WO2021251129A1 - 磁性体検査装置、及び、磁性体検査方法 - Google Patents

磁性体検査装置、及び、磁性体検査方法 Download PDF

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Publication number
WO2021251129A1
WO2021251129A1 PCT/JP2021/019773 JP2021019773W WO2021251129A1 WO 2021251129 A1 WO2021251129 A1 WO 2021251129A1 JP 2021019773 W JP2021019773 W JP 2021019773W WO 2021251129 A1 WO2021251129 A1 WO 2021251129A1
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WIPO (PCT)
Prior art keywords
magnetic
magnetic sensor
magnetic material
magnet
difference
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Ceased
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PCT/JP2021/019773
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English (en)
French (fr)
Japanese (ja)
Inventor
大地 千葉
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University of Osaka NUC
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Osaka University NUC
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Priority to JP2022530110A priority Critical patent/JP7688420B2/ja
Priority to US18/009,113 priority patent/US12235240B2/en
Publication of WO2021251129A1 publication Critical patent/WO2021251129A1/ja
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/07—Hall effect devices
    • G01R33/072—Constructional adaptation of the sensor to specific applications
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • G01N27/83—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws by investigating stray magnetic fields
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/0023—Electronic aspects, e.g. circuits for stimulation, evaluation, control; Treating the measured signals; calibration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/038—Measuring direction or magnitude of magnetic fields or magnetic flux using permanent magnets, e.g. balances, torsion devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/091—Constructional adaptation of the sensor to specific applications

Definitions

  • the present invention relates to a magnetic material inspection device for inspecting the position of a magnetic material existing inside a non-magnetic material such as a concrete structure, a heat insulating material, and a protective material, the presence or absence of breakage, and a magnetic material inspection method.
  • a first-order differential SQUID sensor is arranged in a direction perpendicular to the reinforcing bar in concrete, and the sensor is scanned to determine the direction of the reinforcing bar.
  • a reinforcing bar exploration method using a SQUID sensor which is characterized in that the position and depth of the reinforcing bar are measured by measuring the first derivative in the direction perpendicular to the magnetic flux density of the component (Patent Document 2). ..
  • Patent Document 1 requires that a strong magnetic field is applied to the reinforcing bar from the outside to magnetize the reinforcing bar, and there are problems that a strong magnetic field is required and the inspection accuracy is low. Is.
  • Patent Document 2 Although the inspection method described in Patent Document 2 is a method capable of measuring the position, depth, etc. of the reinforcing bar, equipment for keeping the SQUID sensor at a low temperature is required, and when actually inspecting the reinforcing bar, it is necessary. It was not practical to use for.
  • the present invention has been made in view of the above circumstances, and an object thereof is a new magnetic material inspection device for detecting a magnetic material existing inside a non-magnetic material such as a concrete structure, a heat insulating material, and a protective material, and a new magnetic material inspection device. , To provide a magnetic material inspection method.
  • the magnetic material inspection device of the present invention that has solved the above problems includes a magnet, a first magnetic sensor that is arranged at a predetermined position with respect to the magnet and outputs an electric signal, and a predetermined position with respect to the magnet.
  • a magnetic material inspection device having a second magnetic sensor that is arranged and outputs an electrical signal, from a first electrical signal output from the first magnetic sensor and a second magnetic sensor. It is characterized in that the difference from the output second electric signal is output. It exists inside the non-magnetic material by outputting the difference between the first electrical signal output from the first magnetic sensor and the second electrical signal output from the second magnetic sensor. It is possible to detect the magnetic material.
  • the distance between the first magnetic sensor and the magnet of the magnetic material inspection device and the distance between the second magnetic sensor and the magnet are the same length.
  • the magnet is preferably a permanent magnet.
  • the magnetic sensor is preferably a hall sensor.
  • the magnetic material inspection device further includes a first magnetic sensor and a differential amplifier circuit connected to the second magnetic sensor.
  • the magnetic material inspection device can be preferably used when inspecting a reinforcing bar embedded in a concrete structure.
  • the magnetic substance inspection method of the present invention that has solved the above problems includes a magnet, a first magnetic sensor that is arranged at a predetermined position with respect to the magnet and outputs an electric signal, and a predetermined position with respect to the magnet. It is a magnetic material inspection method using a magnetic material inspection apparatus having a second magnetic sensor which is arranged and outputs an electric signal, and is a step of acquiring a first electric signal from the first magnetic sensor. It is characterized by having a step of acquiring a second electric signal from the second magnetic sensor and a step of outputting the difference between the first electric signal and the second electric signal. Is. By outputting the difference between the first electric signal acquired from the first magnetic sensor and the second electric signal acquired from the second magnetic sensor, the magnetism existing inside the non-magnetic material is output. It can detect the body.
  • the magnetic material inspection method of the present invention that has solved the above problems is a magnetic material inspection method using a magnetic material inspection device having a magnet and a magnetic sensor that outputs an electric signal, and is an inspection target.
  • Step T1 to acquire the electric signal from the magnetic sensor in the presence of the magnetic material
  • step T2 to acquire the electric signal from the magnetic sensor in the absence of the magnetic material
  • step T3 for outputting the difference between the signal and the electrical signal acquired in step T2. It exists inside a non-magnetic material by acquiring an electrical signal in the presence of a magnetic material, acquiring an electrical signal in the absence of a magnetic material, and outputting the difference between these two electrical signals. It is possible to detect the magnetic material.
  • the magnetic material inspection method of the present invention that has solved the above problems is a magnetic material inspection method using a magnetic material inspection device having a magnet and a magnetic sensor that outputs an electric signal, and is the first from the magnetic sensor.
  • the magnetic material inspection device and the magnetic material inspection method of the present invention can detect a magnetic material existing inside a non-magnetic material such as a concrete structure, a heat insulating material, and a protective material.
  • the present invention is a magnetic material inspection device having a magnet and a magnetic sensor that outputs an electric signal, and a magnetic material inspection method, wherein at least two electric signals are acquired and acquired by the magnetic sensor. By outputting the difference between the two electrical signals, it is possible to detect the magnetic material existing inside the non-magnetic material non-destructively.
  • FIG. 1 is a schematic diagram showing an example of a magnetic material inspection device according to an embodiment of the present invention.
