Bridge tower model vibration underwater noise testing device

Abstract

The invention discloses a bridge tower model vibration underwater noise testing device which comprises a pool, a bridge tower, a portal frame, a hydrophone sliding rail, a hydrophone suspension rod, a hydrophone array and a vibration exciter. The water depths of the bridge tower and the water pool are in reduced scale design; a top plate is arranged on the portal frame; the hydrophone slide rail is arranged on the bottom surface of the top plate, the top of the hydrophone suspension rod is slidably mounted on the hydrophone slide rail and can be lifted, and the hydrophone array is mounted at the bottom of the hydrophone suspension rod; the hydrophone array comprises an array plate and a plurality of hydrophones, the working frequency range of each hydrophone is 1Hz-100kHz, and the hydrophones can capture low-frequency noise and are used for evaluating the influence of bridge tower vibration on aquatic organisms; the vibration exciter is arranged on the top plate and can apply vertical or lateral vibration to the top of the bridge tower. According to the method, the reduced scale model of the bridge tower is established, and the hydrophone array is moved in the area around the bridge tower, so that underwater noise generated by vibration of the bridge tower under the action of an external load can be collected in detail, comprehensively and accurately.

Description

Technical Field

[0001] The present invention relates to a device for detecting bridge vibration noise, in particular to a device for testing the underwater noise of a bridge tower model vibration. Background Art

[0002] In recent years, with the improvement of China's comprehensive national strength and bridge construction technology, long-span cable-stayed bridges have developed rapidly in the construction of expressways and urban roads. Such bridges not only have beautiful appearance designs but also possess powerful spanning capabilities, showing significant competitiveness in the construction of modern long-span bridges. However, as a flexible structure, compared with medium and small-span bridges, the vertical and horizontal stiffness of cable-stayed bridges is relatively weak. Therefore, under the action of external loads such as crosswinds, vehicles, and earthquakes, the bridge towers of cable-stayed bridges will generate relatively large deformations or vibrations. Among them, the vibrations will cause the vibrations of each underwater sub-structure of the bridge and generate underwater radiated noise.

[0003] The underwater noise caused by the vibration of the bridge structure will radiate uniformly in all directions. Its frequency band is generally concentrated between 0 - 200 Hz, belonging to low-frequency vibration noise. It has a long propagation distance and a low attenuation rate, bringing serious harm to aquatic organisms, especially endangered species such as the Yangtze finless porpoise. The underwater noise not only directly interferes with and affects the hearing and communication of the finless porpoise but also has a negative impact on other organisms in the river, thereby destroying the biodiversity of the water area and further deteriorating the living environment of the Yangtze finless porpoise.

[0004] Research shows that the average water depth where the Yangtze finless porpoise is distributed is 14.24 m. The underwater low-frequency noise generated by the vibration of the cable-stayed bridge tower has a long propagation distance and a fast propagation speed in water, and it is easy to spread to the waters where the Yangtze finless porpoise is distributed, having an adverse impact on the Yangtze finless porpoise. Moreover, the sound pressure level of the underwater noise generated by the vibration of the bridge tower can reach 126 dB. The Yangtze finless porpoise is at risk of experiencing a hearing threshold shift when exposed to such a noise environment for a long time. Since the bridge towers of cross-river bridges are in direct contact with the water body, their vibration noise will directly enter the water and affect aquatic organisms. Therefore, it is necessary to conduct in-depth research on the underwater noise generated by the vibration of the bridge tower.

[0005] In order to ensure that the underwater noise data generated by the vibration of the bridge tower can be comprehensively and accurately collected, it is necessary to design an effective device for testing the underwater noise of the bridge tower vibration. This will provide strong data support for subsequent underwater noise research, contribute to formulating effective protection measures, and reducing the impact of bridge vibration noise on aquatic organisms. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a vibration underwater noise testing device for a bridge tower model in view of the deficiencies of the above-mentioned prior art. The vibration underwater noise testing device for a bridge tower model can collect the underwater noise generated by vibration under external loads in detail, comprehensively and accurately by establishing a scaled-down model of the bridge tower and moving a hydrophone array in the area around the bridge tower.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A vibration underwater noise testing device for a bridge tower model includes a water tank, a bridge tower, a gantry, a hydrophone slide rail, a hydrophone suspension rod, a hydrophone array and an exciter.

