CN214426651U - Fiber grating strain type reinforcing bar meter measurement calibrating device - Google Patents
Fiber grating strain type reinforcing bar meter measurement calibrating device Download PDFInfo
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Abstract
A fiber grating strain type reinforcing steel bar meter metering and calibrating device. The device comprises a fiber grating strain type steel bar meter, a constant-temperature water tank, a platinum resistance thermometer clamping device, a fiber grating demodulator, a digital multimeter, a standard load device and an upper computer; the utility model discloses the effect: the current situation to at present domestic no special fiber grating strain gauge reinforcing bar meter measurement technical specification, the utility model provides a fiber grating strain gauge reinforcing bar meter measurement calibrating device has solved the influence of ambient temperature influence to fiber grating strain gauge reinforcing bar meter measurement accuracy, provides the technical basis for instrument production unit to fiber grating strain gauge reinforcing bar meter before dispatching from the factory performance test, also provides effectual method for the field data correction of application unit, has promoted fiber grating strain gauge reinforcing bar meter measurement accuracy and data reliability.
Description
Technical Field
The utility model belongs to the technical field of traffic water conservancy diversion, highway engineering structure monitoring equipment measurement calibration, in particular to fiber grating strain gauge rebar meter measurement calibrating device.
Background
In the fields of transportation and water transportation and highway engineering, the infrastructures and structures such as bridges and dams are influenced by external environment, material characteristics of the infrastructures and structural design and other factors in the process of construction and long-term use, so that damage accumulation and resistance attenuation are inevitably generated, the service life of the infrastructures is reduced, and if existing potential safety hazards are not checked in time, catastrophic accidents are caused, and major casualties and economic losses are caused, so that the health monitoring of important structures and infrastructures becomes a research hotspot of water transportation and highway engineering. The reinforcing steel bar is one of main bearing members of modern water transportation and highway engineering structures, is easily damaged under the influence of factors such as environmental corrosion, fatigue and material aging, takes strain and stress as one of important parameters for reacting material and structural mechanical characteristics, can obtain strength reserve information of the member according to strain distribution conditions in the material and the structure, determines stress concentration of the local position of the member and the actual load condition of the member, and has great monitoring significance.
At present, the monitoring means which is commonly used is to rigidly connect the measuring sensor with the steel bar into a whole in a cementing or fixing clamp manner, when the steel bar is axially or radially stretched or twisted, the measuring sensor generates the same change with the steel bar, and the generated strain is converted into light and electric signals and transmitted to an analyzer, so as to realize the dynamic and long-term monitoring of the mechanical property of the steel bar. The steel bar meters developed on the market based on the mode mainly comprise a vibrating wire type steel bar meter, a resistance strain type steel bar meter, a fiber grating strain type steel bar meter and the like, wherein the fiber grating strain type steel bar meter plays an important role in stress monitoring of structures such as highways, water transportation roads, dams, bridges and the like due to the advantages of small insertion loss, good reliability and stability, easiness in forming sensor networks and the like.
In the aspect of measurement and calibration of the fiber grating strain type steel bar meter, a 1-level universal material testing machine is used as a standard in the power industry standard 'basic technical conditions of a fiber grating instrument' (DL/T1736-. The building industry standard fiber grating strain sensor for civil engineering (JG/T42-2013) uses a strain sensor calibration frame as a standard device to regulate the mechanical properties of the fiber grating strain sensor, such as comprehensive error, resolution, repeatability and the like, and the strain sensor calibration frame cannot meet the clamping and calibration requirements of the fiber grating strain type steel bar meter in the measurement range and the measurement mode, so that the calibration method in the standard has high precision but cannot be applied to the fiber grating strain type steel bar meter, the environmental test temperature is regulated to be 20-25 ℃, and the influence of temperature change on the calibration result is not considered. The Chenxin stiffness of the hydrological instrument and the geotechnical engineering instrument quality supervision, inspection and test center of the department of Water conservancy is tested according to the measurement performance indexes such as nonlinearity, nonrecurring degree, hysteresis, comprehensive error, full-scale output and the like of the fiber grating strain type steel bar meter in GB/T13606-2007 Universal technical conditions of a vibrating wire type sensor of geotechnical engineering instruments, but the measurement performance indexes are greatly different from the working principle of the two instruments, so that the measurement method of the vibrating wire type steel bar meter cannot completely reflect all the measurement performance of the fiber grating strain type steel bar meter, cannot effectively control the quality of an instrument manufacturer, and cannot ensure the quality of a product which leaves a factory and the safety of the use engineering of the instrument.