  • FIG. 2 is a schematic view showing a modified example of the magnetic material inspection apparatus according to the embodiment of the present invention.
  • the magnetic material inspection apparatus of the present invention includes a magnet 10, a first magnetic sensor 21 arranged at a predetermined position with respect to the magnet 10 and outputting an electric signal, and a magnetic sensor 21.
  • a magnetic material inspection device 1 having a second magnetic sensor 22 which is arranged at a predetermined position with respect to the magnet 10 and outputs an electric signal, and is a first magnetic substance inspection device 1 which is output from the first magnetic sensor 21. It is characterized in that the difference between the electric signal and the second electric signal output from the second magnetic sensor 22 is output.
  • the magnet 10 included in the magnetic material inspection device 1 may be any one capable of generating a magnetic field, and for example, a permanent magnet or an electromagnet can be used. Although the electromagnet requires electric power, the magnet 10 is preferably a permanent magnet because a permanent magnet can stably generate a magnetic field from itself.
  • the shape of the magnet 10 is not particularly limited, and may be selected from various shapes such as a rectangular parallelepiped shape, a cube shape, a square columnar shape, a polygonal columnar shape, and a cylindrical shape.
  • the number of magnets 10 is not particularly limited, and the magnetic material inspection device 1 may have at least one magnet, and the number of magnets 10 can be increased to two, three, or the like as needed. .. It is preferable that the plurality of magnets 10 are arranged at predetermined positions.
  • the magnet 10 is preferably a permanent magnet, but the magnet 10 may be an electromagnet, and by using an electromagnet, a stronger magnetic field than the permanent magnet can be generated. This makes it possible to detect a magnetic material embedded deeper.
  • a plurality of electromagnets are arranged, for example, a plurality of electromagnets are arranged at predetermined positions, and a plurality of magnetic fields can be formed by turning on some electromagnets and turning off other electromagnets.
  • a plurality of electrical signals obtained from the magnetic sensor 20 it is possible to acquire a plurality of electrical signals obtained from the magnetic sensor 20, and it is possible to improve the accuracy of identifying the position and the fractured portion of the magnetic material existing inside the non-magnetic material.
  • the magnetic sensor 20 may be any as long as it can measure the magnitude of the magnetic field generated by the magnet.
  • the magnetic sensor 20 of the magnetic material inspection device 1 includes a Hall sensor capable of measuring a magnetic field generated by a magnet or a magnetic field generated by an electric current by using the Hall effect, and a magnetoresistive effect in which the electric resistance of an individual changes depending on the magnetic field.
  • An MR sensor magneticto resistive sensor
  • An MR sensor magnetic resistive sensor
  • a high-sensitivity sensor such as an MR sensor has a relatively large output as compared with a hall sensor, the output tends to be saturated in a low magnetic field.
  • the magnetic sensor 20 is a hole in which saturation does not occur up to a relatively high magnetic field or a saturated magnetic field does not exist. It is preferably a sensor.
  • a Hall sensor a Hall element that outputs a Hall voltage when a current is passed, a Hall IC in which an arithmetic amplifier that amplifies a signal on a circuit is integrated with the Hall element, or the like can be used. Since the voltage obtained from the Hall element is relatively small, when the Hall element is used, an operational amplifier may be separately provided.
  • the Hall element has a first supply electrode and a second supply electrode for supplying a current, and a first measurement electrode and a second measurement electrode for measuring a voltage.
  • the current flows in a certain direction (x-axis direction) from the first supply electrode to the second supply electrode.
  • a magnetic field is applied in the direction perpendicular to the current flowing between the two supply electrodes (z-axis direction)
  • the charged particles carrying the current receive Lorentz force and are perpendicular to the straight line connecting the two supply electrodes (x-axis direction).
  • the charge distribution is biased in the y-axis direction, and one is positively charged and the other is negatively charged.
  • the first measuring electrode is arranged on the positively charged side, and the second measuring electrode is arranged on the negatively charged side, and the potential difference between the two measuring electrodes is measured. By measuring this potential difference, it is possible to determine whether or not a magnetic field is generated and the magnitude of the magnetic field.
  • the magnet 10 is a permanent magnet and the direction from the S pole to the N pole of the magnet 10 is perpendicular to the direction in which the first measurement electrode and the second measurement electrode of the magnetic sensor 20 face each other. .. Further, the direction in which the first measurement electrode and the second measurement electrode of the magnetic sensor 20 face each other and the straight line connecting the center of gravity of the first magnetic sensor 21 and the center of gravity of the second magnetic sensor 22 are perpendicular to each other. Is preferable. Further, as shown in FIG. 3, the direction from the S pole to the N pole of the magnet 10 and the straight line connecting the center of gravity of the first magnetic sensor 21 and the center of gravity of the second magnetic sensor 22 are perpendicular to each other, or FIG.
  • the direction from the S pole to the N pole of the magnet 10 is parallel to the straight line connecting the center of gravity of the first magnetic sensor 21 and the center of gravity of the second magnetic sensor 22.
  • the magnetic sensor 20 is arranged so that the magnitude of the magnetic field 12 detected by the first magnetic sensor 21 and the magnitude of the magnetic field 12 detected by the second magnetic sensor 22 are substantially equal to each other. Therefore, it is suitable for the output of the difference of the magnetic material inspection device 1.
  • the magnetic sensor 20 outputs an electrical signal.
  • the electrical signal is a signal output according to the magnitude of the magnetic field detected by the magnetic sensor 20, for example, the magnetic field detected by the magnetic sensor 20 is converted into a signal such as a voltage or a current corresponding to the signal and output.
  • the magnetic material inspection device 1 has a first magnetic sensor 21 which is arranged at a predetermined position with respect to the magnet 10 and outputs an electric signal, and a first magnetic sensor 21 which is arranged at a predetermined position with respect to the magnet 10 and outputs an electric signal. It has at least two magnetic sensors 20 of the second magnetic sensor 22 to output.
  • the first magnetic sensor 21 arranged at a predetermined position with respect to the magnet 10 may be arranged at a position capable of detecting the magnetic field 12 generated by the magnet 10.
  • the second magnetic sensor 22 arranged at a predetermined position with respect to the magnet 10 may be arranged at a position capable of detecting the magnetic field 12 generated by the magnet 10.
