced and making the crack ability of a tunnel known.
  • the ultrasonic wave detection unit may detect the size of ultrasonic waves applied from the outside.
  • Such an implementation may be applicable as a fashion of when a crack takes place at the material of a wall surface of a tunnel (for example: concrete), detecting ultrasonic waves concurrently produced and providing a piece of information used to determine the crack ability of a tunnel more accurately.
  • the ultrasonic wave detection unit may have an ultrasonic wave generator producing ultrasonic waves and an ultrasonic wave detector detecting ultrasonic waves together.
  • the ultrasonic wave detector may detect supersound wave that is produced from an ultrasonic generator installed at the same ultrasonic wave detection unit and reflected at a crack in a tunnel, or detect supersound wave that is produced from an ultrasonic wave generator held on another ultrasonic wave detection unit adjacent to a wall surface of the tunnel and transmitted through a crack of the tunnel.
  • the ultrasonic wave detection unit 120 may apply a PZT (Lead Zirconate Titanate) AE (Acoustic Emission) sensor or a PVDF (polyvinylidene fluoride) sensor, as a detection device for detecting ultrasonic waves applied from the outside.
  • a PZT Lead Zirconate Titanate
  • AE Acoustic Emission
  • PVDF polyvinylidene fluoride
  • the ultrasonic wave detection unit 120 can continuously perform an ultrasonic detecting action at a predetermined time interval, and in this case the storage unit 140 functions to store supersound detection information gained by the continuously performed supersound detection action till it is transmitted to the crack detection server 200.
  • the short-range wireless communication module 160 may be a RF communication module that performs a communication as a RF mode.
  • an RF mode is a communication method used in an RF smart card or an RF tag, and it is desirable to use the short-range wireless communication module having a wider recognition range if applied to the present invention.
  • the short-range wireless communication module 160 may form a wireless communication channel for a data transfer with a communication module 220 of the crack detection server 200.
  • a driving electric power supply unit 180 supplying driving electric power to internal components of the ultrasonic wave sensor tag 100 may be configured to receive electric power via a wired line or produce electric power from a wireless signal.
  • the driving electric power supply unit may include a wireless electric power receptor producing electric power from a wireless signal transmitted from the crack detection server; and a capacitor storing electric power produced from the wireless electric power receptor.
  • the driving electric power supply unit 180 may generate electric power from a power transmission signal emitted by a crack detection server 200, store it in the capacitor, and use electric power stored in the capacitor when monitoring a crack occurrence.
  • the driving electric power supply unit may be configured to include a generator module generating electric power from a physical vibration.
  • a crack determination unit 260 of the crack detection server 200 determines a crack occasion of a tunnel and a crack occurrence position from ultrasonic detection values assembled in the storage part.
  • FIG. 3 One of the crack detection methods is illustrated in FIG. 3.
  • ultrasonic wave sensor tags A, B, C, D are disposed in a square form.
  • a pair of ultrasonic wave sensor tags that is, A and D, C and B
  • supersound wave is detected after a same delay time in a crack non-existing situation but supersound wave is detected after a different delayed time among them in a crack existing situation.
  • FIG. 4 illustrates a crack detection method according to one embodiment of the present invention.
  • a crack detection method applies a mode of manually detecting ultrasonic waves upon a crack occurrence by an ultrasonic wave sensor tag attached to a tunnel wall.
  • a crack detection method of one embodiment as described above includes the steps of: detecting ultrasonic waves in a crack occurrence by an ultrasonic wave sensor tag, in a case a crack occurs (S120); waking up the ultrasonic wave sensor tag (S142), storing the ultrasonic detection time in a storage unit (S148), sleeping the ultrasonic wave sensor tag (S110); in a case the ultrasonic wave sensor tag detects a short-range wireless communication signal of a communication module of a crack detection server (S150), waking up the ultrasonic wave sensor tag (S162), transmitting ultrasonic wave detection information containing an ultrasonic wave detection time stored in the storage unit to a crack detection server (S164); and determining a crack occurrence from the ultrasonic wave detection information by the crack detection server (S180).
  • the ultrasonic wave sensor tag exists in a sleeping mode (S110).
  • a time measurement unit; an ultrasonic wave detection unit; and a communication module for detecting the short-range wireless communication signal may be activated.