Therefore, the device and the method for calibrating the measurement of the fiber grating strain type steel bar meter are researched to realize the high-precision calibration of the mechanical performance of the fiber grating strain type steel bar meter, effectively reduce the influence of the environmental temperature change on the calibration result and have important significance for improving the product quality of the fiber grating strain type steel bar meter.
Disclosure of Invention
In order to solve the problem, an object of the utility model is to provide a fiber grating strain gauge measurement calibrating device.
In order to achieve the purpose, the utility model provides a fiber grating strain gauge reinforcement metering and calibrating device, which comprises a fiber grating strain gauge reinforcement gauge, a constant temperature water tank, a platinum resistance thermometer clamping device, a fiber grating demodulator, a digital multimeter, a standard load device and an upper computer; the fiber bragg grating strain type steel bar meter is vertically placed in a constant-temperature water tank during temperature calibration; the platinum resistance thermometer is vertically placed in the constant-temperature water tank through the platinum resistance thermometer clamping device; the fiber bragg grating demodulator is electrically connected with the fiber bragg grating strain type steel bar gauge and the upper computer at the same time; the platinum resistance thermometer is electrically connected with the digital multimeter; the fiber bragg grating strain type steel bar meter is fixed on the standard load device during mechanical property calibration, and the standard load device is electrically connected with the upper computer.
The fiber grating strain type steel bar meter comprises steel bars, a fiber grating strain type sensor and a fiber grating temperature type sensor; the fiber grating strain sensor and the fiber grating temperature sensor are fixed outside the steel bar, the axial direction of the fixed part on the fiber grating strain sensor and the fiber grating temperature sensor is parallel to the axial direction of the steel bar, and two ends of the fiber grating strain sensor and the fiber grating temperature sensor are connected to the fiber grating demodulator.
The reinforcing steel bar is made of deformed steel bars or round steel bars, and the section diameter is 12mm, 14mm, 16mm, 18mm or 22 mm.
In the constant temperature water tank, the fiber grating strain sensor, the fiber grating temperature sensor and the platinum resistance thermometer are arranged at the same height as each other.
The platinum resistance thermometer adopts a four-wire first-class or second-class standard platinum resistance thermometer.
The utility model has the advantages that: the current situation to at present domestic no special fiber grating strain gauge reinforcing bar meter measurement technical specification, the utility model provides a fiber grating strain gauge reinforcing bar meter measurement calibrating device and method has solved the influence of ambient temperature influence to fiber grating strain gauge reinforcing bar meter measurement accuracy, provides the technical basis for instrument production unit to fiber grating strain gauge reinforcing bar meter before dispatching from the factory performance test, also provides effectual method for the field data correction of application unit, has promoted fiber grating strain gauge reinforcing bar meter measurement accuracy and data credibility.
Drawings
The accompanying drawings, which form a part hereof, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.
Fig. 1 is the utility model provides a fiber grating strain gauge reinforcing bar meter measurement calibrating device structure picture.
Fig. 2 is the utility model provides a fiber grating strain gauge rebar meter measurement calibration method flow chart.
Fig. 3 is the utility model provides a fiber grating strain gauge structure picture among the fiber grating strain gauge measurement calibrating device.
FIG. 4 is a least square linear fitting result diagram of the corresponding temperature measurement points of the fiber grating temperature sensor and the platinum resistance thermometer.
FIG. 5 is a least square method straight line fitting result diagram of the central wavelength value of the fiber grating strain sensor and the temperature correction value of the corresponding temperature measurement point of the fiber grating temperature sensor.
FIG. 6 is a least square method straight line fitting result diagram of the standard load value output by the standard load device and the central wavelength variation measured by the corresponding load measuring point of the fiber grating strain type reinforcing steel meter.
Detailed Description
The following describes the measurement and calibration device of the fiber grating strain gauge steel bar meter in detail with reference to the accompanying drawings and specific embodiments.
It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict.
