A method, device and electronic equipment for optical fiber monitoring of internal flaw detection of carbon fiber

Abstract

The present invention provides a method, device and electronic device for monitoring optical fiber for internal flaw detection of carbon fiber. The method comprises: obtaining a first Brillouin frequency shift and a second Brillouin frequency shift of a plurality of points on an optical fiber. Calculating a first Brillouin frequency shift differential. Calculating a second Brillouin frequency shift differential. Calculating the second Brillouin frequency shift differential of each point minus the first Brillouin frequency shift differential as the third Brillouin frequency shift differential of the point. Calculating the difference of the third Brillouin frequency shift differential of each point as the fourth Brillouin frequency shift differential of the point. If the fourth Brillouin frequency shift differential is greater than a preset value, the position of the point is used as the damage position of the carbon fiber. The present invention compares the difference of the Brillouin frequency shift differential under different tensile states based on the first Brillouin frequency shift differential and the second Brillouin frequency shift differential of each point. By determining the Brillouin frequency shift mutation point through differential calculation as the damage position, the influence of noise on the optical signal measurement result can be reduced, and the accuracy of determining the damage position can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon fiber flaw detection, and in particular to a method, a device and an electronic device for monitoring optical fiber for internal flaw detection of carbon fiber. Background Art

[0002] Carbon fiber conductors have obvious advantages in increasing power transmission capacity, reducing sag, reducing line loss and improving line wind resistance. They have been widely used in important power plant transmission lines, large-capacity 500kV lines and other important lines. The core of the carbon fiber conductor is made of carbon fiber impregnated with resin. It has a low elongation and a limited bending radius, and cannot be bent at sharp angles. It is easily damaged during manufacturing, installation and use, and is prone to hidden defects such as microcracks. Optical fibers are usually implanted in the center of the carbon fiber rods of the twisted carbon fiber conductor. When the carbon fiber conductor is damaged by bending, the optical fiber is also damaged. The damage of the carbon fiber conductor can be reflected by detecting the damage of the internal optical fiber.

[0003] Existing detection methods determine the damage of optical fibers by detecting changes in optical signals of optical fibers. For example, reference light is input into the optical fiber to obtain optical signals in the optical fiber under different stretching states, and the position where the optical signal changes greatly is determined as the damage position. Existing technologies generally determine the damage position by comparing the difference of optical signals under different stretching states, which is greatly affected by the noise of the optical signal measurement results and has low accuracy. Summary of the invention

[0004] The embodiments of the present invention provide a method, device and electronic equipment for monitoring optical fiber for internal flaw detection of carbon fiber, so as to solve the problem that the existing method for determining the damage position of carbon fiber is greatly affected by noise and has low accuracy.

[0005] In a first aspect, an embodiment of the present invention provides a method for monitoring internal flaw detection of carbon fiber, comprising:

[0006] A first Brillouin frequency shift and a second Brillouin frequency shift at multiple points on the optical fiber are obtained, wherein the first Brillouin frequency shift is obtained when the optical fiber is subjected to a first tensile force, and the second Brillouin frequency shift is obtained when the optical fiber is subjected to a second tensile force, and the second tensile force is greater than the first tensile force.

[0007] The difference of the first Brillouin frequency shift at each point is calculated as the first Brillouin frequency shift difference at that point.

[0008] The difference of the second Brillouin frequency shift at each point is calculated as the second Brillouin frequency shift difference at that point.

[0009] The second Brillouin frequency shift difference minus the first Brillouin frequency shift difference of each point is calculated as the third Brillouin frequency shift difference of the point, wherein if the first Brillouin frequency shift difference is greater than the second Brillouin frequency shift difference, the third Brillouin frequency shift difference is set to zero.

[0010] The difference of the third Brillouin frequency shift difference of each point is calculated as the fourth Brillouin frequency shift difference of the point.

[0011] If the fourth Brillouin frequency shift difference is greater than a preset value, the position of this point is taken as the damage position of the carbon fiber.

[0012] In a possible implementation, calculating the difference of the first Brillouin frequency shift of each point as the first Brillouin frequency shift difference of the point includes: calculating the difference of the first Brillouin frequency shift of each point based on the following formula:

[0013] d0(x i )=a(f0(x i )-0(x i-1 ))+(1-a)0(x i-1 )

[0014] Among them, d0(x i ) represents the first Brillouin frequency shift difference of the i-th point, d0(x i-1 ) represents the first Brillouin frequency shift difference of the i-1th point, 0(x i ) represents the first Brillouin frequency shift of the ith point, f0(x i-1 ) represents the first Brillouin frequency shift of the i-1th point, i>1, a is a preset constant, 0≤a≤1.

