KR101036808B1 - Device distance measuring device - Google Patents

Abstract

Device for joining member separation distance according to the present invention, a coil (coil); A variable power supply for supplying a variable step voltage to the coil at a predetermined period; A pulser for generating a pulse signal when the variable power supply supplies the variable step voltage to the coil; An eddy current sensor for detecting a change in the eddy current induced in the member junction part by the variable step voltage, and modifying the pulse signal input from the pulser according to the detected eddy current to output an eddy current flaw detection signal; A receiver configured to receive the eddy current flaw detection signal from the eddy current detection sensor, and compare a selected reference eddy current flaw signal with the input eddy current flaw signal to measure a separation distance of the member joint; And a wireless communication module for wirelessly transmitting a separation distance of the member joint part measured from the receiver.

Member Junction, Separation Distance, Eddy Current, Pulse Eddy Current, Sensor

Description

Spacer distance measuring device for member joints {DEVICE FOR MEASURING DISTANCE BETWEEN JOINING MEMBERS}

The present invention relates to an apparatus for measuring a distance between member joints, and more particularly, to a pulsed eddy-current test (PECT) for monitoring and diagnosing the separation of member joints generated according to an increase in service life in steel structures. A member joining part separation distance measuring device for measuring the separation distance between the members in a member joining portion to which one or more members are joined by using a) technique.

In addition, the present invention relates to a member joint separation distance measuring apparatus that can be integrated, miniaturized, and wireless, including an eddy current sensor, a pulser, a receiver, and a wireless communication module.

In the case of steel structures made of steel such as PEB (Pre-Engineered Building), moving shelter, and bridges, the joint method of bolting joints of steel parts is frequently used.

Steel structures are deformed as the service life increases, which causes a very important influence on the safety of the structure. When deformation of the steel structure occurs, the phenomenon of gaping (separation) of the joint occurs.

Non-destructive testing methods include radiographic testing, ultrasonic testing, magnetic particle testing, liquid penetration testing, visual testing, and eddy current testing. Eddy-current testing (ECT) is mainly used.

To date, visual inspection has been commonly applied to joint inspection of steel structures.

However, due to the nature of the steel structure, there are many points that cannot be visually inspected, and due to the limitation of inaccurate visual inspection and the limitation of long-term period inspection, accurate monitoring and diagnosis are not made.

In addition, in the case of ultrasonic inspection or eddy current inspection, it is impossible to install and operate the inspection apparatus due to the cost and size of the inspection equipment.

In addition, in the case of the ultrasonic inspection, there is a problem that the ultrasonic wave propagation speed of the steel structure is changed according to the corrosion of the steel structure, it is difficult to measure when there is an air layer (space) between the steel structure.

The eddy current flaw detection method mostly inspects defects on the surface of the specimen. In the case of pulsed eddy current flaw detection, information of a deep point of the subject can be obtained. However, even when using such pulse eddy current inspection, a pulser / reserver, a pulse eddy current sensor, and a signal collection server must exist, and thus cannot be used as general equipment for inspecting numerous joints of steel structures. Therefore, the pulse eddy current inspection is used to precisely measure the state of the joint of steel structures, but the pulse eddy current inspection system combines the pulser / reserver and the pulse eddy current sensor with a wireless communication module to form a small module. There is a need for development of a technology for performing data collection.

The present invention has been made to improve the prior art as described above, in the case of steel structures, pulsed current inspection (PECT: Pulsed Eddy-Currents Testing) capable of monitoring and diagnosing the separation of member joints that occur with the increase in the service life Measures the separation distance between members in the member joint to which at least one member is joined by using the method, and includes an integrated device, a miniaturization, and a wireless device including a eddy current sensor, a pulser, a receiver, and a wireless communication module. It aims to provide.

In order to achieve the above object and to solve the problems of the prior art, the member joint separation distance measuring apparatus according to an embodiment of the present invention, a coil (coil); A variable power supply for supplying a variable step voltage to the coil at a predetermined period; A pulser for generating a pulse signal when the variable power supply supplies the variable step voltage to the coil; An eddy current sensor for detecting a change in the eddy current induced in the member junction part by the variable step voltage, and modifying the pulse signal input from the pulser according to the detected eddy current to output an eddy current flaw detection signal; A receiver configured to receive the eddy current flaw detection signal from the eddy current detection sensor, and compare a selected reference eddy current flaw signal with the input eddy current flaw signal to measure a separation distance of the member joint; And a wireless communication module for wirelessly transmitting a separation distance of the member joint part measured from the receiver.

