CN117433748A - Optical cable structure health and safety monitoring system based on distributed optical fiber sensing - Google Patents
Optical cable structure health and safety monitoring system based on distributed optical fiber sensing Download PDFInfo
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- 230000003287 optical effect Effects 0.000 title claims abstract description 141
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/247—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet using distributed sensing elements, e.g. microcapsules
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/0052—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes measuring forces due to impact
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Abstract
The invention relates to the technical field of optical cable structure measurement, in particular to an optical cable structure health and safety monitoring system based on distributed optical fiber sensing, which comprises: the monitoring data acquisition module acquires pressure data through a distributed optical fiber pressure sensor to construct an original sampling matrix which is updated continuously; the characteristic analysis module is used for constructing material deformation suction coefficients at all times and a deflection angle of stress transmission caused by deformation; obtaining an impact detection vector corresponding to an original sampling matrix; extracting each ascending jump point and each descending jump point of the impact detection vector to determine whether the optical cable is impacted; when the optical cable is determined to be impacted, acquiring a material deformation suction coefficient change vector and a stress transfer deviation angle change vector generated by deformation, and constructing a correction coefficient; finally, obtaining a real-time damage detection value; and the optical cable structure monitoring module is used for monitoring the structural state of the optical cable by combining the real-time damage detection value. Thereby realizing the accurate measurement of the structural condition of the optical cable and improving the detection accuracy.
Description
Technical Field
The invention relates to the technical field of optical cable structure measurement, in particular to an optical cable structure health and safety monitoring system based on distributed optical fiber sensing.
Background
The optical cable refers to a transmission line for signal transmission through light, replaces traditional electric signal transmission through light transmission in an optical fiber, has the advantages of long transmission distance, high transmission speed, no electromagnetic signal interference and the like, and plays an important role in the modern electric communication transmission industry. In the daily maintenance of the optical cable, the optical cable needs to be periodically maintained according to the plan of an operation unit, and means such as manual section-by-section investigation, optical time domain reflectometer investigation and the like are needed.
However, in the above optical cable detection method, mostly, data is collected manually, and then health and safety assessment of the optical cable is completed through experience or data processing means. In the process of collecting data, people are required to collect the data, the speed is low, and the efficiency is low. And for the optical cable buried underground, if the optical time domain reflectometer is adopted for investigation, the damage of the optical fiber shell cannot be found in time, and the loss caused by communication interruption can be possibly caused.
In summary, the invention provides a distributed optical fiber sensing-based optical cable structural health safety monitoring system, wherein distributed optical fiber sensors are arranged between jackets of optical cables to obtain monitoring data, and abnormal pressure data is found by calculating characteristic values of the monitoring data, so that the detection of the structural health condition of the optical cable is realized.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide an optical cable structure health and safety monitoring system based on distributed optical fiber sensing, which adopts the following technical scheme:
the invention provides an optical cable structure health and safety monitoring system based on distributed optical fiber sensing, which comprises:
the monitoring data acquisition module is used for installing distributed optical fiber pressure sensors between the optical cable jackets and acquiring pressure data to construct an original sampling matrix which is updated continuously;
the characteristic analysis module is used for constructing material deformation suction coefficients at all moments and a deflection angle of stress transmission caused by deformation according to the relation between pressure data in all column vectors in the original sampling matrix; acquiring an impact detection vector corresponding to the original sampling matrix by combining the sum value of the pressure data of each column vector in the original sampling matrix; acquiring each ascending jump point and each descending jump point of the impact detection vector; determining whether the optical cable is impacted according to each ascending jump point and each descending jump point of the impact detection vector; when the optical cable is determined to be impacted, acquiring a material deformation suction coefficient change vector and a stress transmission deviation angle change vector generated by deformation for the optical cable in an impacting period; constructing a correction coefficient for determining the force of the optical cable when the optical cable is impacted; constructing a real-time damage detection value according to the change vector of the material deformation suction coefficient and the correction coefficient of each element difference and force in the change vector of the deflection angle of stress transmission caused by deformation;
the optical cable structure monitoring module is safe in the structural state of the optical cable when the optical cable is not impacted; when the optical cable is impacted, if the real-time damage detection value is larger than a preset damage threshold value, the optical cable structure state is dangerous, and if the real-time damage detection value is smaller than or equal to the damage threshold value, the optical cable structure state is safe.