As shown in fig. 1, the utility model provides a fiber grating strain gauge measurement calibrating device includes fiber grating strain gauge 10, constant temperature water tank 20, platinum resistance thermometer 30, platinum resistance thermometer clamping device 40, fiber grating demodulator 50, digital multimeter 60, standard load device 70 and host computer 80; the fiber bragg grating strain type steel bar meter 10 is vertically placed in a constant-temperature water tank 20 during temperature calibration; the platinum resistance thermometer 30 is vertically placed in the constant-temperature water tank 20 through a platinum resistance thermometer clamping device 40; the fiber grating demodulator 50 is simultaneously electrically connected with the fiber grating strain type steel bar meter 10 and the upper computer 80; the platinum resistance thermometer 30 is electrically connected with the digital multimeter 60; the fiber grating strain type steel bar meter 10 is fixed on the standard load device 70 during mechanical property calibration, and the standard load device 70 is electrically connected with the upper computer 80.
As shown in fig. 3, the fiber grating strain gauge 10 includes a steel bar 101, a fiber grating strain sensor 102 and a fiber grating temperature sensor 103; the steel bar 101 can be in the form of deformed steel bar, round steel and the like, the material can be 304 steel and the like, and the section diameter can be 12mm, 14mm, 16mm, 18mm, 22mm and other conventional sizes; the fiber grating strain sensor 102 and the fiber grating temperature sensor 103 are fixed at the middle part outside the steel bar 101, the axial direction of the fixed part on the fiber grating strain sensor 102 and the fiber grating temperature sensor 103 is parallel to the axial direction of the steel bar 101, and the two ends are connected to the fiber grating demodulator 50.
In the fiber grating strain gauge 10, the temperature measuring range of the fiber grating temperature sensor 103 is (-30- + 125) DEG C, and the temperature resolution is 0.1 ℃.
In the constant-temperature water tank 20, the fiber grating strain gauge 102 and the fiber grating temperature gauge 103 in the fiber grating strain gauge 10 are placed at the same height as the measurement points of the platinum resistance thermometer 30.
The temperature variation range of the constant temperature water tank 20 is (-5- + 100 ℃), the temperature fluctuation degree is +/-0.05 ℃, and the temperature uniformity degree is +/-0.05 ℃.
The platinum resistance thermometer 30 is a four-wire first-class or second-class standard platinum resistance thermometer.
The strain measuring range of the fiber bragg grating strain type steel bar meter measuring and calibrating device is (-1500- + 1500) mu epsilon, the diameter of the selection steel bar 101 is 16mm, the material is 304 steel, and when the shape is round steel, the measuring uncertainty is U-0.74 kN, and k-2.
As shown in fig. 2, the measurement calibration method using the fiber grating strain gauge measurement calibration apparatus includes the following steps performed in sequence:
step 001: device connection initialization:
vertically placing the fiber bragg grating strain type steel bar meter 10 in a constant-temperature water tank 20; the upper end of a platinum resistance thermometer 30 is fixed on a platinum resistance thermometer clamping device 40, the lower part of the platinum resistance thermometer 30 is placed in a constant temperature water tank 20, the measuring point of the platinum resistance thermometer 30 is arranged to be equal to the measuring point of a fiber grating strain sensor 102 and a fiber grating temperature sensor 103 in a fiber grating strain type rebar meter 10 in height, the fiber grating strain type rebar meter 10 is connected to an upper computer 80 through a fiber grating demodulator 50, the platinum resistance thermometer 30 is connected with a digital multimeter 60, the digital multimeter 60 is adjusted to a resistance level, the machine is started to preheat for 30min, and the serial port of the upper computer 80 is initialized;
adjusting the water temperature in the constant-temperature water tank 20 to 0 ℃, after stabilizing for 30 minutes, reading the temperature value at the height of the fiber grating strain sensor 102 and the like in the constant-temperature water tank 20, which is measured by the platinum resistance thermometer 30 and is displayed by the digital multimeter 60, and respectively reading the central wavelength value measured by the fiber grating strain sensor 102 in the fiber grating strain type steel bar meter 10 and the temperature value measured by the fiber grating temperature type sensor 103 from the upper computer 80;
then, taking every 10 ℃ as a first-stage temperature measuring point, gradually increasing the water temperature in the constant-temperature water tank 20 to 60 ℃, and after the water temperature is stabilized for 30 minutes at each stage of temperature measuring point, sequentially recording the measuring data of the platinum resistance thermometer 30, the fiber grating strain type sensor 102 and the fiber grating temperature type sensor 103 according to the mode;
then, from 60 ℃, taking every 10 ℃ as a first-stage temperature measuring point, gradually reducing the water temperature in the constant-temperature water tank 20 to 0 ℃, and after the temperature at each stage is stabilized for 30 minutes, sequentially recording the measurement data of the platinum resistance thermometer 30, the fiber grating strain sensor 102 and the fiber grating temperature sensor 103 according to the above mode;
