JP6736007B2 - Method for detecting deterioration of structures, etc. and vibration absorber used therefor - Google Patents

Description

The present invention relates to a method for detecting deterioration of a structure or the like and a vibration sensor used for the method.

In recent years, it has been pointed out that there is a tendency that columns for power distribution such as railroad and communication may fall and cause a serious accident. When a vehicle passes by, its vibrations are transmitted and the deteriorated pillars collapse, or as the deterioration progresses due to deterioration over time, its natural frequency changes (decreases), causing vibrations at lower frequency. Reach Here, as an example, the natural frequency of the pillar beside the track owned by the railway company is 3 to 4 Hz, but the natural frequency is 1.5 to 2 Hz due to deterioration over time. As described above, these struts and the like have a high natural frequency at the beginning and emit a high sound when hit, but it is known that when the natural frequency decreases due to deterioration, the sound becomes low. Conventionally, as a measure for knowing the aged deterioration of these stanchions and the like, a skilled worker hits with a hammer or the like and the sound becomes a low sound, so that the abnormality is detected and confirmed.

The present invention focuses on the fact that the natural frequency of a structure mainly made of concrete, for example, a structure such as a pillar on the side of a railroad track, decreases with its deterioration, and a method for detecting the deterioration, The purpose is to provide an effective mechanical vibration absorber for use therein.

In the box B, the vibration absorbers A and A'having a set frequency of about 1.5 to 2 Hz, in which the drop type or non-fall type sensing bodies 1 and 1'which are attracted and suspended by the magnet M whose magnetic force is adjusted, are provided. When the structure is attached to the structure and externally vibrated, if the strength of the structure is normal, even if the structure resonates, the sensing bodies 1 and 1 ′ do not drop, and the sensing body 1 ′. Is a structure in which when the sensor magnet of the sensor 1'moves above the reed switch provided directly below the sensor 1'and the on-off of the reed switch is repeated and the structure deteriorates. The object vibrates at the set frequency, the vibration absorbers A and A'resonate and the sensing body 1 falls, and the sensing body 1'stops the on-off of the reed switch. A method for detecting deterioration of a structure, characterized in that the movement of 1, 1'is transmitted to the outside,
In the box B, the magnet M attached to the center of the support 5 has the inverted cone-shaped large side portion 2 at the center and the weight below the small side portion 3 which follows. The drop type sensor 1 having the part 4 attached thereto is sucked down, while the support rod 7 is provided from the upper side to the lower side in the box, and the operating plate 8 connected to the support rod 7 is arranged at the lower part of the sensor 1. If the strength of the structure is normal when it is attached to the structure and vibration is applied from the outside, even if the structure resonates, the resonance is at a higher frequency than the sensor 1, so that the sensor 1 does not resonate, and when the structure deteriorates and vibrates at a set frequency, the sensing body 1 resonates with it, so that the shake becomes large and falls away from the magnet M, thereby actuating the operating plate 8, The movement of the operating plate 8 is transmitted to the outside by a transmission means, which is a drop type vibration detector A used in the deterioration detecting method described above.
In the box B, a non-falling type sensing in which a hemispherical large side portion 2′ is provided in the upper portion in the center of the magnet M and a weight portion 4 is attached to the lower portion of the small side portion 3 following the center portion of the magnet M A non-falling vibration absorber A'used in the above-described deterioration detecting method, characterized in that the body 1'is sucked down.
Inside the box B, a large cone portion 2 having an inverted conical shape is provided in the upper portion in the center of the magnet M via an annular metal fitting r, and a weight portion 4 is provided in the lower portion of the small cone portion 3 that follows. The non-falling type vibration sensor A'used in the deterioration detecting method described above, wherein the non-falling type sensing body 1'having attached
The non-falling type vibration sensor A′ described above, characterized in that it comprises a magnet M having a hemispherical bottom surface and a sensing body 1′ having an inverted conical-shaped large-sided portion 2 in an upper portion.
It is used in the above-described deterioration detecting method, characterized in that a support metal fitting k made of a magnetic material having a hemispherical lower surface is arranged between a magnet M and a sensing body 1′ having an inverted conical-shaped large-sided portion 2. It is a non-fall type vibration absorber A'.

The present invention focuses on the fact that the natural frequency of a structure mainly made of concrete, for example, a railroad track side strut, a structure such as an iron frame strut, decreases with its deterioration. It is possible to provide a detection method for deterioration diagnosis inspection and an effective mechanical vibration detector used therefor. Even if it is difficult for people to get close to it, if you install the vibration absorber of this invention at the beginning, you can automatically determine the deterioration of the structure etc. This is a method for detecting deterioration over time, and the vibration absorber used for it has a mechanical structure, so it is robust and operates reliably. And there is no need for a large-scale power supply or wiring. As a result, instead of the judgment and judgment of aging deterioration which has hitherto relied on a manual tapping sound inspection, this can be done reliably and easily, and continuous monitoring is carried out for a long period of time.

