CN216284924U - An optical fiber sensor for monitoring the aging of damping oil in viscous dampers - Google Patents

Abstract

The invention belongs to the technical field of sensors, and discloses an optical fiber sensor for monitoring the aging degree of damping oil in a viscous damper. The sensor is based on a multi-beam interference principle, combines and utilizes the property that the optical refractive index of damping oil changes after the damping oil is aged, and indirectly monitors the aging degree of the damping oil in the viscous damper by monitoring the change of a Fabry-Perot cavity reflection spectrum signal under the condition of different aging degrees of the damping oil optical refractive index. The sensor can realize long-term, nondestructive and real-time monitoring of the aging degree of the damping oil in the viscous damper, has high measurement precision, and has the advantages of relatively simple manufacture, small volume, high strength, high sensitivity and the like. The sensor has wide application prospect and is easy to popularize.

Description

An optical fiber sensor for monitoring the aging of damping oil in viscous dampers

technical field

The invention relates to an optical fiber sensor for monitoring the aging degree of damping oil in a viscous damper, belonging to the technical field of sensors, and is especially suitable for monitoring the aging degree of damping oil in a viscous damper in large bridges or high-rise buildings.

Background technique

A damper is an energy-dissipating vibration-damping device installed in a structure. Due to its good vibration reduction effect and strong adaptability, dampers are gradually used in civil engineering structures to suppress structural vibrations caused by earthquakes and reduce earthquake disasters.

Since the 1980s, viscous dampers have been used in civil engineering because of their advantages such as "improving the damping ratio of structures without significantly changing the stiffness characteristics of the structure". For decades, viscous dampers have been used in The application in engineering structure has reached a considerable scale.

Although viscous dampers come in many forms, the working principle is basically the same, as shown in the attached image: the energy input from the earthquake or wind load forces the piston rod to move, and the movement of the piston rod forces the damping oil in the cylinder to flow through the damping hole in the piston , the damping oil flow produces clearance resistance to convert the kinetic energy transferred from the outside to the piston rod into thermal energy, and then transfer the thermal energy to the external environment, thereby dissipating the energy injected by the earthquake or wind.

According to the working principle of the viscous damper: when the piston rod is forced to move by the external energy inputted by the damping oil, the temperature and pressure inside the damping oil will gradually increase. In addition, the working environment in which the viscous damper is located often varies greatly in temperature. Factors such as large temperature difference and pressure will change the viscosity of the damping fluid: when the temperature increases or the pressure decreases, the spacing between the damping fluid molecules increases and the cohesion decreases, which reduces the viscosity of the damping fluid and causes the damping fluid to age, which directly leads to the damping force. decrease, which further leads to the failure of the viscous damper.

Once the damper fails, it is mild: when the earthquake or wind load comes, the damper cannot play the expected energy dissipation and vibration reduction effect, causing unexpected structural damage. If it is heavy, it will directly lead to the failure or even collapse of the structure under the action of lateral loads such as earthquake or wind.

If the aging of the damping oil can be monitored early, and risk avoidance measures and diagnosis and repair of the viscous damper can be taken in time, the probability of the viscous damper working normally can be greatly improved, the safety of the structure can be improved, and the viscous damper can be reduced. Economic losses and casualties due to damper failure.

However, the viscous damper is often very large, and the installation process is complicated and cumbersome. Once installed on the structure, it is basically impossible to regularly disassemble and install the viscous damper in order to detect the aging degree of the damping oil. Therefore, it is of great significance to continuously and accurately monitor the aging degree of damping oil without removing the viscous damper.

Therefore, the present invention proposes an optical fiber sensor embedded in the viscous damper for continuously monitoring the aging degree of damping oil in the viscous damper.

