JP3144143U - Simple signage soundness evaluation device - Google Patents

Abstract

[PROBLEMS] In the present plan, in the signage soundness evaluation device, by installing a clear pass / fail judgment display device such as a lamp, the inspection work is easy and the knowledge of the mechanism of the evaluation device is not sufficient. It is a problem that even a person can easily evaluate.
A signboard is vibrated and its vibration waveform is measured by a natural frequency measuring device to determine the natural frequency of the signboard. The obtained natural frequency and past natural vibrations read from a storage device are obtained. The fluctuation with the number is calculated for each vibration mode, the signboard health is calculated according to the width of the fluctuation, and the signboard health to be inspected is classified into “healthy”, “caution”, “danger”, etc. The signboard soundness evaluation device is to be displayed.
[Selection] Figure 1

Description

The present invention relates to a device that evaluates the soundness of a signboard by its natural frequency and can be easily evaluated using an obvious display device.

Conventionally, visual inspection has been conducted as a method for investigating the strength deterioration and damage caused by corrosion, aging, earthquakes, strong winds, etc., in general structural materials at parts connected to the main body such as the signboard body and the support section and the boundary section. Is widely practiced. In terms of measurement, for example, a frequency response method is known in which a structure is vibrated with a periodic signal and its response is compared, and further, the natural frequency of the structure is obtained and deterioration from the maximum stress is obtained. A diagnosis method is known (see Patent Document 1). In addition, a method is known in which the natural frequency is obtained from the vibration waveform of a structure that vibrates due to an uncertain external force, and strength deterioration of the structure is detected (see Patent Document 2).
JP 2002-22596 A JP 2002-188955 A

In addition, the soundness of the structure is evaluated using the natural frequency of the structure obtained from external forces as the main vibration source, and the natural frequency of the lower to higher modes is used to evaluate the structure. It is already known to evaluate the degree of soundness.

The problem to be solved is that the human being does not judge the soundness level from the range of fluctuation of each vibration mode obtained, but the soundness level is calculated by comparison with past data, and an obvious display device is obtained. By using it, even a person who does not have sufficient knowledge about the device can easily evaluate the soundness.

The signboard soundness evaluation apparatus according to the present invention is to obtain a natural frequency of the signboard by obtaining the natural frequency of the signboard by oscillating the signboard with a vibration means and measuring the vibration waveform with a natural frequency measuring device. And the past natural frequency read from the storage device are obtained for each vibration mode, the soundness of the signboard is evaluated according to the fluctuation range, and the result is displayed.
The vibration mode includes a low-order mode of the primary mode, a high-order mode higher than the secondary mode, and a combined mode of the low-order mode and the high-order mode.

The signboard soundness evaluation apparatus of the present invention can supplement the aging deterioration of the signboard in detail and can display it in a simplified manner. The damaged part can be predicted by the vibration mode of the natural frequency. It is possible to specify the natural frequency and evaluate the soundness at the inspection site. In addition, inspection with a small number of people is possible. The device to be used is a portable personal computer (notebook personal computer), etc., which is small and easy to handle and consumes little power. The skill level is not required for the inspection, and the existing strength can be estimated from the measured natural frequency.

As shown in FIG. 1, the signboard soundness evaluation apparatus according to the present invention includes an acceleration seismometer 1 attached to the surface of an object to be inspected and an A / D converter electrically connected thereto. Device, a soundness evaluation apparatus composed of a built-in memory connected thereto and a data collection system unit 3 having a Fourier transform function, and a notebook personal computer (also connected to a notebook personal computer) connected to this device and displaying a test result 4) are combined. In order to vibrate the object to be inspected, for example, a single inspector strikes with a vibration means such as a hammer.

As shown in FIG. 2 (A), the vibration method by the vibration means is the primary mode when the center position between the fulcrums (Δ marks) of the member is hit, as shown in FIG. 2 (B). The secondary mode strikes a 1/4 position between the fulcrums, and as shown in FIG. 6C, the 1/4 mode center strike is a composite of the primary mode and the secondary mode. Mode.

In the present invention, an ID (management number) is given to the object to be inspected, and the vibration by the vibration means is performed for each mode to inspect which mode has changed the natural frequency, It diagnoses and displays a more detailed degree of soundness of the object to be inspected.