averaging corresponding measurement data of the platinum resistance thermometer 30, the fiber grating strain sensor 102 and the fiber grating temperature sensor 103 at each temperature measurement point in the temperature rising and lowering process and taking the average value as respective final measurement value, and recording the temperature value measured by the fiber grating temperature sensor 103 at 0 ℃ as an initial temperature value TF0The central wavelength value measured by the fiber grating strain sensor 102 at 0 ℃ is recorded as the initial central wavelength value lambdaT0；。
taking the fiber grating strain type reinforcing steel bar meter 10 out of the constant-temperature water tank 20, fixing the upper end and the lower end of a reinforcing steel bar 101 on the standard load device 70, preloading the fiber grating strain type reinforcing steel bar meter 10 within the measuring range of the fiber grating strain type reinforcing steel bar meter 10, recovering the fiber grating strain type reinforcing steel bar meter 10 to be in a zero-load state and stable, reading a central wavelength value measured by the fiber grating strain type sensor 102 demodulated by the fiber grating demodulator 50 from the upper computer 80, and taking the central wavelength value as an initial wavelength value lambda of the fiber grating strain type reinforcing steel bar meter 100；
The preloading method comprises loading the standard load value applied by the standard load device 70 and the corresponding fiber grating strain type reinforcing steel bar meter within the range of 10% of the fiber grating strain type reinforcing steel bar meter by taking 10% of the full range as a first-stage load measuring point step by step until the full-range load value is reached, stabilizing each stage for at least 3min, and recording the standard load value and the corresponding fiber grating strain type reinforcing steel bar meterThe central wavelength value measured by the fiber grating strain type sensor 102 on the reinforcing steel bar meter 10 is synchronously recorded, and the environmental temperature value T near the fiber grating strain type reinforcing steel bar meter 10 measured by the fiber grating temperature type sensor 103 at the corresponding load measuring point is synchronously recordedsThen, gradually reducing the load from the full-scale load value to a zero load state according to the method, recording the measured values, and circularly measuring for 3 times;
temperature value T measured by platinum resistance thermometer 30 at each temperature measurement point in constant temperature water tank 20Ri(i is 0, 1,2,3, 4, 5, 6) as an argument, and the temperature value T at the time of corresponding to different temperature measurement points in the constant-temperature water bath 20 measured by the fiber grating temperature sensor 103Fi(i is 0, 1,2,3, 4, 5, 6) as a dependent variable, and performing least square linear fitting according to formula (1), thereby establishing a corresponding relationship between the platinum resistance thermometer 30 and the temperature value measured by the fiber grating temperature sensor 103, and realizing temperature value calibration measured by the fiber grating temperature sensor 103:
TFWi＝kT×TRi+bR (1)
in the formula (I), the compound is shown in the specification,
TFWi-on the least squares line with TRiCorresponding TFi，i＝0，1，2，3，4，5，6
kT-temperature sensitivity factor;
bRthe fiber grating temperature sensor 103 on the least square straight line measures the temperature value at 0 ℃ in the constant temperature water tank 20 measured by the platinum resistance thermometer 30;
005, establishing a corresponding relation between the temperature calibration value of the fiber grating temperature type sensor 103 and the central wavelength value measured by the fiber grating strain type sensor 102:
the temperature values at the temperature measuring points of each stage in the constant temperature water tank 20 measured by the fiber grating temperature type sensor 103 calibrated by the platinum resistance thermometer 30For initial temperature value TF0Change amount of (Δ T)Fi(ΔTFi＝TFi-TF0I is 0, 1,2,3, 4, 5, 6) as an independent variable, and the center wavelength value λ at each temperature measurement point at a position such as a height of the fiber grating temperature sensor 103 in the constant temperature water tank 20 measured by the fiber grating strain sensor 102TiRelative to the initial central wavelength value λT0Change amount of (a) λTi(ΔλTi＝λTi-λT0I-0, 1,2,3, 4, 5, 6) as a dependent variable, where λTiPerforming least square linear fitting according to a formula (2) for the central wavelength value of each level of temperature measurement points at the same height as the fiber grating temperature sensor 103 in the constant-temperature water tank 20 measured by the fiber grating strain sensor 102, thereby establishing the corresponding relation between the temperature calibration value of the fiber grating temperature sensor 103 and the central wavelength value measured by the fiber grating strain sensor 102;
ΔλTi＝kλ×ΔTFi+bF (2)
in the formula (I), the compound is shown in the specification,
ΔλTWi-least squares on-line with Δ TFiCorresponding delta lambdaTi(i＝0，1，2，3，4，5，6)，nm；
kλ-a strain sensitivity coefficient;
bFthe fiber grating strain gauge sensor 102 on the least squares straight line measures the central wavelength variation, nm, of the temperature value in the constant temperature water tank 20 at 0 ℃ in the platinum resistance thermometer 30.
