Fiber Optic Vibration Sensing Device and Vibration Sensing System with Flexible Support at Both Ends Springs

Abstract

This invention provides a fiber optic vibration sensing device with flexible support at both ends using springs, belonging to the field of photoelectric detection and vibration monitoring. It includes a V-shaped pressure-applying metal prism, a first spring, and a second spring. The V-shaped pressure-applying metal prism comprises a rectangular body and a V-shaped body connected to the rectangular body. The rectangular body, the first spring, and the second spring are all mounted on a guide post. One end of the guide post is fixed to a base, and the other end is fixed to a fixing member. The first spring is located between the rectangular body and the fixing member, and the second spring is located between the rectangular body and the base. The top of the V-shaped body faces the sensitive element of the optical fiber. A vibration sensing system is also provided. By introducing spring support structures at both ends of the optical fiber sensitive element, external vibrations are uniformly applied to the optical fiber through dual channels, improving vibration energy transfer efficiency and enhancing the sensitivity of the optical fiber to low-frequency and weak vibration signals. This solves the problems of low vibration energy transfer efficiency and insufficient response to low-frequency weak vibrations in existing devices.

Description

Technical Field

[0001] This utility model relates to the field of photoelectric detection and vibration monitoring technology, and in particular to a fiber optic vibration sensing device and vibration sensing system with flexible support at both ends of springs. Background Technology

[0002] Currently, high-precision measurement technologies for low-frequency vibrations mainly include accelerometers, electromagnetic vibration sensors, piezoelectric vibration sensors, and laser interferometry. These methods exhibit high sensitivity and accuracy in mid-to-high frequency vibration measurements, but often suffer from insufficient sensitivity in low-frequency vibration detection. Furthermore, traditional measurement methods are susceptible to interference in complex electromagnetic environments, and the large size and high cost of sensing equipment limit their widespread adoption in industrial monitoring and engineering applications. Fiber optic sensing technology, with its advantages of resistance to electromagnetic interference, high sensitivity, and long-distance transmission, has gradually become a research hotspot in the field of vibration measurement. Existing fiber optic vibration sensing technologies are mainly based on intensity modulation, phase modulation, or Brillouin scattering principles, with intensity modulation being widely adopted due to its simple structure and low cost. However, despite the advantages of fiber optic sensors in principle, their structural design still has certain limitations, especially in terms of support methods, which significantly impact performance.

[0003] Most common fiber optic vibration sensing devices currently employ rigid support structures, including single-end rigid fixing and overall rigid clamping. Single-end rigid fixing structures typically firmly connect one end of the fiber optic sensing element to the base, allowing external vibrations to be transmitted to the fiber through a single point. Because vibration energy can only couple along a single channel, the fiber's response to low-frequency and weak vibrations is insufficient. Furthermore, single-point stress easily leads to stress concentration, posing a risk of performance degradation and damage during long-term operation. While overall rigid clamping or frame structures enhance mechanical stability to some extent, they can excessively constrain the fiber during vibration transmission, causing some vibration energy to be consumed or canceled out, making it difficult to fully couple to the fiber's sensitive area. In addition, these rigid structures lack flexible buffering mechanisms, allowing external impacts and environmental noise to be directly transmitted to the fiber, severely affecting measurement accuracy and system reliability.

[0004] It is evident that existing fiber optic vibration sensing devices still have shortcomings in terms of vibration transmission structure, mainly manifested in low energy coupling efficiency, limited response sensitivity to weak low-frequency signals, insufficient anti-interference ability, and poor long-term stability. Utility Model Content

[0005] The technical problem to be solved by this utility model is: how to solve the problems of low energy coupling efficiency and insufficient sensitivity to low frequency and weak vibration in existing fiber optic vibration sensing devices.

[0006] This utility model solves the above-mentioned technical problems through the following technical solution: a fiber optic vibration sensing device with flexible support by double-ended springs, including a V-shaped pressure metal prism, a first spring, and a second spring. The V-shaped pressure metal prism includes a rectangular body and a V-shaped body connected to the rectangular body. The rectangular body, the first spring, and the second spring are all mounted on a guide post. One end of the guide post is fixed to the base, and the other end of the guide post is fixed to a fixing member. The first spring is located between the rectangular body and the fixing member, and the second spring is located between the rectangular body and the base. The top of the V-shaped body faces the sensitive unit of the optical fiber.