[0015] In a possible implementation, calculating the difference of the second Brillouin frequency shift of each point as the second Brillouin frequency shift difference of the point includes: calculating the difference of the second Brillouin frequency shift of each point based on the following formula:

[0016] d j (x i )=a(f j (x i )- j (x i-1 ))+(1-)d j (x i-1 )

[0017] Among them, d j (x i ) represents the second Brillouin frequency shift difference of the i-th point, d j (x i-1 ) represents the second Brillouin frequency shift difference of the i-1th point, f j (x i ) represents the second Brillouin frequency shift of the i-th point, f j (x i-1 ) represents the second Brillouin frequency shift of the i-1th point, i>1, a is a preset constant, 0≤a≤1.

[0018] In a possible implementation, calculating the difference of the third Brillouin frequency shift difference of each point as the fourth Brillouin frequency shift difference of the point includes: calculating the difference of the third Brillouin frequency shift difference of each point based on the following formula:

[0019] R j (x i ) = d′ j (x i )-d′ j (x i-1 ),x i ∈(0,x1,x2,…,x N-1 ,x N )

[0020] Among them, R j (x i ) represents the fourth Brillouin frequency shift difference of the i-th point, d′ j (x i ) represents the third Brillouin frequency shift difference of the i-th point, d′ j (x i-1 ) represents the third Brillouin frequency shift difference of the i-1th point.

[0021] In a possible implementation, if the fourth Brillouin frequency shift difference is greater than a preset value, taking the position of the point as the damage position of the carbon fiber includes: if the fourth Brillouin frequency shift difference satisfies the following formula, taking the position of the point as the damage position of the carbon fiber:

[0022]

[0023] Among them, R j (x i+1 ) represents the fourth Brillouin frequency shift difference of the i+1th point, and P is a preset value.

[0024] In a possible implementation, after the step of taking the position of the point as the damage position of the carbon fiber if the fourth Brillouin frequency shift difference is greater than a preset value, the method further includes: if among N consecutive points, the fourth Brillouin frequency shift difference of N / 2 points is greater than a preset value, taking the center point of the N consecutive points as the damage position of the carbon fiber.

[0025] In a possible implementation, after the fourth Brillouin frequency shift difference is greater than a preset value, the position of the point is taken as the damage position of the carbon fiber, the method further includes: repeatedly acquiring the second Brillouin frequency shift of multiple points on the optical fiber M times, wherein the second tensile force is different each time. Based on the first Brillouin frequency shift and the second Brillouin frequency shift acquired M times, the M fourth Brillouin frequency shift differences of each point are calculated. If the M / 2 fourth Brillouin frequency shift differences of the current point are greater than the preset value, the position of the point is taken as the damage position of the carbon fiber.

[0026] In a second aspect, an embodiment of the present invention provides a carbon fiber internal flaw detection optical fiber monitoring device, comprising:

[0027] An acquisition module is used to acquire a first Brillouin frequency shift and a second Brillouin frequency shift at multiple points on the optical fiber, wherein the first Brillouin frequency shift is acquired when the optical fiber is subjected to a first tensile force, and the second Brillouin frequency shift is acquired when the optical fiber is subjected to a second tensile force, and the second tensile force is greater than the first tensile force.

[0028] The first calculation module is used to calculate the difference of the first Brillouin frequency shift of each point as the first Brillouin frequency shift difference of the point.

[0029] The second calculation module is used to calculate the difference of the second Brillouin frequency shift of each point as the second Brillouin frequency shift difference of the point.

[0030] The third calculation module is used to calculate the second Brillouin frequency shift difference minus the first Brillouin frequency shift difference of each point as the third Brillouin frequency shift difference of the point, wherein if the first Brillouin frequency shift difference is greater than the second Brillouin frequency shift difference, the third Brillouin frequency shift difference is set to zero.

[0031] The fourth calculation module is used to calculate the difference of the third Brillouin frequency shift difference of each point as the fourth Brillouin frequency shift difference of the point.

[0032] The position determination module is used to determine the position of the point as the damage position of the carbon fiber if the fourth Brillouin frequency shift difference is greater than a preset value.

[0033] In a third aspect, an embodiment of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the processor implements the steps of the method described in the first aspect or any possible implementation manner of the first aspect.

[0034] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in the first aspect or any possible implementation method of the first aspect are implemented.

