CN202329535U - Distributed high-accuracy long-gauge-length carbon fiber strain testing device - Google Patents
Distributed high-accuracy long-gauge-length carbon fiber strain testing device Download PDFInfo
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- CN202329535U CN202329535U CN2011204647050U CN201120464705U CN202329535U CN 202329535 U CN202329535 U CN 202329535U CN 2011204647050 U CN2011204647050 U CN 2011204647050U CN 201120464705 U CN201120464705 U CN 201120464705U CN 202329535 U CN202329535 U CN 202329535U
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Abstract
The utility model provides a distributed high-accuracy long-gauge-length carbon fiber strain testing device, which relates to the technical field of health detection and monitoring in a civil engineering traffic structure. According to the utility model, one long-gauge-length carbon fiber strain sensor is used as a working piece while the other one long-gauge-length carbon fiber strain sensor is used as a temperature compensating piece; a signal output end of a Wheatstone temperature compensating electric bridge is connected with a signal input end of a primary signal; a signal output end of the primary signal is connected with a signal input end of a single chip; and a signal output end of the single chip is connected with a signal input end of a high-credibility approximate truth value. The utility model is to provide the distributed high-accuracy long-gauge-length carbon fiber strain testing device, in which sensing performances of carbon fiber material within a small strain range are synthesized; and the micro strain of the structure within a large range under a long-time instable temperature condition is sensed so as to realize continuous detection and monitoring of the stress (strain) of the structure.
Description
Technical field
The utility model has related to a kind of technical field that is used for civil engineering transport structure health detection and monitoring, has related in particular to the technical field of the long gauge length carbon fibre of the distributed high-accuracy strain detection testing device that with the carbon fibre is base material.
Background technology
In structural healthy monitoring system, the detection of the monitoring of long-term static stress (strain) and structure dynamic response after excitation is to be used for evaluation structure long-term behaviour and the important method of damaging identification.In practical application, on the one hand highly sensitive sensor receives the influence of noise and changes in environmental conditions easily in the small strain excitation range, and causes the parameter that monitoring system can not correct response structure self to change; On the other hand, traditional ' point ' formula foil gauge often damages because of stress raisers sensor self or far can't foresee structural damage because of the impaired loci range sensor.At this moment, a kind ofly monitor possible stability sensor on a large scale and seem particularly important.
In xoncrete structure, its surface microfracture will occur under 100 to 200 stretch-draw microstrains.Therefore, economic and selecting for use of highly sensitive sensor is that the prerequisite that correctly obtains structural information guarantees.In practical application, highly sensitive sensor receives the influence of noise and changes in environmental conditions easily in the small strain scope, and causes the parameter that monitoring system can not correct response structure self to change.At this moment, the signal of sensor is handled just seemed particularly important.
Researched and proposed now and utilized the carbon fiber reinforce plastic sheet material under big strained condition, the micro-fracture of carbon filament and the signal step that causes are as the precaution device of structural failure.But it is, also just at the early-stage for the sensing capabilities of carbon fibre material in the small strain scope and the research of characteristics of signals.
Carbon fibre is a kind of high-intensity corrosion-resistant construction material, also has the mechanical resistance characteristic simultaneously.As a kind of novel sensing material; Not only have more long-term stability than traditional metallic resistance strain gauge transducer; And carbon fibre material is stressed and resistance variations that cause mainly comes from the change in size of change in resistance rather than sensor, therefore compares carbon fibre with the metal sensing material of traditional resistor strain gauge transducer and has highly sensitive and the little characteristics of transversal effect.
But carbon fibre itself is a kind of thermo-sensitive material, and in stress/strain conditional stability and under the situation that temperature conditions changes, its resistance can the significant change with variation of temperature, and its temperature coefficient is a negative value.Because the resistance coefficient small resistor initial value of carbon fibre is little, therefore its output signal is less than normal when small strain scope build-in test in addition.In actual measurement through method for testing resistance commonly used, the tested person condition to limit its output signal be not stably to show a value, its sampling deviation discrete phenomena is serious.
Summary of the invention
The purpose of the utility model is at the comprehensive sensing capabilities of carbon fibre material in the small strain scope; The long gauge length carbon fibre of a kind of distributed high-accuracy strain detection testing device is provided, is implemented under the long-term unstable temperature conditions perception to inner structure small strain on a large scale to reach the continuous detecting and the monitoring of stress (strain) to structure.