[0009] The water tank is filled with water to a set depth.

[0010] The bottom of the bridge tower is installed at the center of the bottom of the water tank; both the bridge tower and the water depth of the water tank are designed with scale-down.

[0011] The top of the gantry is provided with a top plate, and the top plate is located directly above or on both sides of the bridge tower.

[0012] The hydrophone slide rail is arranged on the bottom surface of the top plate and is located on the outer periphery of the top of the bridge tower.

[0013] The top of the hydrophone suspension rod is slidably installed on the hydrophone slide rail and its height can be adjusted, and the bottom of the hydrophone suspension rod is installed with the hydrophone array.

[0014] The hydrophone array includes an array board and several hydrophones; the array board is arranged vertically, and several hydrophones are arranged in an array on the array board facing the bridge tower. The working frequency range of each hydrophone is 1 Hz to 100 kHz, and it can capture low-frequency noise and is used to evaluate the impact of bridge tower vibration on aquatic organisms.

[0015] The exciter is arranged on the top plate and can apply vertical or lateral vibration to the top of the bridge tower.

[0016] There are two gantries, symmetrically arranged on both sides of the bridge tower, and each gantry has a top plate; the exciter is installed on one of the top plates.

[0017] The height of the exciter can be adjusted, and the length of the excitation head of the exciter can be telescoped.

[0018] The excitation amplitude and frequency range of the exciter can be adjusted to simulate vibrations under different loads.

[0019] The exciter is an electrodynamic exciter, and the amplitude accuracy is ±0.1 mm.

[0020] The hydrophone slide rail is a rectangular or elliptical slide rail, and the distance between each hydrophone in the hydrophone array and each wall surface of the bridge tower is equal.

[0021] A method for testing the underwater noise of a bridge tower model, characterized in that it includes the following steps.

[0022] Step 1, scaled design: Scale down the bridge tower and the water depth of the pool in equal proportion.

[0023] Step 2, determine the load application method: Determine the application method of the exciter to excite the bridge tower according to the type and magnitude of the load to be simulated.

[0024] Step 3, set the horizontal distance range of noise monitoring: By setting the horizontal distance between the hydrophone slide rail and the bridge tower, the hydrophone array can directly capture the direct sound field of the bridge tower vibration, reducing the interference of the water body boundary effect and secondary reflection on the measurement data.

[0025] Step 4, set the noise monitoring depth: According to the activity depth of the aquatic organisms to be protected, adjust the length of the hydrophone suspension rod so that the center of the hydrophone array is at the activity depth of the aquatic organisms to be protected.

[0026] Step 5, background noise monitoring: The hydrophone array monitors the background noise at the noise monitoring depth set in Step 4.

[0027] Step 6, excitation: The exciter applies a load to the top of the bridge tower according to the load application method determined in Step 2.

[0028] Step 7, vibration noise monitoring: The hydrophone array makes a circumferential movement along the hydrophone slide rail, and during the movement, the vibration noise at each circumferential position at the current noise monitoring depth is collected in real time.

[0029] Step 8, analysis of the impact of vibration on aquatic organisms, specifically including the following steps.

[0030] Step 8-1, noise reduction: Subtract the background noise in Step 5 from the vibration noise at each circumferential position monitored in Step 7.

[0031] Step 8-2, obtain low-frequency noise: Perform Fourier transform and spectral analysis on the vibration noise after noise reduction in Step 8-1 to obtain the 0-200 Hz low-frequency vibration noise that affects aquatic organisms, and then analyze the magnitude of the impact of the low-frequency vibration noise on aquatic organisms.