According to the apparatus for measuring the distance between the member joints of the present invention, in the case of steel structures, the pulsed eddy-current testing (PECT) technique can be used to monitor and diagnose the separation of the member joints that occur as the service life increases. The separation distance between the members may be measured at the member joint to which one or more members are joined, and an integrated current, a miniaturization, and a wireless communication may be obtained, including an eddy current sensor, a pulser, a receiver, and a wireless communication module.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing the configuration of the member joint portion immediately after the operation of joining the member according to an embodiment of the present invention.

The member joint part 100 according to the exemplary embodiment of the present invention may include a first member 110, a second member 120, a third member 130, a fourth member 140, a first bolt 150, And a second bolt 160.

The first member 110, the second member 120, and the fourth member 140 may be joined by the first bolt 150, the first member 110, the third member 130, and The fourth member 140 may be joined by the second bolt 160.

The member joining part 100 may be implemented as a joint part between the members joining the members by fastening one or more members constituting the structure with one or more bolts. The member joint part 100 may be joined in various ways, such as weld joints, rivet joints, etc., according to the judgment of those skilled in the art as well as the one or more bolts.

According to an embodiment of the present invention, an apparatus for measuring a distance between member joints is installed in the member joint and generates an eddy current flaw detection signal according to a change in the magnitude of the eddy current generated while the eddy current induced in the member joint passes through the one or more members. do. For example, the member joining part separation distance measuring device 300 is installed in the fourth member 140 of the member joining part 100 so that the eddy current induced in the member joining part 100 is at least one member 110, 120, 130, and While passing through 140, an eddy current flaw detection signal may be generated according to a change in magnitude of eddy current generated corresponding to the distance 'a' between the first member 110 and the fourth member 140. The distance 'a' between the first member 110 and the fourth member 140 is the distance immediately after the operation of joining the one or more members 110, 120, 130, and 140 constituting the member joint part 100 is completed. to be.

The receiver of the member joint separation distance measuring apparatus according to an embodiment of the present invention is based on the eddy current flaw detection signal based on the eddy current flaw detection signal for the distance between the one or more members immediately after the operation of joining the one or more members constituting the member joint part is completed. Maintain as a flaw detection signal. For example, the receiver 350 of the member joining part distance measuring apparatus 300 may be formed immediately after the operation of joining the one or more members 110, 120, 130, and 140 constituting the member joining part 100 is completed. The eddy current flaw detection signal 410 for the distance 'a' between the first member 110 and the fourth member 140 may be maintained as the reference eddy current flaw detection signal.

In the case of steel structures, separation occurs in the joints due to strong winds, repeated loads, and moving shocks.

2 is a diagram illustrating a configuration of a member joint part in which separation occurs according to an increase in the number of years of use according to an embodiment of the present invention. As illustrated in FIG. 2, one or more members 210, 220, 230, and 240 of the member joint part 200 may be implemented in a structurally unstable state due to a great distance between members. The member joining part separation distance measuring device 300 is installed in the fourth member 240 of the member joining part 200 so that an eddy current induced in the member joining part 200 passes through one or more members 210, 220, 230, and 240. In the meantime, an eddy current flaw detection signal according to a change in the magnitude of the eddy current generated corresponding to the distance 'a + B' between the first member 210 and the fourth member 240 may be generated. The distance 'a + B' between the first member 210 and the fourth member 240 is the first member 210 immediately after the operation of joining the one or more members 210, 220, 230, and 240 is completed; The distance 'a' between the fourth member 240 and the distance 'B' due to the separation caused by the increase in the number of years of use may be implemented. That is, the separation distance of the member joint part 200 is 'B'.

3 is a diagram illustrating a configuration of an apparatus for measuring a distance between member joints according to an exemplary embodiment of the present invention. The member junction distance measurement apparatus 300 according to the embodiment of the present invention may include a coil 310, a variable power supply 320, a pulser 330, an eddy current sensor 340, a receiver 350, and wireless communication. Module 360.