Preferably, the acquiring the pressure data to construct a continuously updated original sampling matrix includes:
the pressure data of all the optical fiber pressure sensors at each sampling moment are used as a column vector, and the column vectors at each preset number of sampling moments form an original sampling matrix;
and deleting the first column vector in the original sampling matrix to form a new original sampling matrix when the column vector at the sampling moment is added, and continuously updating the original sampling matrix by analogy.
Preferably, the material deformation suction coefficient includes:
for a column vector at each moment, sorting pressure data in the column vector from large to small, calculating a sum of squares of maximum pressure data and squares of second maximum pressure data, and recording the sum as a first virtual tangential force value; calculating the sum of the square of the third maximum pressure data and the square of the minimum pressure data, and recording the sum as a second virtual tangential force value; and taking the ratio of the first virtual tangential force value to the second virtual tangential force value as a material deformation suction coefficient at the corresponding moment.
Preferably, the off angle of the stress transmission caused by deformation is specifically:
obtaining a calculation result of dividing the difference value of the maximum pressure data and the second maximum pressure data by the sum value of the maximum pressure data and the second maximum pressure data, and marking the calculation result as the direction of the first virtual tangential force; and obtaining a calculation result of dividing the difference value of the third maximum pressure data and the minimum pressure data by the sum value of the third maximum pressure data and the minimum pressure data, marking the calculation result as the direction of the second virtual tangential force, and taking the difference value of the direction of the first virtual tangential force and the direction of the second virtual tangential force as the radian value of the off angle of stress transmission caused by deformation.
Preferably, the obtaining the impact detection vector corresponding to the original sampling matrix by combining the sum value of the pressure data of each column vector in the original sampling matrix includes:
and calculating the sum value of the column vectors for each column vector in the original sampling matrix, and taking all the sum values as each element of the impact detection vector.
Preferably, the step of obtaining each ascending jump point and each descending jump point of the impact detection vector specifically includes:
acquiring each jump point in the impact detection vector by adopting a Bayesian punctuation detection algorithm;
for each hop; acquiring all elements from the jump point to the left until the first element of the next jump point or the impact detection vector is touched, and calculating the average value of all the elements to be recorded as the left average value of the jump point; acquiring all elements from the jump point to the right until the last element of the next jump point or the impact detection vector is touched, and calculating the average value of all elements to be recorded as the right average value of the jump point;
taking the jump point with the left mean value larger than the right mean value as a descending jump point; and taking the jump point with the left mean value smaller than the right mean value as the rising jump point.
Preferably, the determining whether the optical cable is impacted according to each ascending jump point and each descending jump point of the impact detection vector comprises:
for the impact detection vector, from a falling trip pointThe first rising trip point to the right +.>Monitoring is continued to the right until another falling trip point +.>The method meets the following conditions: the value of the further falling-jump point is smaller than the first rising-jump point to the right thereof +.>If the value of (2) is equal, stopping monitoring, wherein +.>、/>、/>、/>Respectively represent jump pointsA column in the impact detection vector;
will rise to jump pointTo the falling jump point->The time period between the two is determined as the optical cable is impacted; descending jump pointTo the rising jump point->Drop jump->To the rising jump point->The time period therebetween is determined that the optical cable is not impacted.
Preferably, the obtaining the change vector of the suction coefficient of the deformation of the material and the change vector of the deflection angle of the stress transmission caused by the deformation comprises:
extracting optical cables in an original sampling matrix to determine material deformation suction coefficients corresponding to each row of data corresponding to the impacted data, and determining a deflection angle of stress transmission caused by deformation;
sorting the material deformation coefficients corresponding to each column from small to large according to the column number to obtain a material deformation suction coefficient change vector; and ordering the off angles of the stress transfer caused by deformation of each row from small to large to obtain the variation vector of the off angles of the stress transfer caused by deformation.
Preferably, the constructing determines a correction factor for the force when the optical cable is impacted, comprising:
counting the row of the maximum value of the deformation suction coefficient change vector of the materialAnd the maximum value of the deflection angle change vector of stress transmission due to deformation is +.>Let the number of columns->Equal to->And->Maximum value of (2);
acquiring the number of columns in an original sampling matrixThe difference value between the first virtual tangential force value of the last column of the impacted time period is determined by the corresponding optical cable in the original sampling matrix and is recorded as a first difference value; calculating the number of columns +.>The difference value between the corresponding acquisition time and the last row of corresponding acquisition time is recorded as a second difference value; and taking the absolute value of the ratio of the first difference value to the second difference value as a correction coefficient of the force.
