Piezoelectric frequency-adjustable vibration energy acquisition device and method based on high-speed railway bridge

Abstract

The invention relates to the technical field, in particular to a piezoelectric frequency-adjustable vibration energy collection device and method based on a high-speed railway bridge, and the device comprises a platform assembly, a supporting mechanism and a magnetic attraction assembly. The supporting mechanism comprises a stand column assembly and a cantilever beam, the stand column assembly is fixed to the platform assembly, the cantilever beam is rotatably installed on the stand column assembly, and a piezoelectric plate is arranged on the cantilever beam and used for being connected to an energy storage unit; the magnetic attraction assembly comprises two magnet sets corresponding to the two ends of the cantilever beam, each magnet set comprises a lower magnet and an upper magnet, the lower magnets are installed on the platform assembly, and the upper magnets are installed at the bottom of the cantilever beam. According to the invention, the inherent frequency of the device can be adjusted according to the actual working condition of the bridge, so that the device can capture the main vibration frequency of the bridge when a train passes, can capture the energy of the bridge to the greatest extent, and the collected electric energy supplies power to the micro sensor, thereby achieving the self-powered health monitoring of the high-speed railway bridge.

Description

Technical Field

[0001] This invention relates to the field of energy harvesting technology, and in particular to a piezoelectric adjustable frequency vibration energy harvesting device and method based on high-speed railway bridges. Background Technology

[0002] As a key component of the railway network, the safety and durability of bridges directly affect the reliability of railway operations. However, during long-term service, bridges are affected by environmental erosion, train loads, and other factors, causing their structural performance to gradually deteriorate. Traditional manual inspection and regular maintenance methods are insufficient to meet the needs of efficient operation and maintenance of modern railways.

[0003] Bridge health monitoring systems provide crucial data for structural safety assessment and early warning by collecting real-time data on various key parameters such as stress, displacement, vibration, temperature, and corrosion. However, traditional monitoring systems often rely on wired or battery power, which presents several challenges in practical applications: wired systems involve complex wiring and extensive engineering work, making implementation difficult, especially on large or structurally complex bridges; battery power is limited by its battery life, requiring frequent replacements and incurring high maintenance costs. Deploying such systems in remote or inaccessible areas is even more challenging. Furthermore, unstable or interrupted power supply can lead to missing monitoring data or system failure, affecting not only the reliability of long-term continuous monitoring but also potentially masking underlying safety hazards, thereby weakening the actual protective function of the health monitoring system. Summary of the Invention

[0004] The main objective of this invention is to provide a piezoelectric adjustable frequency vibration energy acquisition device and method based on high-speed railway bridges, aiming to solve the technical problem that existing bridge health monitoring systems require power supply through wired power supply systems.

[0005] To achieve the above objectives, the present invention proposes a piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge, comprising a platform assembly, a support mechanism, and a magnetic attraction assembly; the support mechanism includes a column assembly and a cantilever beam, the column assembly being fixed on the platform assembly, the cantilever beam being rotatably mounted on the column assembly, and a piezoelectric plate being provided on the cantilever beam for connecting to an energy storage unit; the magnetic attraction assembly includes two magnet groups corresponding to the two ends of the cantilever beam, the magnet groups including a lower magnet and an upper magnet, the lower magnet being mounted on the platform assembly, and the upper magnet being mounted on the bottom of the cantilever beam.

[0006] The piezoelectric adjustable frequency vibration energy acquisition device based on high-speed railway bridges of the present invention is further improved in that the column assembly includes an H-shaped sleeve, a pin, and two support columns; the two support columns are respectively provided with multiple through holes for the pin to be inserted, and the two support columns are connected to the platform assembly at intervals; the two ends of the H-shaped sleeve are respectively sleeved on the two support columns, the pin passes through the through holes and the inside of the H-shaped sleeve, and the cantilever beam is fixed to both sides of the H-shaped sleeve.

[0007] The piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges of the present invention is further improved in that the lengths of the cantilever beams on both sides of the H-shaped sleeve are different.