The member junction distance measuring apparatus 300 uses a pulsed eddy current flaw detection method.

The principle of the eddy current flaw detection method is as follows. When an alternating current coil is brought close to a conductor, a magnetic field generated around the coil acts on the conductor. Since the magnetic field generated around the coil is caused by the alternating current, the direction of the magnetic flux passing through the conductor also changes in time. At this time, the conductor generates an electromotive force that prevents the change of the magnetic flux passing through the conductor. This is called electromagnetic induction. In the conductor, an AC current called an eddy current is induced by the electromotive force. The magnitude and distribution of the eddy current induced in the conductor is changed by defects such as frequency, conductivity and permeability of the conductor, size and shape of the specimen, shape and size of the coil, current, distance from the conductor, and cracking. do. Therefore, by detecting the change of the eddy current flowing through the test body, it is possible to test whether there is a defect present in the test body, the material or the like. However, due to the skin effect of the alternating current, the eddy current flowing in the conductor flows concentrated in the surface layer of the conductor and rapidly attenuates as it enters the conductor. The degree of attenuation becomes significantly larger as the frequency, the conductivity of the test body, and the permeability become larger. The eddy current flaw detection method due to the phenomenon in which the eddy current is changed by various material factors or defects of the test body is widely used for maintenance inspection of heat exchanger tubes, maintenance inspection of aircraft parts, conductivity measurement of nonferrous metal alloys, and aluminum film thickness measurement. It is used.

The eddy current flaw detection method applies sinusoidal alternating current to the coil. However, the pulse eddy current flaw detection method applies a step voltage to the coil. In the pulse eddy current flaw detection method, a wide frequency band can be applied to the coil by using the step voltage. Therefore, in the pulse and current flaw detector method, the electromagnetic response to various frequencies can be measured through a single step, and the depth information can be measured because the penetration depth depends on the excitation frequency. The variable power supply 320 supplies a variable step voltage to the coil 310 to change the magnetic flux induced in the coil 310. The change in magnetic flux induces an eddy current in the one or more members of the member joint. The induced eddy current is detected by the eddy current sensor 340, the eddy current sensor 340 generates an eddy current detection signal corresponding to the detected eddy current.

For example, the eddy current sensor 340 detects eddy currents induced in one or more members 210, 220, 230, and 240 of the member bonding part 200, and the induced eddy currents are detected by one or more members 210, ie, in one embodiment. According to the magnitude change of the eddy current generated while passing through the 220, 230, and 240, the pulse signal input from the pulser 330 may be modified to output the eddy current flaw detection signal 420 for the member junction part 200. The eddy current flaw detection signal 420 is formed by the first member 210 and the fourth while the eddy current induced in the member junction 200 passes through one or more members 210, 220, 230, and 240 of the member junction 200. The magnitude change of the eddy current generated corresponding to the distance 'a + B' between the members 240 is shown.

The pulser 330 generates a pulse signal when the variable power supply 320 supplies the variable step voltage to the coil 310.

4 is a diagram illustrating a waveform of an eddy current flaw detection signal according to an exemplary embodiment of the present invention.

As described above, the receiver 350 has an eddy current induced in the one or more members 110, 120, 130, and 140 constituting the member joint part 100 immediately after the operation of joining the members is completed. The eddy current flaw detection signal 410 generated according to the change in the magnitude of the eddy current generated corresponding to the distance 'a' between the first member 110 and the fourth member 140 while passing through 110, 120, 130, and 140. Can be maintained as the reference eddy current inspection signal.

The reference eddy current flaw detection signal may be selected according to the judgment of a person skilled in the art, but the member including the one or more members immediately after the operation of joining the members as described above, that is, immediately after the construction work of the structure is completed. It is preferable to select the eddy current flaw detection signal detected at the junction as the reference eddy current flaw signal.

The receiver 350 receives the eddy current flaw detection signal detected by the member junction part from the eddy current detection sensor 340. For example, the receiver 350 may receive the eddy current flaw detection signal 420 detected by the member junction part 200 including one or more members 210, 220, 230, and 240 from the eddy current sensor 340. have.

