A non-contact sensing device for measuring bridge vibration acceleration and use method

Abstract

The present invention belongs to the technical field of bridge vibration measurement, and discloses a non-contact sensing device for measuring bridge vibration acceleration and a method of use. The non-contact sensing device of the present invention includes a connecting bracket, an accelerometer, a concentric circle laser, a camera bracket, an industrial camera and a mobile platform vehicle. It is characterized in that: the connecting bracket is rigidly connected to the mobile platform vehicle; there are four groups of accelerometers, concentric circle lasers and industrial cameras, which are respectively fixed to the four cantilever ends of the connecting bracket to form a square array; the accelerometer and the concentric circle laser are respectively coaxially and vertically fixed to the upper and lower surfaces of the cantilever end of the connecting bracket, and the industrial camera is fixed to the lower surface of the cantilever end of the connecting bracket through the camera bracket; the installation angle of the industrial camera can enable it to fully capture the multiple concentric circle apertures irradiated by the concentric circle laser to the bridge deck. The effect and benefit of the present invention is to realize the non-contact multi-point measurement of the vibration acceleration of the bridge deck, and avoid the repeated installation and disassembly of the accelerometer on the bridge deck.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge vibration measurement, and in particular relates to a non-contact sensing device for measuring bridge vibration acceleration and a use method thereof. Background Art

[0002] As an important node in the transportation network, it is of great significance to conduct regular and timely inspections on bridges to ensure safe service. Bridge dynamic testing is one of the important means of bridge status detection. Artificial external excitation is applied to the bridge to be tested by methods such as hammer impact, exciter excitation or load vehicle jumping. At the same time, the vibration response information of the structure is collected by sensors installed on the bridge. Modal parameter identification using bridge vibration response data can obtain the dynamic characteristic parameters of the structure (frequency, damping and vibration mode). Combined with known external excitation data, the static characteristic parameters of the structure (structural flexibility or stiffness) can be further obtained. By analyzing the dynamic and static characteristic parameters of the bridge and constructing the corresponding structural damage index, the service status of the bridge can be judged, providing decision-making information for the maintenance and reinforcement of the bridge.

[0003] Bridge dynamic testing is an effective method for bridge inspection (patent publication number: CN106197910B, CN103411743B). However, this method requires the installation of sensors on the bridge deck in advance, which consumes a lot of manpower and material resources, prolongs the closure time of the bridge, and seriously affects the normal operation of traffic. Especially when the inspection needs to cover the entire bridge, the inspection area is large. After the test of one sub-area is completed, the sensor needs to be removed and repeatedly installed in another sub-area for testing, which greatly increases the test workload and reduces the test efficiency. It can be seen that a convenient bridge vibration measurement method is the key to improving test efficiency, reducing test costs, and ensuring regular bridge inspections. Therefore, a non-contact vehicle-mounted sensing device capable of collecting bridge vibration acceleration response is invented, which plays an important role in improving test efficiency and simplifying the bridge dynamic testing process. Summary of the invention

[0004] The present invention aims to provide a non-contact sensing device for measuring bridge vibration acceleration. The key lies in how to accurately measure bridge vibration in a non-contact manner, solving the problem that current bridge dynamic testing requires on-site installation of sensors and is difficult to perform rapid vibration measurement of the entire bridge.

[0005] The technical solution of the present invention is: a non-contact sensing device for measuring bridge vibration acceleration, comprising a connecting bracket 1, an accelerometer 2, a concentric circle laser 3, a camera bracket 4, an industrial camera 5, and a mobile platform vehicle 6;

[0006] The connecting bracket 1 is rigidly connected to the mobile platform vehicle 6;

[0007] The accelerometer 2, concentric circle laser 3 and industrial camera 5 are four groups in total, which are respectively fixed to the four cantilever ends of the connecting bracket 1 to form a square array;

[0008] The accelerometer 2 and the concentric circle laser 3 are coaxially and vertically fixed to the upper and lower surfaces of the cantilever end of the connecting bracket 1, respectively, and the industrial camera 5 is fixed to the lower surface of the cantilever end of the connecting bracket 1 through the camera bracket 4;

[0009] The installation angle of the industrial camera 5 allows it to completely capture the n concentric circle apertures 7 irradiated by the concentric circle laser 3 onto the bridge deck 8.

[0010] The beneficial effects of the present invention are as follows: non-contact measurement of the vibration acceleration of a bridge sub-area is achieved, avoiding the installation of accelerometers on the bridge deck; the device can be quickly and flexibly moved to different sub-areas of the bridge deck for vibration acceleration measurement, avoiding repeated disassembly and installation of accelerometers in different bridge sub-areas; multiple groups of measuring devices can be arranged by connecting brackets to perform multi-point synchronous detection; the device provides a powerful tool for bridge inspection personnel to measure bridge acceleration response information on site and further analyze the service status of the bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic diagram of the structure of a non-contact sensing device;

[0012] Figure 2 It is a schematic diagram of the principle of non-contact sensor device measuring vibration.

[0013] In the figure: 1-connecting bracket; 2-accelerometer; 3-concentric circle laser; 4-camera bracket; 5-industrial camera; 6-mobile platform vehicle; 7-concentric circle aperture; 8-bridge deck. DETAILED DESCRIPTION

[0014] The following is a combination of technical solutions and drawings to further illustrate the implementation of the present invention.