  • the magnetic sensor 20 is arranged so that the magnitude of the magnetic field 12 detected by the first magnetic sensor 21 and the magnitude of the magnetic field 12 detected by the second magnetic sensor 22 are substantially equal to each other. Is preferable. For example, it is preferable that the distance between the first magnetic sensor 21 and the magnet 10 shown in FIG. 2 and the distance between the second magnetic sensor 22 and the magnet 10 are the same length. Here, the distance between the first magnetic sensor 21 and the magnet 10 is the distance between the portion of the first magnetic sensor 21 closest to the magnet 10 and the portion of the magnet 10 closest to the first magnetic sensor 21. Should be measured.
  • the distance between the second magnetic sensor 22 and the magnet 10 is the distance between the part of the second magnetic sensor 22 closest to the magnet 10 and the part of the magnet 10 closest to the second magnetic sensor 22. Should be measured.
  • the magnitude of the first electrical signal acquired from the first magnetic sensor 21 The magnitude of the second electrical signal acquired from the second magnetic sensor 22 may be significantly different.
  • the distance between the first magnetic sensor 21 and the magnet 10 and the distance between the second magnetic sensor 22 and the magnet 10 the same length, the magnitude of the first electric signal and the second Since the magnitudes of the electrical signals are close to each other, the inspection accuracy can be improved.
  • the line segment L1 connecting the first magnetic sensor 21 and the magnet 10 and the line segment L2 connecting the second magnetic sensor 22 and the magnet 10 are parallel to each other. .. It is more preferable that the distance between the first magnetic sensor 21 and the magnet 10 and the distance between the second magnetic sensor 22 and the magnet 10 are the same, and the line segment L1 and the line segment L2 are parallel to each other. .. The distance between the first magnetic sensor 21 and the magnet 10 and the distance between the second magnetic sensor 22 and the magnet 10 are the same, and the line L1 and the line L2 are parallel to each other. Since the first magnetic sensor 21 and the second magnetic sensor 22 can detect magnetic fields having similar sizes, the inspection accuracy can be improved.
  • the parallelism of the line segment L1 connecting the first magnetic sensor 21 and the magnet 10 and the line segment L2 connecting the second magnetic sensor 22 and the magnet 10 is substantially parallel to both line segments. It shall mean ⁇ 5 °.
  • the first magnetic sensor is located at a position where the shape of the magnetic field magnetic field line detected by the first magnetic sensor 21 and the shape of the magnetic field magnetic field line detected by the second magnetic sensor 22 are symmetrical. It is preferable that the 21 and the second magnetic sensor 22 are arranged. For example, it is preferable that the first magnetic sensor 21 and the second magnetic sensor 22 are arranged symmetrically with respect to the magnet 10 as shown in FIG. 1 or 2.
  • the symmetrical position via the magnet 10 means that the first magnetic sensor 21 and the second magnetic sensor 22 are arranged at positions that are point-symmetrical with the center of gravity 11 of the magnet 10 as the center of symmetry.
  • the magnet 10 is arranged at a position that is line-symmetrical with respect to a predetermined straight line passing through the center of gravity 11.
  • the shape of the magnetic field lines of the magnetic field 12 generated by the magnet 10 detected by the first magnetic sensor 21 and the second magnetism The shape of the magnetic field lines of the magnetic field 12 generated by the magnet 10 detected by the sensor 22 is the same or symmetrical. If the shape of the magnetic field line of the magnetic field 12 detected by the first magnetic sensor 21 and the shape of the magnetic field line of the magnetic field 12 detected by the second magnetic sensor 22 are not the same or symmetrical, it is necessary to perform a calculation to correct it. There is.
  • the shape of the magnetic field line of the magnetic field 12 detected by the first magnetic sensor 21 the same as or symmetrical with the shape of the magnetic field line of the magnetic field 12 detected by the second magnetic sensor 22, the first electricity
  • the magnetic material inspection device 1 further includes a third magnetic sensor arranged at a predetermined position with respect to the magnet 10 and a fourth magnetic sensor arranged at a predetermined position with respect to the magnet 10. It may be configured to have. For example, when the third magnetic sensor and the fourth magnetic sensor are arranged, the magnetic field 12 having a size different from the size of the magnetic field 12 detected by the first magnetic sensor 21 and the second magnetic sensor 22 is detected. It may be placed in a position where it can be placed.
  • the magnetic sensor may be arranged so that the magnitude of the magnetic field 12 detected by the third magnetic sensor and the magnitude of the magnetic field 12 detected by the fourth magnetic sensor are substantially equal to each other. In this case, the difference between the third electric signal output from the third magnetic sensor and the fourth electric signal output from the fourth magnetic sensor can be output.
  • the inspection accuracy can be improved by increasing the number of magnetic sensors 20 in the magnetic material inspection device 1.
  • the magnetic material inspection device 1 outputs the difference between the first electrical signal output from the first magnetic sensor 21 and the second electrical signal output from the second magnetic sensor 22.
  • the difference between the first electric signal and the second electric signal changes. Therefore, when a change in the difference appears, it is possible to identify that the magnetic material exists in the vicinity of the magnetic material inspection device 1, so that the position of the magnetic material existing in the non-magnetic body is specified. be able to. Further, since the magnetic field 12 of the magnet 10 is concentrated and converges on the end portion of the magnetic material, the difference output at the place where the magnetic material is broken is the place where the magnetic material without breakage exists. It will be larger than the output difference. This makes it possible to identify that the magnetic material is broken at a position where the output difference is larger than the difference at the place where the magnetic material without breakage exists.
  • the magnetic material inspection device 1 has a difference detection unit 30 connected to a first magnetic sensor 21 and a second magnetic sensor 22, and has a first electrical signal.
  • the difference may be amplified by inputting the voltage output of the second electric signal to the difference detection unit 30.
  • the magnetic material inspection device 1 further includes a differential amplifier circuit 31 connected to a first magnetic sensor 21 and a second magnetic sensor 22, and a first. By inputting the voltage outputs of the electric signal of the above and the voltage output of the second electric signal to the differential amplifier circuit 31, the difference can be amplified and output at the same time.
  • the magnetic material inspection device 1 further has an arithmetic processing unit 32, and the arithmetic processing unit 32 converts an electric signal into a digital signal, and the difference between the digital signals is obtained. The calculated and amplified one may be output.