[0035] The embodiment of the present invention provides a method, device and electronic device for monitoring optical fiber for internal flaw detection of carbon fiber, the method comprising: obtaining a first Brillouin frequency shift and a second Brillouin frequency shift of multiple points on an optical fiber, wherein the first Brillouin frequency shift is obtained when the optical fiber is subjected to a first tensile force, and the second Brillouin frequency shift is obtained when the optical fiber is subjected to a second tensile force, and the second tensile force is greater than the first tensile force. Calculate the difference of the first Brillouin frequency shift of each point as the first Brillouin frequency shift difference of the point. Calculate the difference of the second Brillouin frequency shift of each point minus the first Brillouin frequency shift difference as the third Brillouin frequency shift difference of the point, wherein if the first Brillouin frequency shift difference is greater than the second Brillouin frequency shift difference, the third Brillouin frequency shift difference is set to zero. Calculate the difference of the third Brillouin frequency shift difference of each point as the fourth Brillouin frequency shift difference of the point. If the fourth Brillouin frequency shift difference is greater than a preset value, the position of the point is used as the damage position of the carbon fiber. The present invention compares the difference of Brillouin frequency shift differences under different stretching states by first Brillouin frequency shift differences and second Brillouin frequency shift differences based on multiple points on the optical fiber. Based on the above differences, the Brillouin frequency shift mutation point is determined by differential calculation as the damage position, which can reduce the influence of noise on the optical signal measurement result and improve the accuracy of damage position determination. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 is a schematic diagram of the structure of a carbon fiber conductor provided by an embodiment of the present invention;

[0038] Figure 2 is a flow chart of the implementation of the optical fiber monitoring method for internal flaw detection of carbon fiber provided by an embodiment of the present invention;

[0039] Figure 3 is a schematic structural diagram of a carbon fiber internal flaw detection optical fiber monitoring device provided by an embodiment of the present invention;

[0040] Figure 4 is a schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0043] Figure 1 The schematic diagram of the structure of the carbon fiber conductor provided by the embodiment of the present invention is shown in FIG. Figure 1 As shown in the figure, carbon fiber conductor, also known as carbon fiber composite core conductor, is a conductor that uses carbon fiber to replace the core of ordinary steel core aluminum stranded wire. The center of the carbon fiber conductor is generally a single high-strength heat-resistant carbon fiber composite core, and the outer layer is a stranded aluminum wire. The carbon fiber composite core bears the mechanical force of the conductor, and the stranded aluminum wire is used for conduction.

[0044] The core of the carbon fiber conductor is made of carbon fiber impregnated with resin. It has low elongation, limited bending radius, and cannot be bent at sharp angles. It is easily damaged during manufacturing, installation, and use, and is prone to hidden defects such as microcracks. Optical fiber is usually added to the center of the carbon fiber rod of the stranded carbon fiber conductor. When the carbon fiber conductor is damaged by bending, the optical fiber is also damaged. The damage of the carbon fiber conductor can be reflected by detecting the damage of the internal optical fiber.

[0045] Existing detection methods determine the damage of optical fibers by detecting changes in optical signals of optical fibers. For example, reference light is input into the optical fiber to obtain optical signals in the optical fiber under different stretching states, and the position where the optical signal changes greatly is determined as the damage position. Existing technologies generally determine the damage position by comparing the difference of optical signals under different stretching states, which is greatly affected by the noise of the optical signal measurement results and has low accuracy.

[0046] The embodiments of the present invention provide a method, device and electronic equipment for monitoring optical fiber for internal flaw detection of carbon fiber, so as to solve the problem that the existing method for determining the damage position of carbon fiber is greatly affected by noise and has low accuracy.

[0047] Figure 2 The present invention is a flowchart of an implementation method of an optical fiber monitoring method for internal flaw detection of carbon fiber provided in an embodiment of the present invention.

[0048] Reference Figure 2 , the above method comprises:

[0049] In step S1, a first Brillouin frequency shift and a second Brillouin frequency shift at multiple points on the optical fiber are obtained, wherein the first Brillouin frequency shift is obtained when the optical fiber is subjected to a first tensile force, and the second Brillouin frequency shift is obtained when the optical fiber is subjected to a second tensile force, and the second tensile force is greater than the first tensile force.

[0050] Exemplarily, the optical fiber inside the carbon fiber conductor is connected to the monitoring device. The reference light is input into the optical fiber, and the reflected light generated at each point when the reference light is transmitted in the optical fiber is received to measure the Brillouin frequency shift. The following formula is the relationship between the Brillouin frequency shift and the refractive index of the optical fiber:

[0051]

[0052] Among them, the frequency of the reflected light is slightly lower than the frequency of the incident reference light, and the frequency difference V B is equal to the frequency of the radiating phonon. This frequency difference is called the Brillouin frequency shift. When only backscattering occurs, the Brillouin frequency shift can be expressed by the refractive index n, the acoustic velocity V a , and the vacuum light wavelength λ is calculated.

[0053] Due to stress concentration at the damaged position, the refractive index of the optical fiber at this position changes greatly compared with other normal positions. When stretched, the refractive index of the optical fiber at the damaged position also changes greatly.

[0054] Under different tensile stress states, the same reference light is input to obtain corresponding Brillouin frequency shift information. For example, a first Brillouin frequency shift is obtained when the optical fiber is subjected to a first tensile stress, and a second Brillouin frequency shift is obtained when the optical fiber is subjected to a second tensile stress.