Preferably, the real-time damage detection value is constructed by the following expression:
in the method, in the process of the invention,the number of columns corresponding to the impact end time when the optical cable is impacted at this time; />The number of columns corresponding to the moment when the optical cable receives impact force and begins to be reduced; />Is the correction coefficient of the force; />Respectively the values of the t and t+1 columns in the change vector of the material deformation suction coefficient; />Respectively the values of the t th column and the t+1 th column in the deflection angle change vector of stress transmission caused by deformation; />；；/>、/>Is an intermediate function;、/>respectively calculating the numerical value in brackets and the change vector of the deformation suction coefficient of the material +.>Maximum and minimum values of the absolute values of the differences of the elements in (a); />Respectively is maximum->Minimum->A first virtual tangential force value of the column of (a); />And->Calculating the value in brackets and the deviation angle change vector of stress transmission caused by deformation respectively>Maximum and minimum values of the absolute values of the differences of the elements in (a); />Respectively is maximum->Minimum->Is formed by the following steps ofA first virtual tangential force value in the column;the first virtual tangential force value in the column of values a, b, c, d, respectively.
The invention has the following beneficial effects:
according to the invention, the condition that the optical cable receives external impact force is detected in real time by installing the distributed optical fiber sensor in the optical cable, when the optical cable receives strong external impact force, the distribution condition of the impact force in the optical cable is represented by constructing a first virtual tangential force and a second virtual tangential force, and the health condition of materials in the optical cable is represented by calculating the deformation suction coefficient of the materials and the off angle of stress transmission caused by deformation; the real-time damage detection value is obtained by comparing the virtual stress transfer coefficient before and after the optical cable is impacted by external force and the change relation of the off angle of stress transfer caused by deformation along with the magnitude of the first virtual tangential force, and the stress transfer characteristic change of the material inside the optical cable before and after the impact is represented, so that the structural health of the optical cable is accurately monitored. Compared with the traditional means, the method has the advantages that the data collection is more convenient and faster, the real-time detection of faults is completed, the structural damage of the optical fiber can be found in time, the repair speed of the optical fiber faults is increased, and the loss caused by the optical fiber faults is reduced.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions and advantages of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are only some embodiments of the invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a block diagram of a health and safety monitoring system for an optical cable structure based on distributed optical fiber sensing according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a fiber optic sensor distribution;
FIG. 3 is a schematic diagram of virtual tangential stress;
FIG. 4 is a schematic diagram of impact detection vector jump points and cable impact analysis.
Detailed Description
In order to further describe the technical means and effects adopted by the invention to achieve the preset aim, the following is a detailed description of specific implementation, structure, characteristics and effects of the optical cable structure health and safety monitoring system based on distributed optical fiber sensing according to the invention with reference to the accompanying drawings and the preferred embodiment. In the following description, different "one embodiment" or "another embodiment" means that the embodiments are not necessarily the same. Furthermore, the particular features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
The invention provides a specific scheme of an optical cable structure health and safety monitoring system based on distributed optical fiber sensing, which is specifically described below with reference to the accompanying drawings.
Referring to fig. 1, a block diagram of an optical cable structural health and safety monitoring system based on distributed optical fiber sensing according to an embodiment of the present invention is shown, where the system includes: a monitoring data acquisition module 101, a characteristic analysis module 102 and an optical cable structure monitoring module 103.
The monitoring data acquisition module 101 is used for installing distributed optical fiber pressure sensors between sheaths of the optical cables to acquire monitoring data.
Firstly, data acquisition is carried out: the distributed optical fiber sensors are arranged between the jackets of the optical cables, the specific structural schematic diagram is shown in fig. 2, the center circle in fig. 2 is an inner layer signal optical fiber, namely, the area where the optical cable optical fibers are located, the first circular ring is a first layer of jacket, the second circular ring is a second layer of jacket, the black circle between the two layers of jackets is the arranged distributed optical fiber sensors, therefore, the optical fiber sensors are arranged inside the jackets of the traditional optical cables, and four optical fiber sensors are uniformly distributed at one half of the thickness of the jackets, wherein the optical fiber sensors are optical fiber pressure sensors and are used for collecting pressure data of the optical cablesThe method comprises the steps of carrying out a first treatment on the surface of the Every other interval from the head end of the optical cableA reading and signalling device for fibre optic signals is provided for reading and collecting the current device>And (5) finishing the installation of the distributed optical fiber sensor by using the optical fiber sensor signals in the meter. Empirical value->Taking 100.