  • the magnetic material inspection device 1 has a memory, and the personal computer 40 uses a first electric signal and a second electric signal stored in the memory. The signal difference may be calculated and output by the CPU (Central Processing Unit) of the personal computer 40.
  • the differential amplifier circuit 31 is connected to the first magnetic sensor 21 and the second magnetic sensor 22, the differential amplifier circuit 31 can be arranged near the magnetic sensor, which causes noise. Can be reduced. Therefore, the magnetic material inspection device 1 further has a differential amplifier circuit 31, and the voltage outputs of the first electric signal and the second electric signal may be input to the differential amplifier circuit 31. preferable.
  • the magnetic material inspection device 1 may be provided with a power supply unit 50 that adjusts the electric power obtained from the outside and supplies it to the inside of the device. Further, the power supply unit 50 may be provided with a power supply switch for switching on / off of the power supply.
  • the magnetic material inspection device 1 may be provided with a display unit 60 that displays information on the difference between the first electrical signal and the second electrical signal to the user.
  • a display unit 60 for example, a monitor that visualizes the magnitude of each signal, the magnitude of the difference, and the like can be used.
  • the magnetic material inspection device 1 has a first electrical signal output from the first magnetic sensor 21 and a second magnetic signal output from the second magnetic sensor 22. By outputting the difference from the electrical signal of, the position where the magnetic material existing inside the non-magnetic material exists and the presence or absence of breakage can be specified.
  • the magnetic material inspection device 1 has a memory in which a database in which difference data acquired using a standard sample is accumulated is stored.
  • the standard sample is a magnetic material having a thickness of C1.
  • the first electrical signal output from the first magnetic sensor 21 and the second magnetic sensor 22 are output.
  • the difference from the second electrical signal is measured, and the thickness of the standard sample is C1, the distance between the standard sample and the magnetic sensor is C2, and the difference is stored in a mutually linked state. Just do it.
  • the above C1 and C2 are constants larger than 0. It is preferable to obtain differential data by changing the values of C1 and C2 and create a database.
  • a first electrical signal output from the first magnetic sensor 21 and a second magnetic signal output from the second magnetic sensor 22 are used.
  • the difference from the electrical signal can be configured to be fitted with the difference data stored in the above database. From the fitting result of the difference obtained from the inspection target and the difference data on the database, the thickness of the standard sample associated with the difference data on the database and the distance between the standard sample and the magnetic sensor can be derived. This makes it possible to identify the thickness of the magnetic material to be inspected and the distance between the magnetic material to be inspected and the magnetic sensor.
  • the difference between the first electric signal output from the first magnetic sensor 21 and the second electric signal output from the second magnetic sensor 22 is fitted with the difference data on the database.
  • a model function F1 capable of fitting a database is created, and the model function F1 is set so that the fitting parameters D1 and D2 of the model function are uniquely determined for C1 and C2.
  • model functions F21 and F22 are created and modeled again so that D1 and D2 are functions of C1 and C2, respectively.
  • Parameters D1 and D2 can be obtained by making measurements on the object to be inspected and fitting the results.
  • C1 and C2 can be determined by inversely calculating the parameters using F21 and F22.
  • the magnetic material inspection device 1 can identify a corroded portion by using the difference obtained from the magnetic material to be inspected, the distance between the magnetic material and the magnetic sensor, and the thickness. More specifically, when a part of the reinforcing bar buried in the concrete structure is corroded and the diameter is reduced, the difference and the thickness of the reinforcing bar obtained between the corroded part and the non-corroded part of the reinforcing bar are obtained. , The numerical value of the distance between the reinforcing bar and the magnetic sensor will be different.
  • the difference, thickness, and distance between the magnetic material and the magnetic sensor obtained from the magnetic material to be inspected what are the surrounding difference data, the thickness of the magnetic material, and the numerical value of the distance between the magnetic material and the magnetic sensor? If different sites are present, it can be identified that the sites are corroded.
  • the above fitting may be performed by providing an arithmetic processing unit or a control unit. Further, in the above description, the form in which the memory is provided in the magnetic material inspection device 1 and the database is stored in the memory is described, but in addition, the database itself may be a memory attached to a personal computer, an external memory, or the like. It can also be stored in a memory provided in another device.
  • the magnetic material inspection device 1 can be preferably used when inspecting a reinforcing bar embedded in a concrete structure.
  • the reinforcing bar When the reinforcing bar is present inside the concrete structure, the position where the reinforcing bar exists and the presence or absence of fracture can be specified without destroying the concrete structure.
  • pipes, etc. may be buried in addition to the reinforcing bars, or cavities may exist, but of course, if the pipes, etc. are non-magnetic materials, the pipes will be detected. Since it does not detect cavities and does not detect cavities, it is possible to stably inspect only reinforcing bars, which are magnetic materials.
  • the inspection target of the magnetic material inspection apparatus 1 can be an inspection target if it is a magnetic material as well as a reinforcing bar. It is also possible to inspect when a plurality of magnetic materials are lined up or when the magnetic materials are lined up in a grid pattern.
  • FIG. 3 is a diagram showing a modified example of the magnetic material inspection device according to the embodiment of the present invention and a cross section of a concrete structure in which a reinforcing bar is embedded as an example of an inspection target.
  • one magnetic sensor is located so that the distance from the inspection object 70 is closer than the magnet 10, and the other magnetic sensor is located so that the distance from the inspection object 70 is farther than the magnet 10.
  • the magnetic material inspection device 1 is arranged on the inspection object 70.
  • the distance from the magnetic sensor to the inspection object shall be the distance between the part of the magnetic sensor closest to the inspection object and the part of the inspection object farthest from the magnetic sensor.
  • the distance from the magnet to the inspection target is measured by measuring the distance between the part of the magnet closest to the inspection target and the portion of the inspection target farthest from the magnet.
  • the second magnetic sensor 22 is closer to the inspection object 70 than the magnet 10 so that the first magnetic sensor 21 is closer to the inspection object 70 than the magnet 10.
  • the magnetic material inspection device 1 is arranged on the inspection object 70 so as to be in a distant position.
  • the surface of the inspection object 70 is scanned while maintaining the positional relationship between the magnet 10 and the magnetic sensor 20 and the inspection object 70.
