CN108917831B - Polymer-encapsulated grating sensor and correction method for viscoelastic effect of sensor - Google Patents
Polymer-encapsulated grating sensor and correction method for viscoelastic effect of sensor Download PDFInfo
- Publication number
- CN108917831B CN108917831B CN201810630036.6A CN201810630036A CN108917831B CN 108917831 B CN108917831 B CN 108917831B CN 201810630036 A CN201810630036 A CN 201810630036A CN 108917831 B CN108917831 B CN 108917831B
- Authority
- CN
- China
- Prior art keywords
- grating
- test
- sensor
- strain
- load
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
Abstract
The invention discloses a polymer packaging grating sensor, which belongs to the field of sensors and comprises a deformation component, a test component and a grating demodulation system; the deformation component comprises a left fixed end, a large deformation unit, a grating packaging unit and a right fixed end; the test component comprises a grating packaging unit, a strain test grating and a temperature test grating; the grating demodulation system comprises an integrated grating demodulator and an optical fiber; the polymer-encapsulated grating sensor has large deformation capacity by combining with the large deformation unit, and can meet the requirement of accurate measurement of large displacement; the invention also discloses a correction method of the viscoelastic effect of the sensor; the method corrects the viscoelastic effect error in the sensor testing process through the unidirectional stretching experiment and the convolution algorithm, and the viscoelastic effect correction method can meet the correction requirement of the viscoelastic effect error in the polymer packaging grating sensor and the general sensor testing process, and improves the sensor testing accuracy and the measuring range.
Description
Technical Field
The invention relates to the field of sensors, in particular to a polymer-encapsulated fiber grating sensor, and particularly relates to a correction method for viscoelastic effect of the polymer-encapsulated grating sensor and a general sensor.
Background
The fiber Bragg grating sensor is a novel fiber sensing device, has the advantages of high sensitivity, electromagnetic interference resistance, small volume, light weight and the like, and has wide application prospect in the aspects of strain measurement, temperature measurement and the like. Currently, fiber grating sensors have been widely used in the fields of aerospace, civil engineering, transportation, and the like. However, the fiber grating sensor is limited by the material performance, and has the defects of small elastic deformation limit (1-3%), brittle property, poor toughness and the like, so that the fiber grating sensor can not measure large extension deformation and can not bear a severe test environment.
The optical fiber packaging technology is characterized in that the optical fiber grating sensor is embedded into the protective material, so that the optical fiber grating sensor is protected while realizing the test function, and even the test performance of the optical fiber grating is improved. Common packaging materials are metal, concrete, ceramic, composite materials, polymer resins, and the like. Among them, polymer packaging based on additive manufacturing has advantages of low cost, high efficiency, customization, etc., and is receiving increasing favor from academia and industry. However, the polymer material has viscoelasticity, which causes the test result of the polymer-encapsulated fiber grating sensor to change with time, resulting in test errors.
Besides the viscoelastic effect of the polymer in the polymer-encapsulated fiber grating sensor, the viscoelastic effect also exists in the polymer fiber grating sensor and the adhesive for bonding the fiber grating sensor. When the strain of the common polymer fiber grating sensor is more than 2%, the central wavelength of the Bragg grating can change along with time due to the viscoelasticity existing in the material. In addition, the use of a highly viscoelastic adhesive also results in a reduction in the accuracy of the test results of the surface-mounted fiber grating sensor. And for the polymer encapsulated fiber grating sensor, the viscoelastic effect of the sensor is more serious. Up to now, the use of polymer sensors by numerous scholars has been limited to controlling the deformation of the sensor in the linear elastic range, i.e. in the small strain range, so as to realize the measurement of strain or displacement by the grating sensor. This approach limits the strain measurement potential of polymer grating sensors in high strain environments.
Disclosure of Invention
The invention discloses a polymer encapsulated grating sensor aiming at the defects of limited elastic elongation rate, low fracture toughness and the like of the sensor in the prior art, wherein the sensor is provided with a large deformation unit which has large deformation capacity and can bear large elongation; the invention also discloses a correction method of the viscoelasticity effect of the general sensor, which meets the accuracy requirement of large displacement measurement of the sensor.