[0032] It also includes Step 8-3, construct a spatial distribution map of vibration noise: By using the spatial interpolation method, connect the low-frequency vibration noises of each circumferential position and each row of hydrophones obtained in Step 8-2 to obtain a spatial distribution map of vibration noise, so as to further display the noise intensity and propagation path in different regions.

[0033] It also includes step 8-4, evaluating the impact of frequency bands on aquatic organisms: applying beamforming technology to determine the propagation direction of the vibration noise source and its diffusion pattern underwater; using the acoustic holography method to calculate the noise intensity of each row height at each circumferential position to obtain the intensity distribution of underwater noise; and considering the different impacts of different frequency bands on aquatic organisms, performing frequency weighting processing on the sound pressure data, so as to focus on the frequency range that has a greater impact on aquatic organisms. The vibration noise data after weighting will help evaluate the biological impact of noise in different frequency bands.

[0034] It also includes step 9, changing the load application method in step 2, and repeating steps 2 to 8 to evaluate the impact of vibration on aquatic organisms under different loads.

[0035] The present invention has the following beneficial effects: By establishing a scaled-down model of the bridge tower and moving the hydrophone array in the area around the bridge tower, the underwater noise generated by the vibration of the bridge tower under external loads can be collected in detail, comprehensively, and accurately. In addition, in order to simulate the vibration of the bridge tower under external loads such as wind, vehicles, and earthquakes, an electrodynamic shaker is used to act on the bridge tower to cause the bridge tower to vibrate. The shaker applies an accurate input force spectrum to the structure within the frequency range of interest, thereby inducing the expected vibration of the bridge tower. Through this design, the underwater noise caused by the vibration of the bridge tower can be effectively tested and studied. For the underwater noise generated by the vibration of the bridge tower, the present invention uses a bridge tower model for testing and research. The scaled-down model can simulate the vibration characteristics of the bridge tower in a controlled experimental environment, thus avoiding the complexity and uncontrollable factors that may be faced in the test of an actual bridge in a real environment. By using the scaled-down model, the impact of external loads (such as wind force, vehicle load, and earthquake, etc.) on the bridge tower can be simulated in a controllable experimental environment, and the underwater noise caused by the vibration of the bridge tower can be effectively measured. Description of the Drawings

[0036] Figure 1 Shows a schematic structural diagram of a test device for underwater noise caused by the vibration of a bridge tower model of the present invention.

[0037] Figure 2 Shows an exploded view of a test device for underwater noise caused by the vibration of a bridge tower model of the present invention.

[0038] Figure 3 Shows a schematic structural diagram of the hydrophone array of the present invention.

[0039] Among them are:

[0040] 1. Pool; 2. Bridge tower; 3. Gantry; 3-1. Top plate; 3-2. Scaffolding; 4. Hydrophone slide rail; 5. Hydrophone suspension rod; 6. Hydrophone array; 6-1. Array plate; 6-2. Hydrophone; 7. Shaker. Detailed Embodiment

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific preferred embodiments.

[0042] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "left side", "right side", "upper part", "lower part", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second", etc. do not represent the importance of components, so it cannot be understood as a limitation to the present invention. The specific dimensions adopted in this embodiment are only for illustrating the technical solution by way of example and do not limit the protection scope of the present invention.

[0043] As Figure 1 and Figure 2 shown, a vibration underwater noise test device for a bridge tower model includes a water tank 1, a bridge tower 2, a gantry 3, a hydrophone slide rail 4, a hydrophone suspension rod 5, a hydrophone array 6, and an exciter 7.

[0044] The water tank is filled with water to a set depth. In this embodiment, the water tank is preferably a rectangular structure, and its material is preferably corrosion-resistant stainless steel. The corresponding physical properties are preferably: density 7800 kg / m 3 , Young's modulus 20e10 Pa, and Poisson's ratio 0.3. Therefore, it has good water pressure resistance and weather resistance.

[0045] Specifically, in this embodiment, the size of the water tank is preferably rectangular, with a length of 4 m, a width of 2.5 m, and a height of 2 m. It simulates the underwater environment of an actual cross-river bridge at a ratio of 1:50. The thickness of the pool wall is 5 mm, and the thickness of the pool bottom is 6 mm to ensure that the water tank can withstand the underwater experimental load for a long time.

