CN105021330A - Carbon fiber enhanced intelligent steel strand, pre-stress monitoring device and method - Google Patents
Carbon fiber enhanced intelligent steel strand, pre-stress monitoring device and method Download PDFInfo
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Abstract
The invention discloses a carbon fiber enhanced intelligent steel strand, a pre-stress monitoring device and a method, wherein the intelligent steel strand comprises an intelligent sensing rib (1), a tinsel sheet (4) and carbon fiber thread (5); the pre-stress monitoring device comprises a tunable laser (6), a 1:99 beam splitter (7), an external clock trigger system (23) based on Michelson interferometer, a main interferometer system (24) based on Mach-Zehnder interferometer, an acquisition and processing apparatus (22) and a stress generation apparatus (21). According to the invention, the steel strand is monitored in a continuous strain distributed way; the length of the monitored intelligent steel strand is 5m; the positioning precision of the strain distribution is 2mm; the sensing sensitivity is 1.2pm/mu epsilon; the dynamic scope of the strain response is 3 mu epsilon-150 mu epsilon; continuous monitoring can be realized and the strain distribution information of the intelligent steel strand can be obtained at real time.
Description
Technical field
The present invention relates to distributing optical fiber sensing Instrument technology field, be specifically related to a kind of high purity carbon fiberreinforced intelligent steel strand based on optical frequency domain reflection technology and answer monitoring device and method in advance.
Background technology
Along with the sustainable development of Chinese national economy, the input proportion of Large Infrastructure Projects increases year by year.But for some large-scale infrastructure, its structure mostly is xoncrete structure.For xoncrete structure facility, the compressor wire be made up of steel strand wires is very important, the effect that it provides necessary prestress to produce to balance external loads structure.In prestressed reinforced concrete construction, under compressor wire is generally in condition of high ground stress, its performance has significant impact to the security of prestressed reinforced concrete construction and permanance.Loss of prestress can reduce splitting resistance and the rigidity of concrete component, causes component to ftracture time serious, continues downwarp phenomenon, also can produce permanance and have a strong impact on, cause potential safety hazard.
Optical frequency domain reflection technology (OFDR, Optical Frequency Domain Reflectory) by means of it, there is noncontact damage, signal noise is little, fast response time, measurement range are large, signal to noise ratio (S/N ratio) is high, by advantages such as light intensity variable effects, obtain investigation and application widely.This technology adopts high coherent laser to carry out high speed and linear wave long scan, utilizes light that reference arm is reflected by faraday's catoptron and single-mode fiber back-scattering light to interfere.Because the light path of the two is different, interfere end to be actually different frequency two-beam and interfere, form beat frequency.By detecting different beat signals, the back rayleigh scattering information of sensor fibre diverse location just can be detected.
Rayleigh scattering in optical fiber is caused by the refractive index random variation of optical fiber own, and the amplitude of scattering is the function of measuring distance.Owing to there is the character of this more stable stochastic distribution in optical fiber, so optical fiber can regard a kind of longer weak fiber Bragg grating with random period as.And when being subject to extraneous stress stimulation, the spectrum of the back rayleigh scattering signal of optical fiber will drift about, the size of its drift value is directly proportional to the strain suffered by optical fiber.By the spectral drift amount of the back rayleigh scattering signal of detection fiber, the strained distributed intelligence of optical fiber just can be calculated.
Summary of the invention
Based on above-mentioned prior art Problems existing, the present invention proposes a kind of high purity carbon fiberreinforced intelligent steel strand, prestressed monitoring device and method, propose a kind of intelligent steel strand structure, and achieve the prestressed monitoring device utilizing aforementioned intelligent strand structure based on optical frequency domain reflection technology, and propose a kind of prestressed monitoring method.