  • the ultrasonic wave sensor tag when detecting ultrasonic waves upon a crack occurrence, may be activated to produce ultrasonic waves actively to obtain information informing a more precise position in which a crack occurs.
  • the step 140 may further include the steps of: emitting ultrasonic waves; detecting the reflective waves of the emitted ultrasonic waves; and storing the intensity and delayed time of the reflective waves (reflective wave detection time - ultrasonic emitting time) in the storage unit.
  • ultrasonic wave detection information in the step 160 includes a crack occurrence time, and the intensity and delayed time of the reflective wave.
  • FIG. 5 illustrates a crack detection method according to another embodiment of the present invention.
  • a crack detection method of another embodiment of the present invention applies a mode of emitting ultrasonic waves actively by ultrasonic wave sensor tags attached to a tunnel wall, collecting reflective waves thereto and monitoring a crack occurrence.
  • a crack detection method of another embodiment as described above includes the steps of: determining if a given time has elapsed after a sleeping point (S220); waking up an ultrasonic wave sensor tag if it elapsed (S242); emitting ultrasonic waves from the ultrasonic wave sensor tag (S244); detecting the reflective waves of the emitted ultrasonic waves (S246); storing in a storage unit ultrasonic wave detection information containing the intensity and delayed time of the reflective waves (reflective wave detection time - ultrasonic wave emitting time (S248); sleeping the ultrasonic wave sensor tag (S210); in a case the ultrasonic wave sensor tag detects a short-range wireless communication signal of a communication module of a crack detection server (S250), waking up the ultrasonic wave sensor tag (S262); transmitting ultrasonic wave detection information stored in the storage unit to a crack detection server (S264); and determining a crack occurrence from the ultrasonic wave detection information by the crack detection server (S280).
  • the ultrasonic wave sensor tag exists in a sleeping mode (S210).
  • a time measurement unit; and a communication module for detecting the short-range wireless communication signal may be activated.
  • the present invention is to provide a crack detection system and a method thereof with a capability of monitoring cracks in a tunnel at a moderate cost, may be extensively used in a field necessary to monitor cracks in each kind of structure including a tunnel.

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Abstract

Disclosed herein is a crack detection system. The crack detection system comprises an ultrasonic wave sensor tag including a time measurement unit for measuring a current time, an ultrasonic wave detection unit capable of detecting ultrasonic waves applied from the outside, a storage unit storing ultrasonic wave detection information containing a time at which ultrasonic waves are detected by the ultrasonic wave detection unit, a short-range wireless communication module for transmitting the ultrasonic wave detection information to the outside, and a driving electric power supply unit configured to supply driving electric power to said each component; and a crack detection server including a communication module for receiving the ultrasonic wave detection information by forming a communication channel with the short-range wireless communication module, a crack determination unit configured to determine if there occur cracks in a tunnel from the ultrasonic wave detection information.

Description

CRACK DETECTING SYSTEM AND CRACK DETECTING METHOD
The present invention relates to a crack detection system and a method thereof using an ultrasonic sensor and a short-range wireless communication tag.
The present invention relates to a method of simultaneously gauging the length and angle of surface opening cracks of a concrete structure, and more particularly, to a method of simultaneously measuring with a nondestructive test method the length and the angle of surface opening cracks in a concrete structure using an ultrasonic method and an impact-echo method.
For example, in a case cracks occur on the surface of a concrete structure such as obsolete buildings or structures, it is significantly important to measure the depth of the crack for the purpose of the safety of buildings. When a crack exists in the vicinity of a surface alone, a tiny-labored repair work may withhold the unwanted proceedings of a crack, but when a crack occurs deeply into the inner wall of a structure, the only way for the safety of a building is to destruct the building. Thus, it goes without saying that an nondestructive method is always used in measuring a crack depth in a concrete structure.
In the prior art, an ultrasonic method and an impact-echo method are used to measure the depth of a surface crack in a concrete structure nondestructively. A conventional crack measurement will be described in a simple way while referring to FIG. 1.
As illustrated in FIG. 1, after a conventional ultrasonic method disposes an ultrasonic transmission probe 1 and an ultrasonic reception probe 2 at the left and right side of a crack portion 3 (A and B positions in the figure) such that they are equally distant from the crack portion 3, the conventional ultrasonic method measures a transmission time (t) when ultrasonic waves produced from the transmission probe 1 arrives at the reception probe 2 through a vertex point 4 of the crack part 3. The transmission time (t) indicates a time ultrasonic waves from the transmission probe 1 arrives at the reception probe 2 through a shortest range distance. At this time, when setting that the speed of ultrasonic waves is VP, the depth of the crack portion 3 is obtained as shown in the Equation 1.