Thus, the fiber optic cable can obtain a set of fiber optic sensor data every 100 meters. Thus, the data used in this example are: each sampling time of the sensor sends out a column vector with the length of 4; connecting the obtained column vectors from left to right according to the sequence of acquisition to form an original sampling matrixThe vectors formed by the data of the 1 st row, the 2 nd row, the 3 rd row and the 4 th row are respectively called as、/>、/>、/>The four sensor locations corresponding to the top left, top right, bottom right, and bottom left in the fiber optic cable, as shown in FIG. 2, represent pressure measurement data for different fiber optic sensors.
After each sampling time, the original sampling matrixTo the right, a new column of data is added as the original sampling matrixAfter the number of columns exceeds the experience value 10000, adding a column of data every time, deleting the original sampling matrix +.>Column 1 data form a new original sampling matrix +.>。
So far, the continuously updated original sampling matrix can be obtained。
The feature analysis module 102 is configured to calculate a feature value from the monitoring data and find abnormal pressure data.
Summarizing:
a. according to the stress characteristics of the optical cable, a virtual tangential force is constructed, and the deformation suction coefficient of the material and the deflection angle of stress transmission caused by deformation are calculated.
b. Detecting the moment when the optical cable receives the external strong stress impact, and calculating a real-time damage detection value.
The specific development is as follows:
a. according to the stress characteristics of the optical cable, a virtual tangential force is constructed, and the deformation suction coefficient of the material and the deflection angle of stress transmission caused by deformation are calculated.
For the original sampling matrix, any one data corresponds to one sampling moment, thus for the original sampling matrixIs->Conversion into a pressure distribution matrix->And construct the material deformation suction coefficient +.>And the deflection angle of stress transmission due to deformation>The specific process is as follows:
for a pair ofThe four elements are marked as ++from big to small in sequence>、/>Then the virtual tangential stress is calculated as shown in FIG. 3 +.>Is->Element with largest median value->For the second largest element, ++>Third largest element,/->Is the element with the smallest value; />Representation->And->The resultant force in the direction towards the center of the optical cable is denoted as a first virtual tangential force; />Representation->And->The resultant force in the direction far from the center of the optical cable is recorded as a second virtual tangential force; the included angle between the first virtual tangential force and the second virtual tangential force is recorded as +.>Referred to as the off angle. This is because stresses propagate in the material and the material is unevenly distributed and the different materials absorb stresses at different levels when deformed to absorb the stresses, resulting in angular deviations in the final stress transmitted.
When the optical cable is impacted by external force, the optical cable structure is mainly subjected to tangential stress, and the optical fiber sensor is installed along the optical cable direction, so that the sensed pressure is also caused by the tangential stress of the optical cable, and the tangential stress is directed to the center of the optical cable; therefore, when the optical cable is impacted, the tangential stress of the optical cable is applied to the optical cableAnd->Between the represented optical fiber sensors, by +.>And->The value of (2) is taken as the force magnitude, in +.>And->The represented optical fiber sensor points to the center of the optical cable to be used as a direction, force synthesis is carried out, a first virtual tangential force is obtained, and the relative magnitude and the relative direction of the first virtual tangential force are represented.
Also, the process of the present invention is,and->The represented optical fiber sensor is also the pressure reading of the optical fiber sensor caused by the tangential stress to which the optical cable is subjected when the optical cable is impacted. Due to->And->Represented optical fiber sensor and +.>Andthe optical fiber sensor is characterized in that the optical cable structure absorbs stress, so the stress is +.>And->The represented optical fiber sensor is far away from the center of the optical cable to be used as a direction, and force synthesis is carried out to obtain a second virtual tangential force; the second virtual tangential force is reduced in magnitude and in a similar direction as the first virtual tangential force.
Thus constructing material deformation suction coefficientAnd the deflection angle of stress transmission due to deformation>：
In the middle ofIs->Element with largest median value->Is->Larger adjacent element, ++>Is->Smaller adjacent element, +.>Is->Is not adjacent to the element of the group; />Is the coefficient of deformation and suction of the material, < >>Is the angle of departure of the stress transfer due to deformation.
Is a first virtual tangential force value, +.>Is a second virtual tangential force value, the ratio of which represents the tangential force influence from +.>And->The represented optical fiber sensors are transferred to +.>And->In the process between the represented optical fiber sensors, the ratio of the magnitude of stress loss due to material deformation is +.>The greater the stress loss due to deformation of the material, the more so +.>The method can be used for representing the loss condition of stress when the stress is transmitted in the optical cable, corresponds to the condition that the material deforms to absorb the stress, and corresponds to the structural distribution of different materials in the optical cable. When the optical cable structure is healthy, the stress transmission loss condition and the stress magnitude show a one-to-one correspondence, and the deformation suction coefficient of the material is monitored>The abnormal conditions are that the structural health of the optical cable is problematic, such as shell breakage, material overstretching and the like.