[0046] The bottom of the bridge tower is installed at the center of the bottom of the water tank. The material of the bridge tower is preferably C40 concrete, and its physical properties are preferably: density 2400 kg / m 3 , Young's modulus 3e10 Pa, and Poisson's ratio 0.2. Specifically, in this embodiment, the bottom of the bridge tower is placed in the installation hole at the bottom of the water tank and fixed by fasteners to simulate the actual construction environment of a cross-river bridge. The bridge tower is also preferably simulated according to a ratio of 1:50 of the actual bridge tower. The height of the tower body is preferably 3.2 m, the width of the bottom is preferably 0.5 m, and the width of the top is preferably 0.3 m.

[0047] The top of the gantry includes a top plate 3-1 and scaffolds 3-2 on both sides of the bottom of the top plate. The top plate is located directly above or on both sides of the bridge tower. In this embodiment, there are two gantries, symmetrically arranged on both sides of the bridge tower, and each gantry has a top plate.

[0048] The scaffolding is preferably fixed to the edge of the water by bolts and is preferably made of high-strength stainless steel. Its physical properties are preferably as follows: density 7850 kg / m 3 , Young's modulus 21e10 Pa, Poisson's ratio 0.3; the outside of the scaffolding is coated with an anti-rust coating to ensure that it does not rust during long-term use in the water environment. In this embodiment, the diameter of the scaffolding is preferably 40 mm, the height is preferably 1.5 m, the width is preferably 0.5 m, and the height of the support feet is adjustable to adapt to different test requirements.

[0049] The top plate is preferably made of high-quality steel plate. Its physical properties are preferably as follows: density 7850 kg / m 3 , Young's modulus 21e10 Pa, Poisson's ratio 0.3, and the surface is coated with an anti-corrosion layer; the length of the top plate is preferably 2.4 m, the width is preferably 0.8 m, the thickness is preferably 10 mm, and both ends are preferably fixed to the scaffolding by bolt connection.

[0050] The hydrophone slide rail is arranged on the bottom surface of the top plate and is located on the outer periphery of the top of the bridge tower. The hydrophone slide rail is a rectangular or elliptical slide rail, etc. The distance between each hydrophone in the hydrophone array and each wall surface of the bridge tower is preferably equal. In this embodiment, it is preferably 1 m.

[0051] The above-mentioned hydrophone slide rail is preferably made of steel. Its physical properties are preferably as follows: density 7850 kg / m 3 , Young's modulus 21e10 Pa, Poisson's ratio 0.3. In this embodiment, the hydrophone slide rail is preferably a rectangular slide rail, and the corners are preferably rounded. The length of the rectangular slide rail is preferably 2 m, the width is preferably 1 m, and the thickness is preferably 10 mm.

[0052] The top of the hydrophone suspension rod is preferably slidably installed on the hydrophone slide rail through a slider and the height can be adjusted. Among them, the size of the slider is preferably 50 mm × 50 mm. There are installation through holes and fasteners inside the slider, and the slider can slide freely along the hydrophone slide rail.

[0053] Furthermore, the material of the hydrophone suspension rod is preferably the same as that of the hydrophone slide rail. The diameter of the hydrophone suspension rod is preferably 30 mm, and the height can be adjusted in the range of 2 - 2.8 m to cover the main activity layer of the simulated finless porpoise.

[0054] The hydrophone array is arranged at the bottom of the hydrophone suspension rod and can slide along the four sides of the hydrophone slide rail through the hydrophone suspension rod, which is convenient for adjusting the measurement position, so as to realize the comprehensive collection of underwater noise.

[0055] The hydrophone array includes an array board 6-1 and several hydrophones 6-2; the array board is arranged vertically, and several hydrophones are arranged in an array on the array board facing the bridge tower. The working frequency range of each hydrophone is 1 Hz to 100 kHz, which can capture low-frequency noise and is used to evaluate the impact of bridge tower vibration on aquatic organisms.