the environmental temperature value T recorded by the fiber bragg grating temperature type sensor 103 in the step 005 at each level of load measuring pointFij(i is 1,2, … …, 10, j is 1,2,3, … …, 6) is substituted into the formula (2), and the central wavelength variation quantity delta lambda of the fiber grating strain gauge sensor 102 caused by the environmental temperature variation at each stage of load measuring point is calculatedTij(i＝1，2，……，10，j＝1，2，3，……，6)；
Calculating the central wavelength value lambda measured by the fiber grating strain sensor 102 in the 3-time cyclic measurement process of each load measurement point according to the formula (3)ijWith an initial wavelength value λ0Average value of difference:
in the formula (I), the compound is shown in the specification,
Δλithe average value of the difference between the central wavelength value and the initial wavelength value measured by the fiber grating strain gauge 102 on the fiber grating strain gauge 10 in the 3-cycle measurement process at the i-th-level load measurement point (i ═ 1,2,3, … …, 10) is nm;
λijthe central wavelength value, nm, measured by the fiber grating strain gauge 102 on the fiber grating strain gauge 10 during the ith-level load measurement point (i ═ 1,2,3, … …, 10) and the jth (j ═ 1,2,3, … …, m) measurement process;
ΔλTijthe amount of change in the center wavelength measured by the fiber grating strain gauge sensor 102 due to a change in the ambient temperature ( i 1,2, … …, 10, j 1,2,3, … …, 6), nm;
m is the number of times of measuring the loading and unloading travel, and m is 6.
The average value delta lambda of the difference value between the central wavelength value and the initial wavelength value measured by the fiber grating strain type sensor 102 on the fiber grating strain type steel bar meter 10iAs independent variable, the average value F of the load applied by the standard load device 70 is usediPerforming least square method linear fitting according to a formula (5) as a dependent variable, and calculating to obtain a load measurement value F of the fiber grating type reinforcing steel bar meter 10Wi：
Wherein the content of the first and second substances,
in the formula (I), the compound is shown in the specification,
FPi-each stage of load during the loading stroke of the standard loading device 70Loading a standard load applied by a measuring point, kN;
FMithe standard load applied by each level of load measuring point during the load reduction stroke of the standard load device 70 is kN;
FWi＝k×Δλi+C (5)
in the formula:
FWi-on the least squares line with Δ λiCorresponding Fi(i＝0，1，2，3，4，5，6)，nm
k is the sensitivity coefficient of the fiber grating strain type steel bar meter 10, kN/nm;
c is the load measurement value kN of the fiber grating strain type reinforcing steel bar meter 10 in the free state.
calculating the load measurement value F of the fiber grating strain type steel bar meter 10 according to the formula (6)WiAverage value F of load applied by standard load device 70iMaximum error delta betweenL。
In the formula (I), the compound is shown in the specification,
FFSthe full-scale load value kN of the fiber grating strain gauge type rebar meter 10.
