阅读说明：本技术 一种基于分布式光纤传感器的轨道应变测量方法及系统 (Track strain measurement method and system based on distributed optical fiber sensor ) 是由 杨明来 易承东 马强 卞婷 陈宇磊 于 2020-09-04 设计创作，主要内容包括：本发明公开了一种基于分布式光纤传感器的轨道应变测量方法,包括步骤：S1：应变检测仪发出预设频率的探测光；S2：分布式光纤传感器接收步骤S1中所述应变检测仪发出的预设频率的探测光并输出携带所述待测轨道应变信息的偏移信号；S3：应变检测仪接收所述步骤S2中输出的偏移信号,并经NB-IOT模块传输至监控平台；S4：所述监控平台对接收到的信息进行解码,以计算出该待测轨道应变信息；S5：将步骤S4中计算的结果和预设的该待测轨道应变量阈值进行比较,以决定是否停止监测并报警,从而实现了轨道应变精准检测,解决现有技术采用的应变检测方法存在易受环境影响、且误差较大等技术问题。(The invention discloses a track strain measurement method based on a distributed optical fiber sensor, which comprises the following steps: s1: the strain detector emits detection light with preset frequency; s2: the distributed optical fiber sensor receives the detection light with preset frequency sent by the strain detector in the step S1 and outputs an offset signal carrying the strain information of the track to be detected; s3: the strain detector receives the offset signal output in the step S2, and transmits the offset signal to the monitoring platform through the NB-IOT module; s4: the monitoring platform decodes the received information to calculate the strain information of the track to be measured; s5: and (4) comparing the result calculated in the step (S4) with a preset threshold value of the strain quantity of the rail to be detected to determine whether to stop monitoring and give an alarm, so that accurate detection of the strain of the rail is realized, and the technical problems that a strain detection method adopted in the prior art is easily influenced by the environment, has large error and the like are solved.)

1. A track strain measurement method based on a distributed optical fiber sensor is characterized by comprising the following steps:

s1: the strain detector emits detection light serving as a detection light source signal;

s2: respectively arranging distributed optical fiber sensors on two sides of a track to be detected along the horizontal extension direction of the track to be detected, wherein the distributed optical fiber sensors receive detection light with preset frequency sent by the strain detector in the step S1 and output an offset signal carrying strain information of the track to be detected;

s3: the strain detector receives the offset signal output in the step S2, and transmits the offset signal to the monitoring platform through the NB-IOT module;

s4: the monitoring platform decodes the received information to calculate the strain information of the track to be measured;

s5: comparing the result calculated in the step S4 with a preset threshold value of the strain quantity of the track to be detected, and if the calculation result is lower than the preset threshold value of the strain quantity of the track to be detected, returning to the step S1 to continue monitoring in real time; and if the calculation result is higher than the preset strain threshold of the rail to be detected, ending the calculation, and outputting an alarm signal to start an alarm to alarm.

2. The method of claim 1, wherein the offset signal is a back-to-SPBS signal in step S2, and the frequency range is centered at a predetermined frequency and offset by a brillouin frequency shift.

3. The method of claim 2, wherein the Brillouin frequency shift is offset f_B＝(2f₀nv/c) sin (theta/2), wherein,

f₀the frequency of the light wave incident into the optical fiber;

n is the refractive index of the material;

c is the propagation velocity of the vacuum optical wave;

v is the speed of sound in the material;

θ is the angle between the scattered light signal and the original light signal that occurs in the fiber.

4. The distributed fiber optic sensor-based rail strain measurement method of claim 1, wherein the distributed fiber optic sensor in step S2 is a standard communication single mode fiber.

5. A system adopting the track strain measurement method based on the distributed optical fiber sensor as claimed in claims 1-4, is characterized by comprising: respectively arranging a distributed optical fiber sensor, a strain detector, an NB-IOT module, a monitoring platform and an alarm on two sides of a track to be detected along the horizontal extension direction of the track to be detected; wherein: the distributed optical fiber sensor, the strain detector, the NB-IOT module, the monitoring platform and the alarm are in signal connection;

the strain detector is used for emitting probe light with preset frequency as a detection light source signal;

the distributed optical fiber sensor is used for receiving detection light with a preset frequency sent by the strain detector and outputting an offset signal carrying strain information of the track to be detected;

the NB-IOT module is used for receiving an offset signal which is output by the strain detector and carries the strain information of the track to be detected, and transmitting the offset signal to the monitoring platform;

the monitoring platform is used for decoding the received information to calculate the strain information of the track to be detected: when the calculation result is lower than a preset strain threshold of the rail to be detected, continuing to monitor in real time; and when the calculation result is higher than the preset strain threshold of the rail to be detected, outputting an alarm signal to start an alarm to give an alarm.