The invention discloses a kind of high purity carbon fiberreinforced intelligent steel strand for prestressed monitoring, the composition structure of this intelligent steel strand comprises intelligent sensing muscle 1 and tinsel 4 and carbon fiber wire 5; Wherein: intelligent sensing muscle 1 comprises single-mode fiber 2 and light armour optical cable 3, and single-mode fiber 2 is the sensing element of the strain regime of monitoring intelligent steel strand wires, has ultraviolet light coating; Light armour optical cable 3 is at the outer tightly attached tight cover material of multicore of a branch of single-mode fiber 2; Tinsel 4 as cementing medium, is close between intelligent sensing muscle 1 and carbon fiber wire 5 with high ductile metal paillon foil, to keep the cooperative transformation between intelligent sensing muscle 1 and outer carbon fiber wire 5; Carbon fiber wire 5, as primary structure member, forms by carbon fiber wire spiral fashion is stranded, and is close on tinsel 4, stretches or compress it, makes it to produce strain.
The invention allows for one and adopt prestressed monitoring device, this strain monitoring device comprises tunable laser 6,1:99 beam splitter 7, the external clock triggering system 23 based on Michelson interferometer, the main interferometer system 24 based on Mach-Zehnder interferometer, acquisition and processing device 22 and answers force generating apparatus 18; The described external clock triggering system 23 based on Michelson interferometer comprises the first circulator 8,50:50 coupling mechanism 9, first faraday rotation mirror 11, second faraday rotation mirror 12, postpones optical fiber 10 and the first balanced detector 13, for optical frequency spacing samplings such as realizations, suppress the nonlinear sweep of light source; The described main interferometer system 24 based on Mach-Zehnder interferometer comprises the 2nd 50:50 coupling mechanism 14, the 3rd 50:50 coupling mechanism 17, Polarization Controller 15, second circulator 16, second balanced detector 18; Described 1:99 beam splitter 7 also comprises two ports, and namely the first light divides beam port 71, second light to divide beam port 72 and the 3rd light to divide beam port 72; First circulator 8 also comprises two ports, i.e. the first circulator port 1 and the first circulator port 2 82; Second circulator 16 also comprises three ports, i.e. the second circulator port one 161, second circulator port 2 162 and the second circulator port 3 163; One 50:50 coupling mechanism 9 also comprises four ports, i.e. a 50:50 Coupler ports 1, a 50:50 Coupler ports 2 92, a 50:50 Coupler ports 3 93 and a 50:50 Coupler ports 4 94; 2nd 50:50 coupling mechanism 14 also comprises four ports, i.e. the 2nd 50:50 Coupler ports 1, the 2nd 50:50 Coupler ports 2 142, a 50:50 Coupler ports 3 143 and the 2nd 50:50 Coupler ports 4 144; 31 50:50 coupling mechanisms 17 also comprise four ports, i.e. the 3rd 50:50 Coupler ports 1, the 3rd 50:50 Coupler ports 2 172, the 3rd 50:50 Coupler ports 3 173 and the 3rd 50:50 Coupler ports 4 174; Wherein:
The emergent light of described tunable laser 6 divides beam port 71 to enter by the first light of described 1:99 beam splitter 7, and divides beam port 73 to be assigned to the described external clock triggering system 23 based on Michelson interferometer and the described main interferometer system 24 based on Mach-Zehnder interferometer from second of described 1:99 beam splitter 7 the smooth beam splitting end 72 and the 3rd light respectively with the ratio of 1:99;
Described based in the external clock triggering system 23 of Michelson interferometer: a road enters from the first coupling port of a 50:50 coupling mechanism 9 from the light of 1:99 beam splitter 7, from a 50:50 Coupler ports 2 92 and 50:50 Coupler ports 3 93 outgoing of a 50:50 coupling mechanism 9, the first faraday rotation mirror 11 and the second faraday rotation mirror 12 that are arranged at the two-arm of the external clock triggering system 18 based on Michelson interferometer respectively reflect, and turn back to the second coupling port and the 3rd coupling port of a 50:50 coupling mechanism 9, two-beam interferes in a 50:50 coupling mechanism 9, from the first Coupler ports 1 and the output of the second Coupler ports two (92) of a 50:50 coupling mechanism 9, the interference light that one 50:50 coupling mechanism 4 first coupling port returns enters from the first circulator port 2 82 of the first circulator 8, then exports from the first circulator port 2 83, postponing optical fiber 10 is arranged on the input light path of the second faraday rotation mirror 12, for realizing the beat frequency interference of non-equiarm, first balanced detector 13 is converted to electric signal for the light signal external clock triggering system 23 based on Michelson interferometer produced, and exports acquisition and processing device 22 to,
