Curtain wall natural vibration frequency detection device based on millimeter wave radar

Abstract

The utility model belongs to the technical field of engineering detection, and particularly relates to a curtain wall natural vibration frequency detection device based on millimeter wave radar. At present, an appearance observation method and a vibration signal detection method are mainly adopted as detection methods for metal fittings and connecting structures on the back of a curtain wall. The two methods are limited by factors such as weather conditions and observation distance, are difficult to widely use in practical engineering, and cannot realize quantitative detection. The utility model provides a curtain wall natural vibration frequency detection device based on a millimeter wave radar, and particularly relates to a non-contact, remote, accurate, efficient and rapid curtain wall defect detection device. The detection device comprises an excitation unit, a detection unit and a signal processing unit, the excitation unit applies instant vibration force to the to-be-detected curtain wall through the knocking object; the detection unit comprises a millimeter-wave radar and a supporting structure below the millimeter-wave radar; the millimeter wave radar is used for transmitting electromagnetic wave signals to the curtain wall and receiving the electromagnetic wave signals reflected from the curtain wall.

Description

Technical Field

[0001] The utility model belongs to the technical field of engineering detection, and in particular relates to a curtain wall natural frequency detection device based on millimeter wave radar. Background Art

[0002] In recent years, building curtain walls, as a new type of external protective structure, are the product of the development of modern science and technology. Because they can organically integrate the functions of wind protection, rain protection, heat preservation and other functions with decorative functions, they are widely used in public buildings and some residential buildings. With the increase of the service life of curtain walls, due to the lack of metal accessories, colloid aging, loose nodes and connection failure, the curtain walls are prone to fall from high altitudes under wind loads and seismic loads. Therefore, the detection and evaluation of the number of metal accessories and the degree of damage to the connection structure are of great significance for the accurate evaluation of the safety performance of metal accessory curtain walls.

[0003] The Notice on the "Safety Maintenance and Management Measures for Existing Building Curtain Walls" (Jianzhi

[2006] No. 291) issued by the Ministry of Construction on December 5, 2006 stipulates the need for safety appraisal of building curtain walls and gives the procedures for conducting safety appraisal. According to the "Technical Regulations for Reliability Appraisal of Existing Building Curtain Walls" DB42 / T1709-2021, the first appearance defect inspection time is one year after the completion acceptance or delivery of the project, and it should be inspected every five years thereafter; after the curtain wall project has been in use for ten years, it is advisable to inspect it every three years.

[0004] At present, the main detection methods for metal accessories and connection structures on the back of curtain walls are appearance observation method, vibration signal detection method, etc. However, there are technical problems that need to be solved in both methods. For example, the appearance observation method is limited by weather conditions, observation distance, and manpower, and it is difficult to be widely used in actual projects, and quantitative detection cannot be achieved. The vibration signal detection method uses an accumulation to measure the vibration frequency and vibration mode of the excitation feedback by applying an accumulation to the curtain wall, and processes and analyzes the signal. When the curtain wall panel is loose and there is a risk of falling off, the natural vibration frequency (self-vibration frequency) of the curtain wall panel will decrease. The lower the frequency, the greater the risk of falling. The damage detection of the curtain wall is achieved by detecting and analyzing the vibration frequency and vibration mode. However, the vibration signal detection method is a contact test method because its accelerometer needs to be fixed on the curtain wall to be tested (except for the curtain wall in use) during measurement. The number of devices involved in the detection process is large, and the installation of the accelerometer takes a long time, which affects the test efficiency. Therefore, how to perform simple, accurate and efficient detection of curtain walls under non-contact and long-distance conditions has become the direction of industry technology development. Utility Model Content

[0005] In view of this, the utility model provides a curtain wall natural frequency detection device based on millimeter wave radar, which is specifically a device for non-contact, remote, accurate, efficient and rapid detection of curtain wall defects.

[0006] The detection device comprises: an excitation unit, a detection unit, and a signal processing unit;

[0007] The excitation unit applies instantaneous vibration force to the curtain wall to be inspected by striking the object;

[0008] The detection unit includes a millimeter wave radar and a supporting structure thereunder;

[0009] The millimeter wave radar is used to transmit electromagnetic wave signals to the curtain wall and receive electromagnetic wave signals reflected from the curtain wall;

[0010] The signal processing unit is electrically connected to the millimeter wave radar.

[0011] Preferably, the support structure includes a fixed platform and a tripod support;

[0012] The tripod bracket is connected to a fixing platform, and the fixing platform is used to fix the millimeter wave radar on the tripod bracket.

[0013] Preferably, the detection unit further includes a power supply device, which provides power for the millimeter wave radar;

[0014] The power supply device is a mobile charging power supply.

[0015] Preferably, the knocking object is a rubber cone or a wooden hammer.

[0016] Preferably, the millimeter wave radar is provided with a wireless signal transmitting device.

[0017] Beneficial effects:

[0018] (1) The millimeter-wave radar of the detection unit in the detection device can transmit electromagnetic wave signals to the curtain wall at a long distance in a non-contact manner, thereby realizing high-precision detection of the sub-millimeter vibration frequency of the curtain wall.

[0019] (ii) The fixed platform of the device is used to fix the millimeter wave radar on the tripod bracket to ensure the stability of the millimeter wave radar during detection.

[0020] (3) The millimeter-wave radar is equipped with a wireless signal transmitting device to realize wireless signal transmission between the millimeter-wave radar and the computer, thereby expanding the operating range of the device and improving the convenience of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of a curtain wall natural frequency detection device based on millimeter wave radar according to the utility model;

[0022] Among them, 1- curtain wall, 2- striking object, 3- millimeter wave radar, 4- power supply device, 5- fixed platform, 6- triangular bracket,

[0023] 7- Computer. DETAILED DESCRIPTION

[0024] In order to make the purpose, content and advantages of the utility model clearer, the specific implementation of the utility model is described below in conjunction with the drawings and embodiments to facilitate a better understanding of the utility model.