The invention is realized by the following steps:
a polymer packaging grating sensor comprises a deformation component, a test component and a grating demodulation system; the deformation component comprises a left fixed end, a large deformation unit, a grating packaging unit and a right fixed end, wherein the rear end of the left fixed end is sequentially connected with the large deformation unit, the grating packaging unit and the right fixed end; the testing component comprises a grating packaging unit, a strain testing grating and a temperature testing grating; the grating demodulation system comprises an integrated grating demodulator and an optical fiber; the strain test grating and the temperature test grating are sequentially connected in series on an optical fiber, and the optical fiber is connected with the integrated demodulator; the grating area of the strain test grating is completely encapsulated on the grating encapsulation unit; the grating area of the temperature test grating is suspended and is not stressed; the packaging mode comprises an embedding mode or a pasting mode; the wavelength of the grating Bragg of the strain test grating is different from that of the grating Bragg of the temperature test grating, and the distance between the grating Bragg wavelengths is more than one full width at half maximum, so that interference generated in the measuring process is ensured.
The detection result of the strain test grating comprises a temperature signal and a strain signal, the temperature test grating only measures the temperature signal, and the temperature measurement grating can be used for correcting the temperature error during the measurement of the strain grating. The strain test grating and the temperature test grating are connected through optical fibers.
In order to eliminate the interference of temperature on the strain measurement of the strain test grating, the temperature interference in the strain measurement process of the strain test grating needs to be corrected. The temperature test grating grid region can be packaged in the grating packaging unit in a mode of packaging one end, or prestress is applied to enable the grid region to be suspended, the temperature test grating does not receive strain, and the temperature test grating measures temperature change and is used for correcting temperature interference in strain test of the strain test grating. The strain test grating is acted by temperature and strain together, and the temperature test grating is only acted by temperature.
Furthermore, the large deformation unit is a structure or a material with large elastic deformation. The large deformation unit selected by the novel polymer-encapsulated fiber grating sensor provided by the invention has a member or material with large elastic deformation, can be suitable for the situation with large displacement measurement requirements, and has the advantages of electromagnetic interference resistance, corrosion resistance, multiplexing capability and the like of the grating sensor.
Further, the large deformation unit is a spring, the inner diameter of the spring is 16mm, the outer diameter of the spring is 24mm, the number of turns of the spring is 5, and the pitch of the spring is 5 mm.
Further, the diameter of the optical fiber is 250 μm.
Furthermore, the grating packaging unit is made of elastic or viscoelastic material; the packaging method can adopt an embedding or pasting mode; the packaging method of the grating comprises the steps of adhering or embedding the surface of the adhesive; the embedding method is adopted for packaging without using an adhesive.
Furthermore, the diameter of the grating packaging unit is 4mm, and the length of the grating packaging unit is 40 mm.
Further, when the grating is in a surface pasting mode: the strain test grating is completely packaged on the surface of the grating packaging unit through the first adhesive, one side end part of the temperature test grating is packaged on the grating packaging unit through the second adhesive, so that a grating region of the temperature test grating is suspended and does not directly receive strain, the temperature test grating measures temperature change and is used for correcting temperature interference in strain test of the strain test grating, and the adhesive is a viscoelastic material.