[0008] The piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges of the present invention is further improved in that the platform component includes an insulating base and an iron platform. The insulating base is used to place on the bridge surface, and the iron platform is fixed on the insulating base. The iron platform is provided with a slot for mounting a lower magnet.

[0009] In addition, the present invention also provides a piezoelectric adjustable frequency vibration energy harvesting method based on high-speed railway bridges, comprising the following steps: Interferometric radar is deployed in the bridge area to be tested to acquire bridge vibration parameters, displacement, and acceleration data; By processing bridge vibration parameters, displacement, and acceleration data, the dominant frequency of bridge vibration can be obtained. Based on the main vibration frequency of the bridge, install the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge as described above, and adjust the natural frequency of the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge to be consistent with the vibration frequency of the bridge. When a train passes over a bridge and vibrates, the cantilever beam deforms, causing strain in the piezoelectric element and generating current. This current is stored in an energy storage unit to power the bridge health monitoring system. The bridge vibration displacement is measured using a piezoelectric adjustable frequency vibration energy acquisition device based on a high-speed railway bridge.

[0010] The piezoelectric adjustable frequency vibration energy harvesting method based on high-speed railway bridges of the present invention is further improved in that, when the natural frequency of the piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges is adjusted to be consistent with the vibration frequency of the bridge, when the resonant frequency of the piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges is lower than the ambient vibration frequency, the magnetic pole direction of the lower magnet is adjusted so that the lower magnet and the upper magnet generate a repulsive force of the same pole, thereby increasing the resonant frequency of the device. Then, the magnitude of the repulsive force of the same pole is controlled by adjusting the height of the H-shaped sleeve so that the resonant frequency of the device is consistent with the ambient vibration frequency. For example, when the resonant frequency of a piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge is higher than the ambient vibration frequency, the magnetic pole direction of the lower magnet is adjusted so that the lower magnet and the upper magnet attract each other, thereby reducing the resonant frequency of the device. Then, the magnitude of the attractive force is controlled by adjusting the height of the H-shaped sleeve so that the resonant frequency of the device is consistent with the ambient vibration frequency.

[0011] A further improvement of the piezoelectric adjustable frequency vibration energy harvesting method for high-speed railway bridges in this invention is that, in the laboratory, an accelerometer is used to measure the vibration acceleration of the bridge. The open-circuit output voltage of a piezoelectric adjustable frequency vibration energy acquisition device based on a high-speed railway bridge was recorded using an oscilloscope. Calculate the ratio ; Perform frequency sweep tests to obtain sensitivity-frequency curves .

[0012] A further improvement of the piezoelectric adjustable frequency vibration energy harvesting method based on high-speed railway bridges in this invention lies in that, in the application of the piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges, the output voltage of the device... Using the obtained voltage sensitivity coefficient, the acceleration time history of the vibrating bridge is calculated. : ; in, The output voltage is the piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges.

[0013] The piezoelectric adjustable frequency vibration energy harvesting method based on high-speed railway bridges in this invention is further improved in that it obtains acceleration time history data. By performing an integration, the vibration velocity is obtained. : .

[0014] The piezoelectric adjustable frequency vibration energy harvesting method based on high-speed railway bridges in this invention is further improved in that it controls the vibration velocity. Perform another integration, or perform an integral over the acceleration time history. The vibration displacement is obtained by performing two integrations. : .

[0015] The technical solution of the present invention has the following beneficial effects: This invention relates to a piezoelectric adjustable frequency vibration energy harvesting device for high-speed railway bridges. This device can adjust its natural frequency according to the actual bridge conditions, enabling it to capture the main vibration frequencies of the bridge when trains pass, maximizing energy harvesting. The collected electrical energy powers miniature sensors, achieving self-powered health monitoring of high-speed railway bridges. This solves the technical problem of existing bridge health monitoring systems requiring wired power supplies. The invention allows adjustment of the device's natural frequency to match the environmental vibration frequency simply by inserting a pin into through holes at different heights on the support column, overcoming the limitation of simple frequency adjustment in existing energy harvesting devices. Utilizing piezoelectric generator technology, this invention converts environmental vibration energy into electrical energy, providing continuous power to sensors and communication modules. It offers advantages such as flexible deployment, low maintenance costs, and strong environmental adaptability, making it particularly suitable for long-term monitoring of railway bridges. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge according to the present invention.