  • the magnetic sensor 20 acquires an electric signal while scanning.
  • the magnetic field 12 of the magnet 10 is represented by stable magnetic field lines that do not change if there is no magnetic material around them (hereinafter, referred to as "standard magnetic field lines").
  • standard magnetic field lines stable magnetic field lines that do not change if there is no magnetic material around them.
  • the magnetic field 12 of the magnet 10 has a property of converging on the magnetic material, and therefore exhibits a magnetic field line different from the standard magnetic field line.
  • the first magnetic sensor 21 in which the distance from the inspection object 70 is closer than the magnet 10, at least a part of the magnetic field 12 converges on the magnetic material when the magnetic material is present in the inspection object 70.
  • the first magnetic sensor 21 that has detected the magnetic field 12 emits an electric signal corresponding to the magnetic field 12 (first electric signal).
  • first electric signal the electric signal corresponding to the magnetic field 12
  • second magnetic sensor 22 whose distance from the inspection object 70 is farther than the magnet 10
  • the magnetic field 12 close to the standard magnetic field line continues to be generated, and the magnetic field 12 close to the standard magnetic field line is responded to.
  • the second magnetic sensor 22 emits an electrical signal (second electrical signal).
  • the magnetic substance inspection device 1 approaches. Therefore, by outputting the difference between the first electric signal and the second electric signal, the position where the magnetic material is embedded can be identified.
  • the first magnetic sensor 21 and the second magnetic sensor 21 When the magnetic sensor 22 is not arranged, it is necessary to perform a calculation according to the position of the magnetic sensor 20 before outputting the difference between the two electrical signals. The calculation can be performed by providing an arithmetic processing unit or the like.
  • the magnetic substance inspection method includes a magnet 10, a first magnetic sensor 21 arranged at a predetermined position with respect to the magnet 10 and outputting an electric signal, and the magnet 10.
  • it is a magnetic material inspection method using a magnetic material inspection device 1 having a second magnetic sensor 22 arranged at a predetermined position and outputting an electric signal, and the first magnetic sensor 21 to the first.
  • Step S1 a step of acquiring a second electric signal from the second magnetic sensor 22 (step S2), a first electric signal, and a second electric signal. It is characterized by having a step (step S3) for outputting a difference from the above.
  • step S1 the first electric signal is acquired from the first magnetic sensor 21, and more specifically, as shown in FIG. 3, the first electric signal is at least one of the magnetic fields 12 of the magnet 10. It is preferable that the portion is acquired from the first magnetic sensor 21 in a state where the portion is converged on the magnetic material.
  • a second electric signal is acquired from the second magnetic sensor 22, and more specifically, as shown in FIG. 3, the magnetic field 12 of the magnet 10 is a magnetic material in the second electric signal. It is preferable that it is acquired from the second magnetic sensor 22 in a state where it does not converge to.
  • the state in which the magnetic field 12 of the magnet 10 does not converge on the magnetic material is a state in which the magnetic field 12 exhibits a standard magnetic field line.
  • step S3 the difference between the first electric signal acquired in step S1 and the second electric signal acquired in step S2 is output.
  • the number of magnetic sensors included in the magnetic material inspection device 1 that implements the magnetic material inspection method may be two or more.
  • the first magnetic sensor 21 generates a magnetic field 12 generated by the magnet 10 in the presence of the reinforcing bar 71 of the inspection object 70.
  • the second magnetic sensor 22 measures the magnetic field 12 generated by the magnet 10 in the absence of the reinforcing bar 71 of the inspection object 70.
  • step S3 outputs the difference between the first electric signal obtained from the first magnetic sensor 21 in step S1 and the second electric signal obtained from the second magnetic sensor 22 in step S2. Will be done.
  • Step S1 may be performed before step S2, or step 2 may be performed before step 1, but it is preferable that step S1 and step S2 are performed at the same time.
  • step S1 and step S2 are performed at the same time.
  • the difference between the first electric signal obtained from the first magnetic sensor 21 in step S1 and the second electric signal obtained from the second magnetic sensor 22 in step S2 is obtained. It is preferable to have a step (step S4) for amplification.
  • the step S4 for amplifying the difference can be performed before the step S3. That is, the difference between the first electric signal obtained from the first magnetic sensor 21 in step S1 and the second electric signal obtained from the second magnetic sensor 22 in step S2 is amplified and then output. It can be configured.
  • the magnetic material inspection device 1 is provided with an arithmetic processing unit 32 as a difference detection unit 30, and the first electrical signal obtained from the first magnetic sensor 21 in step S1 and the second electric signal in step S2.
  • the second electrical signal obtained from the magnetic sensor 22 is converted into a digital signal by the arithmetic processing unit 32, the difference between the digital signals is calculated, and the difference can be amplified.
  • the step S4 for amplifying the difference can be performed at the same time as the step S3. That is, the difference between the first electric signal obtained from the first magnetic sensor 21 in step S1 and the second electric signal obtained from the second magnetic sensor 22 in step S2 is amplified and output at the same time. It can be configured.
  • the embodiment is preferable in that the time required for the inspection can be shortened by performing step S4 and step S3 at the same time.
  • the magnetic material inspection device 1 has a differential amplification circuit 31 connected to a first magnetic sensor 21 and a second magnetic sensor 22 as a difference detection unit 30, and is first in step S1.
  • the first electric signal obtained from the magnetic sensor 21 of the above and the second electric signal obtained from the second magnetic sensor 22 in step S2 are simultaneously sent to the differential amplification circuit 31, and the two electric signals are sent to the differential amplification circuit 31.
  • It can be configured so that the difference between the signals is amplified by a constant coefficient and output at the same time.
  • the differential amplifier circuit 31 By connecting the differential amplifier circuit 31 to the first magnetic sensor 21 and the second magnetic sensor 22, the differential amplifier circuit 31 can be arranged near the magnetic sensor, thereby causing noise. It can be reduced.
  • step S4 the inspection accuracy of the magnetic material can be improved.
  • the magnetic material inspection method according to the first embodiment of the present invention has a first electrical signal acquired from the first magnetic sensor 21 and a second magnetic signal acquired from the second magnetic sensor 22. By outputting the difference from the electrical signal, it is possible to specify the position where the magnetic material existing inside the non-magnetic material exists and the presence or absence of breakage.