The invention also discloses a correction method for the viscoelastic effect by using the polymer encapsulated grating sensing, which is not only suitable for correcting the viscoelastic effect of the sensor, but also suitable for correcting the viscoelastic effect in the test process of a general sensor, and comprises the following specific steps:
the method comprises the following steps: step load unidirectional tension experiment;
step two: obtaining an effective relaxation modulus of the sensor;
2.1, according to the step one, obtaining a strain response curve delta epsilon of the sensor grating under the action of the step load in the uniaxial tension experimentstep(t)；
2.2, the viscoelastic effect of the sensor is assumed to be linear, assuming the test environment temperature is much less than the glass transition temperature of the polymer adhesive. The grating strain and the displacement load conform to the boltzmann linear superposition principle, and the simple expression of the convolution form is as follows:
Δε(t)＝Y(t)*dΔL(t)＝dY(t)*ΔL(t)
wherein Δ ∈ (t) is the strain measured by the grating, y (t) is the member effective visco-elastic coefficient, a convolution symbol, d Δ l (t) is the member displacement differential with respect to time, dy (t) is the member effective visco-elastic coefficient differential with respect to time, and Δ l (t) is the displacement load;
2.3, according to the formula Δ ∈ (t) ═ y (t) ═ d Δ L (t) ═ dy (t) · Δ L (t) and the step load Δ L in the uniaxial tension teststep(t) and Grating Strain response Deltaεstep(t) calculating the effective visco-elastic modulus y (t) of the sensor by a deconvolution algorithm;
step three: performing complex load unidirectional tensile test;
3.1, applying a unidirectional displacement load along the axial direction of the test piece, wherein the displacement load is a complex load delta Lcomplex(t)；
3.2, according to the wavelength change Delta lambda of the strain test grating and the temperature test grating sensorFBG1And Δ λFBG2Calculating the temperature change delta T (t) in the test process and the strain change delta epsilon in the test piececomplex(t)；
Step four: obtaining a grating strain response curve of a complex load tensile experiment:
obtaining the grating strain response delta epsilon of the time-dependent complex load uniaxial tension experiment according to the step 3.2complex(t)；
Step five: deconvolution:
according to the formula Δ ∈ (t) ═ y (t) · d Δ l (t), effective viscoelastic modulus y (t) in step 2.3, and grating strain response curve Δ ∈ (t) in step fourcomplex(t) calculating the differential d Delta L of the displacement load to the time by combining with a deconvolution algorithmcomplex(t)；
Step six: integral calculation;
for d Δ L (t), completing the integral calculation of the d Δ L (t) over time, and reconstructing the complex load Δ L related to timerc(t), i.e. the reconstructed complex displacement load Δ Lrc(t)。
Further, the uniaxial tension test in the step load uniaxial tension test and the complex load uniaxial tension test specifically comprises the following steps:
1.1, connecting two ends of a polymer packaging fiber grating sensor with a test target, applying unidirectional displacement load along the axial direction of a test piece, wherein the displacement load is respectively step load delta L according to the experimental purposestep(t) or Complex CarrierCharge Δ Lcomplex(t)；
1.2, under the combined action of temperature and displacement load, the central wavelength of the strain test grating sensor drifts; the detection result of the strain test grating comprises a temperature signal and a strain signal, and the temperature test grating only measures the temperature signal. In addition, due to the change of the temperature, the central wavelength of the temperature test grating sensor is also changed;
1.3 according to the formula
And the wavelength variation Delta lambda of the strain test grating and the temperature test grating sensorFBG1And Δ λFBG2Calculating the temperature change delta T and the strain change delta epsilon (T) in the test piece in the test process;
in the formula, Δ λFBG1,ΔλFBG2Respectively is the central wavelength variation, lambda, of the strain test grating (7) and the temperature test grating (8)FBG1,λFBG2The initial central wavelengths of the strain test grating (7) and the temperature test grating (8) are respectively; cεFor strain-testing the strain coefficient, C, of the grating (7)TFor the temperature coefficients of the strain test grating (7) and the temperature test grating (8), Δ T, Δ ε represent the temperature and strain changes, respectively. By detecting a change in the wavelength of the Bragg gratingFBG1And Δ λFBG2The strain of the strain test grating (7) on the packaging unit can be calculated by a formula.
Furthermore, the correction method of the viscoelastic effect of the polymer encapsulated grating sensor is not limited to the application in the polymer encapsulated grating sensor, and can also be applied to correction of the viscoelastic effect in a viscoelastic effect test of a general displacement sensor. The method of the invention can correct the viscoelasticity effect error in the test of a common sensor, improve the accuracy of the displacement measurement of the sensor and enlarge the measurement range.
Compared with the prior art, the invention has the beneficial effects that:
1. the polymer-encapsulated grating sensor has large deformation capacity by combining with the large deformation unit, and can meet the requirement of accurate measurement of large displacement; meanwhile, the polymer-encapsulated grating sensor also keeps the advantages of electromagnetic interference resistance, corrosion resistance, multiplexing property and the like of a common grating sensor;
2. the polymer package can protect the fiber grating sensor and improve the toughness of the sensor; the sensor has large deformation capacity by combining a large deformation unit with a packaging unit, and the measurement range of the sensor is enlarged;
3. according to the polymer encapsulated grating and the correction method of the viscoelastic effect, correction of viscoelastic errors in sensor testing can be realized, and the measurement accuracy of the sensor is improved; the effective viscoelasticity modulus of the sensor is obtained through a unidirectional stretching experiment, and the measurement efficiency and accuracy are improved;
4. the polymer-encapsulated fiber grating sensor has a viscoelastic effect, and a viscoelastic correction method based on a convolution theory can effectively eliminate measurement errors caused by the viscoelastic effect of the polymer-encapsulated grating sensor.