When the device works, a 304-material round steel type fiber grating type reinforcing steel bar meter with the cross section diameter of 22mm is selected for verification, the upper limit of load measurement of the fiber grating type reinforcing steel bar meter 10 is (0-40) kN, temperature correction is firstly carried out on the fiber grating strain type reinforcing steel bar meter 10, a platinum resistance thermometer 30 is used as a measurement standard, the platinum resistance thermometer 30 and a fiber grating temperature type sensor 103 on the fiber grating strain type reinforcing steel bar meter 10 are placed in a constant-temperature water tank 20 at the same height, in the range of 0-60 ℃, every 10 ℃ is used as a first-level temperature measurement point, temperature rise and temperature reduction tests are carried out, and measurement data of each sensor in the temperature rise and temperature reduction process at each temperature measurement point are averaged to be used as a final measurement value, as shown in table 1.
TABLE 1 measurement data of various sensors in constant-temperature water tank
The corresponding relationship between the temperature value measured by the platinum resistance thermometer 30 and the temperature value measured by the fiber grating temperature sensor 103 at the corresponding temperature measurement point at the same height as the platinum resistance thermometer 30 in the constant temperature water tank 30 is established according to the formula (1), as shown in fig. 4, there are:
TFWi＝1.002×TRi+0.249 (7)
thereby obtaining TFWiThe values of (A) are shown in Table 2.
TABLE 2 temperature correction value of fiber grating temperature sensor
| Serial number | Temperature measurement value (. degree. C.) of fiber grating temperature sensor | Temperature correction value (DEG C) of fiber bragg grating |
| 1 | 0.289 | 0.284 |
| 2 | 10.261 | 10.293 |
| 3 | 20.334 | 20.296 |
| 4 | 30.325 | 30.292 |
| 5 | 40.346 | 40.308 |
| 6 | 50.331 | 50.301 |
| 7 | 60.332 | 60.311 |
According to the formula (2), the corresponding relationship between the difference value of the temperature correction value of the fiber grating temperature sensor 103 at each temperature measurement point in the constant temperature water tank 30 relative to the temperature correction value at the initial temperature value and the central wavelength variation value of the fiber grating strain gauge sensor 102 at the corresponding temperature measurement point is established, and because the central wavelength variation is small, the central wavelength variation value is amplified by 1000 times and then subjected to least square method straight line fitting, as shown in fig. 5, the method comprises the following steps:
ΔλTi＝0.631×ΔTFi-0.288 (8)
the fiber grating strain type steel bar meter 10 is fixed on a standard load device 70, a 0.1-level microcomputer control superposition type force standard machine is selected, the measurement range is 0-100kN, the fiber grating strain type steel bar meter 10 is loaded and unloaded step by step according to 10% of full range (F.S) within the measurement range of 0-40kN, and the measurement data are shown in table 3.
TABLE 3 center wavelength values during loading-unloading of fiber grating strain type rebar gauges
During the measurement, the laboratory temperature is kept within (21 ± 2) ° c, and when the temperature reaches the upper limit of 22 ℃, the temperature can be obtained according to the formula (8):
ΔλTi＝[0.631×(23-0)-0.288]/1000＝0.0142nm
then when the temperature reaches the lower limit of 19 ℃, it can be obtained according to equation (8):
ΔλTi＝[0.631×(19-0)-0.288]/1000＝0.0117nm
when the temperature is maintained at 21 ℃, it can be obtained according to the formula (8):
ΔλTi＝[0.631×(21-0)-0.288]/1000＝0.0130nm
then within the range of the upper and lower limits of the temperature change, lambda is tested0Is measured at 0 deg.C, in this embodiment, for the convenience of calculation, the change value of the central wavelength at 23 deg.C of the upper limit value of the temperature change is temporarily taken as Δ λTijA value of (1), i.e. let Δ λTijWhen the average particle diameter is 0.0142nm, Δ λ is calculated according to the formula (3)iThe results are shown in Table 4, where λ0F is calculated by equation (4) at 1584.785nmiThe results are also shown in Table 4.
Table 4 central wavelength variation value and standard load value of fiber grating strain type reinforcing bar meter in loading-unloading process
Calculating a standard load value F according to the formula (5)iCentral wavelength variation delta lambda of strain type steel bar meter with fiber bragg gratingiThe correspondence between them, as shown in fig. 6, includes:
FWi＝16.123×Δλi+2.395 (9)
each level of the standard loading value F applied to the standard loading device 70iThe temperature compensated load values measured by the fiber grating strain gauge 10 are shown in table 5.