[0056] The above array board is preferably a square stainless steel plate, and the physical property parameters of its material are preferably: density 7800 kg / m 3 , Young's modulus 20e10 Pa, Poisson's ratio 0.3, with corrosion resistance and fatigue resistance. In this embodiment, the size of the array board is preferably 800 mm × 800 mm × 20 mm. The distance between the centers of two adjacent hydrophones is preferably 200 mm to ensure that the hydrophones can evenly capture underwater noise signals. Further, the model of the hydrophone is preferably the Japanese AQH hydrophone, and its sensitivity is preferably: -206 dBre 1V / μPa, and the working frequency range is 1 Hz - 100 kHz, focusing on capturing low-frequency noise to evaluate its impact on aquatic organisms.

[0057] The exciter is preferably installed on one of the top plates. The height of the exciter can be adjusted, and the length of the excitation head of the exciter can be extended or retracted, which can apply vertical or lateral vibrations to the top of the bridge tower, thereby simulating the influence of factors such as wind and traffic loads on the bridge tower.

[0058] In this embodiment, an electrodynamic exciter is adopted, which can simulate vibrations under different loads, has an adjustable excitation amplitude and frequency range, the amplitude accuracy is ±0.1 mm, and the frequency is preferably adjustable in the range of 0.1 Hz–200 Hz.

[0059] The exciter generates precise excitation vibrations through electric drive. In this embodiment, the working frequency of the exciter is set to 50 Hz, and the amplitude is 5 mm, which represents simulating the low-frequency vibrations generated by typical traffic loads or wind loads on the bridge tower. The exciter is directly in contact with the top of the bridge tower through mechanical connection, applying periodic longitudinal excitation on the top plate. This causes the bridge tower to start vibrating, and this vibration propagates in the pool, exciting the generation of underwater noise. The exciter can generate 50 periodic vibrations per second, simulating the frequency response of the bridge tower under external loads within the range of 5 mm amplitude. The entire vibration process lasts for 5 minutes to ensure the generation of stable underwater noise and fully simulate the actual working conditions.

[0060] A method for testing underwater noise generated by the vibration of a bridge tower model, characterized by comprising the following steps.

[0061] Step 1, scale design: Scale down the bridge tower and the water depth of the pool in equal proportion. For example, the water depth of the pool is set to 1.5 m, corresponding to the actual water depth of 75 m, which can simulate the living and activity layer of the finless porpoise in the Yangtze River.

[0062] Step 2, determine the load application method: Determine the application method of the exciter's excitation to the bridge tower according to the type and magnitude of the load to be simulated.

[0063] When simulating the influence of traffic loads on the bridge tower, the excitation head of the exciter is pressed against the top surface of the bridge tower, and a vertical (or longitudinal) load is applied to the bridge tower by exciting it, and the load magnitude is adjusted by controlling the amplitude and frequency of the exciter.

[0064] When simulating the influence of wind loads on the bridge tower, the length of the excitation head of the exciter shrinks, and the height drops to the set height. After that, the length of the excitation head extends to contact the side wall of the top of the bridge tower, and a lateral load is applied. Further, the angle of the excitation head can be adjusted, thereby realizing the simulation of wind loads in different directions.

[0065] Step 3: Set the horizontal distance range for noise monitoring: By setting the horizontal distance between the hydrophone slide rail and the bridge tower, the hydrophone array can directly capture the direct sound field of the bridge tower vibration, reducing the interference of the water body boundary effect and secondary reflection on the measurement data. In this embodiment, the horizontal distance between the hydrophone slide rail and the bridge tower is preferably 1 m. The 1-m horizontal distance places the hydrophone array in the near-field acoustic measurement range, which can effectively capture the direct sound field of the bridge tower vibration, avoid excessive signal attenuation, and at the same time is not too close to be interfered by fluid disturbances, improving the measurement signal-to-noise ratio. In addition, this distance ensures that the measured sound field is mainly affected by the direct radiation of the bridge tower vibration, reducing the interference of the water body boundary effect and secondary reflection on the measurement data. The starting length of the hydrophone suspension rod is preferably set to 2 m. The hydrophone array is vertically and horizontally aligned to ensure that each hydrophone can directly receive the underwater noise caused by the bridge tower vibration.