Drawings
FIG. 1 is a schematic view of a polymer-encapsulated fiber grating sensor according to the present invention;
FIG. 2 is a diagram illustrating an example of a polymer-encapsulated FBG sensor according to an embodiment of the present invention;
FIG. 3 is a flow chart of a correction algorithm for viscoelastic effect of a polymer encapsulated fiber grating sensor according to the present invention;
FIG. 4 is a schematic view showing the effect of correcting the viscoelastic effect of the polymer-encapsulated fiber grating sensor according to the present invention;
the optical fiber grating sensor comprises a left fixed end 1, a large deformation unit 2, a first adhesive 3, a grating packaging unit 4, a second adhesive 5, an integrated grating demodulator 6, a strain test grating 7, a temperature test grating 8, a right fixed end 9 and an optical fiber 10.
Detailed Description
In order to make the objects, technical solutions and effects of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be noted that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
As shown in fig. 1, fig. 1 is a schematic diagram of a polymer-encapsulated fiber grating sensor adopting an adhesive surface adhesion encapsulation method, and the polymer-encapsulated fiber grating sensor of the present invention includes a left fixing end 1, a large deformation unit 2, a first adhesive 3, a grating encapsulation unit 4, a second adhesive 5, an integrated grating demodulator 6, a strain test grating 7, a temperature test grating 8, a right fixing end 9, and an optical fiber 10.
Wherein, the left fixed end 1, the large deformation unit 2, the grating packaging unit 4 and the right fixed end 9 form a deformation component; the first adhesive 3, the second adhesive 5, the grating packaging unit 4, the strain test grating 7 and the temperature test grating 8 form a test component, and the integrated grating demodulator 6 and the optical fiber 10 form a grating demodulation system.
As shown in fig. 2, fig. 2 is a diagram of an example of a structure of a polymer-packaged fiber grating sensor according to an embodiment of the present invention, a large deformation unit 2 employs a spring, wherein the grating is packaged by using an adhesive to adhere to the surface, a strain test grating 7 is packaged on the surface of a grating packaging unit 4 by using a first adhesive 3, and one side end of a temperature test grating 8 is packaged on the grating packaging unit 4 by using a second adhesive 5, wherein a bonding area of the strain test grating 7 is a grating area, and a bonding area of the temperature test grating 8 is one end of the grating area, so that the grating area of the temperature test grating 8 is suspended, and the temperature test grating is only affected by temperature.
The deformation member is made by a 3D printer (using additive manufacturing techniques) using a resin material. Wherein sensor deformation unit comprises left stiff end 1, spring, grating encapsulation unit 4, and 4 diameters of grating encapsulation unit are 4mm, and grating encapsulation unit length is 40mm, and the spring internal diameter is 16mm, and the spring external diameter is 24mm, and the spring number of turns is 5 circles, and the spring pitch is 5 mm.
The diameter of the optical fiber of the embodiment is set to be 250 μm, the grating lengths of the strain test grating 7 and the temperature test grating 8 are both 10mm, the central wavelength of the strain test grating 7 is 1550nm, and the central wavelength of the temperature test grating 8 is 1530 nm.
The use method of the polymer encapsulated fiber grating sensor comprises the following steps:
two ends of the polymer encapsulated fiber grating sensor are connected with a test target to apply displacement load. Under the combined action of the displacement load and the temperature load, the central wavelength of the strain test grating changes; under the action of temperature load, the central wavelength of the temperature test grating changes.
The output end of the polymer-encapsulated fiber grating sensor fiber 10 is connected with the grating demodulation system 6 to measure the variation of the center wavelength of the Bragg grating spectrum. According to the formula
And the variation delta lambda of the Bragg grating wavelengthFBG1And Δ λFBG2The ambient temperature Δ T and the strain Δ ∈ are calculated.
Due to the viscoelasticity of the polymer material used in the polymer-encapsulated fiber grating sensor, the strain measured by the grating sensor may change with time, resulting in errors. The research on the viscoelastic effect and the error correction method of the polymer-encapsulated fiber bragg grating sensor and the polymer-encapsulated sensor is very important for reconstructing a test result and improving the accuracy of the sensor.