TABLE 5 Standard and measured load values at the load measurement points
In table 5, when the load is 0kN, that is, the fiber grating strain gauge 10 is in a free state, through the three preloading-unloading processes and the forward and backward stroke test processes, although the load is 0, the fiber grating strain gauge 10 does not return to an unstressed state, so that the error is large when the load is 0kN, and this data can be rejected during calculation, which is shown in formula (6):
when the field application, generally for using the unit to provide k, C value, if not according to the utility model provides a method carries out steady compensation calibration, then when 23 ℃, fiber grating strain gauge rebar meter 10 will have because the central wavelength variation delta lambda that temperature variation arousesTijThe load measurement value of the fiber grating strain gauge 10 has an error of 16.123 × 0.0142 ═ 0.229kN at 0.0142nm, which affects the accuracy and reliability of the field measurement data.
The above-mentioned embodiments are only used for illustrating the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention accordingly, the scope of the present invention should not be limited by the embodiment, that is, all equivalent changes or modifications made by the spirit of the present invention should still fall within the scope of the present invention.
Claims (5)
1. The utility model provides a fiber grating strain gauge rebar meter measurement calibrating device which characterized in that: the fiber grating strain type steel bar meter measuring and calibrating device comprises a fiber grating strain type steel bar meter (10), a constant-temperature water tank (20), a platinum resistance thermometer (30), a platinum resistance thermometer clamping device (40), a fiber grating demodulator (50), a digital multimeter (60), a standard load device (70) and an upper computer (80); the fiber bragg grating strain type steel bar meter (10) is vertically placed in a constant-temperature water tank (20) during temperature calibration; the platinum resistance thermometer (30) is vertically placed in the constant-temperature water tank (20) through a platinum resistance thermometer clamping device (40); the fiber grating demodulator (50) is simultaneously electrically connected with the fiber grating strain type steel bar meter (10) and the upper computer (80); the platinum resistance thermometer (30) is electrically connected with the digital multimeter (60); the fiber bragg grating strain type steel bar meter (10) is fixed on a standard load device (70) during mechanical property calibration, and the standard load device (70) is electrically connected with an upper computer (80).
2. The fiber grating strain gauge rebar gauge metering and calibrating device of claim 1, wherein: the fiber grating strain type steel bar meter (10) comprises steel bars (101), a fiber grating strain type sensor (102) and a fiber grating temperature type sensor (103); the fiber grating strain sensor (102) and the fiber grating temperature sensor (103) are fixed at the middle parts outside the steel bar (101), the axial directions of the fixed parts on the fiber grating strain sensor (102) and the fiber grating temperature sensor (103) are parallel to the axial direction of the steel bar (101), and two ends of the fixed parts are connected to the fiber grating demodulator (50).
3. The fiber grating strain gauge rebar gauge metering and calibrating device of claim 2, wherein: the steel bar (101) is made of deformed steel bars or round steel bars, and the section diameter is 12mm, 14mm, 16mm, 18mm or 22 mm.
4. The fiber grating strain gauge rebar gauge metering and calibrating device of claim 1, wherein: in the constant temperature water tank (20), the fiber grating strain type sensor (102) and the fiber grating temperature type sensor (103) are arranged at the same height as the measuring point of the platinum resistance thermometer (30).
5. The fiber grating strain gauge rebar gauge metering and calibrating device of claim 1, wherein: the platinum resistance thermometer (30) adopts a four-wire first-class or second-class standard platinum resistance thermometer.
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| CN112945127A (en) * | 2021-04-07 | 2021-06-11 | 交通运输部天津水运工程科学研究所 | Fiber grating strain type rebar meter metering calibration device and method |
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| CN112945127A (en) * | 2021-04-07 | 2021-06-11 | 交通运输部天津水运工程科学研究所 | Fiber grating strain type rebar meter metering calibration device and method |
| CN112945127B (en) * | 2021-04-07 | 2024-05-31 | 交通运输部天津水运工程科学研究所 | Fiber bragg grating strain type rebar meter metering calibration device and method |
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