MathFigure 1
Figure PCTKR2010007421-appb-M000001
If ultrasonic wave speed VP may not be learnt, the method disposes an ultrasonic wave transmission probe 1 and an ultrasonic wave reception probe 2 at equal distance from a crack portion 3 at the left and right side of the crack portion 3 (A and B positions in the Figure), and measures a transmission time (t1) through which ultrasonic waves produced from a transmission probe 1 arrives at a reception probe 2. In the next step, the method places a transmission probe 1 at its original position and shifts a reception probe 2 by distance X again to the outside (C position in the Figure), and repeatedly measures a transmission time (t2) through which ultrasonic waves produced from the transmission probe 1 arrives at a reception probe 2'. In this case, the depth D of the crack portion 3 may be calculated by the following Equation 2.
MathFigure 2
Figure PCTKR2010007421-appb-M000002
However, a crack detection method by the prior-art technology detects a crack only in a case a crack detection vehicle passes through tunnels, etc. Therefore, it is difficult to perform a continuous management of cracks in a tunnel in terms of a cost and a tunnel use time.
The present invention is to provide a crack detection system and a method thereof that can monitor cracks in a tunnel at a cheap cost.
In accordance with one embodiment of the present invention, a crack detection system comprises an ultrasonic wave sensor tag including a time measurement unit for measuring a current time, an ultrasonic wave detection unit capable of detecting ultrasonic waves applied from the outside, a storage unit storing ultrasonic wave detection information containing a time at which ultrasonic waves are detected by the ultrasonic wave detection unit, a short-range wireless communication module for transmitting the ultrasonic wave detection information to the outside, and a driving electric power supply unit configured to supply driving electric power to said each component; and
a crack detection server including a communication module for receiving the ultrasonic wave detection information by forming a communication channel with the short-range wireless communication module, a crack determination unit configured to determine if there occur cracks in a tunnel from the ultrasonic wave detection information.
Also, in accordance with one embodiment of the present invention, a crack detection method includes detecting ultrasonic waves in a case there occur cracks by an ultrasonic wave sensor tag; storing ultrasonic wave detection information including the ultrasonic wave detected time; determining if a short-range wireless communication signal is detected; transmitting the stored ultrasonic wave detection information from the ultrasonic wave sensor tag to a crack detection server; and determining the occurrence of a crack from the ultrasonic wave detection information by the crack detection server.
Also, in accordance with another embodiment of the present invention, a crack detection method includes determining if a preset time has elapsed after the sleeping time of an ultrasonic wave sensor tag; emitting ultrasonic waves from the ultrasonic wave sensor tag; detecting the reflective waves of the emitted ultrasonic waves; storing ultrasonic wave detection information containing the intensity and delayed time of the reflective waves; determining if a short-range wireless communication signal is detected; transmitting the ultrasonic wave detection information from the ultrasonic wave sensor tag to a crack detection server; and determining the occurrence of a crack from the ultrasonic wave detection information by the crack detection server.
In a case a crack detection system featuring such a configuration is implemented, there is a pragmatic benefit of monitoring cracks in a tunnel at a moderate cost.
FIG. 1 is a description view schematically showing a method of measuring the depth of cracks vertically taken place on the surface of a concrete structure using a conventional ultrasonic method,
FIG. 2 is a construction view showing a crack detection system according to one embodiment of the present invention,
FIG. 3 is a conceptional view showing one example of a crack detection method applicable to the present invention,
FIG. 4 is a flow chart showing a crack detection method according to one embodiment of the present invention, and
FIG. 5 is a flowchart showing a crack detection method according to another embodiment of the present invention.
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 2 shows a crack detection system according to one embodiment of the present invention.