Is the direction of the first virtual tangential force and +.>The radian value of the included angle of the shaft in the clockwise direction,is the direction of the second virtual tangential force and +.>The angle radian value of the shaft in the anticlockwise direction, and the angle difference of the two angle radian values can obtain the deviation angle +.>Is a radian value of (a). Deviation angle->The stress is characterized in the transmission process, the stress release direction changes caused by material distribution and deformation, when the deflection angle is +>And when the structure is stable and unchanged, the structural distribution of the stress absorption of the inner material of the optical cable due to deformation is stable, and the inner structure of the optical cable is not damaged.
b. Detecting the moment when the optical cable is impacted by external strong stress, and calculating a real-time damage detection value.
After each sampling time is finished, the original sampling matrix is obtainedIs added to the data of each column to obtain a vector named impact detection vector +.>. The impact detection vector is taken as input, a Bayesian variable point detection algorithm is adopted, the output is a plurality of numerical values, and the positions of the middle Bayesian jump points of the impact vector are represented. It should be noted that, the bayesian variable point detection algorithm is the prior art, which is not described herein, and the implementer may select other prior art to perform the jump point detection, which is not limited in this embodiment.
Impact detection and trip point marking are performed next:
for any Bayesian jump point in the impact detection vector, obtaining all elements from the jump point to the left until the next jump point or the first element of the impact detection vector is touched, and calculating the average value of the elements to be recorded as the left average value of the jump point; obtaining all elements from the jump point to the right until the last element of the next jump point or the impact detection vector is touched, and calculating the average value of the elements to be recorded as the right average value of the jump point; if the left mean value of the jump point is larger than the right mean value, the jump point is a descending jump point, if the left mean value of the jump point is smaller than the right mean value, the jump point is an ascending jump point, and if the left mean value is equal to the right mean value, the jump point is a false detection jump point.
In order to detect all rising jump points and falling jump points of the impact detection vector from left to right and detect the impact on the optical cable, the following example is performed in this embodiment, which is used for explaining the situation that the optical cable is impacted and is not impacted:
as shown in fig. 4, if a jump from a falling point is detectedThe first rising trip point on the right side +.>Monitoring is continued to the right until a falling trip point +.>(e.g. the jump point corresponding to r3 in FIG. 4) is smaller than the first rising jump point to the right>Until all right->To->All data between which the two hops are comprised are marked as detected points;
wherein,、/>、/>、/>respectively represent the impact detection vector +.>Is>、/>、/>、/>Column elements, as shown in FIG. 4, +.>、/>、/>、/>Representing the column of the corresponding jump point in the impact detection vector, the monitored jump points comprise rising jump points and falling jump points, wherein +.>And->Between and->And->Corresponds to a period of time during which the optical cable is not impacted by strong external stress, and +.>Column and->The columns correspond to the time period when the optical cable is impacted by strong external stress once, and the optical cable is regarded as being impacted once.
After a sampling time, the corresponding impact detection vectorThe data whose last sampling instant has been marked as detected point is skipped when a new round of skip point marking is performed, because the mark obtained at the last sampling instant is shifted one bit to the right.
When the optical cable is not monitored to be impacted, the corresponding optical cable structure state is safe; when the optical cable is monitored to be impacted once, further, the embodiment analyzes the pressure data change condition of the optical cable in the impact process, calculates a real-time damage detection value, monitors the structural state of the optical cable based on the real-time damage detection value, and the construction process of the real-time damage detection value is as follows:
calculating an original sampling matrixCorresponds to the->Column to the->Material deformation suction coefficient of all column data between columns +.>And the deflection angle of stress transmission due to deformation>Will->Column to the->The material deformation suction coefficients of each column among the columns are ordered from small columns to large columns to obtain a material deformation suction coefficient change vector +.>And a deviation angle change vector of stress transmission due to deformation>。
Detection ofMaximum number of columns>Detection->Maximum number of columns>Let the number of columns->Equal to->And->Is the maximum value of (a).
Constructing real-time damage detection valuesThe following are provided:
in the method, in the process of the invention,the number of columns corresponding to the impact end time when the optical cable is impacted at this time; />The number of columns corresponding to the moment when the impact force of the optical cable is reduced is +.>Equal to->And->Is selected from the group consisting of a maximum value of (c),respectively the values of the t and t+1 columns in the change vector of the material deformation suction coefficient; />The values of the t and t+1 th columns in the deflection angle change vector of the stress transmission caused by deformation are respectively shown.