[0007] In a static state, the first and second springs jointly support the V-shaped pressure-applying metal prism, maintaining its horizontal equilibrium. When external structures vibrate, the V-shaped pressure-applying metal prism undergoes a slight vertical displacement under the combined action of the four sets of first and second springs. The first and second springs absorb and release external energy, achieving flexible reset and strain transfer. Since the top of the V-shaped body faces the sensitive element of the optical fiber, when the V-shaped pressure-applying metal prism vibrates up and down, the top of the V-shaped body applies periodic, minute pressure to the sensitive element of the optical fiber, causing strain in the fiber and converting mechanical vibration into optical signal changes. This invention, by introducing spring support structures at both ends of the optical fiber sensitive element, allows external vibration to act uniformly on the optical fiber through dual channels, thereby improving the vibration energy transfer efficiency and enhancing the fiber's sensitivity to low-frequency and weak vibration signals. This solves the problems of low vibration energy transfer efficiency and insufficient response to low-frequency weak vibrations in existing devices.

[0008] Preferably, one end of the first spring abuts against the rectangular body, and the other end abuts against the fixing member; one end of the second spring abuts against the rectangular body, and the other end abuts against the base. The upper and lower springs complement each other through this alternating compression and tension, effectively maintaining the stable vertical movement of the V-shaped pressure-applying metal prism and suppressing its lateral displacement or swaying, thereby avoiding fiber optic force shift due to lateral instability. With this structure, external vibrations can be stably, uniformly, and efficiently transmitted to the fiber optic sensing unit, causing the fiber to undergo minute deformation under pressure.

[0009] This invention utilizes the flexibility of springs to buffer and filter external impacts and environmental noise during vibration transmission, effectively preventing invalid and interference signals from directly coupling to the optical fiber. This improves the anti-interference capability and detection accuracy of the sensing system, thus solving the problems of insufficient buffering and susceptibility to external interference in existing devices. The double-ended flexible support disperses stress concentration on the optical fiber, avoiding localized fatigue and damage caused by single-point fixation. This allows the sensing device to maintain higher stability and reliability during long-term operation, addressing the problem of insufficient long-term stability in existing devices.

[0010] Preferably, a through hole is provided at each right angle of the rectangular body, and a guide post is inserted through each through hole. The first spring and the second spring jointly support the V-shaped pressure metal prism.

[0011] Preferably, the outer surface of the guide post is provided with external threads, and the base and the fixing part are respectively provided with threaded holes, and the external threads at the end of the guide post are fitted with the threaded holes for installation.

[0012] Preferably, a nut is fitted onto the end of the guide post near the fixing member, and the nut is located between the end of the first spring and the fixing member. The compression of the first spring can be adjusted by adjusting the nut.

[0013] Preferably, the V-shaped body is located at the center of the rectangular body, the cross-section of the V-shaped body is an isosceles triangle, the connection point of the two sides is the top of the V-shaped body, and the side directly opposite the top is fixedly connected to the rectangular body.

[0014] Preferably, the top of the V-shaped body is rounded. The rectangular body is used to receive and evenly distribute the pressure or vibration load applied from the outside, avoiding the force concentration in a local area and causing instability. The V-shaped body further concentrates and stably applies the pressure to the fiber optic sensitive unit, thereby causing the fiber to undergo slight bending or compression deformation.

[0015] Preferably, external vibrations act on the sensitive element of the optical fiber through two channels. In one channel, the external vibrations act on the sensitive element of the optical fiber in sequence through the fixing member, the first spring, the rectangular body, and the top of the V-shaped body. In the other channel, the external vibrations act on the sensitive element of the optical fiber in sequence through the base, the second spring, the rectangular body, and the top of the V-shaped body.

[0016] Preferably, it also includes a mounting base with a semi-circular fiber optic groove. The sensing element of the fiber optic cable is located within the semi-circular fiber optic groove, and the width of the fiber optic groove matches the outer diameter of the fiber optic cable. This ensures that the fiber optic cable does not slip under pressure.