Referring to FIG. 2, a crack detection system according to the present invention is comprised of an ultrasonic wave sensor tag 100 attached to the inner wall of a tunnel, that is an object for which a crack or not is monitored; and a crack detection server 200 mounted on a transportation means such as tunnel-passing vehicles, receiving a piece of information from the ultrasonic wave sensor tag 100, and determining a crack or not in a tunnel. The ultrasonic wave sensor tag 100 includes a time measurement unit 110 for measuring a current time, an ultrasonic wave detection unit 120 detectable of ultrasonic waves applied from the outside, a storage part 140 storing an ultrasonic wave detection information containing a time at which the ultrasonic wave detection part 120 detects ultrasonic waves, a short-range wireless communication module 160 for transmitting ultrasonic wave detection information stored in the storage part 140 to the following crack detection server 200, and a driving electric power supply unit 180 supplying driving electric power to said each component.
The crack detection server 200 includes a communication module 220 for receiving information stored in the storage unit 140 of the ultrasonic wave sensor tag 100; and a crack (fracture) determination unit 260 determining cracks of the tunnel from the received values.
The ultrasonic wave detection unit 120 is configured to detect ultrasonic waves, and when ultrasonic waves are detected, it stores a detected value (for example: intensity) and a detected time together in the storage part 140. The ultrasonic wave detection unit 120 can be applicable as one of the following three implementations.
As a first implementation, the ultrasonic wave detection unit simply detects only whether ultrasonic waves have occurred. Such an implementation may be applicable as a fashion of when a crack takes place at the material of a wall surface of a tunnel (for example: concrete), detecting ultrasonic waves concurrently produced and making the crack ability of a tunnel known.
As a second implementation, the ultrasonic wave detection unit may detect the size of ultrasonic waves applied from the outside. Such an implementation may be applicable as a fashion of when a crack takes place at the material of a wall surface of a tunnel (for example: concrete), detecting ultrasonic waves concurrently produced and providing a piece of information used to determine the crack ability of a tunnel more accurately.
As a third implementation, the ultrasonic wave detection unit may have an ultrasonic wave generator producing ultrasonic waves and an ultrasonic wave detector detecting ultrasonic waves together. Pursuant to an implementation, the ultrasonic wave detector may detect supersound wave that is produced from an ultrasonic generator installed at the same ultrasonic wave detection unit and reflected at a crack in a tunnel, or detect supersound wave that is produced from an ultrasonic wave generator held on another ultrasonic wave detection unit adjacent to a wall surface of the tunnel and transmitted through a crack of the tunnel.
The ultrasonic wave detection unit 120 may apply a PZT (Lead Zirconate Titanate) AE (Acoustic Emission) sensor or a PVDF (polyvinylidene fluoride) sensor, as a detection device for detecting ultrasonic waves applied from the outside.
The ultrasonic wave detection unit 120 can continuously perform an ultrasonic detecting action at a predetermined time interval, and in this case the storage unit 140 functions to store supersound detection information gained by the continuously performed supersound detection action till it is transmitted to the crack detection server 200.
The short-range wireless communication module 160 may be a RF communication module that performs a communication as a RF mode. Herein, an RF mode is a communication method used in an RF smart card or an RF tag, and it is desirable to use the short-range wireless communication module having a wider recognition range if applied to the present invention.
The short-range wireless communication module 160 may form a wireless communication channel for a data transfer with a communication module 220 of the crack detection server 200.
On the one hand, a driving electric power supply unit 180 supplying driving electric power to internal components of the ultrasonic wave sensor tag 100 may be configured to receive electric power via a wired line or produce electric power from a wireless signal. In another implementation, the driving electric power supply unit may include a wireless electric power receptor producing electric power from a wireless signal transmitted from the crack detection server; and a capacitor storing electric power produced from the wireless electric power receptor. In this case, whenever the crack detection server 200 passes, the driving electric power supply unit 180 may generate electric power from a power transmission signal emitted by a crack detection server 200, store it in the capacitor, and use electric power stored in the capacitor when monitoring a crack occurrence.
Also, in a case of an ultrasonic wave sensor tag installed in an environment in which a certain vibration occurs periodically, such as in a subway tunnel, the driving electric power supply unit may be configured to include a generator module generating electric power from a physical vibration.
A crack determination unit 260 of the crack detection server 200 determines a crack occasion of a tunnel and a crack occurrence position from ultrasonic detection values assembled in the storage part.
One of the crack detection methods is illustrated in FIG. 3.
As shown in FIG. 3, four of ultrasonic wave sensor tags A, B, C, D are disposed in a square form. In a case a pair of ultrasonic wave sensor tags (that is, A and D, C and B) in a diagonal direction generates a same frequency ultrasonic wave, supersound wave is detected after a same delay time in a crack non-existing situation but supersound wave is detected after a different delayed time among them in a crack existing situation.