The optical fiber sensor has a series of advantages such as small size, light weight, anti-electromagnetic interference, strong corrosion resistance, high monitoring accuracy and real-time continuous monitoring. Therefore, using the optical fiber sensor to monitor the aging degree of the damping oil in the viscous damper has significant advantages. , hopefully to provide a new idea and method for the current monitoring technology of damping oil aging degree in viscous damper.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides an optical fiber sensor for monitoring the aging degree of damping oil in a viscous damper. The change in the refractive index of light indirectly monitors the aging degree of the damping oil. The damping oil aging degree monitoring sensor based on the Fabry-Plato cavity is simple to manufacture, and can monitor the damping oil aging degree of the viscous damper in real time without damage, so as to reasonably evaluate the performance state of the viscous damper and ensure the viscous damper. The normal performance of the damper's vibration reduction effect further ensures the safety of the structure.

Technical scheme of the present invention:

An optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper, characterized in that the optical fiber sensor comprises a single-mode optical fiber (1), a stainless steel casing (2), an oil inlet hole (3), and a reflective end face (4). );

The reflective end face (4) is formed by polishing one end face of a metal rod (8) connected to the sensor or pasting the reflective mirror surface;

The stainless steel casing (2) is provided with a sufficient number of oil inlet holes (3) to ensure that the damping oil outside the optical fiber sensor fully flows into and out of the optical fiber sensor;

The single-mode optical fiber (1) forms a Fabry cavity with the reflective end face (4) and the damping oil (5) entering the sensor;

The single-mode optical fiber (1) is used as an input and output optical fiber, is fixed by a fiber ceramic ferrule (6), and is inserted into the optical fiber sensor through the through hole where the sealing ring (7) is located;

When the damping oil in the viscous damper continuously flows into and out of the optical fiber sensor through the oil inlet hole (3), and forms a Fab cavity with the single-mode optical fiber (1) and the reflective end face (4), once the damping oil (5) occurs Aging, its optical refractive index will change, which further leads to the change of the spectral signal in the optical fiber demodulator connected to the optical fiber (1), which in turn reflects the degree of aging of the damping oil to be tested.

The optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper is characterized in that the size and number of the small oil inlet holes (3) can ensure that the damping oil can fully flow into and out of the sensor. Adjust according to the specific conditions of different viscous dampers.

The optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper is characterized in that the specific realization method and size of the reflective end face (4) can be adjusted according to the sensor manufacturing process and specific monitoring requirements.

The optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper is characterized in that, under the condition of ensuring optical signal transmission, the distance between the optical fiber and the reflective end face (4) can be adjusted according to different conditions and requirements of monitoring work .

The optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper is characterized in that after the single-mode optical fiber (1) passes through the piston rod of the viscous damper, it is fixed on the piston rod and embedded in the viscous damper. Internal and external fiber demodulator to continuously monitor the changes of spectral signals.

The working principle of the present invention:

The principle of the optical fiber sensor for monitoring the aging degree of the damping oil of the viscous damper is shown in the schematic diagram. Due to the existence of a sufficient number and size of oil inlet holes on the sensor shell, the damping oil can be fully flowed into and out of the sensor, so it can be considered that the optical fiber sensor The internal damping oil (that is, the damping oil that constitutes the medium part of the Faplatin cavity) and the damping oil in the viscous damper have the same properties in real time.

As the damping oil in the viscous damper ages, its optical refractive index changes.

Changes in the refractive index of light can cause changes in the shape of the spectrum obtained by the fiber demodulator. The relationship between the free spectral range (FSR) in the spectrogram and the refractive index n of damped oil is as follows:

where n is the refractive index of the medium, λ is the wavelength of the light, and L is the cavity length. In the working situation of the present invention, the medium is damping oil, and n is the refractive index of the damping oil. It can be further deduced:

Therefore, from the FSR in the spectrum returned by the sensor continuously obtained from the spectrometer, the change Δn of the light refractive index of the damping oil can be deduced, and thus the aging of the damping oil in the viscous damper can be deduced.

Beneficial effects of the present invention:

(1) The present invention combines the properties of the Fabry-Plato cavity and damping oil's aging-induced changes in its own light refractive index, so that the present invention has higher sensitivity.

(2) The present invention can realize continuous real-time monitoring of the aging degree of damping oil in the viscous damper.