When the object to be inspected is vibrated by the vibration means, the acceleration seismometer attached to the surface measures the waveform as shown in FIG. As shown in FIGS. 4A and 4B, the waveform is Fourier-transformed by the charge amplifier and the data collection system unit to obtain an amplitude spectrum and a phase difference spectrum, and A / D converted. Data is sent to the notebook computer, the natural frequency of the object to be inspected is determined by the determination program, and the degree of soundness for each mode of vibration is determined from the degree of change, and this is displayed on the evaluation device.

The natural frequency of the object to be inspected has an excellent amplitude spectrum (high frequency) and the phase difference spectrum at that time shows a resonance frequency (0 °, 180 ° for speed, 90 °, 270 ° for acceleration). It is decided.

This soundness determination flow is the flow shown in FIG. In the determination program in the notebook computer 4, in each vibration mode, for example, a four-step soundness evaluation is performed.
Rank I Decrease rate 10% or less: Can be used immediately after rust prevention etc. Rank II Decrease rate 10-20%: Need small scale reinforcement: Can be used after reinforcement repair Rank III Decrease rate 20-40%: Medium scale Reinforcement / repair required: Can be used after reinforcement / repair Rank IV Reduction rate 40% or more: If necessary, replacement of parts is necessary. Disassembly: Can be used after completion of construction. It is displayed on the display unit of the evaluation device, and the details are displayed on the personal computer screen.

Also, if the natural frequency has changed in the low-order mode only in the primary mode, it is assumed that the member connection is deformed, and the countermeasures are displayed. Also, only in the secondary mode or higher In the case of the higher order mode, the deformation of the member itself is displayed, and in the case of these combined modes, the deformation of the member itself and the joint is displayed. As described above, in each vibration mode, a portion corresponding to the vibration mode is displayed, and further, a soundness evaluation for each rank according to the reduction rate of the natural frequency is displayed and a response is made.

FIG. 6 shows an example of the case where the natural frequency is obtained by vibrating the object to be inspected by the vibration means 5 to the center part and the quarter part between the fulcrums and the combination position. FIG. 5B shows the secondary mode amplitude spectrum (upper stage) and phase difference spectrum (lower stage), and FIG. 8C shows the primary mode amplitude spectrum (upper stage) and phase difference spectrum (lower stage). D) is the amplitude spectrum (upper stage) and phase difference spectrum (lower stage) of the primary mode + secondary mode (composite mode).

The natural frequency is determined from the dominant spectrum obtained from these, and the past natural frequency of the object to be inspected to which the ID is assigned from the storage device of the notebook personal computer 4 is compared. And the soundness of member itself or a member junction part is evaluated and displayed from the decreasing rate in each vibration mode.

It is system configuration explanatory drawing used for the signboard soundness evaluation apparatus which concerns on this invention. It is explanatory drawing explaining the vibration method of the soundness evaluation apparatus of the signboard of the same invention. It is explanatory drawing of the waveform measured by the acceleration seismometer. It is explanatory drawing of the amplitude spectrum and phase difference spectrum which were Fourier-transformed. It is a flowchart of the soundness evaluation method of the signboard which concerns on this invention. An explanatory diagram of an excitation method, an illustration of a secondary mode amplitude spectrum and a phase difference spectrum (B) of an embodiment of a signboard soundness evaluation method according to the present invention, and a primary mode amplitude spectrum (C) of a phase difference spectrum, and (D) of an amplitude spectrum and a phase difference spectrum of a composite mode which is a primary mode + secondary mode.

Claims (2)

The signboard is vibrated, its vibration waveform is measured with a natural frequency measuring device to determine the natural frequency of the signboard, and the obtained natural frequency and the past natural frequency read from the storage device are changed. For each vibration mode, and for each vibration mode, the soundness of the signboard is obtained by internal calculation according to the width of the fluctuation, and the lamps or the monitor etc. An apparatus characterized by providing a clear display so that even a person who does not have sufficient knowledge about the mechanism of the evaluation apparatus can easily evaluate. The sign mode according to claim 1, wherein the vibration mode is a low-order mode of the primary mode, a high-order mode of the secondary mode or higher, and a combined mode of the low-order mode and the high-order mode. Degree evaluation device.

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