In addition to a method shown in the above FIG. 3, other methods, such as a method of grasping the form of a generated ultrasonic wave upon a crack occurrence, may be applied.
FIG. 4 illustrates a crack detection method according to one embodiment of the present invention.
Referring to FIG. 4, a crack detection method according to one embodiment of the present invention applies a mode of manually detecting ultrasonic waves upon a crack occurrence by an ultrasonic wave sensor tag attached to a tunnel wall.
A crack detection method of one embodiment as described above includes the steps of: detecting ultrasonic waves in a crack occurrence by an ultrasonic wave sensor tag, in a case a crack occurs (S120); waking up the ultrasonic wave sensor tag (S142), storing the ultrasonic detection time in a storage unit (S148), sleeping the ultrasonic wave sensor tag (S110); in a case the ultrasonic wave sensor tag detects a short-range wireless communication signal of a communication module of a crack detection server (S150), waking up the ultrasonic wave sensor tag (S162), transmitting ultrasonic wave detection information containing an ultrasonic wave detection time stored in the storage unit to a crack detection server (S164); and determining a crack occurrence from the ultrasonic wave detection information by the crack detection server (S180).
To prohibit the consumption of driving electric power of the ultrasonic wave sensor tag, in a normal case, the ultrasonic wave sensor tag exists in a sleeping mode (S110). In an ultrasonic wave sensor tag of the sleeping mode, only a time measurement unit; an ultrasonic wave detection unit; and a communication module for detecting the short-range wireless communication signal may be activated.
On the other hand, in another implementation, when detecting ultrasonic waves upon a crack occurrence, the ultrasonic wave sensor tag may be activated to produce ultrasonic waves actively to obtain information informing a more precise position in which a crack occurs.
In this case, the step 140 may further include the steps of: emitting ultrasonic waves; detecting the reflective waves of the emitted ultrasonic waves; and storing the intensity and delayed time of the reflective waves (reflective wave detection time - ultrasonic emitting time) in the storage unit. Also, ultrasonic wave detection information in the step 160 includes a crack occurrence time, and the intensity and delayed time of the reflective wave.
Since a course of collecting and storing the ultrasonic wave detection information in the ultrasonic wave sensor tag and a course of determining a crack occurrence in the crack detection server have been previously presented, a redundant description will be omitted.
FIG. 5 illustrates a crack detection method according to another embodiment of the present invention.
Referring to FIG. 5, a crack detection method of another embodiment of the present invention applies a mode of emitting ultrasonic waves actively by ultrasonic wave sensor tags attached to a tunnel wall, collecting reflective waves thereto and monitoring a crack occurrence.
A crack detection method of another embodiment as described above includes the steps of: determining if a given time has elapsed after a sleeping point (S220); waking up an ultrasonic wave sensor tag if it elapsed (S242); emitting ultrasonic waves from the ultrasonic wave sensor tag (S244); detecting the reflective waves of the emitted ultrasonic waves (S246); storing in a storage unit ultrasonic wave detection information containing the intensity and delayed time of the reflective waves (reflective wave detection time - ultrasonic wave emitting time (S248); sleeping the ultrasonic wave sensor tag (S210); in a case the ultrasonic wave sensor tag detects a short-range wireless communication signal of a communication module of a crack detection server (S250), waking up the ultrasonic wave sensor tag (S262); transmitting ultrasonic wave detection information stored in the storage unit to a crack detection server (S264); and determining a crack occurrence from the ultrasonic wave detection information by the crack detection server (S280).
To prohibit the consumption of driving electric power of the ultrasonic wave sensor tag, in a normal case, the ultrasonic wave sensor tag exists in a sleeping mode (S210). In an ultrasonic wave detection tag of the sleeping mode, only a time measurement unit; and a communication module for detecting the short-range wireless communication signal may be activated.
Since a course of collecting and storing the ultrasonic wave detection information in the ultrasonic wave sensor tag and a course of determining a crack occurrence in the crack detection server have been previously presented, a redundant description will be omitted.
While the spirit of the present invention technology has been specifically described according to the preferred embodiment, it should be noted that the described embodiment is for explanatory of this and not intended in a limiting sense. Also, experts skilled in the art of the present invention would understand that various embodiments can be made within the spirit of the present invention technology.