The utility model adopts following technical scheme for realizing above-mentioned purpose:
The long gauge length carbon fibre of a kind of distributed high-accuracy strain detection testing device; Comprise two long gauge length carbon fibre strain transducers, two resistances and the identical resistance of long gauge length carbon fibre strain transducer; Long gauge length carbon fibre strain transducer, resistance, constant-current supply are according to Hui Sideng temperature compensation electric bridge arranged in form; One of them long gauge length carbon fibre strain transducer is as active gage, and another long gauge length carbon fibre strain transducer is as the temperature compensation sheet; The signal output part of Hui Sideng temperature compensation electric bridge is connected with the signal input part of primary signal, and the signal output part of primary signal is connected with the signal input part of single-chip microcomputer, and the signal output part of single-chip microcomputer is connected with the signal input part of the approximate true value of high confidence level.
The long gauge length carbon fibre strain transducer of the utility model comprises continuous carbon fibre silk, resin-coated layer, test electrode; The resin-coated clad of periphery along continuous carbon fibre filament length degree direction; The electroconductive resin of 5mm-10mm length is smeared at the two ends of continuous carbon fibre silk respectively; Form conductive resin layer after the electroconductive resin full solidification, welding lead on conductive resin layer forms said test electrode again.
The length of the utility model continuous carbon fibre silk is 50cm.
The utility model continuous carbon fibre silk is to arrange braiding by many unidirectional carbon fiber dimension silks along machine direction to form.
The utility model continuous carbon fibre silk is the carbon fiber wire of high-intensity carbon fiber wire or high-elastic mould.
The width of the long gauge length carbon fibre of the utility model strain transducer and the ratio of length are less than 0.02, and thickness is 0.1～0.5mm.
Method of testing based on the long gauge length carbon fibre of the distributed high-accuracy of the utility model strain detection testing device comprises the steps:
The first step: build test electric bridge: at first one of them long gauge length carbon fibre strain transducer is installed on the monitored parts of structure as active gage; Secondly another long gauge length carbon fibre strain transducer is installed on the insensitive parts of the same space inner structure strain as the temperature compensation sheet, again two resistance is inserted Hui Sideng temperature compensation electric bridge;
Second step: signal instrumentation: the Hui Sideng temperature compensation electric bridge that the above-mentioned first step is built inserts single-chip microcomputer through primary signal; When active gage is under the tensile state; In instrumentation process, the output signal of Hui Sideng temperature compensation electric bridge is carried out continuous instrumentation with frequency f and obtain one group of primary signal, wherein f >=25;
The 3rd step: approximate true value is calculated: through the digital filtering algorithm of single-chip microcomputer, be used for above-mentioned primary signal is carried out filtering, finally export the approximate true value of a high confidence level.
The beneficial effect of the signal testing method of the utility model is: the primary signal of acquisition is the output signal of Hui Sideng temperature compensation electric bridge, and its signal does not receive Influence of Temperature; The primary signal that obtains is the approximate true value that the primary signal of repeatedly duplicate measurements is obtained the confidence level letter through single-chip microcomputer; Reduced the step of signal post-processed; Improved the linearity of sensor, the influence that the signal fluctuation of sensor brings when having solved the small strain measurement.
The beneficial effect of the long gauge length carbon fibre of the distributed high-accuracy of the utility model strain detection testing device is: realized being the novel long gauge length carbon fibre strain transducer of matrix with the carbon fibre, its permanent performance is superior to sensing metallic resistance strain gauge transducer; The monitoring and the detection of structural strain have been realized, have compared with the point type foil gauge and be more suitable for that not only practice thrift the monitoring cost, also the whole monitoring for large scale structure such as Longspan Bridge and side slope provides effective instrument in big monitoring range internal reaction structural entity information; In the small strain scope, assurance is provided for high-precision strain measurement.The utility model is applicable to high-precision static test, also is applicable to high-frequency dynamic test.
Description of drawings
Fig. 1 is the long gauge length carbon fibre of a utility model distributed high-accuracy strain detection testing device operating circuit synoptic diagram.
Fig. 2 is the structural representation of the long gauge length carbon fibre of the utility model strain transducer.
Fig. 3 is the vertical view of long gauge length carbon fibre strain transducer end among the utility model Fig. 1.
Among the figure: 1, continuous carbon fibre silk; 2, resin-coated layer; 3, test electrode; 4, conductive resin layer; 5, lead; 6, active gage; 7, temperature compensation sheet; 8, resistance; 9, single-chip microcomputer; 10, primary signal; 11, constant-current supply; 12, the approximate true value of high confidence level.