  • the magnetic material inspection apparatus 1 has a memory in which a database is stored, and a step (step S5) of fitting the difference output in step S3 and the database stored in the memory is performed. It can be configured to have.
  • the database stored in the memory includes, for example, a first electrical signal output from the first magnetic sensor 21 of the standard sample and a second magnetic signal at a distance C2 between the standard sample and the magnetic sensor.
  • the difference from the second electrical signal output from the sensor 22 is measured and stored in a state where the thickness C1 of the standard sample, the distance C2 between the standard sample and the magnetic sensor, and the above difference are interconnected. Anything that exists will do.
  • step S5 the difference between the first electric signal and the second electric signal actually obtained by using the magnetic material inspection device 1 with respect to the inspection symmetry, and the difference data on the database are fitted. do. From the result of fitting the difference output in step S5 and the difference data on the database, the thickness of the standard sample associated with the difference data on the database and the distance between the standard sample and the magnetic sensor can be derived. .. This makes it possible to identify the thickness of the magnetic material to be inspected and the distance between the magnetic material to be inspected and the magnetic sensor.
  • the magnetic material inspection apparatus 1 has a memory in which a database is stored, and the first electrical signal acquired in step S1.
  • step S5 It has a step (step S5) of outputting the difference between the and the second electrical signal acquired in step S2 and the second electrical signal (step S3), and fitting the difference output in step S3 and the data stored in the above database.
  • step S3 a method using a model function can also be adopted.
  • a model function F1 capable of fitting a database is created, and the model function F1 is set so that the fitting parameters D1 and D2 of the model function are uniquely determined for C1 and C2.
  • model functions F21 and F22 are created and modeled again so that D1 and D2 are functions of C1 and C2, respectively.
  • Parameters D1 and D2 can be obtained by making measurements on the object to be inspected and fitting the results.
  • C1 and C2 can be determined by inversely calculating the parameters using F21 and F22.
  • the above-mentioned magnetic material inspection method can also identify a corroded part by using the difference obtained from the magnetic material to be inspected, the distance between the magnetic material and the magnetic sensor, and the thickness. This makes it possible to identify the distance between the magnetic material and the magnetic sensor, the thickness of the magnetic material, the fractured part, and even the corroded part.
  • the fitting as described above may be performed by further providing an arithmetic processing unit and a control unit.
  • a method of providing a memory in the magnetic material inspection device 1 and storing the database in the memory is described, but in addition, the database itself may be a memory attached to a personal computer, an external memory, or the like. It can also be stored in a memory provided in another device.
  • the first electrical signal acquired from the first magnetic sensor 21 and the second magnetic signal acquired from the second magnetic sensor 22 By outputting the difference from the electrical signal and fitting the difference to the database, the position and thickness of the magnetic material existing inside the non-magnetic material, the distance between the magnetic material and the magnetic sensor, and corrosion. It is possible to specify the location and the presence or absence of breakage.
  • FIG. 4 is a diagram showing a modified example of the magnetic material inspection device according to the embodiment of the present invention and a cross section of a concrete structure in which a reinforcing bar is embedded as an example of an inspection object.
  • the magnetic material inspection method according to the second embodiment of the present invention is a magnetic material inspection method using a magnetic material inspection device 1 having a magnet 10 and a magnetic sensor 20 for outputting an electric signal.
  • Step T1 to acquire the electric signal from the magnetic sensor 20 in the presence of the magnetic material to be inspected
  • step T2 to acquire the electric signal from the magnetic sensor 20 in the absence of the magnetic material
  • step T1 It is characterized by having step T3 which outputs the difference between the electric signal acquired in step T2 and the electric signal acquired in step T2.
  • the electrical signal acquired in step T1 is acquired in the presence of the magnetic material to be inspected, and more specifically, a state in which at least a part of the magnetic field 12 of the magnet 10 converges on the magnetic material. It is acquired from the magnetic sensor 20 under the above.
  • the electrical signal acquired in step T2 is acquired in the absence of the magnetic material to be inspected, and more specifically, under a state where the magnetic field 12 of the magnet 10 does not converge on the magnetic material. It is acquired from the magnetic sensor 20.
  • the state in which the magnetic field 12 of the magnet 10 does not converge on the magnetic material is a state in which the magnetic field exhibits standard magnetic field lines.
  • Step T3 is a step of outputting the difference between the electrical signal acquired in step T1 and the electrical signal acquired in step T2.
  • the magnetic sensor 1 of the magnetic material inspection device 1 that carries out the magnetic material inspection method may have one or more magnetic sensors.
  • step T1 of acquiring an electric signal from one magnetic sensor 20 (21) in the presence of a magnetic material is performed. It may be configured to carry out step T2 to acquire an electric signal from another magnetic sensor 20 (22) in the absence of a magnetic material. Further, an electric signal is acquired from one magnetic sensor 20 (21) in the presence of a magnetic material (step T1), and an electric signal in the absence of the magnetic material is also acquired from the magnetic sensor 20 (21). (Step T2) may be configured.
  • a step T1 of acquiring an electrical signal from one magnetic sensor 20 (21) in the presence of a magnetic material is performed, and a step of acquiring an electrical signal from another magnetic sensor 20 (22) in the absence of a magnetic material.
  • step T1 may be carried out before step T2
  • step T2 may be carried out before step T1
  • step T1 and step T2 may be carried out at the same time. good.
  • a method of using only one magnetic sensor can be considered. For example, an electric signal is acquired from one magnetic sensor 20 (21) in the presence of a magnetic material, and an electric signal is also acquired from the magnetic sensor 20 (21) in the absence of a magnetic material. be able to.
  • step T1 may be carried out before step T2, or step T2 may be carried out before step T1.
  • one magnetic sensor 20 acquires an electric signal in the presence of the magnetic material (step T1). After moving the magnetic sensor 20 in the absence of the magnetic material, the magnetic sensor 20 can also acquire an electrical signal in the absence of the magnetic material (step T2). Further, after one magnetic sensor 20 acquires an electric signal in the absence of the magnetic material (step T2) and moves the magnetic sensor 20 in the presence of the magnetic material, the magnetic sensor 20 becomes magnetic. It is also possible to obtain an electrical signal in the presence of a body (step T2).