[0055] Exemplarily, the first tensile force is zero, that is, when the carbon fiber wire is in a relaxed state, the carbon fiber wire is only stretched by its own gravity. The second tensile force is greater than the first tensile force. Applying a larger tensile force to the carbon fiber wire can simulate the force on the carbon fiber wire in an ice-covered state, and potential damage defects can be found. Exemplarily, the second tensile force can be multiple different tensile forces, that is, multiple second tensile forces are applied to the optical fiber, each time the second tensile force is different, and multiple groups of second Brillouin frequency shifts are measured accordingly.

[0056] Exemplarily, the first Brillouin frequency shift of each point on the optical fiber can be expressed as:

[0057] f0(x),x∈(0,x1,x2,…,x N-1 ,x N )

[0058] Where f0(x) represents the first Brillouin frequency shift at point x on the optical fiber. x represents the position of each point on the optical fiber. When x is 0, it represents the input end of the optical fiber, that is, the starting end of the carbon fiber conductor. x is x N Indicates the output end of the optical fiber, that is, the end position of the carbon fiber conductor.

[0059] Exemplarily, the second Brillouin frequency shift of each point on the optical fiber can be expressed as:

[0060] f j (x),x∈(0,x1,x2,…,x N-1 ,x N ),j∈(1,2,…,M)

[0061] Among them, f j (x) represents the second Brillouin frequency shift at point x on the optical fiber, and j represents the number of different second tensile forces applied to the optical fiber. Exemplarily, M is 1, that is, only one second tensile force is applied to the optical fiber to obtain a set of second Brillouin frequency shifts. Exemplarily, M is 3, that is, three different second tensile forces are applied to the optical fiber to obtain three sets of second Brillouin frequency shifts corresponding to each second tensile force.

[0062] In step S2, the difference of the first Brillouin frequency shift at each point is calculated as the first Brillouin frequency shift difference at the point.

[0063] Exemplarily, the difference of the first Brillouin frequency shift is the first Brillouin frequency shift of a point on the optical fiber minus the first Brillouin frequency shift of the previous adjacent point. Exemplarily, the difference of the first Brillouin frequency shift is the first Brillouin frequency shift of a point on the optical fiber minus the first Brillouin frequency shift of the next adjacent point.

[0064] In a possible implementation, calculating the difference of the first Brillouin frequency shift of each point as the first Brillouin frequency shift difference of the point includes: calculating the difference of the first Brillouin frequency shift of each point based on the following formula:

[0065] d0(x i )=a(f0(x i )-0(x i-1 ))+(1-a)0(x i-1 )

[0066] Among them, d0(x i ) represents the first Brillouin frequency shift difference of the i-th point, d0(x i-1 ) represents the first Brillouin frequency shift difference of the i-1th point, 0(x i ) represents the first Brillouin frequency shift of the ith point, f0(x i-1 ) represents the first Brillouin frequency shift of the i-1th point, i>1, a is a preset constant, 0≤a≤1. The difference of the first Brillouin frequency shift corresponding to the current point and the difference of the first Brillouin frequency shift corresponding to the previous adjacent point are weightedly added to obtain the first Brillouin frequency shift difference corresponding to the point.

[0067] In step S3, the difference of the second Brillouin frequency shift at each point is calculated as the second Brillouin frequency shift difference at the point.

[0068] Exemplarily, the difference of the second Brillouin frequency shift is the second Brillouin frequency shift of a point on the optical fiber minus the second Brillouin frequency shift of the last adjacent point. Exemplarily, the difference of the second Brillouin frequency shift is the second Brillouin frequency shift of a point on the optical fiber minus the second Brillouin frequency shift of the next adjacent point.

[0069] In a possible implementation, calculating the difference of the second Brillouin frequency shift of each point as the second Brillouin frequency shift difference of the point includes: calculating the difference of the second Brillouin frequency shift of each point based on the following formula:

[0070] d j (x i )=a(f j (x i )- j (x i-1 ))+(1-)d j (x i-1 )

[0071] Among them, d j (x i ) represents the second Brillouin frequency shift difference of the i-th point, d j (x i-1 ) represents the second Brillouin frequency shift difference of the i-1th point, f j (x i ) represents the second Brillouin frequency shift of the i-th point, f j (x i-1 ) represents the second Brillouin frequency shift of the i-1th point, i>1, a is a preset constant, 0≤a≤1. The difference of the second Brillouin frequency shift corresponding to the current point and the difference of the second Brillouin frequency shift corresponding to the previous adjacent point are weightedly added to obtain the second Brillouin frequency shift difference corresponding to the point.