6. The distributed fiber optic sensor-based track strain measurement system of claim 5, wherein the offset signal is a back SPBS signal having a frequency range centered at a predetermined frequency and offset by a Brillouin frequency shift.

7. The distributed fiber optic sensor-based rail strain measurement system of claim 6, further comprisingCharacterized in that the Brillouin frequency shift is an offset f_B＝(2f₀nv/c) sin (theta/2), wherein,

f₀the frequency of the light wave incident into the optical fiber;

n is the refractive index of the material;

c is the propagation velocity of the vacuum optical wave;

v is the speed of sound in the material;

θ is the angle between the scattered light signal and the original light signal that occurs in the fiber.

8. The distributed fiber optic sensor-based rail strain measurement system of claim 5 wherein the distributed fiber optic sensor is a standard communications single mode fiber.

Technical Field

The invention belongs to the field of track detection, and particularly relates to a track strain measurement method and system based on a distributed optical fiber sensor.

Background

The strain is the local relative deformation of an object under the action of factors such as external force, non-uniform temperature field and the like, and is one of important parameters reflecting the stress or health state of an engineering structure; by detecting the critical facilities in real time, the early warning of facility disasters and the scientific management of facilities can be realized.

The traditional strain detection method mainly adopts a resistance strain gauge, can convert strain change on a mechanical member into resistance change, and calculates the change of resistance by measuring the change of output current or voltage so as to reversely deduce the strain; however, this method is susceptible to environmental influences and has large errors, and therefore, the measurement result is not satisfactory; therefore, a strain measurement method and system with strong interference resistance and high measurement accuracy are needed.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides a track strain measurement method and system based on a distributed optical fiber sensor, and aims to detect strain by adopting the distributed optical fiber sensor and combining a corresponding data processing method, so that the technical problems that the strain detection method adopted by the prior art is easily influenced by environment, has large error and the like are solved.

To achieve the above object, according to one aspect of the present invention, there is provided a track strain measurement method based on a distributed optical fiber sensor, comprising the steps of:

s1: the strain detector sends out probe light with preset frequency as a detection light source signal;

s2: respectively arranging distributed optical fiber sensors on two sides of a track to be detected along the horizontal extension direction of the track to be detected, wherein the distributed optical fiber sensors receive detection light with preset frequency sent by the strain detector in the step S1 and output an offset signal carrying strain information of the track to be detected;

s3: the strain detector receives the offset signal output in the step S2, and transmits the offset signal to the monitoring platform through the NB-IOT module;

s4: the monitoring platform decodes the received information to calculate the strain information of the track to be measured;

s5: comparing the result calculated in the step S4 with a preset threshold value of the strain quantity of the track to be detected, and if the calculation result is lower than the preset threshold value of the strain quantity of the track to be detected, returning to the step S1 to continue monitoring in real time; and if the calculation result is higher than the preset strain threshold of the rail to be detected, ending the calculation, and outputting an alarm signal to start an alarm to alarm.

Preferably, in the method for measuring track strain based on the distributed optical fiber sensor, in step S2, the offset signal is a back SPBS signal, and the frequency range thereof is centered at a preset frequency and offset at a brillouin frequency shift.

Preferably, in the track strain measurement method based on the distributed optical fiber sensor, the brillouin frequency shift is an offset f_B＝(2f₀nv/c) sin (theta/2), wherein,

f₀the frequency of the light wave incident into the optical fiber;

n is the refractive index of the material;

c is the propagation velocity of the vacuum optical wave;

v is the speed of sound in the material;

θ is the angle between the scattered light signal and the original light signal that occurs in the fiber.

Preferably, in the method for measuring track strain based on the distributed optical fiber sensor, the distributed optical fiber sensor in step S2 is a standard communication single-mode optical fiber.