  • the magnetic material inspection method preferably includes step T4 for amplifying the difference between the electrical signal obtained from the magnetic sensor 20 in step T1 and the electrical signal obtained from the magnetic sensor 20 in step T2.
  • the step T4 for amplifying the difference may be performed before the step T3. That is, the configuration can be configured such that the difference between the electric signal obtained from the magnetic sensor 20 in step T1 and the electric signal obtained from the magnetic sensor 20 in step T2 is amplified and then output.
  • the magnetic material inspection device 1 is provided with an arithmetic processing unit 32 as a difference detection unit 30, and the electrical signal obtained from the magnetic sensor 20 in step T1 and the electrical signal obtained from the magnetic sensor 20 in step T2.
  • the signal is converted into a digital signal by the arithmetic processing unit 32, the difference between the digital signals is calculated, and the difference can be amplified.
  • the step T4 for amplifying the difference may be performed at the same time as the step T3. That is, the difference between the electrical signal obtained from the magnetic sensor 20 in step T1 and the electrical signal obtained from the magnetic sensor 20 in step T2 may be amplified and output at the same time.
  • the embodiment is preferable in that the time required for the inspection can be shortened by performing step T4 and step T3 at the same time.
  • the magnetic material inspection device 1 is provided with a differential amplifier circuit 31 as a difference detection unit 30, and the electrical signal obtained from the magnetic sensor 20 in step T1 and the electricity obtained from the magnetic sensor 20 in step T2.
  • the target signal can be simultaneously sent to the differential amplifier circuit 31, and the difference between the signals can be amplified by a constant coefficient and output at the same time.
  • step T4 for amplifying the difference between the electric signal obtained from the magnetic sensor 20 in step T1 and the electric signal obtained from the magnetic sensor 20 in step T2 the inspection accuracy of the magnetic material can be improved. Can be improved.
  • the magnetic material inspection method acquires an electric signal in the presence of a magnetic material, acquires an electric signal in the absence of a magnetic material, and outputs the difference. By doing so, it is possible to specify the position where the magnetic material existing inside the non-magnetic material exists and the presence or absence of breakage.
  • the magnetic material inspection device 1 has a memory in which a database is stored, and an electrical signal output from the magnetic sensor 20 in the presence of the magnetic material and a magnetic material non-existence from the magnetic sensor 20.
  • the configuration may include step T5 for fitting the difference from the electrical signal output below to the database stored in the memory.
  • the database stored in the memory is, for example, an electrical signal output from the magnetic sensor 20 in the presence of a magnetic material and magnetism from the magnetic sensor 20 when the distance between the standard sample and the magnetic sensor is the distance C2.
  • the difference from the electrical signal output in the absence of the body is measured, and the thickness C1 of the standard sample, the distance C2 between the standard sample and the magnetic sensor, and the above difference are stored in a state of being interconnected. Anything is fine.
  • step T5 the difference between the electrical signal obtained in step T1 and the electrical signal obtained in step T2 using the magnetic material inspection device 1 for the inspection symmetry is stored in the memory. Fit with the database. From the result of fitting the difference and the database in step T5, the thickness of the standard sample associated with the difference data on the database and the distance between the standard sample and the magnetic sensor can be derived, thereby inside the inspection object. It is possible to identify the thickness of the magnetic material present in the magnetic material and the distance between the magnetic material and the magnetic sensor. As another embodiment of fitting, a method using a model function can also be adopted. A model function F1 capable of fitting a database is created, and the model function F1 is set so that the fitting parameters D1 and D2 of the model function are uniquely determined for C1 and C2.
  • model functions F21 and F22 are created and modeled again so that D1 and D2 are functions of C1 and C2, respectively.
  • Parameters D1 and D2 can be obtained by making measurements on the object to be inspected and fitting the results.
  • C1 and C2 can be determined by inversely calculating the parameters using F21 and F22.
  • the fitting as described above may be performed by further providing an arithmetic processing unit and a control unit in the magnetic material inspection device 1.
  • the magnetic material inspection method outputs the difference between the electrical signal acquired in the presence of the magnetic material and the electrical signal acquired in the absence of the magnetic material.
  • the difference By fitting the difference to the database, it is possible to specify the position and thickness of the magnetic material existing inside the non-magnetic material, the distance between the magnetic material and the magnetic sensor, and the presence or absence of breakage.
  • the above-mentioned magnetic material inspection method can also identify a corroded part by using the difference obtained from the magnetic material to be inspected, the distance between the magnetic material and the magnetic sensor, and the thickness. This makes it possible to identify the distance between the magnetic material and the magnetic sensor, the thickness of the magnetic material, and even the corroded part.
  • a method of providing a memory in the magnetic material inspection device 1 and storing the database in the memory is described, but in addition, the database itself may be a memory attached to a personal computer, an external memory, or the like. It can also be stored in a memory provided in another device.
  • the magnetic material inspection method is a magnetic material inspection method using a magnetic material inspection device 1 having a magnet 10 and a magnetic sensor 20 for outputting an electric signal.
  • a step of acquiring an electric signal of a first point from the magnetic sensor 20 (step U1), a step of moving the magnetic sensor 20 from the first point to a second point (step U2), and a step of moving the magnetic sensor 20 from the first point to the second point (step U2).
  • step U3 Having a step of acquiring an electric signal at a point 2 (step U3) and a step of outputting a difference between an electric signal at a first point and an electric signal at a second point. It is characterized by.
  • Step U1 acquires an electrical signal at the first point from the magnetic sensor 20.
  • the first point is preferably a point where an electric signal can be acquired in the presence of a magnetic material. More specifically, it is preferable that the first point is a point where it is possible to measure a state in which at least a part of the magnetic field 12 of the magnet 10 is converged on the magnetic material.
  • the magnetic sensor 20 is moved from the first point to the second point.
  • the second point may be a place other than the first point, but the second point is preferably a point where an electric signal can be acquired in the absence of a magnetic material. More specifically, it is preferable that the second point is a point where the magnetic field 12 of the magnet 10 can be measured in a state where it does not converge on the magnetic material.
  • the state in which the magnetic field 12 of the magnet 10 does not converge on the magnetic material is a state in which the magnetic field exhibits standard magnetic field lines.
  • Step U3 acquires an electrical signal at a second point from the magnetic sensor 20.