The viscoelasticity correction method of the polymer encapsulated fiber grating sensor comprises the following steps:
as shown in fig. 3, before correcting the viscoelastic error of the sensor under a complex load, the effective relaxation modulus of the sensor needs to be obtained first.
As shown in fig. 3, step 1 is a step load uniaxial tension experiment, and a sensor grating strain response curve under the action of a step load is obtained. According to the formula Δ ∈ (t) ═ y (t) · d Δ L (t) ═ dy (t) · Δ L (t) and the load Δ L obtained by the uniaxial tension teststep(t) and Grating Strain response Deltaεstep(t) calculating the effective viscoelasticity modulus Y (t) of the polymer-encapsulated fiber grating sensor.
As shown in fig. 3, in data 2, the effective viscoelastic modulus y (t), i.e. the effective relaxation modulus y (t), of the polymer-encapsulated fiber grating sensor is obtained through the uniaxial tension experiment. The experimental method for measuring the effective viscoelasticity modulus of the sensor can reduce complex calculation and is convenient to obtain. In addition, the effective viscoelastic modulus is directly obtained by the experimental method, so that the difference of effective viscoelastic parameters among the sensors caused by the difference of the manufacturing process can be avoided, and the influence of environmental change on the effective viscoelastic parameters of the sensors can be reduced when the viscoelastic modulus test is performed before the complex load test.
As shown in fig. 3, the complex load uniaxial tensile test is performed by using a polymer-encapsulated fiber grating sensor. Data 4 is then obtained for the grating strain response curve measured for the complex load test. Since the sensor is encapsulated with a polymer material, there is an error in the test results due to the viscoelastic effect.
As shown in fig. 3, the strain response Δ ∈ (t) of the grating during the complex load test is shown according to the formula Δ ∈ (t) ═ y (t) × d Δ l (t), and the effective viscoelastic modulus y (t) and the strain response Δ ∈ (t) of the grating during the complex load testcomplex(t) calculating the differential d Δ L of the displacement load with respect to time by deconvolution algorithmcomplex(t) of (d). Data 6 is the differential d Δ L of the displacement load with respect to timecomplex(t)。
Finally, for d Δ Lcomplex(t) performing an integral calculation with respect to time, reconstructing a complex load Δ L related to timerc(t)。
As shown in fig. 3, data 8 is the reconstructed loading calculated from the grating strain response. Viscoelastic errors caused by polymer materials in the sensor have been eliminated in the reconstructed load compared to the grating strain curve.
FIG. 4 is a schematic view of correcting viscoelastic effect of the novel polymer-encapsulated fiber grating sensor according to the present invention. FIG. 4(a) shows displacement load and grating strain response of experimental tests, and it can be seen that there is a significant viscoelastic effect in the grating strain response; fig. 4(b) shows the results of viscoelastic correction of the polymer encapsulated grating sensor, including experimental test displacement load and reconstruction load.
It should be noted that the correction method can effectively eliminate measurement errors caused by the viscoelastic effect of the polymer-encapsulated grating sensor. In addition, the correction method for the viscoelastic effect in the sensor test can correct the viscoelastic effect error in the measurement of a common sensor, and improve the measurement accuracy of the common sensor.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that modifications can be made by those skilled in the art without departing from the principle of the present invention, and these modifications should also be construed as the protection scope of the present invention.
