CN203083877U - Staged monitoring system for tensile fracture state of carbon fiber structure - Google Patents
Staged monitoring system for tensile fracture state of carbon fiber structure Download PDFInfo
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- CN203083877U CN203083877U CN 201320062726 CN201320062726U CN203083877U CN 203083877 U CN203083877 U CN 203083877U CN 201320062726 CN201320062726 CN 201320062726 CN 201320062726 U CN201320062726 U CN 201320062726U CN 203083877 U CN203083877 U CN 203083877U
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Abstract
The utility model discloses a staged monitoring system for a tensile fracture state of a carbon fiber structure. The staged monitoring system is characterized by comprising a computer, a fiber bragg grating analyzer, a Y-type optical fiber coupler, an FBG (Fiber Bragg Grating) strain sensing probe, an FBG strain wave sensing probe, a first coupler joint, a first sensing optical fiber, a second coupler joint and a second sensing optical fiber, wherein the computer is connected with the fiber bragg grating analyzer; and the Y-type optical fiber coupler comprises a Y-type optical fiber coupler input end and two Y-type optical fiber coupler output ends, wherein the Y-type optical fiber coupler input end is connected with the fiber bragg grating analyzer, one of the two Y-type optical fiber coupler output ends is connected with the first coupler joint, the first sensing optical fiber and the FBG strain sensing probe in sequence, and the other Y-type optical fiber coupler output end is connected with the second coupler joint, the second sensing optical fiber and the FBG strain wave sensing probe in sequence. The staged monitoring system for the tensile fracture state of the carbon fiber structure can be used for realizing the whole-process monitoring of the carbon fiber structure fracture.
Description
Technical field
The utility model relates to a kind of monitoring system stage by stage of carbon fiber structural tension failure state.
Background technology
Based on characteristics such as light weight, intensity height, design flexibility be strong, as a kind of high performance structures with strong permanance, higher reliability, carbon fiber structural has solved the technical barrier that single performance material in the past can't be crossed over, become the constantly main flow trend of development of high-tech area such as Aeronautics and Astronautics, be widely used in the structures such as fixed fin, fuselage, wing of aircraft.Yet, such material make and long-term military service process in, may produce the structural damage of forms such as inner breakpoint, crackle, delamination, as if untimely discovery with take corresponding maintenance measure, will cause the rapid destruction of total, hidden danger causes a serious accident.Fracture damage is one of structure main damage form, and the study on monitoring of fracture damage is had positive effect.
The method of lossless detection carbon fiber structural breaking state comprises X-ray detection X method, supersonic sounding, acoustic emission detection method etc. at present.The advantage of X-ray detection X method be image relatively directly perceived, the judgement ratio of flaw size and character is easier to, but its detection sensitivity to fine crack is low, acquisition cost is higher.Supersonic sounding has characteristics such as detectable thickness is big, detection sensitivity is high, cost is low, but it has certain blind area, near field when surveying, and it is easily contaminated to survey test specimen.Compare with above-mentioned detection method, acoustic emission detection has highly sensitive, the inspection area coverage is big, loss is low and can be in the test specimen advantage of surveying in service, therefore, this method is widely used in the fracture damage monitoring of carbon fiber structural, is the mainstream technology in monitoring structural health conditions field present stage and even one period in the future.
Since optical fiber sensing system have light weight, volume little, corrosion-resistant, be easy to long-haul telemetry and realize advantages such as distributed measurement, make that the structural health monitoring technology based on Fibre Optical Sensor becomes the new focus that current domestic and international aviation field researchers pay close attention to.The seventies in 20th century, the C1aus of state university of the Virginia, US Institute of Technology etc. has imbedded enhancing structural carbon fiber to optical fiber first, makes material have the function of sensing and detecting broken damage.Subsequently, Ge Lumen company adopts the damage and the strain of fiber-optic grating sensor monitoring F-18 wing, LMT is applied in optical fiber grating sensing network on the stress and monitoring temperature of X-33 space shuttle, has used the health monitoring systems based on fiber Bragg grating sensor network on the structure engine case of DALTA II rocket.But above-mentioned application all is unrealized to the overall process monitoring of carbon fiber structural fracture.
The utility model content
The utility model purpose: in order to address the above problem, the utility model provides a kind of monitoring system stage by stage of carbon fiber structural tension failure state.