[0018] Explanation of icon numbers: 1. Insulating base; 2. Iron platform; 3. Support column; 4. H-shaped sleeve; 5. Pin; 6. Cantilever beam; 7. Upper magnet; 8. Lower magnet; 9. Piezoelectric element; 10. Wire; 11. Nut. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0021] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0024] like Figure 1 As shown, this invention proposes a piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge, including a platform assembly, a support mechanism, and a magnetic attraction assembly. The support mechanism includes a column assembly and a cantilever beam 6. The column assembly is fixed on the platform assembly, and the cantilever beam 6 is rotatably mounted on the column assembly. The cantilever beam 6 is provided with a piezoelectric sheet 9, which is used to connect to an energy storage unit. The magnetic attraction assembly includes two magnet groups corresponding to the two ends of the cantilever beam 6. The magnet groups include a lower magnet 8 and an upper magnet 7. The lower magnet 8 is mounted on the platform assembly, and the upper magnet 7 is mounted on the bottom of the cantilever beam 6.

[0025] In this embodiment, the piezoelectric element 9 is a PZT (lead zirconate titanate piezoelectric ceramic) piezoelectric element 9, and the substrate is copper. There are four piezoelectric elements 9, which are fixed to the upper and lower sides of the two cantilever beams 6. In actual use, the four piezoelectric elements 9 can be connected in parallel as a whole to the energy management circuit for energy management and output. The piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges of this invention can be sealed to increase the device's corrosion resistance.

[0026] Preferably, the column assembly includes an H-shaped sleeve 4, a pin 5, and two support columns 3. The two support columns 3 have multiple through holes for the pin 5 to be inserted into, and the two support columns 3 are connected to the platform assembly at intervals. The two ends of the H-shaped sleeve 4 are respectively fitted onto the two support columns 3, and the pin 5 passes through the through holes and inside the H-shaped sleeve 4. The cantilever beam 6 is fixed to both sides of the H-shaped sleeve 4. The support columns 3 need to be made of aluminum alloy with a slightly larger diameter to increase their rigidity and reduce their deformation. The spacing between two adjacent through holes on the support column 3 should be as small as possible to allow for more precise adjustment of the height of the H-shaped sleeve 4, thereby adjusting the frequency.

[0027] The H-shaped sleeve 4 is made of aluminum alloy, which has low density, is lightweight, and has high toughness, making it less prone to breakage when deformed. The inner diameter of the vertical sleeves at both ends needs to match the diameter of the support column 3 to prevent excessive gaps between them from causing collisions. The lengths of the cantilever beams 6 on both sides of the H-shaped sleeve 4 are inconsistent.

[0028] The vertical sleeves at both ends of the H-shaped sleeve 4 need to pass through the support column 3, so that the holes on the sleeves are flush with the holes in the support column 3, so that the pin 5 can pass through. The other end of the pin 5 is threaded and is fastened with a nut 11. Tightening the nut 11 can completely fix the sleeve of the bidirectional cantilever beam 6. Then, use AB glue to fix the upper magnet 7 to the free ends of the two cantilever beams 6 as a mass block to provide inertial force to drive the cantilever beams 6 to generate strain. Fix four piezoelectric plates 9 to the upper and lower sides of the two cantilever beams 6, and use a welding gun to weld the wires 10 to the piezoelectric layer of the piezoelectric plate 9 and the metal substrate respectively. It should be noted here that the connection of the wires 10 should ensure that it does not affect the normal operation of the energy harvester.

[0029] Preferably, the lengths of the cantilever beams 6 on both sides of the H-shaped sleeve 4 are different, so that the natural frequencies of the two cantilever beams 6 are inconsistent. This can improve the operating bandwidth of the vibration energy harvester device, enabling it to collect vibration energy over a wider range and improve energy harvesting efficiency.