Claims (8)
1. The correction method of the viscoelastic effect of the grating sensor encapsulated by the polymer is characterized in that the sensor comprises a deformation component, a test component and a grating demodulation system; the deformation component comprises a left fixed end (1), a large deformation unit (2), a grating packaging unit (4) and a right fixed end (9), wherein the rear ends of the left fixed end (1) and the large deformation unit are sequentially connected; the deformation component is made of resin; the testing component comprises a grating packaging unit (4), a strain testing grating (7) and a temperature testing grating (8); the grating demodulation system comprises an integrated grating demodulator (6) and an optical fiber (10); the strain test grating (7) and the temperature test grating (8) are sequentially connected in series on an optical fiber (10), and the optical fiber (10) is connected with the integrated grating demodulator (6); the grating area of the strain test grating (7) is completely encapsulated on the grating encapsulation unit (4); the grating area of the temperature test grating (8) is suspended and does not receive stress; the strain test grating (7) and the temperature test grating (8) have different grating Bragg wavelengths and are separated by more than one full width at half maximum; the large deformation unit (2) is a structure or a material with large elastic deformation capacity; the grating packaging unit (4) is made of elastic or viscoelastic material;
the correction method comprises the following steps:
the method comprises the following steps: step load unidirectional tension experiment;
step two: obtaining an effective relaxation modulus of the sensor;
2.1, according to the step one, obtaining a strain response curve delta epsilon of the sensor grating under the action of the step load in the uniaxial tension experimentstep(t)；
2.2, the grating strain and the displacement load conform to the boltzmann linear superposition principle, and can be simply expressed as follows by adopting a convolution form:
Δε(t)＝Y(t)*dΔL(t)＝dY(t)*ΔL(t)
wherein Δ ∈ (t) is the strain measured by the grating, y (t) is the member effective viscoelastic coefficient, × is the convolution sign, d Δ l (t) is the differential of the member displacement with respect to time, dy (t) is the differential of the member effective viscoelastic coefficient with respect to time, and Δ l (t) is the displacement load;
2.3, according to the formula Δ ∈ (t) ═ y (t) ═ d Δ L (t) ═ dy (t) · Δ L (t) and the step load Δ L in the uniaxial tension teststep(t) and grating strain response curve Deltaεstep(t) calculating the effective visco-elastic modulus Y (t) of the sensor by means of a deconvolution algorithm, wherein the step load Δ Lstep(t) the differential over time is the dirac function δ (t);
step three: a complex load unidirectional tension experiment;
3.1, applying a unidirectional displacement load along the axial direction of the test piece, wherein the displacement load is a complex load delta Lcomplex(t)；
3.2, according to the change delta lambda of the sensor wavelength of the strain test grating (7) and the temperature test grating (8)FBG1And Δ λFBG2Calculating the temperature change delta T (t) and the strain change delta epsilon in the test piececomplex(t)；
Step four: obtaining a grating strain response curve of a complex load tensile experiment:
obtaining the grating strain response delta epsilon of the time-dependent complex load uniaxial tension experiment according to the step 3.2complex(t)；
Step five: deconvolution:
according to the formula Δ ∈ (t) ═ y (t) · d Δ l (t), effective viscoelastic modulus y (t) in step 2.3, and grating strain response curve Δ ∈ (t) in step fourcomplex(t) calculating the differential d Delta L of the displacement load to the time by combining with a deconvolution algorithmcomplex(t)；
Step six: integral calculation;
for d Δ Lcomplex(t) performing its integral calculation over time, reconstructing the complex load related to time, i.e. the reconstructed complex displacement load DeltaLrc(t)。
2. The method for correcting the viscoelastic effect of the polymer encapsulated grating sensor according to claim 1, wherein the uniaxial tension test specifically comprises:
1.1, connecting two ends of a polymer-packaged fiber grating sensor with a test target, applying a unidirectional displacement load along the axial direction of a test piece, and respectively adopting a step load delta L as the displacement load according to the experimental requirementsstep(t) or complex load Δ Lcomplex(t)；
1.2, under the combined action of temperature and displacement load, the central wavelength of the strain test grating (7) drifts; in addition, the central wavelength of the temperature test grating (8) is changed due to the change of the temperature;
1.3 according to the formula
And the wavelength changes Delta lambda of the strain test grating (7) and the temperature test grating (8)FBG1And Δ λFBG2Calculating the temperature change delta T and the strain change delta epsilon (T) in the test piece in the test process;
in the formula, Δ λFBG1，ΔλFBG2Respectively is the central wavelength variation, lambda, of the strain test grating (7) and the temperature test grating (8)FBG1，λFBG2The initial central wavelengths of the strain test grating (7) and the temperature test grating (8) are respectively; cεFor strain-testing the strain coefficient, C, of the grating (7)TFor the temperature coefficients of the strain test grating (7) and the temperature test grating (8), Δ T, Δ ε represent the temperature and strain changes, respectively.
3. The method for correcting the viscoelastic effect of the polymer encapsulated grating sensor as recited in claim 1, wherein the large deformation unit (2) is a spring, the inner diameter of the spring is 16mm, the outer diameter of the spring is 24mm, the number of the spring turns is 5, and the pitch of the spring is 5 mm.