Technical scheme: a kind of monitoring system stage by stage of carbon fiber structural tension failure state comprises computing machine, fiber grating analyser, y-type optical fiber coupling mechanism, FBG strain sensing probe, FBG strain wave sensing probe, the first coupling mechanism joint, first sensor fibre, the second coupling mechanism joint and second sensor fibre; Computing machine links to each other with the fiber grating analyser, and the y-type optical fiber coupling mechanism comprises a y-type optical fiber coupling mechanism input end and two y-type optical fiber coupling mechanism output terminals, and y-type optical fiber coupling mechanism input end links to each other with the fiber grating analyser; Two y-type optical fiber coupling mechanism output terminals, one of them y-type optical fiber coupling mechanism output terminal links to each other with the first coupling mechanism joint, first sensor fibre, FBG strain sensing probe successively, and another y-type optical fiber coupling mechanism output terminal links to each other with the second coupling mechanism joint, second sensor fibre, FBG strain wave sensing probe successively.
In order to improve the accuracy of detection, the full gluing glue-line that described FBG strain sensing probe comprises first sensor fibre, is located at the FBG strain sensing grid region of the first sensor fibre fibre core inside and is located at FBG strain sensing probe top layer, during use, gluing glue-line and test specimen glued joint coupling entirely.
The restriction of FBG strain wave sensing probe range in the observation process, the local viscose point that described FBG strain wave sensing probe comprises second sensor fibre, is located at the FBG strain wave sensing grid region of the second sensor fibre fibre core inside, is used for fixing the grid region fixed mount of FBG strain wave sensing probe and is located at FBG strain wave sensing probe top layer, during use, local viscose point was coupled with local splicing of test specimen.
In order further to improve the accuracy that detects, described FBG strain sensing probe and FBG strain wave sensing probe are more than two, and arrange for distributed network.
Above-mentioned sensor-based system, comprise the preceding FBG strain sensing device of stress relaxation, the FBG strain wave sensing device in the stress relaxation process, all there is supporting sensing scheme said apparatus inside, and then realizes the whole process monitoring to carbon fiber structural tensioning member Tensile Fracture Process; Adopt the full coupling of glueing joint in the FBG strain sensing device before the stress relaxation between CFRP tensioning member and the FBG sensing probe, to improve the strain sensitivity; FBG strain wave sensing device in the stress relaxation process adopts the formula of coming unstuck locally coupled, avoids owing to the excessive sensing device that causes of strain range lost efficacy in advance; In observation process, the FBG sensing probe is always distributed network and arranges, and effectively controls the sensor network redundancy issue.The composition of Distributed FBG carbon fiber structural tension failure monitoring system is: can prepare a plurality of online FBG strain sensing probes and FBG strain wave sensing probe on same optical fiber, and different root optical fiber can be in parallel, effectively controls the sensor network redundancy issue.
The method of the monitoring of the monitoring system stage by stage carbon fiber structural tension failure state of above-mentioned carbon fiber structural tension failure state comprises the steps:
A, phase one monitoring: when the carbon fiber structural internal break constantly carries out, the FBG peak value that causes by FBG strain sensing probe strain variation changes, and then realization is to the monitoring of carbon fiber structural tensioning member macroscopic view elastic modulus change situation, when the stretching rate of change of FBG centre wavelength tends towards stability, when carbon fiber structural tensioning member macroscopic view elastic modulus is tending towards constant, test specimen reaches the damage critical conditions gradually, along with constantly carrying out of stretching, stress relaxation phenomenon takes place gradually, saltus step appears in the peak value of FBG strain wave sensor, enters the next stage measurement;
B, subordinate phase monitoring: this stage, because what stretch constantly carries out, the stress relaxation phenomenon of carbon fiber structural tensile test specimen inside constantly takes place, by monitor test specimen to be measured in Tensile Fracture Process because stress relaxation causes the strain wave response condition of diverse location, and then acquisition institute carbon determination fibre structure tensile test specimen internal break distribution situation, be breaking state, realize real-time monitoring fracture position.
Above-mentioned FBG strain sensing probe strain variation is actually the strain variation on surface, FBG strain sensing grid region.
Above-mentioned detection method utilizes the FBG reflection spectrometry to monitor; Strengthen the abbreviation of construction stretch part and FBG(Fiber Bragg Grating FBG at CFRP(carbon fiber to be monitored) adopt between the sensing probe complete glued joint coupling and the formula of coming unstuck locally coupled; In observation process, the FBG sensing probe is always distributed network and arranges.