Embodiment
Be elaborated below in conjunction with the technical scheme of accompanying drawing to the utility model:
As shown in Figure 1; The long gauge length carbon fibre of a kind of distributed high-accuracy strain detection testing device; Comprise two long gauge length carbon fibre strain transducers, two resistances and the identical resistance 8 of long gauge length carbon fibre strain transducer; Long gauge length carbon fibre strain transducer, resistance 8, constant-current supply 11 are according to Hui Sideng temperature compensation electric bridge arranged in form, and one of them long gauge length carbon fibre strain transducer is as active gage 6, and another long gauge length carbon fibre strain transducer is as temperature compensation sheet 7; The signal output part of Hui Sideng temperature compensation electric bridge is connected with the signal input part of primary signal 10; The signal output part of primary signal 10 is connected with the signal input part of single-chip microcomputer 9, and the signal output part of single-chip microcomputer 9 is connected with the signal input part of the approximate true value 12 of high confidence level.
Like Fig. 2, shown in Figure 3; The long gauge length carbon fibre strain transducer of the utility model comprises continuous carbon fibre silk 1, resin-coated layer 2, test electrode 3; Along the resin-coated clad 2 of the periphery of continuous carbon fibre silk 1 length direction, the electroconductive resin of 5mm-10mm length is smeared at the two ends of continuous carbon fibre silk 1 respectively, forms conductive resin layer 4 after the electroconductive resin full solidification; Welding lead 5 on conductive resin layer 4 forms said test electrode 3 again.
The long gauge length carbon fibre strain transducer of the utility model needs following making step:
1), will arrange braiding along machine direction by many carbon fiber wires and form continuous carbon fibre silk 1 stretching being tiled on the plastic sheeting in smooth desktop upper berth layer of plastic film;
2) at the two ends of continuous carbon fibre silk 1 along machine direction stretch-draw, the stretch-draw condition and keeps tensile state constant below 100 microstrains;
3) length of on continuous carbon fibre silk 1, selecting one section 50cm is as the sensing section, and the electroconductive resin of distributing and painting 5mm-10mm length forms conductive resin layer after the electroconductive resin full solidification at the two ends of sensing section, and its electroconductive resin is for filling out silver-colored electroconductive resin;
4) welding lead on conductive resin layer again forms test electrode 3, welding manner spot welding, and welding temperature is unsuitable too high, and each joint is no more than 3 seconds weld interval, guarantees not oxidation of conductive resin layer non-scale;
5) dip in extracting epoxy resin with banister brush the sensing section of continuous carbon fibre silk is carried out the impregnation processing, the smearing thickness of resin is 0.1～0.5mm;
6) under normal temperature condition, leave standstill treat the resin full solidification after 1 week after, loosen the continuous carbon fibre silk, cut off the unnecessary fiber in the test electrode outside.
The length of the continuous carbon fibre silk 1 of the utility model is 50cm.
The continuous carbon fibre silk 1 of the utility model is to arrange braiding by many unidirectional carbon fiber dimension silks along machine direction to form.
The continuous carbon fibre silk 1 of the utility model is the carbon fiber wire of high-intensity carbon fiber wire or high-elastic mould.
The width of the long gauge length carbon fibre strain transducer of the utility model and the ratio of length are less than 0.02, and thickness is 0.1～0.5mm.
Method of testing based on the long gauge length carbon fibre of the distributed high-accuracy of the utility model strain detection testing device comprises the steps:
The first step: build test electric bridge: at first one of them long gauge length carbon fibre strain transducer is installed on the monitored parts of structure as active gage 6; Secondly another long gauge length carbon fibre strain transducer is installed on the insensitive parts of the same space inner structure strain as temperature compensation sheet 7, again two resistance is inserted Hui Sideng temperature compensation electric bridge;
Second step: signal instrumentation: the Hui Sideng temperature compensation electric bridge that the above-mentioned first step is built inserts single-chip microcomputer 9 through primary signal 10; When active gage 6 is under the tensile state; In instrumentation process, the output signal of Hui Sideng temperature compensation electric bridge is carried out continuous instrumentation with frequency f and obtain one group of primary signal 10, wherein f >=25;
The 3rd step: approximate true value is calculated: through the digital filtering algorithm of single-chip microcomputer 9, be used for above-mentioned primary signal 10 is carried out filtering, finally export the approximate true value 12 of a high confidence level.
As shown in Figure 1; The signal of the long gauge length carbon fibre of the distributed high-accuracy of the utility model strain detection testing device is obtained by Hui Sideng temperature compensation bridge test, and its Hui Sideng temperature compensation electric bridge is made up of an active gage 6, temperature compensation sheet 7, a constant-current supply 11 and two measuring resistances 8; The primary signal 10 of its Hui Sideng temperature compensation electric bridge inserts in the single-chip microcomputers 9, obtains the approximate true value 12 of high confidence level through digital filtering algorithm, has used amplitude limit average filter algorithm in this example.