[0017] This invention also provides a vibration sensing system, including a fiber optic vibration sensing device with flexible support at both ends by springs, and further including a modulation signal generator and a laser. The modulation signal generator outputs an electrical signal, and the laser is modulated under the drive of the electrical signal, outputting modulated light. The modulated light enters the optical fiber and propagates in the sensitive unit of the optical fiber. External vibrations are transmitted to the V-shaped pressure metal prism through the first spring and the second spring, respectively. The V-shaped body applies periodic pressure to the sensitive unit of the optical fiber, causing strain in the optical fiber. The light emitted from the output end of the optical fiber is shaped by the optical fiber collimator and enters the photodetector. The photodetector converts the modulated light signal into an electrical signal and transmits it to the data acquisition card.

[0018] The advantages of this invention are as follows: This invention introduces a double-ended spring flexible support structure at both ends of the fiber optic sensing unit, replacing the traditional rigid fixing method, fundamentally changing the transmission path of external vibration energy. External vibration or impact signals no longer act directly on the optical fiber, but first pass through the elastic deformation and mechanical buffering of the upper and lower springs, where some energy is absorbed and released with delay, significantly reducing the stress on the optical fiber. During operation, the double-ended springs alternately compress and stretch, ensuring the stable vertical movement of the V-shaped pressure metal prism while suppressing lateral offset and side sway, thus preventing environmental noise from coupling to the optical fiber through an asymmetric path. This structure achieves flexible adjustment and directional transmission of vibration energy, enabling the effective signal to be coupled stably and efficiently, while random impacts and environmental noise are weakened or canceled during transmission, thereby significantly improving the anti-interference capability and detection stability of the sensing system.

[0019] The double-end spring flexible support structure of this utility model has a compact design, which facilitates the miniaturization and integration of the device. At the same time, it has good environmental adaptability and can meet the application requirements of fiber optic vibration sensors in complex industrial scenarios. It can solve the problems of low integration and limited application adaptability of existing devices. Attached Figure Description

[0020] Figure 1 A perspective view of the fiber optic vibration sensing device with double-ended spring flexible support provided in Embodiment 1 of this utility model; Figure 2 Another perspective view of the fiber optic vibration sensing device with flexible support at both ends springs provided in Embodiment 1 of this utility model. Figure 3 The front view of the fiber optic vibration sensing device with double-ended spring flexible support provided in Embodiment 1 of this utility model; Figure 4 The front view of the V-shaped pressure metal prism in the fiber optic vibration sensing device with double-ended spring flexible support provided in Embodiment 1 of this utility model. Figure 5 This is a structural block diagram of the vibration sensing system provided in Embodiment 2 of this utility model; In the diagram: 1 Modulation signal generator, 2 Laser, 3 Fiber collimator, 4 Photodetector, 5 Signal demodulator, 6 Data acquisition card, 7 Host computer, 10 Guide post, 20 V-shaped pressure metal prism, 21 Rectangular body, 22 V-shaped body, 31 First spring, 32 Second spring, 40 Base, 50 Fixing component, 60 Fiber optic cable, 61 Sensing unit. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model are described clearly and completely below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0022] Current fiber optic vibration sensing devices primarily transmit external vibrations to the fiber optic sensing element through a rigid support structure. Typical structures include single-end rigid fixation and overall rigid clamping. In the single-end rigid fixation structure, one end of the fiber optic sensing element is firmly fixed, and vibration is transmitted to the fiber through a single point. Although this structure is simple, the vibration energy attenuates significantly during transmission due to the single energy transfer path, resulting in insufficient response of the fiber to low-frequency and weak vibrations. Furthermore, single-point loading leads to highly concentrated stress, making the fiber prone to localized stress fatigue during long-term operation, which can cause decreased sensitivity or even structural damage.

[0023] In rigid clamping or frame structures, fiber optic sensing elements are typically fixed over a large area to enhance overall stability. However, rigid constraints consume or cancel out some energy during vibration transmission, making it difficult for effective vibration signals to be fully coupled to the fiber optic sensing area. Furthermore, rigid structures offer almost no buffering capacity; external environmental noise and transient impacts act directly on the fiber along a fixed path, easily causing false alarms or false alarms, severely impacting the sensor's anti-interference performance and measurement reliability.