According to another aspect of the present invention, there is also provided a system using the method for measuring track strain based on a distributed optical fiber sensor, including: respectively arranging a distributed optical fiber sensor, a strain detector, an NB-IOT module, a monitoring platform and an alarm on two sides of a track to be detected along the horizontal extension direction of the track to be detected; wherein: the distributed optical fiber sensor, the strain detector, the NB-IOT module, the monitoring platform and the alarm are in signal connection;

the strain detector is used for emitting probe light with preset frequency as a detection light source signal;

the distributed optical fiber sensor is used for receiving detection light with a preset frequency sent by the strain detector and outputting an offset signal carrying strain information of the track to be detected;

the NB-IOT module is used for receiving an offset signal which is output by the strain detector and carries the strain information of the track to be detected, and transmitting the offset signal to the monitoring platform;

the monitoring platform is used for decoding the received information to calculate the strain information of the track to be detected: when the calculation result is lower than a preset strain threshold of the rail to be detected, continuing to monitor in real time; and when the calculation result is higher than the preset strain threshold of the rail to be detected, outputting an alarm signal to start an alarm to give an alarm.

Preferably, in the track strain measurement system based on the distributed optical fiber sensor, the offset signal is a back SPBS signal, and the frequency range is centered at a preset frequency and offset at a brillouin frequency shift.

Preferably, the brillouin frequency shift of the track strain measurement system based on the distributed optical fiber sensor is f_B＝(2f₀nv/c) sin (theta/2), wherein,

f₀the frequency of the light wave incident into the optical fiber;

n is the refractive index of the material;

c is the propagation velocity of the vacuum optical wave;

v is the speed of sound in the material;

θ is the angle between the scattered light signal and the original light signal that occurs in the fiber.

Preferably, in the track strain measurement system based on the distributed optical fiber sensor, the distributed optical fiber sensor is a standard communication single-mode optical fiber.

Generally, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

(1) by the track strain measurement method based on the distributed optical fiber sensor provided by the invention, by respectively arranging the distributed optical fiber sensors on the two sides of the track to be measured along the horizontal extension direction of the track to be measured, thereby collecting the strain information of the track to be detected, the distributed optical fiber sensor receives the detection light with preset frequency sent by the strain detector and outputs an offset signal carrying the strain information of the track to be detected, thereby converting the strain information of the track to be tested into transmittable optical information, transmitting the transmittable optical information to the monitoring platform through the NB-IOT module, decoding the received information by the monitoring platform, finally reversely pushing out the strain information of the track to be tested, therefore, accurate detection of track strain is achieved, and the technical problems that a strain detection method adopted in the prior art is easily influenced by the environment, has large errors and the like are solved.

Drawings

FIG. 1 is a schematic flow chart of a track strain measurement method based on a distributed optical fiber sensor provided by the invention;

fig. 2 is a schematic structural diagram of a track strain measurement system based on a distributed optical fiber sensor provided by the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The rail is taken as a main vehicle and a transport means, occupies an important position in life, and the safety of the rail is also concerned; in practice, the rails are subjected to variable vertical, transverse and longitudinal static and dynamic loads, which are transmitted from the rails to the roadbed through the sleepers and the track bed, and therefore are necessarily subjected to a deformation, known as a strain, due to the forces.

The strain is the local relative deformation of an object under the action of factors such as external force, non-uniform temperature field and the like, and is one of important parameters reflecting the stress or health state of an engineering structure; by detecting the critical facilities in real time, the early warning of facility disasters and the scientific management of facilities can be realized.

The traditional strain detection method mainly adopts a resistance strain gauge, can convert strain change on a mechanical member into resistance change, and calculates the change of resistance by measuring the change of output current or voltage so as to reversely deduce the strain; however, this method is susceptible to environmental influences and has large errors, and therefore, the measurement result is not satisfactory; therefore, a strain measurement method and system with strong interference resistance and high measurement accuracy are needed.

With the development of optical fiber technology, the situation of a fully distributed optical fiber sensing system based on the nonlinear effect of optical fibers is rapidly changing; the system is a real sensing and sensing integrated fully distributed detection system; the optical fiber strain detection device can provide more accurate and timely optical fiber strain detection, thereby improving the strain detection effect; thus, distributed fiber optic sensors offer significant advantages over conventional electrical sensors.