Described based in the main interferometer system 24 of Mach-Zehnder interferometer: another road enters from the 2nd 50:50 Coupler ports 1 of the 2nd 50:50 coupling mechanism 14 from the light of 1:99 beam splitter 7, enter Polarization Controller 15 through the 2nd 50:50 Coupler ports 2 142, and enter the second circulator port 1 of the second circulator 16 in test arm through the 2nd 50:50 Coupler ports 3 143; Light enters the sensing optic cable 20 intelligent steel strand 19 from the second circulator port 1 of the second circulator 16, and the back-scattering light of sensing optic cable 20 enters from the second circulator port 1 of the second circulator 16, exports from the second circulator port 2 162; The back-scattering light exported from Polarization Controller 15 and the second circulator port 2 162 enters the 3rd 50:50 coupling mechanism 17 by the 3rd 50:50 Coupler ports 1 of the 3rd 50:50 coupling mechanism 17 and the 3rd 50:50 Coupler ports 2 172 and carries out conjunctions bundle, forms beat frequency interference and from the 3rd 50:50 Coupler ports 3 173 of the 3rd 50:50 coupling mechanism 12 and the output of the 3rd 50:50 Coupler ports 4 174; Second balanced detector 18: the light signal for the main interferometer system 19 based on Mach-Zehnder interferometer being produced is converted to electric signal, second balanced detector 18 is converted to electric signal for the light signal main interferometer system 25 based on Mach-Zehnder interferometer produced, and exports acquisition and processing device 22 to; Answer force generating apparatus 21 reverse cyclic loadings, produce the tension to intelligent steel strand 19 or compressive stress.
And the present invention has reintroduced a kind of prestressed monitoring method, comprises the following steps:
Step one, utilize described prestressed monitoring device to carry out the measurement of single-mode fiber back rayleigh scattering signal in twice pair of intelligent steel strand, obtain two signals, the back rayleigh scattering signal namely under static back rayleigh scattering reference signal and stress stimulation;
Step 2, Fast Fourier Transform (FFT) is carried out to above-mentioned two groups of signals, make main interference signal be converted to distance domain from wavelength domain;
Step 3, the local distance domain information of an employing Moving Window to whole optical cable scan, and obtain the distance domain information of this locality of whole optical cable, and whole distance domain information is divided into the equal length backscatter signals of diverse location;
Step 4, inverse Fourier transform is done to the signal of same position in two groups of signals simultaneously, make it to revert to light frequency-region signal;
Step 5, make computing cross-correlation to the light frequency-region signal of each position successively, the position that spectral drift occurs is the position that there is strain, and the position of generation then can be thought not strain in the position that there is not spectral drift;
In step 6, calculating optical cable, the Rayleigh Scattering Spectra drift value of each position, can demarcate the strain size suffered by corresponding position;
Step 7, obtain the Strain Distribution information of each position in optical cable.
Compared with prior art, the invention has the beneficial effects as follows:
Adopt technology of the present invention can realize the monitoring of steel strand wires continuous Strain Distribution formula, overcome in current monitoring technology the technical matters that cannot realize the monitoring within the scope of the strained entire length of steel strand wires; The length of the intelligent steel strand of the monitoring of the method can reach 5m, and the positioning precision of Strain Distribution is 2mm; Its sensing sensitivity is 1.2pm/ μ ε, and the dynamic range of strain-responsive is 3 μ ε-150 μ ε; The present invention can realize long-time continuous monitoring, the Strain Distribution information in Real-time Obtaining intelligent steel strand.