[0024] Existing fiber optic vibration sensing devices generally use rigid support structures to transmit external vibrations to the fiber optic sensing unit. The defects are as follows: (1) The vibration signal transmission path is single or constrained, and the energy coupling efficiency is low, resulting in insufficient response sensitivity of the fiber to low frequency and weak vibrations; (2) The lack of flexible buffer design means that environmental noise and external impacts can easily act directly on the fiber, resulting in poor anti-interference performance and affecting detection accuracy; (3) The rigid structure has obvious stress concentration, and the fiber is prone to fatigue damage during long-term operation, resulting in low reliability and insufficient long-term stability; (4) Existing devices are large in size and have a single structural form, which makes it difficult to meet the needs of industrial sites for miniaturization, integration and adaptability to complex environments, resulting in limited application adaptability.

[0025] To address the problems of low energy coupling efficiency, insufficient response to low-frequency weak vibrations, direct impact of external shocks and environmental noise on the optical fiber, poor system anti-interference capability, and insufficient long-term stability due to stress concentration in existing fiber optic vibration sensing devices, this utility model provides a fiber optic vibration sensing device with flexible support at both ends springs, as detailed below: Example 1 like Figure 1 and Figure 2 As shown, this embodiment provides a fiber optic vibration sensing device with flexible support by double-ended springs, including a V-shaped pressure metal prism 20, a first spring 31, and a second spring 32. The V-shaped pressure metal prism 20 includes a rectangular body 21 and a V-shaped body 22 connected to the rectangular body 21. The rectangular body 21, the first spring 31, and the second spring 32 are all inserted through guide posts 10. A through hole is opened at each right angle of the rectangular body 21, and a guide post 10 is inserted through each through hole. The first spring 31 and the second spring 32 jointly support the V-shaped pressure metal prism 20. One end of the guide post 10 is fixed to the base 40, and the other end of the guide post 10 is fixed to the fixing member 50. The outer surface of the guide post 10 is provided with external threads. The base 40 and the fixing member 50 are respectively provided with threaded holes. The external threads at the end of the guide post 10 are installed in conjunction with the threaded holes, so that the upper end of each guide post 10 is fixed in conjunction with the corresponding threaded hole on the fixing member 50, and the lower end of each guide post 10 is fixed in conjunction with the corresponding threaded hole on the base 40. The overall positioning and constraint are achieved by locking through the threaded holes.

[0026] Four guide posts 10 are installed at the four right angles of the rectangular body 21. Each guide post 10 is equipped with a first spring 31 and a second spring 32, forming a four-point symmetrical double-end spring flexible support structure. In a static state, the first spring 31 and the second spring 32 jointly support the V-shaped pressure metal prism 20, keeping it in a horizontal equilibrium state. When the external structure vibrates, the V-shaped pressure metal prism 20 undergoes a slight displacement in the vertical direction under the combined action of the four sets of first springs 31 and second springs 32. The first springs 31 and second springs 32 can absorb and release external energy, achieving flexible reset and strain transfer. Since the top of the V-shaped body 22 is directly opposite the sensitive element of the optical fiber 60, when the V-shaped pressure metal prism 20 vibrates up and down, the top of the V-shaped body 22 applies periodic small pressure to the sensitive element 61 of the optical fiber 60, causing strain in the optical fiber, thereby converting mechanical vibration into changes in optical signal.

[0027] External vibrations act on the sensitive element of optical fiber 60 through two channels. In one channel, the external vibrations act on the sensitive element of optical fiber 60 sequentially through the top of the fixing member 50, the first spring 31, the rectangular body 21, and the V-shaped body 22. In the other channel, the external vibrations act on the sensitive element of optical fiber 60 sequentially through the top of the base 40, the second spring 32, the rectangular body 21, and the V-shaped body 22. This invention, by introducing spring support structures at both ends of the optical fiber sensitive element, allows external vibrations to act uniformly on the optical fiber through two channels, improving the transmission efficiency of vibration energy and enhancing the sensitivity of the optical fiber to low-frequency and weak vibration signals. This solves the problems of low vibration energy transmission efficiency and insufficient response to low-frequency weak vibrations in existing devices.

[0028] To ensure the stability of vibration energy transmission, this invention incorporates springs at both the upper and lower ends of the V-shaped pressure-applying metal prism 20, forming a double-ended flexible support system. (See also...) Figure 3 The first spring 31 is located between the rectangular body 21 and the fixing member 50, and the second spring 32 is located between the rectangular body 21 and the base 40. The top of the V-shaped body 22 faces the sensitive unit of the optical fiber 60. Under the action of the spring's own elastic force, one end of the first spring 31 abuts against the rectangular body 21, and the other end of the first spring 31 abuts against the fixing member 50; one end of the second spring 32 abuts against the rectangular body 21, and the other end of the second spring 32 abuts against the base 40.