、/>As an intermediate function, the aim is to simplify the formulation of real-time damage detection values; />、/>Respectively calculate the values in brackets and the deformation of the materialSuction coefficient variation vector->Maximum, minimum, maximum of absolute value of difference of elements in (a)>Respectively is maximum->Minimum->A first virtual tangential force value of the column of (a); />And->Calculating the value in brackets and the deviation angle change vector of stress transmission caused by deformation respectively>Maximum, minimum, maximum of absolute value of difference of elements in (a)>Respectively is maximum->Minimum->A first virtual tangential force value of the column of (a); 0.001 is to prevent the occurrence of correction with denominator 0; />The first virtual tangential force value in the column of values a, b, c, d, respectively.
The +.f. of the original sampling matrix FNO>The first virtual tangential force value of the column element, expression logic is used for calculating the original sampling matrix +.>Is>Column maximum element->And the second largest element->The arithmetic square root of the sum of squares of (c). />Recorded as the first difference->The second difference value is noted as a second difference value,column number->Is a first virtual tangential force value, +.>Column number->Corresponding acquisition time.
Correction coefficientIs the ratio of the difference between the first virtual tangential force value and the time difference between the beginning moment and the ending moment of the weakening of the impact force, and represents the change strength of the virtual tangential force with the time change when the impact force is weakened. Correction factor->Eliminates the impact force applied to the optical cable and detects the real-time damage value>Influence. The larger the impact force applied to the optical cable, the faster the rebound speed of the deformation of the material, without multiplying by a correction factor +.>Corresponding->The smaller the value is, the rebound speed of the material deformation is irrelevant to the change of the material structure in the optical cable, so that the method is unfavorable for setting the final fault judgment threshold value, and the invention uses correction coefficient ∈ ->To solve this problem.
In (I)>When the impact force is weakened, the change strength of the deflection angle of stress transmission caused by deformation along with the first virtual tangential force is +.>Is when the impact force is increased, and +.>And->The variation degree of the variation of the deflection angle of the stress transmission caused by deformation along with the variation strength of the first virtual tangential force under the condition that the first virtual tangential force is similar, and the difference between the deflection angle and the variation strength represents the variation degree of the deflection angle of the stress transmission caused by deformation along with the variation strength of the first virtual tangential force before and after the impact, and the variation degree is small or even unchanged when the structure of the optical cable is still healthy after the impact, so that>The larger the cable structure, the more likely it is that the cable structure will fail.
In (I)>When the impact force is weakened, the change strength of the deformation suction coefficient of the material along with the first virtual tangential force is +.>Is when the impact force is increased, and +.>And->The variation intensity of the material deformation suction coefficient along with the first virtual tangential force under the condition that the first virtual tangential force is similar, the difference between the two values represents the variation degree of the material deformation suction coefficient along with the variation intensity of the first virtual tangential force before and after the impact, and the variation degree is small or even unchanged when the structure of the optical cable is still healthy after the impact, so that>The larger the cable structure, the more likely it is that the cable structure will fail.
The deformation suction coefficient of the material is changed along with the change intensity variation degree of the first virtual tangential force before and after impactThe degree of variation of the deflection angle of stress transmission due to deformation along with the variation intensity of the first virtual tangential force before and after impact +.>Multiplying and averaging to obtain real-time damage detection value +.>The greater the value, the greater the likelihood of structural health damage to the cable after the impact is received.
The optical cable structure monitoring module 103 is used for combining the real-time damage detection value to complete the monitoring of the health and safety of the optical cable structure.
According to the above process of the embodiment, a distributed optical fiber sensor is installed in the optical cable and data is collected, and then the real-time damage detection value is calculated through analysis. For the condition that the optical cable is not detected to be impacted, the structural state of the optical cable is safe; when detecting that one section of the optical cable is impacted by a strong external force, a real-time damage detection value can be obtained>Further, the present embodiment sets the damage threshold value U when the real-time damage detection value +.>When the optical cable is greater than U, judging that the optical cable is subjected to impact force threatening structural health and safety at the moment, then the optical cable structural state is dangerous, recording the time at the moment and the position of the corresponding distributed optical fiber sensor, sending out an alarm, and reporting that the optical cable section corresponding to the distributed optical fiber sensor has structural failure, so that related operation technicians overhaul and maintain the optical cable. Wherein the setting operator of U can set the setting according to the actual situation, and the setting is +.>。
In summary, according to the above-mentioned process of the present embodiment, the accurate detection of the health condition of the optical cable structure can be realized, and the damage condition of the optical cable structure can be measured. Compared with the traditional means, the data collection method is more convenient and rapid, real-time fault detection is completed, structural damage of the optical fiber can be found in time, the repair speed of the optical fiber fault is increased, and loss caused by the optical fiber fault is reduced.