The present invention is to provide a crack detection system and a method thereof with a capability of monitoring cracks in a tunnel at a moderate cost, may be extensively used in a field necessary to monitor cracks in each kind of structure including a tunnel.

Claims (12)

  1. A crack detection system, comprising;
    an ultrasonic wave sensor tag including
    a time measurement unit for measuring a current time,
    an ultrasonic wave detection unit capable of detecting ultrasonic waves applied from the outside,
    a storage unit storing ultrasonic wave detection information containing a time at which ultrasonic waves are detected by the ultrasonic wave detection unit,
    a short-range wireless communication module for transmitting the ultrasonic wave detection information to the outside, and
    a driving electric power supply unit configured to supply driving electric power to said each component; and
    a crack detection server including
    a communication module for receiving the ultrasonic wave detection information by forming a communication channel with the short-range wireless communication module,
    a crack determination unit configured to determine if there occur cracks in a tunnel from the ultrasonic wave detection information.
  2. The crack detection system according to claim 1, wherein the ultrasonic wave detection information contains a detection time and a detection intensity of the ultrasonic waves.
  3. The crack detection system according to claim 1, wherein the ultrasonic wave detection unit includes
    an ultrasonic wave generator emitting ultrasonic waves, and
    an ultrasonic wave detector detecting ultrasonic waves emitted by the ultrasonic wave generator.
  4. The crack detection system according to claim 1, wherein the driving electric power supply unit includes
    a wireless electric power receptor producing driving electric power from a wireless signal transmitted by the crack detection server, and
    a capacitor storing electric power produced from the wireless electric power receptor.
  5. The crack detection system according to claim 1, wherein the driving electric power supply unit includes a generation module generating electric power from a physical vibration.
  6. A crack detection method, comprising:
    detecting ultrasonic waves in a case there occur cracks by an ultrasonic wave sensor tag;
    storing ultrasonic wave detection information including the ultrasonic wave detected time;
    determining if a short-range wireless communication signal is detected;
    transmitting the stored ultrasonic wave detection information from the ultrasonic wave sensor tag to a crack detection server; and
    determining the occurrence of a crack from the ultrasonic wave detection information by the crack detection server.
  7. The crack detection method according to claim 6, further including
    waking up the ultrasonic wave sensor tag before the ultrasonic wave detection information storage step, and
    sleeping the ultrasonic wave sensor tag after the ultrasonic wave detection information storage step.
  8. The crack detection method according to claim 6, wherein the step of storing the ultrasonic wave detection information includes
    emitting ultrasonic waves,
    detecting the reflective waves of the emitted ultrasonic waves, and
    storing the intensity and delayed time of the reflective waves in the storage unit.
  9. The crack detection method according to claim 6, further including
    waking up the ultrasonic wave sensor tag before the ultrasonic wave detection information transmission step, and
    sleeping the ultrasonic wave sensor tag after the ultrasonic wave detection information transmission step.
  10. A crack detection method, comprising:
    determining if a given time has elapsed after a sleeping point of an ultrasonic wave sensor tag;
    emitting ultrasonic waves from the ultrasonic wave sensor tag;
    detecting reflective waves of the emitted ultrasonic waves;
    storing in a storage unit ultrasonic wave detection information containing the intensity and delayed time of the reflective waves;
    determining if a short-range wireless communication signal is detected;
    transmitting the ultrasonic wave detection information from the ultrasonic wave sensor tag to a crack detection server; and
    determining the occurrence of a crack from the ultrasonic wave detection information, in the crack detection server.
  11. The crack detection method according to claim 10, further including
    waking up the ultrasonic wave sensor tag before the ultrasonic wave emission step, and
    sleeping the ultrasonic wave sensor tag after the ultrasonic wave detection information storage step.
  12. The crack detection method according to claim 10, further including
    waking up the ultrasonic wave sensor tag before the ultrasonic wave detection information transmission step, and
    sleeping the ultrasonic wave sensor tag after the ultrasonic wave detection information transmission step.
PCT/KR2010/007421 2009-12-11 2010-10-27 Crack detecting system and crack detecting method WO2011071241A2 (en)

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CN106124626A (en) * 2016-06-30 2016-11-16 中国航天空气动力技术研究院 Postpone hypersonic boundary layer material and turn the Study system and experiment research twisted
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