[0066] Step 4: Set the noise monitoring depth: According to the activity depth of the aquatic organisms to be protected, adjust the length of the hydrophone suspension rod so that the center of the hydrophone array is at the activity depth of the aquatic organisms to be protected.

[0067] Step 5: Background noise monitoring: The hydrophone array monitors the background noise at the noise monitoring depth set in Step 4 as a reference for subsequent elimination of underwater background noise.

[0068] Step 6: Excitation: The exciter applies a load to the top of the bridge tower according to the load application method determined in Step 2.

[0069] Step 7: Vibration noise monitoring: The hydrophone array makes a circumferential movement along the hydrophone slide rail, and during the movement, the vibration noise at each circumferential position at the current noise monitoring depth is collected in real time.

[0070] In this embodiment, each time the hydrophone array moves, the moving step size is preferably 800 mm, and it slides smoothly and precisely along each side of the hydrophone slide rail. The duration of each measurement point is 5 seconds, which is sufficient to capture the characteristic frequency and amplitude of the underwater noise. The entire hydrophone array makes multiple back-and-forth movements in the pool to ensure comprehensive measurement of the noise at different distances and different water depths.

[0071] Each time the hydrophone array stays at the measurement position, it captures underwater noise in real time and transmits it to the data acquisition system through a cable. The frequency range that the hydrophone can measure is from 1 Hz to 100 kHz. It has a good effect on capturing low-frequency vibrations of 0 - 200 Hz and can accurately record the noise intensity at different frequencies. All data will be synchronously transmitted to the computer through the signal acquisition system for further spectral analysis.

[0072] Step 8: Analysis of the impact of vibration on aquatic organisms, which specifically includes the following steps.

[0073] Step 8-1: Denoising: Remove the background noise in Step 5 from the vibration noise at each circumferential position monitored in Step 7. That is, denoise the measured sound pressure data according to the background sound pressure measured without applying excitation to ensure that the sound pressure data only reflects the underwater noise caused by the vibration of the bridge tower.

[0074] Step 8-2: Obtain low-frequency noise: Perform Fourier transform and spectral analysis on the vibration noise after denoising in Step 8-1, convert the sound pressure signal in the time domain into a frequency-domain signal, and obtain the spectral information of the sound pressure. Spectral analysis can reveal the frequency components of the noise. For the underwater noise generated by the bridge tower, the key is to analyze the low-vibration frequency noise of 0 - 200 Hz because this type of noise has a greater impact on aquatic organisms, especially species sensitive to low-frequency sounds such as finless porpoises. In spectral analysis, calculate the frequency distribution, intensity of the noise signal, and its trend over time to help better understand the propagation characteristics of the noise.

[0075] Step 8-3: Construct a spatial distribution map of vibration noise: Since multiple hydrophone arrays are evenly distributed at different spatial positions, interpolate the local sound pressure information obtained from each hydrophone, that is, through spatial interpolation methods, connect the low-frequency vibration noises of each hydrophone at each circumferential position in each row to convert the discrete sound pressure data into a continuous spatial distribution map, thereby obtaining a spatial distribution map of vibration noise, which can further display the noise intensity and propagation path in different regions, that is, display the distribution law and propagation characteristics of the underwater noise caused by the vibration of the bridge tower.

[0076] Step 8-4: Evaluate the impact of the frequency band on aquatic organisms

[0077] Applying beamforming and acoustic holography analysis techniques can help determine the direction and radiation pattern of noise propagation. Finally, through calculating the noise intensity level and weighted average processing, it provides data support for evaluating the potential impact of noise on the aquatic ecosystem.