[0030] Preferably, the platform assembly includes an insulating base 1 and an iron platform 2. The insulating base 1 is placed on the bridge deck, and the iron platform 2 is fixed to the insulating base 1. The iron platform 2 has a slot for mounting the lower magnet 8. The insulating base 1 is made of insulating rubber or other insulating materials, primarily to isolate other electrical energy on the bridge and prevent it from affecting the energy harvester. The insulating base 1 is placed directly on the bridge deck of the energy harvester, preferably at the mid-span (where deflection is greatest). The iron platform 2 is then fixed to the insulating base 1 using an adhesive that can bond metal and rubber bases, such as AB glue.

[0031] Specifically, both the upper magnet 7 and the lower magnet 8 are neodymium iron boron magnets, which have high magnetic properties and strong machinability. The lower magnet 8 is larger than the upper magnet 7. The lower magnet 8 is placed in the slot of the iron platform 2 and fixed with a small amount of glue to facilitate the adjustment of the resonant frequency of the magnetic pole direction adjustment device later. The size of the lower magnet 8 needs to be compatible with the size of the slot to ensure better fixation. In addition, it should be noted that the slots on the iron platform 2 are not symmetrical on both sides. The slots are located directly below the upper magnet 7 at the free end of the cantilever beam 6, and the two slots are the same size.

[0032] Furthermore, the iron platform 2 is provided with screw holes for mounting the support column 3. The support column 3 is screwed into the screw holes on the iron platform 2. The screw holes on the iron platform 2 need to match the threads at the lower end of the support column 3 for better fixation and to prevent loosening. The iron platform 2 has high density and heavy weight, which makes the center of gravity of the device lower and more stable. At the same time, the iron platform 2 can attract the lower magnet 8 in the slot, making the lower magnet 8 more securely fixed.

[0033] In addition, the present invention also provides a piezoelectric adjustable frequency vibration energy harvesting method based on high-speed railway bridges, comprising the following steps: Before fabricating a piezoelectric adjustable frequency vibration energy acquisition device based on a high-speed railway bridge, it is essential to obtain the actual vibration parameters of the bridge. This embodiment uses interferometric radar to conduct on-site measurements of the bridge. The interferometric radar is deployed in the area of ​​the bridge to be tested to acquire vibration parameters, displacement, and acceleration data. The interferometric radar must be aimed at the mid-span of the bridge for monitoring. The bridge vibration parameters, displacement, and acceleration data are processed to obtain the dominant vibration frequency. Specifically, the acquired displacement and acceleration data are processed, high-pass and low-pass filters are used to eliminate interference in the signal, and Fast Fourier Transform (FFT) is used to analyze the data to obtain the main vibration frequency, providing a reference for the design of a piezoelectric adjustable frequency vibration energy acquisition device based on high-speed railway bridges. The data processing methods are all existing technologies and will not be elaborated here.

[0034] After obtaining the vibration frequency of the bridge, the design of a piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge is guided. This is mainly reflected in adjusting the fixed height of the H-shaped sleeve 4 and the magnetic pole direction of the lower magnet 8 in the slot of the iron platform 2. Based on the obtained bridge vibration information, the fixed height of the H-shaped sleeve 4 and the magnetic pole direction of the lower magnet 8 in the slot of the iron platform 2 are controlled to match the natural frequency of the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge with the vibration frequency of the environment, thereby maximizing the acquisition of vibration energy.

[0035] Based on the main vibration frequency of the bridge, a piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge as described above is installed, and the natural frequency of the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge is adjusted to be consistent with the vibration frequency of the bridge, so that the device can achieve resonance and generate greater piezoelectricity when the bridge vibrates. When a train passes over a bridge and vibrates, the cantilever beam 6 deforms, causing the piezoelectric element 9 to strain and generate current, thereby collecting the vibration energy of the bridge. The current is stored in an energy storage unit to power the bridge health monitoring system. The bridge vibration displacement is measured by a piezoelectric adjustable frequency vibration energy acquisition device based on a high-speed railway bridge, thus it can be used as a vibration energy sensing device.