It should be noted that: the sequence of the embodiment is only for description, and does not represent the advantages and disadvantages of the embodiment. The processes depicted in the accompanying drawings do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.
In this specification, each embodiment is described in a progressive manner, and the same or similar parts of each embodiment are referred to each other, and each embodiment mainly describes differences from other embodiments.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; the technical solutions described in the foregoing embodiments are modified or some of the technical features are replaced equivalently, so that the essence of the corresponding technical solutions does not deviate from the scope of the technical solutions of the embodiments of the present application, and all the technical solutions are included in the protection scope of the present application.
Claims (10)
1. An optical cable structural health and safety monitoring system based on distributed optical fiber sensing, characterized in that the system comprises:
the monitoring data acquisition module is used for installing distributed optical fiber pressure sensors between the optical cable jackets and acquiring pressure data to construct an original sampling matrix which is updated continuously;
the characteristic analysis module is used for constructing material deformation suction coefficients at all moments and a deflection angle of stress transmission caused by deformation according to the relation between pressure data in all column vectors in the original sampling matrix; acquiring an impact detection vector corresponding to the original sampling matrix by combining the sum value of the pressure data of each column vector in the original sampling matrix; acquiring each ascending jump point and each descending jump point of the impact detection vector; determining whether the optical cable is impacted according to each ascending jump point and each descending jump point of the impact detection vector; when the optical cable is determined to be impacted, acquiring a material deformation suction coefficient change vector and a stress transmission deviation angle change vector generated by deformation for the optical cable in an impacting period; constructing a correction coefficient for determining the force of the optical cable when the optical cable is impacted; constructing a real-time damage detection value according to the change vector of the material deformation suction coefficient and the correction coefficient of each element difference and force in the change vector of the deflection angle of stress transmission caused by deformation;
the optical cable structure monitoring module is safe in the structural state of the optical cable when the optical cable is not impacted; when the optical cable is impacted, if the real-time damage detection value is larger than a preset damage threshold value, the optical cable structure state is dangerous, and if the real-time damage detection value is smaller than or equal to the damage threshold value, the optical cable structure state is safe.
2. The distributed fiber optic sensor based cable structural health safety monitoring system of claim 1, wherein said collecting pressure data to construct a continuously updated raw sampling matrix comprises:
the pressure data of all the optical fiber pressure sensors at each sampling moment are used as a column vector, and the column vectors at each preset number of sampling moments form an original sampling matrix;
and deleting the first column vector in the original sampling matrix to form a new original sampling matrix when the column vector at the sampling moment is added, and continuously updating the original sampling matrix by analogy.
3. The distributed fiber optic cable configuration health and safety monitoring system based on fiber optic sensing of claim 2, wherein the material deformation suction coefficient comprises:
for a column vector at each moment, sorting pressure data in the column vector from large to small, calculating a sum of squares of maximum pressure data and squares of second maximum pressure data, and recording the sum as a first virtual tangential force value; calculating the sum of the square of the third maximum pressure data and the square of the minimum pressure data, and recording the sum as a second virtual tangential force value; and taking the ratio of the first virtual tangential force value to the second virtual tangential force value as a material deformation suction coefficient at the corresponding moment.
4. A distributed optical fiber sensing based optical cable structural health and safety monitoring system according to claim 3, wherein the deflection angle of stress transmission due to deformation is specifically:
obtaining a calculation result of dividing the difference value of the maximum pressure data and the second maximum pressure data by the sum value of the maximum pressure data and the second maximum pressure data, and marking the calculation result as the direction of the first virtual tangential force; and obtaining a calculation result of dividing the difference value of the third maximum pressure data and the minimum pressure data by the sum value of the third maximum pressure data and the minimum pressure data, marking the calculation result as the direction of the second virtual tangential force, and taking the difference value of the direction of the first virtual tangential force and the direction of the second virtual tangential force as the radian value of the off angle of stress transmission caused by deformation.