The signal testing method of the utility model is realized through following steps: test electric bridge is built step; Be used at first a long gauge length carbon fibre strain detection testing device being installed in the monitored parts of structure as active gage 6; Secondly a long gauge length carbon fibre strain detection testing device is installed on the insensitive parts of the same space inner structure strain as temperature compensation sheet 7; Again 2 resistances are inserted Hui Sideng temperature compensation electric bridge with active gage 6 and temperature compensation sheet 7 the same measuring resistances 8; Wherein choosing of measuring resistance 8 need be debugged repeatedly, and the resistance of measuring resistance 8 is 17～18 ohm in this example; Signal instrumentation step; Be used for electric bridge is inserted constant-current supply 9; Active gage 6 is applied the CYCLIC LOADING unloading of small strain level, kept 1～2 second and carry out instrumentation one time at each point of load application, the output signal to Hui Sideng temperature compensation electric bridge in each time instrumentation process carries out the primary signal 10 that continuous instrumentation obtains corresponding loads at different levels with frequency f; The whole circulation process continues one day, and frequency f is 25Hz in this example; Approximate true value calculation procedure is used for the corresponding primary signal 10 of above-mentioned loads at different levels is carried out digital filtering, through signal averaging in amplitude limit average filter algorithm computation 95% fiducial interval, obtains the approximate true value 12 of the corresponding high confidence level of loads at different levels.
Can find out that according to test findings although temperature presents fluctuation up and down in one day circulation, picked up signal does not have the variation that changes thereupon but reacted load really; Although in the noise effect of the primary signal 10 of points of load application at different levels the identification that small strains at different levels are changed; Show tangible convergence but advance the corresponding approximate true value of handling 12 of high confidence level of loads at different levels at the points of load application at different levels of correspondence, handled the linear very good of back signal in the whole circulation.Therefore, be fit to structure is carried out long term monitoring based on the signal after the stationary singnal disposal methods of above-mentioned long gauge length carbon fibre strain detection testing device.
The distributed long gauge length carbon fibre strain detection testing device of the utility model can be arranged on the beams of concrete.With 3 gauge lengths is that the long gauge length carbon fibre strain detection testing device of 50cm is installed on the beams of concrete of a long 1.8m successively, all corresponding displacement meter that corresponding monitoring length is installed in each sensor middle part.Be carved with one section damage in advance at the beams of concrete middle part,, contrast the result of long gauge length carbon fibre strain detection testing device and displacement meter in the stretch-draw of beam two ends.
Test findings shows: long gauge length carbon fibre strain detection testing device can be monitored the Strain Distribution in the elongated scope of beam accurately; Can pass through eigenwert and actual response to inequality in the sensor gauge length scope and strain; The bulk deformation of structure can be successfully monitored.
The distributed long gauge length carbon fibre strain detection testing device of the utility model can be used for Dynamic Signal and measures.With 3 gauge lengths is that the long gauge length carbon fibre strain transducer of 50cm is installed in a long 1.5m successively as active gage, on the Simply-supported Steel Beams of wide 5cm, and all corresponding accelerometer that a SF 50Hz is installed in each sensor middle part.
The Dynamic Signal measuring process of long in this example gauge length carbon fibre strain transducer realizes through following steps: signal instrumentation step; After being used for being installed in active gage on the girder steel; The execution cycling time of adjustment single-chip microcomputer; The output signal frequency that makes active gage is 50HZ, and after the girder steel excited target, instrumentation output signal obtains initial dynamic strain signal continuously; Step is removed in baseline wander; Be used for initial dynamic strain signal by the time series arrangement; Write down the time point of each crest and trough then successively; Interior all signal averagings of time point that calculate each crest and trough again obtain baseline wander lines, at last initial dynamic strain signal are deducted the signal that the baseline wander line obtains baseline stability; The signal de-noising step is used for signal to the baseline stability that obtains through the threshold value that Birge-Massart strategy is confirmed, with small echo soft-threshold method of weighting the baseline stability signal is carried out noise reduction acquisition de-noising signal again.