[0029] When the device moves downward, the lower spring (second spring 32) is compressed, while the upper spring (first spring 31) is stretched. When the device moves upward, the upper spring returns to its original position under the action of restoring force, and the lower spring remains stretched. The two springs complement each other through this alternating compression and stretching, effectively maintaining the smooth vertical movement of the V-shaped pressure-applying metal prism 20 and suppressing its lateral displacement or swaying, thereby avoiding fiber optic force shift due to lateral instability. With this structure, external vibrations can be stably, uniformly, and efficiently transmitted to the fiber optic sensing unit, causing the fiber to undergo minute deformation under pressure. As a sensing medium, the refractive index, light intensity, or phase of the fiber optic cable undergoes detectable changes when subjected to mechanical disturbances. This invention achieves the inversion and measurement of external vibration parameters by detecting fluctuations in the fiber optic output signal.

[0030] This invention utilizes the flexibility of springs to buffer and filter external impacts and environmental noise during vibration transmission, effectively preventing invalid and interference signals from directly coupling to the optical fiber. This improves the anti-interference capability and detection accuracy of the sensing system, thus solving the problems of insufficient buffering and susceptibility to external interference in existing devices. The double-ended flexible support disperses stress concentration on the optical fiber, avoiding localized fatigue and damage caused by single-point fixation. This allows the sensing device to maintain higher stability and reliability during long-term operation, addressing the problem of insufficient long-term stability in existing devices.

[0031] The V-shaped pressure-applying metal prism 20 is used to effectively transfer external vibration energy to the fiber optic sensing element. (See also...) Figure 4 The rectangular body 21 and the V-shaped body 22 are integrally formed or fixedly connected by welding. The V-shaped body 22 is located at the center of the rectangular body 21. The cross-section of the V-shaped body 22 is an isosceles triangle, and the connection point of the two legs is the apex of the V-shaped body 22. The side directly opposite the apex is fixedly connected to the rectangular body 21. The apex of the V-shaped body 22 is arc-shaped.

[0032] The V-shaped pressure-applying metal prism 20 consists of two parts: the upper rectangular body 21 is a cuboid base structure used to receive and evenly distribute the external pressure or vibration load, preventing force concentration in a localized area and causing instability; the lower V-shaped body 22 is a right triangular prism structure with an isosceles triangle cross-section, forming a stable V-shaped geometric interface. This part is in direct contact with the optical fiber and is the key area for coupling vibration signals to the optical fiber. When external vibration acts on the device, the cuboid base part evenly transmits the force to the lower right triangular prism, and the triangular structure further concentrates and stably applies pressure to the optical fiber sensing element, thereby causing the optical fiber to undergo slight bending or compression deformation.

[0033] A nut is fitted on the end of the guide post 10 near the fixing member 50. The nut is located between the end of the first spring 31 and the fixing member 50. The nut is used to adjust the compression of the first spring 31.

[0034] The optical fiber 60 is placed on a mounting base with a semi-circular fiber slot. The sensing element of the optical fiber 60 is located within the semi-circular fiber slot. The width of the fiber slot matches the outer diameter of the optical fiber 60 to ensure that the fiber does not slip under pressure. Both ends of the optical fiber are fixed with strong adhesive. The input end of the optical fiber is connected to the output end of an external laser, and the output end of the optical fiber is connected to a photodetector, both using FC / APC standard fiber optic connectors.

[0035] Working principle: In practical applications, the fiber optic vibration sensing device with double-end spring flexible support of this utility model can be installed on the structure to be measured, such as the beam of a building structure, the surface of a pipe, or the housing of an electrical equipment. Clean the surface of the structure to be measured to ensure that it is flat, open the mounting holes on the base 40, and use bolt assemblies to fix the base 40 on the surface of the structure to be measured for monitoring vibration signals.

[0036] When no external vibration is applied, the optical fiber maintains normal transmission and outputs a stable optical signal. When periodic vibration is applied, the vibration energy is applied to the optical fiber vibration sensing device by the vibration table and then transmitted to the V-shaped pressure metal prism 20 through the flexible spring support system at both ends. The upper part of the V-shaped pressure metal prism 20 is a cuboid base structure used to evenly distribute the input load, and the lower part is a right triangular prism structure with an isosceles triangle cross-section that directly acts on the sensitive area of ​​the optical fiber.