Accompanying drawing explanation
Fig. 1 is the structural representation of intelligent steel strand; Wherein: the transverse cross-sectional view that (A) is intelligent steel strand, the radial junction composition that (B) is intelligent steel strand; Reference numeral is: 1, intelligent sensing muscle; 2, single-mode fiber 3, light armour optical cable; 4, tinsel; 5, carbon fiber wire;
Fig. 2 is that the intelligent steel strand strain gauge means that the present invention is based on optical frequency domain reflection technology forms schematic diagram;
6, tunable laser; 7,1:99 light beam splitter; 8, the first circulator; 9, a 50:50 coupling mechanism; 10, optical fiber is postponed; 11, the first faraday rotation mirror; 12, the second faraday rotation mirror; 13, the first balanced detector; 14, the 2nd 50:50 coupling mechanism; 15, Polarization Controller; 16, the second circulator; 17, the 3rd 50:50 coupling mechanism; 18, based on the external clock triggering system of Michelson interferometer; 19, intelligent steel strand; 20, sensing optic cable; 21, the second balanced detector; 22, acquisition and processing device; 23, based on the main interferometer system of Mach-Zehnder interferometer; 24, based on the external clock triggering system of Michelson interferometer; 71, the first light divides beam port; 72, the second light divides beam port; 73, the 3rd light divides beam port; 81, the first circulator port one; 82, the first circulator port two; 91, a 50:50 Coupler ports one; 92, a 50:50 Coupler ports two; 93, a 50:50 Coupler ports three; 94, a 50:50 Coupler ports four; 141, the 2nd 50:50 Coupler ports one; 142, the 2nd 50:50 Coupler ports two; 143, the 2nd 50:50 Coupler ports three; 144, the 2nd 50:50 Coupler ports four; 161, the first circulator port one; 162, the first circulator port two; 163, the first circulator port three; 171, the 3rd 50:50 Coupler ports one; 172, the 3rd 50:50 Coupler ports two; 173, the 3rd 50:50 Coupler ports three; 174, the 3rd 50:50 Coupler ports four; First light divides beam port;
Fig. 3 is the intelligent steel strand strain monitoring method schematic diagram based on optical frequency domain reflection technology;
Fig. 4 is the computing cross-correlation wave length shift schematic diagram after intelligent steel strand position produces strain;
Fig. 5 is the strained matched curve of intelligent steel strand inner core fiber spectrum drift value and optical fiber;
Embodiment
Below in conjunction with embodiment, the present invention is described in further detail.
High purity carbon fiberreinforced intelligent steel strand for prestressed monitoring of the present invention, as shown in Figure 1, this intelligent steel strand composition structure comprises: intelligent sensing muscle 1 and tinsel 4 and carbon fiber wire 5.Intelligent sensing muscle 1 is wherein the main sensing element of high purity carbon fiberreinforced intelligent steel strand, comprises single-mode fiber 2 and light armour optical cable 3; Single-mode fiber 2 is the sensing element of the strain regime of monitoring intelligent steel strand wires, has ultraviolet light coating; Light armour optical cable 3 is at the outer tightly attached tight cover material of multicore of a branch of single-mode fiber 2; Tinsel 4, with high ductile metal paillon foil as cementing medium, is close between intelligent sensing muscle 1 and carbon fiber wire 5, to keep the cooperative transformation between intelligent sensing muscle 1 and outer carbon fiber wire 5; Carbon fiber wire 5, as primary structure member, forms by carbon fiber wire spiral fashion is stranded, and is close on tinsel 4, stretch or compress it, makes it to produce strain.