5. The system for monitoring health and safety of a fiber optic cable structure based on distributed optical fiber sensing according to claim 4, wherein the obtaining the impact detection vector corresponding to the original sampling matrix by combining the sum of the pressure data of each column vector in the original sampling matrix comprises:
and calculating the sum value of the column vectors for each column vector in the original sampling matrix, and taking all the sum values as each element of the impact detection vector.
6. The system for monitoring the health and safety of an optical cable structure based on distributed optical fiber sensing according to claim 5, wherein each ascending and descending jump points for obtaining the impact detection vector are specifically:
acquiring each jump point in the impact detection vector by adopting a Bayesian punctuation detection algorithm;
for each hop; acquiring all elements from the jump point to the left until the first element of the next jump point or the impact detection vector is touched, and calculating the average value of all the elements to be recorded as the left average value of the jump point; acquiring all elements from the jump point to the right until the last element of the next jump point or the impact detection vector is touched, and calculating the average value of all elements to be recorded as the right average value of the jump point;
taking the jump point with the left mean value larger than the right mean value as a descending jump point; and taking the jump point with the left mean value smaller than the right mean value as the rising jump point.
7. The distributed fiber optic cable configuration health and safety monitoring system as set forth in claim 6, wherein said determining whether the fiber optic cable is impacted based on each of the ascending and descending hops of the impact detection vector comprises:
for the impact detection vector, from a falling trip pointThe first rising trip point to the right +.>Monitoring is continued to the right until another falling trip point +.>The method meets the following conditions: the value of the other falling jump point is smaller than the first rising jump point on the right sideIf the value of (2) is equal, stopping monitoring, wherein +.>、/>、/>、/>Respectively represent jump points->A column in the impact detection vector;
will rise to jump pointTo the falling jump point->The time period between the two is determined as the optical cable is impacted; descending jump point->To the rising jump point->Drop jump->To the rising jump point->The time period therebetween is determined that the optical cable is not impacted.
8. The system for monitoring the health and safety of an optical cable structure based on distributed optical fiber sensing according to claim 7, wherein the obtaining of the change vector of the material deformation suction coefficient and the change vector of the stress transfer off angle due to deformation comprises:
extracting optical cables in an original sampling matrix to determine material deformation suction coefficients corresponding to each row of data corresponding to the impacted data, and determining a deflection angle of stress transmission caused by deformation;
sorting the material deformation coefficients corresponding to each column from small to large according to the column number to obtain a material deformation suction coefficient change vector; and ordering the off angles of the stress transfer caused by deformation of each row from small to large to obtain the variation vector of the off angles of the stress transfer caused by deformation.
9. The distributed fiber optic cable configuration health and safety monitoring system of claim 8, wherein said constructing a correction factor that determines the force of the cable when impacted comprises:
counting the row of the maximum value of the deformation suction coefficient change vector of the materialAnd the maximum value of the deflection angle change vector of stress transmission due to deformation is +.>Let the number of columns->Equal to->And->Maximum value of (2);
acquiring the number of columns in an original sampling matrixThe difference value between the first virtual tangential force value of the last column of the impacted time period is determined by the corresponding optical cable in the original sampling matrix and is recorded as a first difference value; calculating the number of columnsThe difference value between the corresponding acquisition time and the last row of corresponding acquisition time is recorded as a second difference value; and taking the absolute value of the ratio of the first difference value to the second difference value as a correction coefficient of the force.
10. The distributed optical fiber sensing based optical cable structural health safety monitoring system according to claim 9, wherein the real-time damage detection value is constructed by the following expression:
in the method, in the process of the invention,the number of columns corresponding to the impact end time when the optical cable is impacted at this time; />The number of columns corresponding to the moment when the optical cable receives impact force and begins to be reduced; />Is the correction coefficient of the force; />Respectively the values of the t and t+1 columns in the change vector of the material deformation suction coefficient; />Respectively the values of the t th column and the t+1 th column in the deflection angle change vector of stress transmission caused by deformation; />；；/>、/>Is an intermediate function; />、/>Respectively calculating the numerical value in brackets and the change vector of the deformation suction coefficient of the material +.>Maximum and minimum values of the absolute values of the differences of the elements in (a); />Respectively is maximum->Minimum->A first virtual tangential force value of the column of (a); />And->Calculating the value in brackets and the deviation angle change vector of stress transmission caused by deformation respectively>Maximum and minimum values of the absolute values of the differences of the elements in (a); />Respectively is maximum->Minimum->A first virtual tangential force value of the column of (a); />The first virtual tangential force value in the column of values a, b, c, d, respectively.
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