[0025] The utility model provides a curtain wall natural frequency detection device based on millimeter wave radar, such as Figure 1 As shown, the detection device includes: an excitation unit, a detection unit, and a signal processing unit; wherein the detection unit is at a certain distance from the excitation unit and faces the excitation unit, and the signal processing unit is connected to the detection unit.

[0026] The excitation unit is used to apply transient excitation (a very short-term force) to the curtain wall 1 to be detected, so that the curtain wall 1 undergoes short-term forced vibration in a very short time (the vibration will gradually decay, and the vibration will almost stop after a certain period of time). As an example, the excitation unit is a striking object 2.

[0027] As an example, the knocking object is a rubber cone or a wooden hammer.

[0028] The detection unit transmits a detection signal to the curtain wall 1 in a non-contact manner. Specifically, the detection unit includes a millimeter-wave radar 3 and a supporting structure thereunder; the millimeter-wave radar 3 is connected to a signal processing unit, and the millimeter-wave radar 3 is used to transmit a millimeter-wave electromagnetic wave signal to the curtain wall 1 (the millimeter-wave radar 3 converts an electrical signal into an electromagnetic wave signal through a transmitting antenna carried thereon and radiates it outward, and then receives the electromagnetic wave signal reflected back by the target through a receiving antenna carried thereon and converts it into an electrical signal); then, the millimeter-wave radar 3 obtains a digital signal through mixing, filtering, amplification, sampling and other processing, and sends the digital signal to the signal processing unit through a connecting line or a network; the signal processing unit measures the vibration frequency of the curtain wall 1 by processing the digital signal (existing technology).

[0029] The supporting structure includes a fixed platform 5 and a triangular bracket 6. The triangular bracket 6 is connected to the fixed platform 5, and the fixed platform 5 is used to fix the millimeter wave radar 3 on the triangular bracket 6 to ensure the stability of the millimeter wave radar 3 during detection. The triangular bracket 6 is used to adjust the placement position and height of the millimeter wave radar 3 so that it can detect different positions of the curtain wall 1.

[0030] In addition, the detection unit further includes a power supply device 4; the power supply device 4 is used to provide power for the millimeter wave radar 3. As an example, the power supply device is a mobile charging power supply.

[0031] The signal processing unit includes a computer 7, which is internally installed with data acquisition software and data analysis software; the data acquisition software (used to remotely control the millimeter wave radar, process the digital signal and display the processing results) is used to receive the digital signal output by the millimeter wave radar 3, and extract the vibration displacement curve information through signal processing. The data analysis software is used to perform a short-time Fourier transform on the vibration displacement curve information (using a sliding window to perform a Fourier transform on the signal in the window), obtain a time-varying spectrum diagram of the signal, complete the automatic processing of the data, realize the real-time measurement of the vibration of the curtain wall 1, thereby obtaining the natural frequency of the curtain wall, and further realize the evaluation of the safety and reliability performance of the curtain wall based on dynamic parameters (the data acquisition and data analysis functions in the signal processing unit are both existing technologies).

[0032] As an example, the millimeter wave radar 3 is connected to the computer 7 of the signal processing unit through a USB cable, and the data acquisition software in the computer 7 processes the digital signal to obtain the vibration displacement curve information, and then the vibration displacement curve information is short-time Fourier transformed in the data analysis software. As an example, the data acquisition software is mmWaveStudio; the data analysis software is Matlab; in the Matlab, the short-time Fourier transform of the vibration displacement curve is performed by the stft function; the transformation expression of the stft function in the Matlab is:

[0033]

[0034] As an example, the millimeter wave radar 3 is provided with a wireless signal transmitting device, which transmits the digital signal to the computer 7 through the network, and extracts the vibration displacement curve information through data acquisition software (including wireless acquisition system).

[0035] The utility model device is aimed at the safety performance evaluation of curtain walls and can be used for the construction acceptance of new curtain wall structures, non-destructive testing of existing building curtain walls and rapid safety inspection of large-scale building curtain wall structures, so as to effectively predict the sudden fall of curtain walls and has a wide application market in new curtain wall buildings.

[0036] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention.

Claims

1. A curtain wall natural frequency detection device based on millimeter wave radar, characterized in that: It includes an excitation unit, a detection unit, and a signal processing unit; The excitation unit applies an instantaneous vibration force to the curtain wall (1) to be inspected by means of a knocking object; The detection unit comprises a millimeter wave radar (3) and a supporting structure below the radar; The millimeter wave radar (3) is used to transmit electromagnetic wave signals to the curtain wall (1) and receive electromagnetic wave signals reflected from the curtain wall (1); The signal processing unit is electrically connected to the millimeter wave radar (3).

2. The curtain wall natural frequency detection device based on millimeter wave radar according to claim 1 is characterized in that: The supporting structure comprises a fixed platform (5) and a tripod support (6); The triangular bracket (6) is connected to a fixing platform (5), and the fixing platform (5) is used to fix the millimeter wave radar (3) on the triangular bracket (6).

3. The curtain wall natural frequency detection device based on millimeter wave radar according to claim 1 is characterized in that: The detection unit further comprises a power supply device (4) which provides power to the millimeter wave radar (3); The power supply device (4) is a mobile charging power source.

4. The curtain wall natural frequency detection device based on millimeter wave radar according to claim 1 is characterized in that: The knocking object is a rubber cone or a wooden hammer.

5. A curtain wall natural frequency detection device based on millimeter wave radar according to any one of claims 1 to 4, characterized in that: The millimeter wave radar (3) is provided with a wireless signal transmitting device.

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