[0072] In step S4, the second Brillouin frequency shift difference minus the first Brillouin frequency shift difference of each point is calculated as the third Brillouin frequency shift difference of the point, wherein if the first Brillouin frequency shift difference is greater than the second Brillouin frequency shift difference, the third Brillouin frequency shift difference is set to zero.

[0073] Exemplarily, the third Brillouin frequency shift difference is d j (x i )-0(x i ), and if d0(x i )> j (x i ), then d j (x i )=0.

[0074] In step S5, the difference of the third Brillouin frequency shift difference of each point is calculated as the fourth Brillouin frequency shift difference of the point.

[0075] Exemplarily, the difference of the third Brillouin frequency shift differential is the third Brillouin frequency shift differential corresponding to a point on the optical fiber minus the third Brillouin frequency shift differential of the previous adjacent point. Exemplarily, the difference of the third Brillouin frequency shift differential is the third Brillouin frequency shift differential corresponding to a point on the optical fiber minus the third Brillouin frequency shift differential of the next adjacent point.

[0076] In a possible implementation, calculating the difference of the third Brillouin frequency shift difference of each point as the fourth Brillouin frequency shift difference of the point includes: calculating the difference of the third Brillouin frequency shift difference of each point based on the following formula:

[0077] R j (x i ) = d′ j (x i )-d′ j (x i-1 ),x i ∈(0,x1,x2,…,x N-1 ,x N )

[0078] Among them, R j (x i ) represents the fourth Brillouin frequency shift difference of the i-th point, d′ j (x i ) represents the third Brillouin frequency shift difference of the i-th point, d′ j (x i-1 ) represents the third Brillouin frequency shift difference of the i-1th point.

[0079] In step S6, if the fourth Brillouin frequency shift difference is greater than a preset value, the position of the point is taken as the damage position of the carbon fiber.

[0080] The fourth Brillouin frequency shift difference indicates the change of the Brillouin frequency shift of the same point on the optical fiber under different tensile forces. When the change of the above Brillouin frequency shift is large, it means that the refractive index of the optical fiber at this point has changed greatly, that is, it means that the optical fiber at this point is a damaged position.

[0081] In a possible implementation, if the fourth Brillouin frequency shift difference is greater than a preset value, taking the position of the point as the damage position of the carbon fiber includes: if the fourth Brillouin frequency shift difference satisfies the following formula, taking the position of the point as the damage position of the carbon fiber:

[0082]

[0083] Among them, R j(x i+1 ) represents the fourth Brillouin frequency shift difference of the i+1th point, and P is a preset value. When the fourth Brillouin frequency shift difference of a certain point is greater than 0 and greater than P, and the fourth Brillouin frequency shift difference of the next adjacent point of the current point is less than 0, it means that the current point corresponds to a peak of the fourth Brillouin frequency shift difference curve.

[0084] The embodiment of the present invention compares the difference of Brillouin frequency shift differences under different stretching states by first Brillouin frequency shift differences and second Brillouin frequency shift differences based on multiple points on the optical fiber. Based on the above differences, the Brillouin frequency shift mutation point is determined by differential calculation as the damage position, which can reduce the influence of noise on the Brillouin frequency shift (i.e., optical signal) measurement results and improve the accuracy of damage position determination.

[0085] In a possible implementation, if the fourth Brillouin frequency shift difference is greater than a preset value, then the position of the point is taken as the damage position of the carbon fiber, and it also includes: if the fourth Brillouin frequency shift difference of N / 2 points among N consecutive points is greater than a preset value, then the center point of the N consecutive points is taken as the damage position of the carbon fiber.

[0086] After repeating step S6 to obtain multiple points where the fourth Brillouin frequency shift difference is greater than the preset value, if the fourth Brillouin frequency shift difference of more than half of the multiple consecutive points is greater than the preset value, it means that the damaged length of the optical fiber section is long, and the damage points are numerous and concentrated. The center point of the above multiple consecutive points can be used as the carbon fiber damage position to reduce the data points representing the damage position, so as to improve the efficiency of subsequent data processing.

[0087] In a possible implementation, if the fourth Brillouin frequency shift difference is greater than a preset value, then the position of the point is taken as the damage position of the carbon fiber, and further includes: repeatedly acquiring the second Brillouin frequency shift of multiple points on the optical fiber M times, wherein the second tensile force is different each time. Based on the first Brillouin frequency shift and the second Brillouin frequency shift acquired M times, the M fourth Brillouin frequency shift differences of each point are calculated. If the M / 2 fourth Brillouin frequency shift differences of the current point are greater than the preset value, the position of the point is taken as the damage position of the carbon fiber.