[0078] A. Apply beamforming technology to determine the propagation direction of the vibration noise source and its diffusion pattern underwater. That is, using the data of multiple hydrophone arrays, beamforming technology can be applied to analyze the propagation direction of sound pressure data from multiple angles. Beamforming can enhance the signal in a specific direction by combining the signals at multiple measurement points and suppress the interference in other directions, thereby improving the measurement accuracy. By analyzing the results of beamforming, the propagation direction of the noise source and its diffusion pattern underwater can be determined.

[0079] B. Use the acoustic holography method to calculate the noise intensity of each row height at each circumferential position to obtain the intensity distribution of underwater noise; and considering that different frequency bands have different effects on aquatic organisms, frequency weighting processing is performed on the sound pressure data, and then the frequency range that has a greater impact on aquatic organisms can be focused on. The weighted vibration noise data will help evaluate the biological effects of noise in different frequency bands.

[0080] Furthermore, using the acoustic holography method, the underwater sound field can be reconstructed by processing the sound pressure data to further analyze the radiation pattern of the noise and its impact on the surrounding environment; finally, for the sound pressure data at each measurement point, the sound pressure level (SPL) can be calculated and its potential impact on aquatic organisms can be further evaluated. The noise intensity is usually expressed in decibels (dB), and the calculation of the sound pressure level needs to consider the sound pressure value at each measurement point. By calculating the noise intensity at each position, the intensity distribution of underwater noise can be obtained. In addition, considering that different frequency bands have different effects on aquatic organisms, frequency weighting processing (for example, using A-weighting or C-weighting) can be performed on the sound pressure data to focus on the frequency range that has a greater impact on aquatic organisms. The weighted data will help evaluate the biological effects of noise in different frequency bands.

[0081] As an alternative, the noise monitoring depth in step 4 can be changed, that is, the length of the suspension rod is changed, with a step size of 800 mm, and steps 5 to 8 are repeated to complete the measurement of underwater vibration noise of the bridge tower.

[0082] Step 9. Change the load application method in step 2 and repeat steps 2 to 8 to evaluate the impact of vibration on aquatic organisms under different loads.

[0083] The vibration underwater noise test device for the scaled bridge tower model of the present invention has the advantages of simple structure, convenient manufacturing, low cost, and easy operation. By precisely controlling the setting of each parameter, the high precision and reliability of the test results are ensured. The device can stably simulate the vibration of the bridge tower and comprehensively capture and analyze the underwater noise at different positions and different depths.

[0084] The present invention is applicable to the noise research of traffic facilities such as bridges and tunnels, and has important application value especially in the research of structural vibration noise under various external loads such as wind force, traffic load, and earthquake. Through the accurate measurement of the underwater noise of the vibration of the scaled bridge tower model, it can provide data support for bridge design, noise isolation, and environmental protection. At the same time, this device can also be widely applied to the vibration noise measurement in other water environments, expanding its application scope.

[0085] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A bridge tower model vibration underwater noise test device, characterized by: It includes a water pool, a bridge tower, a gantry, a hydrophone slide rail, a hydrophone suspension rod, a hydrophone array and an exciter; The pool is filled with water of a set depth; The bottom of the bridge tower is installed in the center of the bottom of the pool; the bridge tower and the pool water depth are both scaled designs; A top plate is provided on the top of the gantry, and the top plate is located directly above or on both sides of the bridge tower; The hydrophone slide rail is arranged on the bottom surface of the top plate and is located at the outer periphery of the top of the bridge tower; The top of the hydrophone suspension rod is slidably mounted on the hydrophone slide rail and can be raised or lowered, and the hydrophone array is mounted at the bottom of the hydrophone suspension rod; The hydrophone array includes an array plate and a number of hydrophones; the array plate is arranged vertically, and a number of hydrophones are arranged in an array on the array plate facing the bridge tower. The operating frequency range of each hydrophone is 1Hz to 100kHz, which can capture low-frequency noise and is used to evaluate the impact of bridge tower vibration on aquatic organisms; The exciter is set on the top plate and can apply vertical or lateral vibration to the top of the bridge tower.