Among the above-mentioned steps A, utilize the sensitive natur of FBG sensing grid region to CFRP tensioning member surface strain variations, because inside configuration fracture, layering cause that FBG center wavelength variation speed reduces degree, detect the CFRP test specimen macroscopic view elastic modulus change situation and the internal break state thereof that exceed stretch section by measuring in the drawing process.
Above-mentioned monitoring method, the monitoring parameter of phase one is for characterizing the characteristic parameter of construction stretch part rigidity, that is: macroscopical elastic modulus of test specimen.Utilize elastic modulus as characterization parameter, the FBG spectral characteristic combined with carbon fiber structural tensioning member stiffness variation status monitoring before the stress relaxation, realize to the degree of impairment before the structural break state of saturation carry out in real time, on-line monitoring.
Above-mentioned monitoring method, the monitoring parameter of subordinate phase is the wavy attitude of tensioning member surface strain in the stress relaxation process, after entering critical conditions, utilize the wavy attitude of tensioning member surface strain as characterization parameter, by monitor test specimen to be measured in Tensile Fracture Process because stress relaxation causes the strain wave response condition of diverse location, and then obtain the CFRP tensile test specimen internal break distribution situation of surveying, promptly breaking state is realized the real-time monitoring to fracture position.
Said method, for monitoring accuracy and convenience, break up a little as the stage with the damage critical conditions, to after CFRP test specimen macroscopic view elastic modulus change situation before the damage critical conditions and the damage critical conditions because stress relaxation causes the strain wave response condition to be monitored.
CFRP test specimen macroscopic view elastic modulus reduces with the increase of internal injury before the damage critical conditions, and near the damage critical conditions time, CFRP tensile test specimen macroscopic view elastic modulus occurs and be tending towards steady state.
Said method, in order to improve monitoring accuracy, use before the stress relaxation in FBG strain sensing probe and the stress relaxation process with FBG strain wave sensing probe, wherein adopt the full coupling of glueing joint between the probe of the FBG strain sensing before the stress relaxation and the carbon fiber structural to be measured, adopt local splicing to be coupled between the FBG strain wave sensing probe in the stress relaxation process and the carbon fiber structural to be measured.
In the FBG strain sensing data analysis before the above-mentioned stress relaxation, by FBG sensing curve is carried out the slope variation analysis of local data's section, and then can obtain the situation of change of macroscopical elastic modulus of carbon fiber structural.
Carbon fiber structural described in the utility model is meant carbon fibre composite.
The technology that the utility model does not limit especially is prior art.
Beneficial effect: the monitoring of carbon fiber structural tensioning member fracture process is divided into two stages, that is: break up a little as the stage with the damage critical conditions, to after CFRP test specimen macroscopic view elastic modulus change situation before the damage critical conditions and the damage critical conditions because stress relaxation causes monitoring of strain wave response condition, prolonged the operational use time of carbon fiber structural tensioning member breaking state monitoring system; Utilize that FBG is fast to surface strain variations resolution height, response, high flux, sensitivity, special, easy, to advantages such as the own not damageds of sample, realize the monitoring of carbon fiber structural spare Tensile Fracture Process, determine the internal break state and the fracture position of construction stretch part, can be applicable to the carbon fiber structural tension failure condition monitoring in fields such as aviation, naval vessel; Simultaneously owing to adopted optical fiber as the sensing matrix, have again anti-electromagnetic interference capability strong, high pressure resistant, corrosion-resistant, can realize advantages such as distributed measurement and long-haul telemetry monitoring; By simplifying the sensor-based system structure and adopting spectrum detection technique, can improve measuring accuracy, overcome luminous intensity measurement and be subject to the shortcoming that the flashing photographic fixing rings; By adopting corresponding encapsulation and protected mode, can avoid because the influence that extraneous factors such as temperature, humidity are brought the FBG sensor-based system guarantees reliability and permanance that breaking state is monitored.
Description of drawings
Fig. 1 is the synoptic diagram of monitoring system stage by stage of carbon fiber structural tension failure state;
Fig. 2 is a y-type optical fiber coupling mechanism synoptic diagram;
Fig. 3 is the FBG strain sensing probe synoptic diagram before the stress relaxation;
Fig. 4 is the FBG strain wave sensing probe synoptic diagram in the stress relaxation process;
Fig. 5 is the synoptic diagram of monitoring system stage by stage of distributed carbon fiber structural tension failure state;
Among the figure, 1 is the fiber grating analyser, 2 is the y-type optical fiber coupling mechanism, and 31 is the first coupling mechanism joint, and 32 is the second coupling mechanism joint, 41 is first sensor fibre, 42 is second sensor fibre, and 5 are FBG strain sensing probe, and 6 is FBG strain wave sensing probe, 7 is computing machine, 8 is y-type optical fiber coupling mechanism input end, and 9 is y-type optical fiber coupling mechanism output terminal, and 10 is the first sensing grid region, 16 is the second sensing grid region, 11 is full gluing glue-line, and 12 is first fibre core, and 15 is second fibre core, 13 is the grid region fixed mount, and 14 is local viscose point.