[0088] Exemplarily, a second tensile force of different magnitudes is applied to the optical fiber M times to obtain the second Brillouin frequency shift corresponding to each second tensile force. Based on the first Brillouin frequency shift of each point on the optical fiber and the M groups of first Brillouin frequency shifts in turn, the M fourth Brillouin frequency shift differences of each point are calculated through the above steps S2-S6. If among the M fourth Brillouin frequency shift differences of a certain point, M / 2 fourth Brillouin frequency shift differences are greater than a preset value, the position of the point is used as the carbon fiber damage position. The embodiment of the present invention can reduce the damage position judgment error caused by the Brillouin frequency shift measurement error, determine the damage position through the second Brillouin frequency shift under different tensile forces, and improve the accuracy of damage position determination.

[0089] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0090] The following is an embodiment of the device of the present invention. For details not described in detail therein, reference may be made to the corresponding method embodiment described above.

[0091] Figure 3 FIG. 1 is a schematic diagram of the structure of a carbon fiber internal flaw detection optical fiber monitoring device provided by an embodiment of the present invention. For the sake of convenience, only the parts related to the embodiment of the present invention are shown, which are described in detail as follows: Figure 3 As shown, the carbon fiber internal flaw detection optical fiber monitoring device 2 includes:

[0092] The acquisition module 21 is used to acquire the first Brillouin frequency shift and the second Brillouin frequency shift of multiple points on the optical fiber, wherein the first Brillouin frequency shift is acquired when the optical fiber is subjected to a first tensile force, and the second Brillouin frequency shift is acquired when the optical fiber is subjected to a second tensile force, and the second tensile force is greater than the first tensile force.

[0093] The first calculation module 22 is used to calculate the difference of the first Brillouin frequency shift of each point as the first Brillouin frequency shift difference of the point.

[0094] The second calculation module 23 is used to calculate the difference of the second Brillouin frequency shift of each point as the second Brillouin frequency shift difference of the point.

[0095] The third calculation module 24 is used to calculate the second Brillouin frequency shift difference minus the first Brillouin frequency shift difference of each point as the third Brillouin frequency shift difference of the point, wherein if the first Brillouin frequency shift difference is greater than the second Brillouin frequency shift difference, the third Brillouin frequency shift difference is set to zero.

[0096] The fourth calculation module 25 is used to calculate the difference of the third Brillouin frequency shift difference of each point as the fourth Brillouin frequency shift difference of the point.

[0097] The position determination module 26 is used to determine the position of the point as the damage position of the carbon fiber if the fourth Brillouin frequency shift difference is greater than a preset value.

[0098] The embodiment of the present invention compares the difference of Brillouin frequency shift differences under different stretching states by first Brillouin frequency shift differences and second Brillouin frequency shift differences based on multiple points on the optical fiber. Based on the above differences, the Brillouin frequency shift mutation point is determined by differential calculation as the damage position, which can reduce the influence of noise on the Brillouin frequency shift (i.e., optical signal) measurement results and improve the accuracy of damage position determination.

[0099] In a possible implementation, calculating the difference of the first Brillouin frequency shift of each point as the first Brillouin frequency shift difference of the point includes: calculating the difference of the first Brillouin frequency shift of each point based on the following formula:

[0100] d0(x i )=a(f0(x i )-f0(x i-1 ))+(1-a)d0(x i-1 )

[0101] Among them, d0(x i ) represents the first Brillouin frequency shift difference of the i-th point, d0(x i-1 ) represents the first Brillouin frequency shift difference of the i-1th point, f0(x i ) represents the first Brillouin frequency shift of the ith point, f0(x i-1 ) represents the first Brillouin frequency shift of the i-1th point, i>1, a is a preset constant, 0≤a≤1.

[0102] In a possible implementation, calculating the difference of the second Brillouin frequency shift of each point as the second Brillouin frequency shift difference of the point includes: calculating the difference of the second Brillouin frequency shift of each point based on the following formula:

[0103] d j (x i )=a(f j (x i )-f j (x i-1 ))+(1-a)d j (x i-1 )

[0104] Among them, d j (x i ) represents the second Brillouin frequency shift difference of the i-th point, d j (x i-1 ) represents the second Brillouin frequency shift difference of the i-1th point, f j (x i) represents the second Brillouin frequency shift of the i-th point, f j (x i-1 ) represents the second Brillouin frequency shift of the i-1th point, i>1, a is a preset constant, 0≤a≤1.

[0105] In a possible implementation, calculating the difference of the third Brillouin frequency shift difference of each point as the fourth Brillouin frequency shift difference of the point includes: calculating the difference of the third Brillouin frequency shift difference of each point based on the following formula:

[0106] R j (x i ) = d′ j (x i )-d′ j (x i-1 ),x i ∈(0,x1,x2,…,x N-1 ,x N )

[0107] Among them, R j (x i ) represents the fourth Brillouin frequency shift difference of the i-th point, d′ j (x i ) represents the third Brillouin frequency shift difference of the i-th point, d′ j (x i-1 ) represents the third Brillouin frequency shift difference of the i-1th point.