(3) The volume of the present invention is small, it can be embedded in the tested viscous damper without affecting the normal operation of the viscous damper, and the non-destructive monitoring of the aging degree of the damping oil can be realized.

(4) The present invention uses a demodulator to calculate the aging degree of the damping oil from the spectrogram, and has strong anti-interference performance and accurate monitoring results.

(5) The present invention is relatively simple to manufacture, convenient to use, and reasonable in cost, suitable for promotion, and has a high application prospect.

Description of drawings

Fig. 1 is the schematic diagram of the sensor of the present invention;

Fig. 2 is the internal elevation schematic diagram of the present invention;

Fig. 3 is the appearance schematic diagram of the present invention;

Fig. 4 is the top surface schematic diagram of the present invention;

Fig. 5 is the working principle diagram of the present invention;

6 is a schematic diagram of the sensor arrangement of the present invention;

In Figures 1 to 5: (1) Single-mode fiber; (2) Stainless steel housing; (3) Oil inlet hole; (4) Reflective end face; (5) Damping oil; (6) Optical fiber ceramic ferrule; (7) ) sealing ring; (8) metal rod;

In Figure 6: (9) piston rod; (10) fiber hole 1; (11) fiber hole 2; (12) sensor; (13) piston; (14) damping hole; (15) damping oil in the damper; ( 16) Piston Cylinder; (17) External Parts.

Detailed ways

In order to make the objectives, features and advantages of the present invention more intuitive and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the following descriptions The embodiments are only some of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

As shown in the schematic diagram, an optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper, comprising a single-mode optical fiber (1), a stainless steel housing (2), an oil inlet hole (3), and a reflective end face (4);

The reflective end face (4) is made of one end face of a metal rod (8) connected to the sensor by polishing and grinding;

The stainless steel casing (2) is provided with a sufficient number of oil inlet holes (3) to ensure that the damping oil outside the optical fiber sensor fully flows into and out of the optical fiber sensor;

The single-mode optical fiber (1), the reflective end face (4) and the damping oil (5) entering the sensor form a Fabry-Plato cavity;

The single-mode optical fiber (1) is used as an input and output optical fiber, is supported by the optical fiber ceramic ferrule (6), and is inserted into the optical fiber sensor through the through hole where the sealing ring (7) is located;

For the optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper, the size and number of the oil inlet holes (3) can be adjusted according to the specific conditions of different viscous dampers under the premise that the damping oil can fully flow into and out of the sensor. adjusted according to the situation.

For the optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper, the specific realization method and size of the reflective end face (4) can be adjusted according to the sensor manufacturing process and specific monitoring requirements.

In the optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper, the distance between the optical fiber and the reflective end face (4) can be adjusted according to different conditions and requirements of monitoring work under the condition of ensuring optical signal transmission.

The optical fiber sensor for monitoring the aging degree of damping oil of a viscous damper, the single-mode optical fiber (1) of the sensor is fixed on the piston rod after passing through the piston rod of the viscous damper, and is embedded in the viscous damper , an external fiber demodulator to continuously monitor the changes of the spectral signal.

Step 1: Take a stainless steel block of suitable size, and according to the schematic diagram, use a machine to grind it into a circular plate with a metal rod, and polish the small end face of the metal rod.

Step 2: Use a machine to make a cylindrical hollow stainless steel shell, which is required to be made according to the shape shown in the schematic diagram.

Step 3: Combined with the schematic diagram, open a suitable number and size of oil inlet holes and a suitable size of optical fiber hole in the stainless steel casing of Step 2. In order to ensure that the damping oil can fully flow into and out of the sensor in the future, and the optical fiber can smoothly extend into the sensor through the stainless steel casing.

Step 4: Combine the schematic diagram, splicing the circular plate made in step 1 with the stainless steel shell after step 3 (the specific splicing method can be welding, mechanical connection, etc., but care must be taken to protect the reflective end face to ensure its reflective effect), pay attention to metal The reflective end face of the rod faces the fiber hole.