  • step U4 the difference between the electrical signal at the first point and the electrical signal at the second point is output.
  • the first point can be a point where the magnetic field in the presence of the magnetic material can be measured
  • the second point can be the point where the magnetic field in the absence of the magnetic material can be measured.
  • the first point can be a point where the magnetic field in the absence of the magnetic material can be measured
  • the second point can be the point where the magnetic field in the presence of the magnetic material can be measured.
  • the magnetic material inspection method includes a step (step U0) of arranging the magnetic sensor 20 at the first point before the step of acquiring an electrical signal at the first point from the magnetic sensor 20 (step U1). You may be doing it.
  • the magnetic sensor 20 included in the magnetic material inspection device that carries out the magnetic material inspection method may be one or more.
  • one magnetic sensor 20 acquires an electrical signal at a first point (step U1), moves it from a first point to a second point (step U2), and electrically at a second point.
  • the configuration may be such that the step of acquiring the signal (step U3) is carried out.
  • a plurality of magnetic sensors 20 may be configured to carry out step U1, step U2, and step U3, respectively.
  • the first point is at a different position for each magnetic sensor 20
  • the second point is also preferably at a different position for each magnetic sensor 20. .. With this configuration, the inspection accuracy by the magnetic substance inspection method can be improved.
  • the magnetic material inspection method preferably includes step U5 for amplifying the difference between the electrical signal at the first point and the electrical signal at the second point.
  • the step U5 for amplifying the difference may be performed before the step U4. That is, the configuration can be such that the difference between the electric signal obtained at the first point and the electric signal obtained at the second point is amplified and then output.
  • the magnetic material inspection device 1 is provided with an arithmetic processing unit 32 as a difference detection unit 30, and the electrical signal at the first point obtained from the magnetic sensor 20 in step U1 and the magnetic sensor 20 in step U3.
  • the obtained electrical signal at the second point is converted into a digital signal by the arithmetic processing unit 32, the difference between the digital signals is calculated, and the difference can be amplified.
  • the step U5 for amplifying the difference can be performed at the same time as the step U4. That is, the difference between the electrical signal at the first point obtained from the magnetic sensor 20 in step U1 and the electrical signal at the second point obtained from the magnetic sensor 20 in step U3 is amplified and output at the same time. You can also do it.
  • the embodiment is preferable in that the time required for the inspection can be shortened by performing step U5 and step U4 at the same time.
  • the magnetic material inspection device 1 is provided with a differential amplifier circuit 31 as a difference detection unit 30, and the electrical signal at the first point obtained from the magnetic sensor 20 in step U1 and the magnetic sensor 20 in step U3.
  • the electrical signal at the second point obtained from the above can be simultaneously sent to the differential amplifier circuit 31, and the difference between the signals can be amplified by a constant coefficient and output at the same time.
  • the inspection accuracy of the magnetic material can be improved.
  • the magnetic material inspection method according to the third embodiment of the present invention is non-magnetic by outputting the difference between the electric signal at the first point and the electric signal at the second point. It is possible to specify the position where the magnetic material existing inside the body exists and the presence or absence of breakage.
  • the magnetic material inspection device 1 has a memory in which a database is stored, and an electric signal acquired from the magnetic sensor 20 at the first point and a magnetic signal 20 from the magnetic sensor 20 at the second point.
  • the difference from the acquired electrical signal can be configured to include a step U6 for fitting the difference to the database stored in the memory.
  • the database stored in the memory is, for example, an electrical signal output from the magnetic sensor 20 at the first point of the standard sample and a second point at the state of the distance C2 between the standard sample and the magnetic sensor.
  • the difference from the second electrical signal output from the magnetic sensor 20 is measured, and the thickness C1 of the standard sample, the distance C2 between the standard sample and the magnetic sensor, and the above difference are stored in a state of being interconnected.
  • step U6 the difference between the electrical signal obtained in step U1 and the electrical signal obtained in step U3 by actually using the magnetic material inspection device 1 for the inspection symmetry is stored in the memory. Fit with the database. From the result of fitting the difference and the database in step U6, the thickness of the standard sample associated with the difference data on the database and the distance between the standard sample and the magnetic sensor can be derived, thereby the magnetic material to be inspected. It is possible to identify the thickness of the material and the distance between the magnetic material to be inspected and the magnetic sensor. As another embodiment of fitting, a method using a model function can also be adopted.
  • a model function F1 capable of fitting a database is created, and the model function F1 is set so that the fitting parameters D1 and D2 of the model function are uniquely determined for C1 and C2. Further, model functions F21 and F22 are created and modeled again so that D1 and D2 are functions of C1 and C2, respectively. Parameters D1 and D2 can be obtained by making measurements on the object to be inspected and fitting the results. C1 and C2 can be determined by inversely calculating the parameters using F21 and F22.
  • the fitting as described above may be performed by further providing an arithmetic processing unit and a control unit in the magnetic material inspection device 1.
  • an arithmetic processing unit and a control unit in the magnetic material inspection device 1.
  • the form in which the memory is provided in the magnetic material inspection device 1 and the database is stored in the memory is described, but in addition, the database itself may be a memory attached to a personal computer, an external memory, or the like. It can also be stored in a memory provided in another device.
  • the magnetic material inspection method outputs the difference between the electric signal at the first point and the electric signal at the second point, and uses the difference as a database.
  • the magnetic material inspection method outputs the difference between the electric signal at the first point and the electric signal at the second point, and uses the difference as a database.
  • the above-mentioned magnetic material inspection method can also identify a corroded part by using the difference obtained from the magnetic material to be inspected, the distance between the magnetic material and the magnetic sensor, and the thickness. This makes it possible to identify the distance between the magnetic material and the magnetic sensor, the thickness of the magnetic material, the fractured part, and even the corroded part.
  • Magnetic material inspection device 10 Magnet 11: Center of gravity 12: Magnetic field 20: Magnetic sensor 21: First magnetic sensor 22: Second magnetic sensor 30: Difference detection unit 31: Differential amplification circuit 32: Arithmetic processing unit 40 : Personal computer 50: Power supply unit 60: Display unit 70: Inspection target 71: Reinforcing bar 72: Concrete structure L1: Line connecting the first magnetic sensor and magnet L2: Connecting the second magnetic sensor and magnet line segment

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