The Dynamic Signal after handling from long gauge length carbon fibre type of dynamic strain sensor respectively through FFT and the signal of accelerometer obtain each rank natural frequency of girder steel again from the frequency curve of the response of acquisition girder steel from each section peak value of frequency curve.Can find out according to test findings; Each the rank natural frequency that obtains the Dynamic Signal after long gauge length carbon fibre type of dynamic strain sensor is handled and each the rank natural frequency that obtains from the signal of accelerometer are very identical; The long gauge length carbon fibre type of dynamic strain sensor that is installed in Simply-supported Steel Beams middle part simultaneously can only obtain 1 and 3 first order modes and the long gauge length carbon fibre type of dynamic strain sensor that is installed in the Simply-supported Steel Beams two ends can obtain 1,2 and 3 first order modes, and this also meets the dynamic mode shape of vibration of free beam.Therefore, be fit to dynamic monitoring in the long gauge length scope of structure based on the signal after the Dynamic Signal disposal methods of above-mentioned long gauge length carbon fibre type of dynamic strain sensor.
Claims (6)
1. the long gauge length carbon fibre of distributed high-accuracy strain detection testing device; It is characterized in that: comprise two long gauge length carbon fibre strain transducers, two resistance (8) that resistance is identical with long gauge length carbon fibre strain transducer; Long gauge length carbon fibre strain transducer, resistance (8), constant-current supply (11) are according to Hui Sideng temperature compensation electric bridge arranged in form; One of them long gauge length carbon fibre strain transducer is as active gage (6), and another long gauge length carbon fibre strain transducer is as temperature compensation sheet (7); The signal output part of Hui Sideng temperature compensation electric bridge is connected with the signal input part of primary signal (10); The signal output part of primary signal (10) is connected with the signal input part of single-chip microcomputer (9), and the signal output part of single-chip microcomputer (9) is connected with the signal input part of the approximate true value (12) of high confidence level.
2. the long gauge length carbon fibre of distributed high-accuracy according to claim 1 strain detection testing device; It is characterized in that: above-mentioned long gauge length carbon fibre strain transducer comprises continuous carbon fibre silk (1), resin-coated layer (2), test electrode (3); The resin-coated clad of periphery (2) along continuous carbon fibre silk (1) length direction; The electroconductive resin of 5mm-10mm length is smeared at the two ends of continuous carbon fibre silk (1) respectively; Form conductive resin layer (4) after the electroconductive resin full solidification, go up welding lead (5) at conductive resin layer (4) again, form said test electrode (3).
3. the long gauge length carbon fibre of distributed high-accuracy according to claim 2 strain detection testing device is characterized in that: the length of above-mentioned continuous carbon fibre silk (1) is 50cm or more than the 50cm.
4. the long gauge length carbon fibre of distributed high-accuracy according to claim 2 strain detection testing device is characterized in that: above-mentioned continuous carbon fibre silk (1) is to arrange braiding by many unidirectional carbon fiber dimension silks along machine direction to form.
5. the long gauge length carbon fibre of distributed high-accuracy according to claim 2 strain detection testing device is characterized in that: above-mentioned continuous carbon fibre silk (1) is the carbon fiber wire of high-intensity carbon fiber wire or high-elastic mould.
6. the long gauge length carbon fibre of distributed high-accuracy according to claim 2 strain detection testing device is characterized in that: the width of above-mentioned strain transducer and the ratio of length are less than 0.02, and thickness is 0.1～0.5mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011204647050U CN202329535U (en) | 2011-11-22 | 2011-11-22 | Distributed high-accuracy long-gauge-length carbon fiber strain testing device |
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| CN2011204647050U CN202329535U (en) | 2011-11-22 | 2011-11-22 | Distributed high-accuracy long-gauge-length carbon fiber strain testing device |
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| CN202329535U true CN202329535U (en) | 2012-07-11 |
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| CN2011204647050U Expired - Lifetime CN202329535U (en) | 2011-11-22 | 2011-11-22 | Distributed high-accuracy long-gauge-length carbon fiber strain testing device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102494603A (en) * | 2011-11-22 | 2012-06-13 | 东南大学 | Distributed high-precision long-gauge-length carbon fiber strain test device and method |
| CN104142118A (en) * | 2013-05-10 | 2014-11-12 | 雅马哈株式会社 | Strain sensor |
-
2011
- 2011-11-22 CN CN2011204647050U patent/CN202329535U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102494603A (en) * | 2011-11-22 | 2012-06-13 | 东南大学 | Distributed high-precision long-gauge-length carbon fiber strain test device and method |
| CN104142118A (en) * | 2013-05-10 | 2014-11-12 | 雅马哈株式会社 | Strain sensor |
| US9476782B2 (en) | 2013-05-10 | 2016-10-25 | Yamaha Corporation | Strain sensor |
| CN104142118B (en) * | 2013-05-10 | 2017-07-07 | 雅马哈株式会社 | Strain transducer |
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Granted publication date: 20120711 |