[0036] Preferably, when the natural frequency of the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge is adjusted to be consistent with the vibration frequency of the bridge, when the resonant frequency of the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge is lower than the ambient vibration frequency, the magnetic pole direction of the lower magnet 8 is adjusted so that the lower magnet 8 and the upper magnet 7 generate a repulsive force of the same pole, thereby increasing the resonant frequency of the device. Then, the magnitude of the repulsive force of the same pole is controlled by adjusting the height of the H-shaped sleeve 4 so that the resonant frequency of the device is consistent with the ambient vibration frequency. For example, when the resonant frequency of the piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge is higher than the ambient vibration frequency, the magnetic pole direction of the lower magnet 8 is adjusted so that the lower magnet 8 and the upper magnet 7 generate an attraction force between opposite poles, thereby reducing the resonant frequency of the device. Then, the magnitude of the attraction force is controlled by adjusting the height of the H-shaped sleeve 4 so that the resonant frequency of the device is consistent with the ambient vibration frequency.

[0037] Different heights result in varying forces between the magnets; the closer the magnets are, the stronger both the repulsive and attractive forces become. This allows the natural frequency of the device to be altered by changing the height. The ambient vibration frequency, i.e., the bridge's vibration frequency, is a fixed value. By adjusting the device's natural frequency to match the bridge's vibration frequency, resonance is achieved, generating greater piezoelectricity. Existing energy harvesters require altering component dimensions or disassembling and reinstalling the energy harvester to adjust the natural frequency. The device of this invention simplifies the adjustment process; the natural frequency can be adjusted to match the ambient vibration frequency simply by using pin 5.

[0038] Preferably, in a laboratory setting, an accelerometer is used to measure the vibration acceleration of the bridge. The open-circuit output voltage of a piezoelectric adjustable frequency vibration energy acquisition device based on a high-speed railway bridge was recorded using an oscilloscope. Calculate the ratio ; Perform frequency sweep tests to obtain sensitivity-frequency curves .

[0039] In the application of piezoelectric adjustable frequency vibration energy harvesting devices based on high-speed railway bridges, the output voltage of the device... Using the obtained voltage sensitivity coefficient, the acceleration time history of the vibrating bridge is calculated. : ; in, The output voltage is the piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges.

[0040] For acceleration time history By performing an integration, the vibration velocity is obtained. : .

[0041] Vibration velocity Perform another integration, or perform an integral over the acceleration time history. The vibration displacement is obtained by performing two integrations. : .

[0042] The piezoelectric adjustable frequency vibration energy acquisition device based on high-speed railway bridges converts the vibration energy of the bridge into electrical energy when collecting the vibration energy of the bridge. The electrical energy is expressed in the form of electrical signals such as output voltage. The vibration state of the bridge at that time can be inferred from these electrical signals. Therefore, this invention can be used as a vibration energy sensing device.

[0043] The above description is only a preferred embodiment of the present invention and does not limit the scope of the present invention. All equivalent structural transformations made under the inventive concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the protection scope of the present invention.

Claims

1. A piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges, characterized in that, The system includes a platform assembly, a support mechanism, and a magnetic attraction assembly. The support mechanism includes a column assembly and a cantilever beam (6). The column assembly is fixed to the platform assembly, and the cantilever beam (6) is rotatably mounted on the column assembly. The cantilever beam (6) is provided with a piezoelectric sheet (9), which is used to connect to an energy storage unit. The magnetic attraction assembly includes two magnet groups corresponding to the two ends of the cantilever beam (6). The magnet groups include a lower magnet (8) and an upper magnet (7). The lower magnet (8) is mounted on the platform assembly, and the upper magnet (7) is mounted on the bottom of the cantilever beam (6).