The receiver 350 compares the reference eddy current flaw detection signal and the eddy current flaw signal received from the eddy current detection sensor 340 and measures the separation distance of the member junction part. For example, the receiver 350 has a separation distance 'B' of the member junction part 200 through a voltage difference 430 between the reference eddy current flaw detection signal 410 and the eddy current flaw detection signal 420 detected by the member junction part 200. Can be measured.

The receiver 350 maintains a table in which the separation distance of the member junction part corresponding to the voltage difference between the eddy current flaw detection signal and the reference eddy current flaw signal received from the eddy current detection sensor 340 is recorded. That is, the receiver 350 may include a memory for recording a separation distance of the member junction part corresponding to the voltage difference between the eddy current flaw detection signal and the reference eddy current flaw signal received from the eddy current detection sensor 340. The receiver 350 reads the separation distance of the member joint part corresponding to the voltage difference between the eddy current flaw detection signal and the reference eddy current flaw signal received from the eddy current detection sensor 340 from the table to detect the eddy current flaw signal. Measure the separation distance of the member joint.

For example, the receiver 350 may read a separation distance corresponding to the voltage difference 430 between the eddy current flaw detection signal 420 and the reference eddy current flaw detection signal 410 detected by the member junction unit 200 from the table. The read distance is “B” as the separation distance of the member junction part 200 in which the eddy current flaw detection signal 420 is detected. That is, the receiver 350 may measure the separation distance between one or more members 210, 220, 230, and 240 of the member bonding part 200 as 'B', which is the separation distance read from the table.

The wireless communication module 360 wirelessly transmits the measured separation distance from the receiver 350. For example, the wireless communication module 360 may transmit the separation distance 'B' of the member bonding unit 200 measured from the receiver 350 to one or more terminals or one or more external PCs through wireless communication. As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will belong to the scope of the present invention.

1 is a view showing the configuration of the member joint portion immediately after the operation of joining the member according to an embodiment of the present invention.

Figure 2 is a view showing the configuration of the member joint portion spaced apart according to the increase in the number of years of use according to an embodiment of the present invention.

Figure 3 is a view showing the configuration of a member joint separation distance measuring apparatus according to an embodiment of the present invention.

4 is a view showing the waveform of the eddy current flaw detection signal according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

300: distance measurement device for member joint

310: coil

320: variable power supply

330: Pulsar

340: Eddy current sensor

350: receiver

360: wireless communication module

Claims (5)

Coils; A variable power supply for supplying a variable step voltage to the coil at a predetermined period; A pulser for generating a pulse signal when the variable power supply supplies the variable step voltage to the coil; An eddy current sensor for detecting a change in the eddy current induced in the member junction part by the variable step voltage, and modifying the pulse signal input from the pulser according to the detected eddy current to output an eddy current flaw detection signal; A receiver configured to receive the eddy current flaw detection signal from the eddy current detection sensor, and compare a selected reference eddy current flaw signal with the input eddy current flaw signal to measure a separation distance of the member joint; And Wireless communication module for wirelessly transmitting the separation distance of the member joint portion measured from the receiver &Lt; / RTI &gt; The eddy current sensing sensor deforms the pulse signal input from the pulser in response to the magnitude change of the eddy current generated while the induced eddy current passes through at least one member of the member joint part. Measuring device. The method of claim 1, The member joining part separation distance measuring apparatus, characterized in that it comprises one or more members fastened by one or more bolts. delete The method of claim 1, The receiver maintains the selected reference eddy current flaw detection signal and measures the separation distance of the member joint part through a voltage difference between the eddy current flaw detection signal and the reference eddy current flaw signal received from the eddy current sensing sensor. Distance measuring device. The method of claim 4, wherein The receiver maintains a table in which the separation distance of the member joint part corresponding to the voltage difference between the eddy current flaw detection signal and the reference eddy current flaw signal input from the eddy current detection sensor is recorded, and the eddy current received from the eddy current detection sensor. And a separation distance of the member junction part is measured by reading a separation distance of the member joint part corresponding to the voltage difference between the flaw detection signal and the reference eddy current flaw signal from the table.

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