[0108] In a possible implementation, if the fourth Brillouin frequency shift difference is greater than a preset value, taking the position of the point as the damage position of the carbon fiber includes: if the fourth Brillouin frequency shift difference satisfies the following formula, taking the position of the point as the damage position of the carbon fiber:

[0109]

[0110] Among them, R j (x i+1 ) represents the fourth Brillouin frequency shift difference of the i+1th point, and P is a preset value.

[0111] In a possible implementation, if the fourth Brillouin frequency shift difference is greater than a preset value, then the position of the point is taken as the damage position of the carbon fiber, and it also includes: if the fourth Brillouin frequency shift difference of N / 2 points among N consecutive points is greater than a preset value, then the center point of the N consecutive points is taken as the damage position of the carbon fiber.

[0112] In a possible implementation, if the fourth Brillouin frequency shift difference is greater than a preset value, then the position of the point is taken as the damage position of the carbon fiber, and further includes: repeatedly acquiring the second Brillouin frequency shift of multiple points on the optical fiber M times, wherein the second tensile force is different each time. Based on the first Brillouin frequency shift and the second Brillouin frequency shift acquired M times, the M fourth Brillouin frequency shift differences of each point are calculated. If the M / 2 fourth Brillouin frequency shift differences of the current point are greater than the preset value, the position of the point is taken as the damage position of the carbon fiber.

[0113] Figure 4 Schematic diagram of an electronic device provided by an embodiment of the present invention. Figure 4 As shown, the electronic device 3 of this embodiment includes: a processor 30, a memory 31, and a computer program 32 stored in the memory 31 and executable on the processor 30. When the processor 30 executes the computer program 32, the steps in the above-mentioned various carbon fiber internal flaw detection optical fiber monitoring method embodiments are implemented, such as Figure 2 Alternatively, when the processor 30 executes the computer program 32, the functions of each module / unit in the above-mentioned device embodiments are realized, for example Figure 3 The functions of modules 21 to 26 are shown.

[0114] Exemplarily, the computer program 32 may be divided into one or more modules / units, which are stored in the memory 31 and executed by the processor 30 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 32 in the electronic device 3. For example, the computer program 32 may be divided into Figure 3 Modules 21 to 26 are shown.

[0115] The electronic device 3 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The electronic device 3 may include, but is not limited to, a processor 30 and a memory 31. Those skilled in the art will appreciate that Figure 4 It is only an example of the electronic device 3 and does not constitute a limitation of the electronic device 3. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the electronic device may also include input and output devices, network access devices, buses, etc.

[0116] The processor 30 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0117] The memory 31 may be an internal storage unit of the electronic device 3, such as a hard disk or memory of the electronic device 3. The memory 31 may also be an external storage device of the electronic device 3, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 3. Further, the memory 31 may also include both an internal storage unit and an external storage device of the electronic device 3. The memory 31 is used to store the computer program and other programs and data required by the electronic device. The memory 31 may also be used to temporarily store data that has been output or is to be output.

[0118] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0119] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0120] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0121] In the embodiments provided by the present invention, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0122] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0123] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0124] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, it can implement the steps of the above-mentioned various carbon fiber internal flaw detection optical fiber monitoring method embodiments. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (Read-Only wave signal, telecommunication signal and software distribution medium, etc.

[0125] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for monitoring internal flaw detection of carbon fiber, characterized in that: The method comprises: Obtaining the first Brillouin frequency shift and the second Brillouin frequency shift of multiple points on the optical fiber, wherein the first Brillouin frequency shift is obtained when the optical fiber is subjected to a first tensile force, and the second Brillouin frequency shift is obtained when the optical fiber is subjected to a second tensile force, and the second tensile force is greater than the first tensile force; calculating the difference of the first Brillouin frequency shift of each point as the first Brillouin frequency shift difference of the point; calculating the difference of the second Brillouin frequency shift of each point minus the first Brillouin frequency shift difference as the third Brillouin frequency shift difference of the point, wherein if the first Brillouin frequency shift difference is greater than the second Brillouin frequency shift difference, the third Brillouin frequency shift difference is set to zero; calculating the difference of the third Brillouin frequency shift difference of each point as the fourth Brillouin frequency shift difference of the point; If the fourth Brillouin frequency shift difference is greater than a preset value, the position of the point is taken as the damage position of the carbon fiber.