[0037] Driven by external vibration, the V-shaped pressure-applying metal prism 20 moves stably vertically under the constraint of upper and lower springs: when the device moves downward, the lower spring is compressed and the upper spring is stretched; when the device moves upward, the upper spring returns to its original position and the lower spring is stretched. Through this alternating compression and stretching, the upper and lower springs work together to effectively suppress the horizontal displacement of the V-shaped pressure-applying metal prism 20, ensuring that the periodic load is applied uniformly and stably to the sensitive area of ​​the optical fiber. Under pressure, the optical fiber undergoes slight bending or strain, and the intensity, phase, or polarization characteristics of its transmitted optical signal change accordingly, forming an optical response consistent with the external vibration.

[0038] The double-ended spring flexible support system is mechanically equivalent to a mass-spring second-order vibration system, possessing elastic energy absorption and frequency selectivity characteristics. When external impacts or high-frequency noise occur, the elastic deformation of the springs can absorb instantaneous energy and smooth out the impact force through their own damping effect, thereby effectively reducing the direct impact on the optical fiber. Simultaneously, the symmetrical arrangement of the springs creates complementary constraints, making the system sensitive only to vertical target vibrations, while exhibiting a natural suppression effect on lateral disturbances and random noise.

[0039] The double-ended spring flexible support structure allows the optical fiber to evenly distribute the load along both ends during stress. When external vibrations are transmitted through the V-shaped pressure-applying metal prism 20, the force is first evenly distributed by the rectangular body 21 at the top of the prism, and then stabilized by the top of the lower V-shaped body 22 onto the optical fiber. The springs at both ends deform simultaneously and share the load, thus avoiding the problem of stress concentration at a single point. This symmetrical support method ensures that the V-shaped pressure-applying metal prism 20 is subjected to uniform force and moves stably during operation, avoiding tilting or lateral displacement caused by single-point or eccentric forces, and significantly improving measurement sensitivity and repeatability.

[0040] This invention introduces a double-ended spring flexible support structure at both ends of the fiber optic sensing unit, replacing the traditional rigid fixing method and fundamentally changing the transmission path of external vibration energy. External vibration or impact signals no longer act directly on the optical fiber, but first pass through the elastic deformation and mechanical buffering of the upper and lower springs, where some energy is absorbed and released with delay, significantly reducing the stress on the optical fiber. During operation, the double-ended springs alternately compress and stretch, ensuring the stable vertical movement of the V-shaped pressure metal prism while suppressing lateral offset and side sway, thus preventing environmental noise from coupling to the optical fiber through an asymmetric path. This structure achieves flexible adjustment and directional transmission of vibration energy, enabling stable and efficient coupling of effective signals, while random impacts and environmental noise are weakened or canceled during transmission, thereby significantly improving the anti-interference capability and detection stability of the sensing system.

[0041] The double-end spring flexible support structure of this utility model has a compact design, which facilitates the miniaturization and integration of the device. At the same time, it has good environmental adaptability and can meet the application requirements of fiber optic vibration sensors in complex industrial scenarios. It can solve the problems of low integration and limited application adaptability of existing devices.

[0042] Example 2 This embodiment provides a vibration sensing system, including the fiber optic vibration sensing device with flexible support at both ends of springs as described in Embodiment 1, and also includes a modulation signal generator 1 and a laser 2. The modulation signal generator 1 outputs an electrical signal, and the laser 2 is modulated under the drive of the electrical signal, outputting modulated light. The modulated light carries modulation information that changes over time. The modulated light is coupled to a single-mode fiber through a flange and enters the fiber optic 60, propagating in the sensitive unit of the fiber optic 60. External vibrations are transmitted to the V-shaped pressure metal prism 20 through the first spring 31 and the second spring 32, respectively. The V-shaped body 22 applies periodic pressure to the sensitive unit of the fiber optic 60, causing strain in the fiber optic 60. The light emitted from the output end of the fiber optic 60 is shaped by the fiber collimator 3 and enters the photodetector 4. The photodetector 4 converts the modulated optical signal into an electrical signal, and the electrical signal is transmitted to the data acquisition card 6 via the signal demodulator 5.