As shown in Figure 2, for strain monitoring device of the present invention, comprise tunable laser 6,1:99 beam splitter 7, the external clock triggering system 23 based on Michelson interferometer, the main interferometer system 24 based on Mach-Zehnder interferometer, acquisition and processing device and answer force generating apparatus 22; Wherein:
Tunable laser 6, for providing light source for this device, light source adopts super-narrow line width Linear Tuning Whispering-gallery-mode self seeding mode-locked laser light source, and its optical frequency can carry out linear sweep;
1:99 beam splitter 7, the emergent light of tunable laser 6 divides beam port 71 to enter by the first light of described 1:99 beam splitter 7, and divides beam port 72 port and c port assignment to the external clock triggering system 23 based on Michelson interferometer and the main interferometer system 24 based on Mach-Zehnder interferometer from the second light of described 1:99 beam splitter 7 respectively with the ratio of 1:99;
Based on the external clock triggering system 18 of Michelson interferometer, the optical frequency spacing samplings such as realization, its objective is the nonlinear sweep suppressing light source, its structure comprises the first circulator 8,50:50 coupling mechanism 9, first faraday rotation mirror 11, second faraday rotation mirror 12, postpones optical fiber 10 and the first balanced detector 13;
One 50:50 coupling mechanism 9 is for the interference of light, light enters from a 50:50 Coupler ports 1 of a 50:50 coupling mechanism 9, from a 50:50 Coupler ports 2 92 and 50:50 Coupler ports 3 93 outgoing, reflected by the first faraday rotation mirror 11 of the two-arm of the external clock triggering system 23 based on Michelson interferometer and the second faraday rotation mirror 12 respectively, and turn back to b port and the c port of a 50:50 coupling mechanism 9, two-beam interferes in a 50:50 coupling mechanism 9, from a port and the output of b port of a 50:50 coupling mechanism 9; First circulator 8 is for receiving the interference light returned from a port of a 50:50 coupling mechanism 9; Light enters from the b port of the first circulator 8, is exporting from c port; First faraday rotation mirror 11 and the second faraday rotation mirror 12 for providing reflection, and can eliminate polarization decay phenomenon; Postpone optical fiber 10 for realizing the beat frequency interference of non-equiarm; Balanced detector 13 is converted to electric signal for the light signal external clock triggering system 24 based on Michelson interferometer produced, employing be low noise balanced detector, for eliminate enter detector two paths of signals exist common-mode noise;
Main interferometer system 23 based on Mach-Zehnder interferometer is cores of monitoring device, comprises the 2nd 50:50 coupling mechanism 14, the 3rd 50:50 coupling mechanism 17, Polarization Controller 15, second circulator 16, second balanced detector 21;
2nd 50:50 coupling mechanism 14, for Mach-Zehnder interferometer beam splitting, light enters from the 2nd 50:50 Coupler ports 1 of the 2nd 50:50 coupling mechanism 14, enter Polarization Controller 15 through the 2nd 50:50 Coupler ports 2 142, enter test arm second circulator port 1 through the 2nd 50:50 Coupler ports 3 143; Polarization Controller 15 regulates the polarization state of reference light, and light intensity is basically identical in that orthogonal direction to make it; Second circulator 16 makes light enter sensing optic cable 20 intelligent steel strand 19 from the second circulator port 1, and the back-scattering light of sensing optic cable 20 is from entering from the second circulator port 3 163, from exporting from the second circulator port 2 162; The effect of the 3rd 50:50 coupling mechanism 17 is by from Polarization Controller 15 with enter the 3rd 50:50 coupling mechanism 17 from the back-scattering light that the second circulator port 2 162 exports by the 3rd 50:50 Coupler ports 1 and the 3rd 50:50 Coupler ports 2 172 and carry out conjunctions bundle, forms beat frequency interference also from the 3rd 50:50 Coupler ports 3 173 and the output of the 3rd 50:50 Coupler ports 3 174; Balanced detector 18 is converted to electric signal for the light signal main interferometer system 24 based on Mach-Zehnder interferometer produced, and what balanced detector 18 adopted is low noise balanced detector, for eliminating the common-mode noise entering detector two paths of signals and exist;
Acquisition and processing device 22: the analog electrical signal that balanced detector 18 exports is collected computing machine, the clock source of acquisition and processing device 22 is from the external clock triggering system 23 based on Michelson interferometer;
Answer force generating apparatus 22: utilize, by reverse cyclic loadings, tension or compressive stress are produced to intelligent steel strand 19.