2. The piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge according to claim 1, characterized in that, The column assembly includes an H-shaped sleeve (4), a pin (5), and two support columns (3); the two support columns (3) are provided with multiple through holes for the pin (5) to be inserted, and the two support columns (3) are connected to the platform assembly at intervals; the two ends of the H-shaped sleeve (4) are respectively sleeved on the two support columns (3), the pin (5) passes through the through holes and the inside of the H-shaped sleeve (4), and the cantilever beam (6) is fixed to both sides of the H-shaped sleeve (4).

3. The piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge according to claim 2, characterized in that, The lengths of the cantilever beams (6) on both sides of the H-shaped sleeve (4) are different.

4. The piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge according to claim 3, characterized in that, The platform assembly includes an insulating base (1) and an iron platform (2). The insulating base (1) is used to place on the bridge deck, and the iron platform (2) is fixed on the insulating base (1). The iron platform (2) is provided with a slot for mounting a lower magnet (8).

5. A piezoelectric adjustable frequency vibration energy harvesting method based on high-speed railway bridges, characterized in that, Includes the following steps: Interferometric radar is deployed in the bridge area to be tested to acquire bridge vibration parameters, displacement, and acceleration data; By processing bridge vibration parameters, displacement, and acceleration data, the dominant frequency of bridge vibration can be obtained. Based on the dominant vibration frequency of the bridge, install the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge as described in claim 3, and adjust the natural frequency of the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge to be consistent with the vibration frequency of the bridge. When the train passes over the bridge and vibrates, the cantilever beam (6) deforms, causing the piezoelectric sheet (9) to strain and generate current. The current is stored in the energy storage unit for power supply of the bridge health monitoring system. The bridge vibration displacement is measured by a piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge.

6. The piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge according to claim 5, characterized in that, When the natural frequency of the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge is adjusted to be consistent with the vibration frequency of the bridge, when the resonance frequency of the piezoelectric adjustable frequency vibration energy acquisition device based on the high-speed railway bridge is lower than the ambient vibration frequency, the magnetic pole direction of the lower magnet (8) is adjusted so that the lower magnet (8) and the upper magnet (7) generate the same pole repulsion force, thereby increasing the resonance frequency of the device. Then, the magnitude of the same pole repulsion force is controlled by adjusting the height of the H-shaped sleeve (4) so ​​that the resonance frequency of the device is consistent with the ambient vibration frequency. For example, when the resonant frequency of the piezoelectric adjustable frequency vibration energy harvesting device based on the high-speed railway bridge is higher than the ambient vibration frequency, the magnetic pole direction of the lower magnet (8) is adjusted so that the lower magnet (8) and the upper magnet (7) generate an attraction force between opposite poles, thereby reducing the resonant frequency of the device. Then, the magnitude of the attraction force is controlled by adjusting the height of the H-shaped sleeve (4) so ​​that the resonant frequency of the device is consistent with the ambient vibration frequency.

7. The piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge according to claim 6, wherein an accelerometer is used to measure the bridge vibration acceleration in the laboratory. The open-circuit output voltage of a piezoelectric adjustable frequency vibration energy acquisition device based on a high-speed railway bridge was recorded using an oscilloscope. Calculate the ratio ; Perform frequency sweep tests to obtain sensitivity-frequency curves .

8. The piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge according to claim 7, characterized in that, In the application of piezoelectric adjustable frequency vibration energy harvesting devices based on high-speed railway bridges, the output voltage of the device... Using the obtained voltage sensitivity coefficient, the acceleration time history of the vibrating bridge is calculated. : ； in, The output voltage is the piezoelectric adjustable frequency vibration energy harvesting device based on high-speed railway bridges.

9. The piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge according to claim 8, characterized in that, For acceleration time history By performing an integration, the vibration velocity is obtained. : 。 10. The piezoelectric adjustable frequency vibration energy harvesting device based on a high-speed railway bridge according to claim 9, characterized in that, Vibration velocity Perform another integration, or perform an integral over the acceleration time history. The vibration displacement is obtained by performing two integrations. : 。

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