Embodiment
Below in conjunction with accompanying drawing the utility model is done further explanation.
Shown in Fig. 1-5, the monitoring system stage by stage of carbon fiber structural tension failure state comprises computing machine 7, fiber grating analyser 1, y-type optical fiber coupling mechanism 2, the first coupling mechanism joint 31, the second coupling mechanism joint 32, first sensor fibre 41, second sensor fibre 42, FBG strain sensing probe 5 and FBG strain wave sensing probe 6; Computing machine 7 links to each other with fiber grating analyser 1, and y-type optical fiber coupling mechanism 2 comprises a y-type optical fiber coupling mechanism input end 8 and two y-type optical fiber coupling mechanism output terminals 9, and y-type optical fiber coupling mechanism input end 8 links to each other with fiber grating analyser 1; Two y-type optical fiber coupling mechanism output terminals 9, one of them y-type optical fiber coupling mechanism output terminal 9 links to each other with the first coupling mechanism joint 31, first sensor fibre 41, FBG strain sensing probe 5 successively, and another y-type optical fiber coupling mechanism output terminal 9 links to each other with the second coupling mechanism joint 32, second sensor fibre 42, FBG strain wave sensing probe 6 successively.
Fiber grating analyser 1(can adopt si425 type fiber grating analyser) middle built-in light source, enter y-type optical fiber coupling mechanism input end 8(as shown in Figure 2), propagate into y-type optical fiber coupling mechanism output terminal 9, again by the first coupling mechanism joint 31, propagate into FBG strain sensing probe 5 or pass through the second coupling mechanism joint 32 through first sensor fibre 41, propagate into FBG strain wave sensing probe 6 through second sensor fibre 42, produce coupling effect with the surface strain interaction of test specimen to be measured, in through FBG strain sensing probe 5 or FBG strain wave sensing probe 6, the formation reflection ray enters fiber Bragg grating (FBG) demodulator 1 by the reflection end of y-type optical fiber coupling mechanism 2 after the reflex in grid region, process computing machine 7 is handled the relation curve between output reflection optical wavelength and the variation parameter again, thereby has realized the full fiberize of whole measurement light path part.
According to FBG spectrum output characteristics, can realize the distributed carbon fiber structural tension failure monitoring system of multidigit point detection by the FBG of different centre wavelengths to the carbon fiber structural tensile test specimen.When FBG strain sensing probe 5 or FBG strain wave sensing probe 6 are in different test position, the Strain Distribution situation of different positions to be measured and sensor interaction, thus cause each FBG center sensor wavelength change.By the detection that sensor is exported the different centre wavelengths of FBG spectrum, can obtain the signal of Distributed Detection.
Fig. 3 is 5 synoptic diagram of popping one's head in of the FBG strain sensing before the stress relaxation, described FBG strain sensing probe 5 comprises the fibre core that is located at first sensor fibre, 41 inside, be located at the first sensing grid region 10 of first sensor fibre, 41 fibre core inside and be located at the pop one's head in full gluing glue-line 11 on 5 top layers of FBG strain sensing, utilize the responsive grid region of FBG to the reflection of light effect, the special wavelength light that transmits is reflected back, make itself and test specimen glued joint coupling entirely by full gluing glue-line 11.
The influence of the fracture degree of saturation of research carbon fiber structural tensioning member and test specimen macroscopic view elastic modulus, utilize the sensitive natur of FBG sensing grid region to CFRP tensioning member surface strain variations, by measuring in the drawing process because the inside configuration fracture, layering causes the rate of change of FBG centre wavelength, detection exceeds the CFRP test specimen macroscopic view elastic modulus change situation and the internal break state thereof of stretch section, that is: when the CFRP internal break constantly carries out, by detecting the rate of change that the grid region surface strain variations causes the FBG peak value, and then realize that the variation of the macroscopical elastic modulus of CFRP tensioning member is just measured in said measurement FBG sensing grid region to tensile test specimen surface strain variations speed to the monitoring of CFRP tensioning member macroscopic view elastic modulus change situation.