The present invention proposes the intelligent steel strand strain monitoring method based on optical frequency domain reflection technology simultaneously, and flow process as shown in Figure 3, comprises the following steps:
Step one: the measurement carrying out single-mode fiber back rayleigh scattering signal in twice pair of intelligent steel strand, obtain two signals, that is: static back rayleigh scattering reference signal (first time measure optical cable not by the signal under any ectocine as with reference to signal) and stress stimulation under back rayleigh scattering signal (measurement optical cable is subject to signal under extraneous effect of stress as measured signal for the second time);
Step 2: Fast Fourier Transform (FFT) is carried out to above-mentioned two groups of signals, makes main interference signal be converted to distance domain from wavelength domain;
Step 3: adopt the local distance domain information of a Moving Window to whole optical cable to scan, obtain the distance domain information of this locality of whole optical cable, and whole distance domain information is divided into the equal length backscatter signals of diverse location;
Step 4: inverse Fourier transform is done to the signal of same position in two groups of signals simultaneously, make it to revert to light frequency-region signal;
Step 5: successively computing cross-correlation is done to the light frequency-region signal of each position, the position that spectral drift occurs is the position that there is strain, and the position of generation then can be thought not strain in the position that there is not spectral drift;
Step 6: the Rayleigh Scattering Spectra drift value calculating each position in optical cable, can demarcate the strain size suffered by corresponding position;
Step 7, obtain the Strain Distribution information of each position in optical cable.
As shown in Figure 4, when intelligent steel strand is subject to certain stress, when the strain numerical value making it to produce is 3 μ ε, the spectral drift amount that this intelligent steel strand produces is 4pm, utilizes cross correlation algorithm described in invention to measure accurately and obtains;
Intelligent steel strand is applied to the stress of different size, the dependent variable making itself produce progressively increases, and records the spectroscopic studying amount of optical fiber itself simultaneously.Record corresponding numerical value successively and make linear fit, as shown in Figure 5.Obtained by data in analysis chart, fiber spectrum drift value is directly proportional substantially to dependent variable suffered by intelligent steel strand, and its goodness of fit reaches 0.9977, can calculate that the sensing sensitivity obtaining intelligent steel strand is 1.22pm/ μ ε thus.
Although invention has been described for composition graphs above; but the present invention is not limited to above-mentioned embodiment; above-mentioned embodiment is only schematic; instead of it is restrictive; those of ordinary skill in the art is under enlightenment of the present invention; when not departing from present inventive concept, can also make a lot of distortion, these all belong within protection of the present invention.
Claims (3)
1. a high purity carbon fiberreinforced intelligent steel strand, is characterized in that: the composition structure of this intelligent steel strand comprises intelligent sensing muscle (1) and tinsel (4) and carbon fiber wire (5); Wherein: intelligent sensing muscle (1) comprises single-mode fiber (2) and light armour optical cable (3), and the sensing element that single-mode fiber (2) is the strain regime of monitoring intelligent steel strand wires, has ultraviolet light coating; Light armour optical cable (3) is at a branch of single-mode fiber (2) tight cover material of multicore tightly attached outward; Tinsel (4) with high ductile metal paillon foil as cementing medium, be close between intelligent sensing muscle (1) and carbon fiber wire (5), to keep the cooperative transformation between intelligent sensing muscle (1) and outer carbon fiber wire (5); Carbon fiber wire (5), as primary structure member, forms by carbon fiber wire spiral fashion is stranded, and is close on tinsel (4), stretches or compress it, makes it to produce strain.