It is a figure explaining the fall type vibration sensor of this invention, and the state before and after the operation inside. It is a figure explaining various examples of the non-falling type vibration sensor of this invention. It is a figure which shows the state which attached the vibration damper of this invention to the support|pillar. It is a figure which shows the state which attached the vibration damper of this invention to the support|pillar made from an iron frame.

FIG. 1(a) is a view showing the inside of the drop type vibration detector A of the present invention, which is in a state before operation, and in the box B, the sensing body 1 made of a magnetic material is inside the box B. It is attracted and suspended by a magnet M (magnetic force is properly selected) attached to the upper surface via a support 5. 6 is a mounting base. That is, in the center of the circular magnet M attached to the center of the support 5, there is an inverted cone-shaped large side portion 2 in the upper part, and a weight portion 4 in the lower part of the subsequent small side portion 3. The attached sensor 1 is sucked down. Here, 7 is a support rod attached downward from the upper part of the box B, and 8 is an operating plate connected to it. FIG. 1B shows a state in which the sensing body 1 resonates and falls to operate the operating plate 8.

The vibration sensor A designed to determine the entire length of the sensing body 1 and sense and operate at a set frequency [as an example, a natural frequency of about 1.5 to 2.5 Hz] FIG. 3 shows a state in which the structure is attached to a pillar C made of concrete, an iron pipe or the like with a band b, and FIG. 4 is attached to an iron frame pillar C′ by an appropriate means (adhesion, tacking, etc.). Indicates the state. 1(a) and 1(b), when vibrations from the outside are applied and the strength of the above-mentioned structures is normal, even if these structures vibrate, they are more sensitive than the sensor 1. The sensor 1 does not resonate because it resonates at a high frequency. Then, the sensor 1 does not drop, and the vibration detector A does not operate. When the structure deteriorates, the structure gradually vibrates at a low frequency, approaches the set frequency of the vibration sensor A, and vibrates at the set low frequency set. Here, since the sensor 1 resonates, the shaking becomes large [swings at the resonance frequency], and finally falls apart from the magnet M. At that time, the operating plate 8 is operated as shown in FIG. The movement of the operating plate 8 is transmitted to a mechanical or electrical means (switch or the like) separately installed, and the movement is notified to the outside. The shape and configuration of the sensing body 1 are free, such as a cylindrical shape as a whole. As shown in the figure, a protrusion 5'is provided on the support base 5 where the magnet M comes off to prevent the sensor 1 from slipping sideways. In this example, the sensor 1 in surface contact with the magnet M drops, and the sensor 1 that has fallen pushes down the operating plate 8, and a reset function is added separately.

FIG. 2(a) is a diagram showing a prototype of the non-falling type vibration sensor A'of the present invention, in which the upper part 2'of the sensing body 1'has an upper hemispherical shape (a conical shape or the like is also possible). In principle, this is due to the operation of attracting to the magnet M by point contact and swaying, and the sensing body 1′ in contact with the magnet M by point contact can oscillate with a small force (friction force, energy).

FIG. 2(b) is a view showing the non-falling type vibration sensor A'-1 of the present invention. As described above, the large diameter portion 2'of the sensing body 1'has a hemispherical upper side and a magnet M In principle, this is due to the operation of attracting and swinging by point contact, and the sensing body 1′ in contact with the magnet M by point contact can swing with a small force. Then, as shown in the drawing, by disposing an annular metal fitting r between the magnet M provided in the center of the support 5 and the sensing body 1', the shaking of the sensing body 1'is restricted, whereby the sensing body 1' It can be designed to make it hard to shake, increase the force required to cause shaking, and shake in the resonant frequency band. The sensing body 1′ comes into line contact with the magnet M in an annular shape, and when the annular metal fitting r is added, the thickness thereof is adjusted or the diameter thereof is changed, and particularly, the sensing body 1′ sways by the size of the inner diameter of the annular metal fitting r. The width of the frequency band can be adjusted. If the inner diameter of the annular metal fitting r is small, the force required for shaking becomes small. In this way, the suction force can be adjusted and the swaying frequency band can be set narrowly and precisely, and the desired frequency detection can be made even more accurate. The operation of the non-falling type vibrator A'-1 is as follows. A reed switch [not shown] is provided just below the sensor 1', and when the sensor 1'resonates and shakes greatly, the sensor 1' 1 [not shown] sensing magnet attached to the governor weight portions 4 'is moved directly over the reed switch, is detected by repeating the on-off of the reed switch. A stopper s is provided around the small-diameter portion 3 to restrict the sensor 1′ from swinging to a certain amplitude or more, and prevent the sensor 1′ from unintentionally falling from the magnet M.