[0043] The electrical signal is sent to the host computer 7 via data acquisition card 6 for processing. First, the dominant frequency component of the signal is extracted through spectrum analysis to obtain the frequency information corresponding to the external vibration. Then, the amplitude of the harmonic signal is extracted using digital phase-locked loop demodulation, and the correlation between the amplitude and the vibration is used to invert and measure the external vibration parameters. Throughout the process, the synergistic effect of the double-ended spring flexible support and the V-shaped pressure metal prism ensures the effective transmission of external vibration energy and the stable stress on the optical fiber, thus giving the optical signal high sensitivity and high reliability, enabling accurate vibration detection in complex environments.

[0044] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A fiber optic vibration sensing device with flexible support at both ends springs, characterized in that: It includes a V-shaped pressure-applying metal prism, a first spring, and a second spring. The V-shaped pressure-applying metal prism includes a rectangular body and a V-shaped body connected to the rectangular body. The rectangular body, the first spring, and the second spring are all mounted on the guide post. One end of the guide post is fixed to the base, and the other end of the guide post is fixed to the fixing member. The first spring is located between the rectangular body and the fixing member, and the second spring is located between the rectangular body and the base. The top of the V-shaped body faces the sensitive unit of the optical fiber.

2. The fiber optic vibration sensing device with flexible double-end spring support according to claim 1, characterized in that: One end of the first spring abuts against the rectangular body, and the other end of the first spring abuts against the fixing member; one end of the second spring abuts against the rectangular body, and the other end of the second spring abuts against the base.

3. The fiber optic vibration sensing device with flexible double-end spring support according to claim 1, characterized in that: A through hole is provided at each right angle of the rectangular body, and a guide post is inserted through each through hole. The first spring and the second spring together support the V-shaped pressure metal prism.

4. The fiber optic vibration sensing device with flexible double-end spring support according to claim 1, characterized in that: The outer surface of the guide post is provided with external threads, and the base and the fixing part are respectively provided with threaded holes. The external threads at the end of the guide post are fitted with the threaded holes for installation.

5. The fiber optic vibration sensing device with flexible double-end spring support according to claim 1, characterized in that: A nut is fitted on the end of the guide post near the fixing member, and the nut is located between the end of the first spring and the fixing member.

6. The fiber optic vibration sensing device with flexible double-end spring support according to claim 1, characterized in that: The V-shaped body is located at the center of the rectangular body. The cross-section of the V-shaped body is an isosceles triangle. The connection point of the two legs is the top of the V-shaped body, and the side directly opposite the top is fixedly connected to the rectangular body.

7. The fiber optic vibration sensing device with flexible double-end spring support according to claim 1, characterized in that: The top of the V-shaped body is rounded.

8. The fiber optic vibration sensing device with flexible double-end spring support according to claim 1, characterized in that: External vibrations act on the sensitive element of the optical fiber through two channels. In one channel, the external vibrations act on the sensitive element of the optical fiber in sequence through the fixing component, the first spring, the rectangular body, and the top of the V-shaped body. In the other channel, the external vibrations act on the sensitive element of the optical fiber in sequence through the base, the second spring, the rectangular body, and the top of the V-shaped body.

9. The fiber optic vibration sensing device with flexible double-end spring support according to claim 1, characterized in that: It also includes a mounting base with a semi-circular fiber optic groove. The sensitive element of the fiber optic cable is located inside the semi-circular fiber optic groove, and the width of the fiber optic groove matches the outer diameter of the fiber optic cable.

10. A vibration sensing system, characterized in that: The fiber optic vibration sensing device with double-end spring flexible support as described in any one of claims 1-9 further includes a modulation signal generator and a laser. The modulation signal generator outputs an electrical signal, and the laser is modulated under the drive of the electrical signal to output modulated light. The modulated light enters the optical fiber and propagates in the sensitive element of the optical fiber. External vibrations are transmitted to the V-shaped pressure metal prism through the first spring and the second spring, respectively. The V-shaped body applies periodic pressure to the sensitive element of the optical fiber, causing strain in the optical fiber. The light emitted from the output end of the optical fiber is shaped by the optical fiber collimator and enters the photodetector. The photodetector converts the modulated light signal into an electrical signal and transmits it to the data acquisition card.

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