2. one kind adopts the prestressed monitoring device of high purity carbon fiberreinforced intelligent steel strand as claimed in claim 1, it is characterized in that, this strain monitoring device comprises tunable laser (6), 1:99 beam splitter (7), the external clock triggering system (23) based on Michelson interferometer, the main interferometer system (24) based on Mach-Zehnder interferometer, acquisition and processing device (22) and answers force generating apparatus (21); The described external clock triggering system (23) based on Michelson interferometer comprises the first circulator (8), a 50:50 coupling mechanism (9), the first faraday rotation mirror (11), the second faraday rotation mirror (12), postpones optical fiber (10) and the first balanced detector (13), for optical frequency spacing samplings such as realizations, suppress the nonlinear sweep of light source; The described main interferometer system (24) based on Mach-Zehnder interferometer comprises the 2nd 50:50 coupling mechanism (14), the 3rd 50:50 coupling mechanism (17), Polarization Controller (15), the second circulator (16), the second balanced detector (18); Described 1:99 beam splitter (7) also comprises two ports, and namely the first light divides beam port (71), the second light divides beam port (72) and the 3rd light divides beam port (72); First circulator (8) also comprises two ports, i.e. the first circulator port one (81) and the first circulator port two (82); Second circulator (16) also comprises three ports, i.e. the second circulator port one (161), second circulator port two (162) and the second circulator port three (163); One 50:50 coupling mechanism (9) also comprises four ports, i.e. 50:50 Coupler ports the (91), the one 50:50 Coupler ports the two (92), the one 50:50 Coupler ports the three (93) and an one 50:50 Coupler ports four (94); 2nd 50:50 coupling mechanism (14) also comprises four ports, i.e. the 2nd 50:50 Coupler ports the (141), the 2nd 50:50 Coupler ports the two (142), the one 50:50 Coupler ports the three (143) and the 2nd 50:50 Coupler ports four (144); 31 50:50 coupling mechanisms (17) also comprise four ports, i.e. the 3rd 50:50 Coupler ports the (171), the 3rd 50:50 Coupler ports the two (172), the 3rd 50:50 Coupler ports the three (173) and the 3rd 50:50 Coupler ports four (174); Wherein:
The emergent light of described tunable laser (6) divides beam port (71) to enter by the first light of described 1:99 beam splitter (7), and divides beam port (72) and the 3rd light to divide beam port (73) to be assigned to the described external clock triggering system (23) based on Michelson interferometer and the described main interferometer system (24) based on Mach-Zehnder interferometer from the second light of described 1:99 beam splitter (7) respectively with the ratio of 1:99;
Described based in the external clock triggering system (23) of Michelson interferometer: a road enters from the first coupling port of a 50:50 coupling mechanism (9) from the light of 1:99 beam splitter (7), from 50:50 Coupler ports the two (92) and the one 50:50 Coupler ports three (93) outgoing of a 50:50 coupling mechanism (9), be arranged at the first faraday rotation mirror (11) and the second faraday rotation mirror (12) reflection of the two-arm of the external clock triggering system (18) based on Michelson interferometer respectively, and turn back to the second coupling port and the 3rd coupling port of a 50:50 coupling mechanism (9), two-beam interferes in a 50:50 coupling mechanism (9), from the first Coupler ports one (91) and the output of the second Coupler ports two (92) of a 50:50 coupling mechanism (9), the interference light that one 50:50 coupling mechanism (4) first coupling port returns enters from the first circulator port two (82) of the first circulator (8), then exports from the first circulator port two (83), postponing optical fiber (10) is arranged on the input light path of the second faraday rotation mirror (12), for realizing the beat frequency interference of non-equiarm, first balanced detector (13) is converted to electric signal for the light signal external clock triggering system (23) based on Michelson interferometer produced, and exports acquisition and processing device (22) to,