FIG. 2(c) is a view showing a non-falling type vibration sensor A'-2 of the present invention, in which the lower surface of the magnet M is hemispherical and the upper side of the large side part 2 of the sensor 1'is flat. In this case, the sensing body 1'is placed directly on the magnet M to make point contact.

FIG. 2(d) is a view showing a non-falling type vibration absorber A'-3 of the present invention, in which a support bracket k made of a magnetic material is arranged between the sensing body 1'and the magnet M. The contact surface of k is hemispherical, and the upper side of the large side part 2 of the sensor 1'is flat. This is also due to the operation of attracting and swinging by point contact, and the sensing body 1'which is also in point contact with FIG. 2C described above can swing with a small force. Further, when the resonance frequency is shaken, the sensor 1'sows particularly greatly. As shown in FIGS. 3 and 4, vibration absorbers A'-1 to A'-1 having a set frequency, in which the entire length of the sensing body 1'is properly designed, are similarly attached to the structure. The shape and configuration of the sensing body 1'is free, such as a cylindrical shape as a whole.

Put two sensors of the same type (if they are the drop type) in a box of a vibration absorber and attach it to the structure. In other words, it is possible to combine a sensor that operates during normal operation and a sensor that operates during deterioration (designed to resonate at a lower frequency than normal) to detect changes in vibration from normal to deterioration. .. When strong low-frequency vibrations are applied to a wide area due to strong winds or earthquakes, even if the structure is normal, the attached vibration absorber may operate accidentally. Since the shaker operates in the same manner, it can be regarded as a malfunction. The present invention is intended for a structure that repeats operation under conditions without strong reasons such as strong winds, earthquakes, etc., as a risk of deterioration, and an effective deterioration detection method and sensor for automatically censoring and issuing a warning. Become a shaker. The deterioration detecting method and the vibration sensor thereof according to the present invention can be widely used for structures such as piers, buildings, dams, and tunnels.

A, A'Vibrator B Box C Column C'Steel frame column M Magnet 1, 1'Sensor 2, 2'Greater part 3 Smaller part 4 Weight part 5 Support 5'Protruding part 6 Mounting base 7 Support rod 8 Operating plate k Support metal fitting r Annular metal fitting s Stopper

Claims (6)

A vibration sensor with a set frequency of about 1.5 to 2 Hz, which is equipped with a drop-type or non-fall type sensor that is attracted and suspended by a magnet whose magnetic force is adjusted, is attached to the structure to prevent external vibration. If the strength of the structure is normal when given, even if the structure resonates, the falling type or non-falling type sensor remains as it is, and when the structure deteriorates, The structure vibrates at the set frequency , the vibration sensor resonates, the falling type sensor falls, and the non-falling type sensor turns on-off of the reed switch provided directly under the sensor. A method for detecting deterioration of a structure, characterized in that the movement of the falling type or non-falling type sensing body is repeatedly transmitted to the outside. In the box, the magnet attached to the center of the support has a large inverted large cone-shaped upper part in the upper part, and a weight part is attached to the lower part of the small small part that follows. The sensing body is sucked down, and on the other hand, a support rod mounted from the upper side to the lower side in the box is provided, and an operating plate connected to the supporting rod is arranged at a lower portion of the sensing body. A drop type vibration detector used in the method for detecting deterioration according to Item 1. In the box, a non-falling type sensor with a hemispherical large part in the upper part in the upper part of the magnet, and a weight part attached to the lower part of the small part following it was attracted by suction. The non-falling type vibration sensor used in the deterioration detecting method according to claim 1. In the box, a non-falling type of sensing with a hemispherical large ridge in the upper part at the center of the magnet through an annular metal fitting, and a weight attached to the lower part of the small ridge following it. The non-falling type vibration sensor used in the deterioration detecting method according to claim 1, wherein the body is sucked and hung down. The non-falling type vibration sensor used in the deterioration detecting method according to claim 1, wherein the lower surface is composed of a magnet having a hemispherical shape and a sensing body having an inverted conical-shaped large-sided portion at an upper portion thereof. The non-falling type used in the deterioration detecting method according to claim 1, further comprising: a support member made of a magnetic material having a hemispherical lower surface disposed between the magnet and the sensing body having an inverted conical-shaped large ridge. Shaker.

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