2. The method for monitoring internal flaw detection of carbon fiber according to claim 1, characterized in that: The calculating the difference of the first Brillouin frequency shift of each point as the first Brillouin frequency shift difference of the point includes: The difference of the first Brillouin frequency shift at each point is calculated based on the following formula: d0(x i )=a(f0(x i )-f0(x i-1 ))+(1-a)d0(x i-1 ) Among them, d0(x i ) represents the first Brillouin frequency shift difference of the i-th point, d0(x i-1 ) represents the first Brillouin frequency shift difference of the i-1th point, f0(x i ) represents the first Brillouin frequency shift of the ith point, f0(x i-1 ) represents the first Brillouin frequency shift of the i-1th point, i>1, a is a preset constant, 0≤a≤1.

3. The method for monitoring internal flaw detection of carbon fiber according to claim 2, characterized in that: The calculating the difference of the second Brillouin frequency shift of each point as the second Brillouin frequency shift difference of the point includes: The difference of the second Brillouin frequency shift at each point is calculated based on the following formula: d j (x i )=a(f j (x i )-f j (x i-1 ))+(1-a)d j (x i-1 ) Among them, d j (x i ) represents the second Brillouin frequency shift difference of the i-th point, d j (x i-1 ) represents the second Brillouin frequency shift difference of the i-1th point, f j (x i ) represents the second Brillouin frequency shift of the ith point, f j (x i-1 ) represents the second Brillouin frequency shift of the i-1th point, i>1, a is a preset constant, 0≤a≤1.

4. The method for monitoring internal flaw detection of carbon fiber according to claim 3, characterized in that: The calculating the difference of the third Brillouin frequency shift difference of each point as the fourth Brillouin frequency shift difference of the point includes: The difference of the third Brillouin frequency shift difference at each point is calculated based on the following formula: R j (x i )=d j ′(x i )-d j ′(x i-1 ),x i ∈(0,x1,x2,…,x N-1 ,x N ) Among them, R j (x i ) represents the fourth Brillouin frequency shift difference of the i-th point, d j ′(x i ) represents the third Brillouin frequency shift difference of the i-th point, d j ′ (x i-1 ) represents the third Brillouin frequency shift difference of the i-1th point.

5. The method for monitoring internal flaw detection of carbon fiber according to claim 4, characterized in that: If the fourth Brillouin frequency shift difference is greater than a preset value, taking the position of the point as the damage position of the carbon fiber includes: If the fourth Brillouin frequency shift difference meets the following formula, the position of this point is taken as the carbon fiber damage position: Among them, R j (x i+1 ) represents the fourth Brillouin frequency shift difference of the i+1th point, and P is a preset value.

6. The method for monitoring internal flaw detection of carbon fiber according to claim 1, characterized in that: After the step of taking the position of the point as the damage position of the carbon fiber if the fourth Brillouin frequency shift difference is greater than the preset value, the method further includes: If the fourth Brillouin frequency shift difference of N / 2 points among the consecutive N points is greater than a preset value, the center point of the consecutive N points is taken as the carbon fiber damage position.

7. The method for monitoring internal flaw detection of carbon fiber according to claim 1, characterized in that: After the step of taking the position of the point as the damage position of the carbon fiber if the fourth Brillouin frequency shift difference is greater than the preset value, the method further includes: Repeating M times to obtain the second Brillouin frequency shift of multiple points on the optical fiber, wherein the second tensile force during each acquisition is different; Based on the first Brillouin frequency shift and the second Brillouin frequency shift obtained by repeating M times, calculating M fourth Brillouin frequency shift differences at each point; If the M / 2 fourth Brillouin frequency shift difference of the current point is greater than a preset value, the position of the point is taken as the carbon fiber damage position.

8. A carbon fiber internal flaw detection optical fiber monitoring device, characterized in that: include: an acquisition module, configured to acquire a first Brillouin frequency shift and a second Brillouin frequency shift at a plurality of points on the optical fiber, wherein the first Brillouin frequency shift is acquired when the optical fiber is subjected to a first tensile force, and the second Brillouin frequency shift is acquired when the optical fiber is subjected to a second tensile force, and the second tensile force is greater than the first tensile force; A first calculation module, used for calculating the difference of the first Brillouin frequency shift of each point as the first Brillouin frequency shift difference of the point; A second calculation module, used for calculating the difference of the second Brillouin frequency shift of each point as the second Brillouin frequency shift difference of the point; a third calculation module, used for calculating the second Brillouin frequency shift difference minus the first Brillouin frequency shift difference of each point as the third Brillouin frequency shift difference of the point, wherein if the first Brillouin frequency shift difference is greater than the second Brillouin frequency shift difference, the third Brillouin frequency shift difference is set to zero; A fourth calculation module, used for calculating the difference of the third Brillouin frequency shift difference of each point as the fourth Brillouin frequency shift difference of the point; The position determination module is used to determine the position of the point as the damage position of the carbon fiber if the fourth Brillouin frequency shift difference is greater than a preset value.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for monitoring internal flaws of carbon fiber according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for monitoring internal flaws of carbon fiber according to any one of claims 1 to 7 are implemented.

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