Fig. 4 is FBG strain wave sensing probe 6 synoptic diagram in the stress relaxation process.Described FBG strain wave sensing probe 6 comprises the fibre core that is located at second sensor fibre, 42 inside, is located at the second sensing grid region 16 of second sensor fibre, 42 fibre core inside, the local viscose point 14 that is used for fixing the grid region fixed mount 13 of FBG strain wave sensing probe 6 and is located at FBG strain wave sensing probe top layer, utilize the responsive grid region of FBG to the reflection of light effect, the special wavelength light that transmits is reflected back, by local viscose point 14 itself and local splicing of test specimen are coupled, avoid the restriction of FBG strain wave sensing probe 6 ranges in the observation process.
The influence of stress relaxation phenomenon and test specimen tension failure state in the research stress relaxation process, by monitor test specimen to be measured in Tensile Fracture Process because stress relaxation causes the strain wave response condition of diverse location, and then the acquisition CFRP tensile test specimen internal break distribution situation of surveying, be breaking state, realize real-time monitoring fracture position.
Fig. 5 is distributed carbon fiber structural tensile test specimen fracture monitoring system synoptic diagram.Its concrete composition is the FBG sensing grid region that is carved into different centre wavelengths at the diverse location of same fiber core.Therefore a plurality of FBG strain sensing probes 5 and FBG strain wave sensing probe 6 can be set simultaneously, and multifiber can be in parallel on same optical fiber.
Claims (4)
1. the monitoring system stage by stage of a carbon fiber structural tension failure state is characterized in that: comprise computing machine, fiber grating analyser, y-type optical fiber coupling mechanism, FBG strain sensing probe, FBG strain wave sensing probe, the first coupling mechanism joint, first sensor fibre, the second coupling mechanism joint and second sensor fibre; Computing machine links to each other with the fiber grating analyser, and the y-type optical fiber coupling mechanism comprises a y-type optical fiber coupling mechanism input end and two y-type optical fiber coupling mechanism output terminals, and y-type optical fiber coupling mechanism input end links to each other with the fiber grating analyser; Two y-type optical fiber coupling mechanism output terminals, one of them y-type optical fiber coupling mechanism output terminal links to each other with the first coupling mechanism joint, first sensor fibre, FBG strain sensing probe successively, and another y-type optical fiber coupling mechanism output terminal links to each other with the second coupling mechanism joint, second sensor fibre, FBG strain wave sensing probe successively.
2. the monitoring system stage by stage of carbon fiber structural tension failure state as claimed in claim 1, it is characterized in that: the full gluing glue-line that described FBG strain sensing probe comprises first sensor fibre, is located at the FBG strain sensing grid region of the first sensor fibre fibre core inside and is located at FBG strain sensing probe top layer, during use, gluing glue-line and test specimen glued joint coupling entirely.
3. the monitoring system stage by stage of carbon fiber structural tension failure state as claimed in claim 1 is characterized in that: the local viscose point that described FBG strain wave sensing probe comprises second sensor fibre, is located at the FBG strain wave sensing grid region of the second sensor fibre fibre core inside, is used for fixing the grid region fixed mount of FBG strain wave sensing probe and is located at FBG strain wave sensing probe top layer.
4. the monitoring system stage by stage of carbon fiber structural tension failure state as claimed in claim 1 is characterized in that: described FBG strain sensing probe and FBG strain wave sensing probe are more than two, and arrange for distributed network.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103149089A (en) * | 2013-02-04 | 2013-06-12 | 东南大学 | Multi-stage monitoring system of stretching and fracture state of carbon fiber structure and monitoring method thereof |
| CN113959838A (en) * | 2021-09-15 | 2022-01-21 | 深圳市比洋光通信科技股份有限公司 | Stress monitoring method for optical fiber capillary tube |
-
2013
- 2013-02-04 CN CN 201320062726 patent/CN203083877U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103149089A (en) * | 2013-02-04 | 2013-06-12 | 东南大学 | Multi-stage monitoring system of stretching and fracture state of carbon fiber structure and monitoring method thereof |
| CN113959838A (en) * | 2021-09-15 | 2022-01-21 | 深圳市比洋光通信科技股份有限公司 | Stress monitoring method for optical fiber capillary tube |
| CN113959838B (en) * | 2021-09-15 | 2024-03-29 | 深圳市比洋光通信科技股份有限公司 | Method for monitoring stress of optical fiber capillary tube |
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