Described based in the main interferometer system (24) of Mach-Zehnder interferometer: another road enters from the 2nd 50:50 Coupler ports one (141) of the 2nd 50:50 coupling mechanism (14) from the light of 1:99 beam splitter (7), enter Polarization Controller (15) through the 2nd 50:50 Coupler ports two (142), and enter the second circulator port one (161) of the second circulator (16) in test arm through the 2nd 50:50 Coupler ports three (143); Light enters the sensing optic cable (20) intelligent steel strand (19) from the second circulator port one (161) of the second circulator (16), and the back-scattering light of sensing optic cable (20) enters from the second circulator port one (161) of the second circulator (16), export from the second circulator port two (162); The back-scattering light exported from Polarization Controller (15) and the second circulator port two (162) enters the 3rd 50:50 coupling mechanism (17) by the 3rd 50:50 Coupler ports the (171) and the 3rd 50:50 Coupler ports two (172) of the 3rd 50:50 coupling mechanism (17) and carries out conjunction bundle, forms beat frequency interference also from the 3rd 50:50 Coupler ports the three (173) and the 3rd 50:50 Coupler ports four (174) output of the 3rd 50:50 coupling mechanism (12); Second balanced detector (18): the light signal for the main interferometer system (19) based on Mach-Zehnder interferometer being produced is converted to electric signal, second balanced detector (18) is converted to electric signal for the light signal main interferometer system (25) based on Mach-Zehnder interferometer produced, and exports acquisition and processing device (22) to; Answer force generating apparatus (21) reverse cyclic loadings, produce the tension to intelligent steel strand (19) or compressive stress.
3. utilize a prestressed monitoring method for prestressed monitoring device as claimed in claim 2, it is characterized in that, the method comprises the following steps:
Step one, utilize described prestressed monitoring device to carry out the measurement of single-mode fiber back rayleigh scattering signal in twice pair of intelligent steel strand, obtain two signals, that is: the back rayleigh scattering signal under static back rayleigh scattering reference signal and stress stimulation;
Step 2, Fast Fourier Transform (FFT) is carried out to above-mentioned two groups of signals, make main interference signal be converted to distance domain from wavelength domain;
Step 3, the local distance domain information of an employing Moving Window to whole optical cable scan, and obtain the distance domain information of this locality of whole optical cable, and whole distance domain information is divided into the equal length backscatter signals of diverse location;
Step 4, inverse Fourier transform is done to the signal of same position in two groups of signals simultaneously, make it to revert to light frequency-region signal;
Step 5, make computing cross-correlation to the light frequency-region signal of each position successively, the position that spectral drift occurs is the position that there is strain, and the position of generation then can be thought not strain in the position that there is not spectral drift;
In step 6, calculating optical cable, the Rayleigh Scattering Spectra drift value of each position, can demarcate the strain size suffered by corresponding position;
Step 7, obtain the Strain Distribution information of each position in optical cable.
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| CN105466349A (en) * | 2016-01-18 | 2016-04-06 | 天津大学 | Method of employing thin cladding fibers to improve strain measurement sensitivity in optical frequency domain refection |
| CN106197303A (en) * | 2016-06-24 | 2016-12-07 | 天津大学 | A kind of probe beam deflation utilizes the optical fiber laying method of spiral of Archimedes |
| CN107589180A (en) * | 2017-10-11 | 2018-01-16 | 大连理工大学 | A kind of Prestressed concrete cylinder pipe fracture of wire optical fiber acoustic emission monitoring system and its monitoring method |
| CN112461148A (en) * | 2020-10-19 | 2021-03-09 | 南京东智安全科技有限公司 | Distributed cooperative sensing device and method for structural strain monitoring |
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| WO2017219568A1 (en) * | 2016-06-24 | 2017-12-28 | 天津大学 | Optical fiber laying method employing archimedean spiral in optical frequency domain reflection |
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