Step 5: Take a single-mode fiber, pass it through the fiber ceramic ferrule, and pass the fiber ceramic ferrule through the reserved fiber hole to ensure that the single-mode fiber is aligned with the reflective end face of the metal rod spliced in step 4. Use the sealing ring to seal the reserved hole in combination with the schematic diagram.

Step 6: Take a container of suitable size in the laboratory, pour an appropriate amount of damping oil into the container (the commonly used damping oils in viscous dampers are: hydraulic oil, methyl silicone oil, etc., which can be monitored according to the actual situation of the viscous damper. situation adjustment). Put the finished sensor into the container containing damping oil, and the damping oil is required to completely submerge the sensor. The sensor is connected to a fiber optic demodulator, and then the damping oil is continuously stirred mechanically. During this process, the spectral signal shift and the degree of damping oil aging are continuously recorded (the damping oil aging degree can be detected by traditional methods such as analyzing alkali equivalent). By establishing the relationship between the damping oil aging degree and the sensor spectral signal offset, the sensor laboratory calibration is completed.

Step 7: As shown in the schematic diagram, insert the calibrated sensor through the piston rod and then embed it in the specific viscous damper that needs to monitor the aging degree of damping oil, and fix the sensor on the piston rod in combination with the schematic diagram (the fixation method can choose mechanical connection. , gluing, welding, etc., can be freely selected according to the situation, but it should be noted that the fixing process needs to protect the sensor and must not affect the normal operation of the sensor, and pay attention to sealing the fiber hole). The fiber-optic external demodulator is used to monitor the aging degree of the damping oil in the viscous damper.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The recorded technical solutions are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (5)

1. The optical fiber sensor for monitoring the aging of the damping oil of the viscous damper is characterized by comprising a single-mode optical fiber (1), a stainless steel shell (2), an oil inlet small hole (3) and a light reflecting end face (4);

the reflecting end face (4) is formed by polishing and grinding one end face of a metal rod (8) connected with the sensor;

the stainless steel shell (2) is provided with enough oil inlet holes (3) to ensure that damping oil outside the optical fiber sensor flows into and out of the optical fiber sensor fully;

the single-mode optical fiber (1), the reflecting end face (4) and damping oil (5) entering the sensor form a platinum cavity;

the single-mode optical fiber (1) is used as an input/output optical fiber, is supported by the optical fiber ceramic ferrule (6), and is inserted into the optical fiber sensor through a through hole where the sealing ring (7) is located;

after damping oil in the viscous damper continuously flows into and flows out of the optical fiber sensor through the oil inlet small holes (3) and forms a platinum cavity with the single-mode optical fiber (1) and the reflecting end face (4), once the damping oil (5) is aged, the light refractive index of the damping oil can be changed, spectral signals in an optical fiber demodulator connected with the single-mode optical fiber (1) are further changed, and the aging degree of the damping oil to be measured is reflected.

2. The optical fiber sensor for monitoring the aging of the damping oil of the viscous damper as claimed in claim 1, wherein the size and the number of the oil inlet holes (3) can be adjusted according to the specific conditions of the viscous damper on the premise of ensuring that the damping oil can fully flow into and out of the sensor.

3. An optical fiber sensor for monitoring the aging of the damping oil of a viscous damper, according to claim 1, characterized in that the specific implementation method and size of the reflecting end face (4) can be adjusted according to the manufacturing process and specific monitoring requirements of the sensor.

4. An optical fiber sensor for monitoring the aging of damping oil of a viscous damper, according to claim 1, characterized in that the distance between the optical fiber and the reflecting end face (4) can be adjusted according to different conditions and requirements of monitoring operation under the condition of ensuring the transmission of optical signals.

5. The optical fiber sensor for monitoring the aging of the damping oil of the viscous damper as claimed in claim 1, wherein the single mode optical fiber (1) of the sensor is fixed on the piston rod after passing through the piston rod of the viscous damper, embedded in the viscous damper, externally connected with an optical fiber demodulator, and continuously monitors the change of the spectral signal.

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