[0015] A non-contact sensing device for measuring bridge vibration acceleration is mainly composed of a connecting bracket 1, an accelerometer 2, a concentric circle laser 3, a camera bracket 4, an industrial camera 5, and a mobile platform vehicle 6.

[0016] Before the bridge dynamic test, each group of accelerometers 2, concentric circle lasers 3, industrial cameras 5 and connecting brackets 1 are assembled into a measurement array and rigidly connected to the mobile platform vehicle 6. The shooting angle of the industrial camera 5 is adjusted to ensure that it can capture the complete n concentric circle apertures 7. The direction and position of the accelerometer 2 and the concentric circle laser 3 are adjusted to ensure that they are coaxial and perpendicular to the bridge deck 8.

[0017] A method for using a non-contact sensor device for measuring bridge vibration acceleration, the steps are as follows:

[0018] The measuring vehicle drives to the bridge area to be measured. The cantilever end of the connecting bracket 1 vibrates along with the bridge deck 8 through the mobile platform vehicle 6. The accelerometer 2 collects the vibration acceleration a(t) of the cantilever end of the connecting bracket 1 at time t. The concentric circle laser 3 irradiates n concentric circle apertures 7 to the bridge deck 8. The angles of the straight line formed by any point on each concentric circle to the laser emission point and the vertical direction are θ 1 ,θ 2 ,…,θ n , the industrial camera 5 shoots the concentric circle aperture 7 at a frame rate f, and the radius changes of each concentric circle at time t are respectively Then, the relative displacement change between the bridge deck 8 and the cantilever end of the connecting bracket 1 corresponding to each concentric circle is It can be calculated as follows:

[0019]

[0020] In order to reduce the measurement error caused by the roughness of the bridge deck, the relative displacements obtained by the n concentric circle apertures are averaged to obtain the final relative displacement δ between the bridge deck 8 and the cantilever end of the connecting bracket 1 y (t):

[0021]

[0022] Relative displacement δ y (t) is derived to obtain the relative acceleration a between the bridge deck 8 and the cantilever end of the connecting bracket 1 y (t):

[0023]

[0024] Finally, the absolute acceleration a of the cantilever end of bracket 1 and the relative acceleration a of the bridge deck 8 and the cantilever end of the connecting bracket 1 are used to calculate the relative acceleration a of the bridge deck 8 and the cantilever end of the connecting bracket 1. y (t) can be subtracted to obtain the vibration acceleration Acc of the bridge deck point to be measured:

[0025] Acc(t)=a(t)-a y (t)

[0026] The non-contact multi-point measurement of bridge deck vibration acceleration is realized, avoiding the repeated installation and disassembly of the accelerometer on the bridge deck.

Claims

1. A method for using a non-contact sensing device for measuring bridge vibration acceleration, characterized in that: The non-contact sensing device for measuring bridge vibration acceleration comprises a connecting bracket (1), an accelerometer (2), a concentric circle laser (3), a camera bracket (4), an industrial camera (5) and a mobile platform vehicle (6); The connecting bracket (1) is rigidly connected to the mobile platform vehicle (6) and is located at both ends; The accelerometer (2), concentric circle laser (3) and industrial camera (5) are four groups in total and are respectively fixed to the four cantilever ends of the connecting bracket (1) to form a square array; The accelerometer (2) and the concentric circle laser (3) are respectively coaxially and vertically fixed to the upper and lower surfaces of the cantilever end of the connecting bracket (1), and the industrial camera (5) is fixed to the lower surface of the cantilever end of the connecting bracket (1) through the camera bracket (4); The industrial camera (5) is installed at an angle such that it can completely capture the n concentric circle apertures (7) irradiated by the concentric circle laser (3) onto the bridge deck (8); Here are the steps: The measuring vehicle travels to the bridge area to be measured, the cantilever end of the connecting bracket (1) vibrates along with the bridge deck (8) through the mobile platform vehicle (6), the accelerometer (2) collects the vibration acceleration a(t) of the cantilever end of the connecting bracket (1) at time t, the concentric laser (3) irradiates n concentric apertures (7) to the bridge deck (8), and the angles between the straight line formed by any point on each concentric aperture (7) to the laser emission point and the vertical direction are θ and θ, respectively. 1 ,θ 2 ,…,θ n , the industrial camera (5) photographs the concentric circular apertures (7) at a frame rate f, and the radius changes of the concentric circular apertures (7) at time t are respectively Then, the relative displacement change between the bridge deck (8) corresponding to each concentric circular aperture (7) and the cantilever end of the connecting bracket (1) is The calculation is as follows: In order to reduce the measurement error caused by the roughness of the bridge deck, the relative displacements obtained by the n concentric circular apertures (7) are averaged to obtain the final relative displacement δ between the bridge deck (8) and the cantilever end of the connecting bracket (1). y (t): Relative displacement δ y (t) is derived to obtain the relative acceleration a between the bridge deck (8) and the cantilever end of the connecting bracket (1) y (t): Finally, the absolute acceleration a of the cantilever end of the connecting bracket (1) and the relative acceleration a between the bridge deck (8) and the cantilever end of the connecting bracket (1) are used to calculate the relative acceleration a between the bridge deck (8) and the cantilever end of the connecting bracket (1). y (t) is subtracted to obtain the vibration acceleration Acc of the bridge deck point to be measured: Acc(t)=a(t)-a y (t) The non-contact multi-point measurement of bridge deck vibration acceleration is realized, avoiding the repeated installation and disassembly of the accelerometer on the bridge deck.

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