2. The bridge tower model vibration underwater noise testing device according to claim 1 is characterized by: There are two gantries, which are symmetrically arranged on both sides of the bridge tower, and each gantry has a top plate; the exciter is installed on one of the top plates.

3. The bridge tower model vibration underwater noise testing device according to claim 1 or 2, characterized in that: The height of the vibrator can be raised or lowered, and the length of the vibrator head can be extended or retracted.

4. The bridge tower model vibration underwater noise testing device according to claim 1 or 2, characterized in that: The excitation amplitude and frequency range of the exciter can be adjusted to simulate vibrations under load.

5. The bridge tower model vibration underwater noise testing device according to claim 4 is characterized by: The exciter is an electric exciter with an amplitude accuracy of ±0.1mm.

6. The bridge tower model vibration underwater noise testing device according to claim 1, characterized in that: The hydrophone slide rail is a rectangular or elliptical slide rail, and the distance between each hydrophone in the hydrophone array and each wall surface of the bridge tower is equal.

7. A bridge tower model vibration underwater noise testing method, characterized in that: The steps include: Step 1: Scaled design: Scale the bridge tower and the pool water depth in equal proportions; Step 2: Determine the load application method: Determine the application method of the vibration exciter on the bridge tower according to the load type and load size to be simulated; Step 3: Set the horizontal distance range for noise monitoring: By setting the horizontal distance between the hydrophone rail and the bridge tower, the hydrophone array can directly capture the direct sound field of the bridge tower vibration, reducing the interference of water boundary effects and secondary reflections on the measurement data; Step 4, setting the noise monitoring depth: according to the activity depth of the aquatic organisms to be protected, adjust the length of the hydrophone suspension rod so that the center of the hydrophone array is at the activity depth of the aquatic organisms to be protected; Step 5, background noise monitoring: the hydrophone array monitors the background noise at the noise monitoring depth set in step 4; Step 6, vibration excitation: the vibration exciter applies load to the top of the bridge tower according to the load application method determined in step 2; Step 7, vibration noise monitoring: the hydrophone array moves circumferentially along the hydrophone slide rail, and during the movement, the vibration noise at each circumferential position at the current noise monitoring depth is collected in real time; Step 8: Analysis of the impact of vibration on aquatic organisms, including the following steps: Step 8-1, denoising: remove the background noise of step 5 from the vibration noise at each circumferential position monitored in step 7; Step 8-2, obtain low-frequency noise: perform Fourier transform and spectrum analysis on the vibration noise denoised in step 8-1 to obtain the 0-200 Hz low-frequency vibration noise that affects aquatic organisms, and then analyze the impact of the low-frequency vibration noise on aquatic organisms.

8. The bridge tower model vibration underwater noise testing method according to claim 7 is characterized by: The method also includes step 8-3, constructing a vibration noise spatial distribution map: by using a spatial interpolation method, the low-frequency vibration noise of each row of high hydrophones at each circumferential position obtained in step 8-2 is connected to obtain a vibration noise spatial distribution map, thereby further demonstrating the noise intensity and propagation path in different areas.

9. The bridge tower model vibration underwater noise testing method according to claim 8, characterized in that: It also includes step 8-4, evaluating the impact of frequency bands on aquatic organisms: applying beamforming technology to determine the propagation direction of the vibration noise source and its underwater diffusion pattern; using the acoustic holography method to calculate the noise intensity of each row height at each circumferential position to obtain the intensity distribution of underwater noise; and taking into account the different impacts of different frequency bands on aquatic organisms, frequency-weighted processing is performed on the sound pressure data, thereby focusing on the frequency range that has a greater impact on aquatic organisms. The weighted vibration noise data will help evaluate the biological impact of noise in different frequency bands.

10. The bridge tower model vibration underwater noise testing method according to claim 7, characterized in that: The method also includes step 9, changing the load application method in step 2, and repeating steps 2 to 8, so as to evaluate the impact of vibration on aquatic organisms under different loads.

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