4. The method for correcting the viscoelastic effect of the polymer encapsulated grating sensor as recited in claim 1, wherein the optical fiber (10) has a diameter of 250 μm.
5. The method for correcting the viscoelastic effect of the polymer encapsulated grating sensor as claimed in claim 1, wherein the grating encapsulation method comprises surface pasting or embedding by an adhesive.
6. The method for correcting the viscoelastic effect of the polymer encapsulated grating sensor as recited in claim 1, wherein the grating encapsulating unit (4) has a diameter of 4mm and a length of 40 mm.
7. The method for correcting the viscoelastic effect of the polymer encapsulated grating sensor as claimed in claim 1, wherein when the grating is adhered on the surface: the strain test grating (7) is completely packaged on the grating packaging unit (4) through the first adhesive (3), one side end part of the temperature test grating (8) is packaged on the grating packaging unit (4) through the second adhesive (5), so that the grating area of the temperature test grating (8) is suspended, and the adhesive is a viscoelastic material; when the grating is packaged in an embedding mode, the packaging component is made of a viscoelastic material.
8. The method for correcting the viscoelastic effect of the polymer encapsulated grating sensor as recited in claim 7, which can be applied to correction of the viscoelastic effect in a general sensor testing process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810630036.6A CN108917831B (en) | 2018-06-19 | 2018-06-19 | Polymer-encapsulated grating sensor and correction method for viscoelastic effect of sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810630036.6A CN108917831B (en) | 2018-06-19 | 2018-06-19 | Polymer-encapsulated grating sensor and correction method for viscoelastic effect of sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108917831A CN108917831A (en) | 2018-11-30 |
| CN108917831B true CN108917831B (en) | 2021-02-12 |
Family
ID=64420552
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810630036.6A Active CN108917831B (en) | 2018-06-19 | 2018-06-19 | Polymer-encapsulated grating sensor and correction method for viscoelastic effect of sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108917831B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110455213B (en) * | 2019-09-19 | 2024-03-08 | 沈阳理工大学 | Correcting device for detecting deformation of fiber bragg grating |
| CN113432639A (en) * | 2021-05-25 | 2021-09-24 | 上海大学 | Bidirectional fiber grating bivariate sensor based on optical fiber sensing |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1412530A (en) * | 2002-12-18 | 2003-04-23 | 南开大学 | Slrain and temperature change simultaneously-measured single fibre grating packaging method and its sensor |
| US9791334B2 (en) * | 2014-05-16 | 2017-10-17 | Halliburton Energy Services, Inc. | Polymer composite wireline cables comprising optical fiber sensors |
| CN105115438B (en) * | 2015-08-16 | 2017-10-17 | 北京航空航天大学 | A kind of optical fiber sensing system temperature compensation |
| CN105928468A (en) * | 2016-06-24 | 2016-09-07 | 深圳市畅格光电有限公司 | Fiber grating strain sensor and manufacturing method thereof |
| CN106370121B (en) * | 2016-08-15 | 2019-03-22 | 沈阳建筑大学 | The matrix strain correction method of clipping fiber grating |
| CN107024234B (en) * | 2017-05-10 | 2020-01-14 | 武汉理工大学 | Packaging device and method of fiber grating sensor |
-
2018
- 2018-06-19 CN CN201810630036.6A patent/CN108917831B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN108917831A (en) | 2018-11-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Luyckx et al. | Multi-axial strain transfer from laminated CFRP composites to embedded Bragg sensor: I. Parametric study | |
| Kuang et al. | Packaging and temperature compensation of fiber Bragg grating for strain sensing: a survey | |
| CN105115438B (en) | A kind of optical fiber sensing system temperature compensation | |
| CN104279973B (en) | A kind of wide range fiber grating strain transducer | |
| CN108917831B (en) | Polymer-encapsulated grating sensor and correction method for viscoelastic effect of sensor | |
| WO2015032364A1 (en) | Long gauge length carbon fiber strain sensing device and testing method therefor | |
| Zhang et al. | Comparison of metal-packaged and adhesive-packaged fiber Bragg grating sensors | |
| CN106525277B (en) | A kind of Non-stress packaging fiber grating temperature sensor string | |
| Motwani et al. | Experimental investigation of strain sensitivity for surface bonded fibre optic sensors | |
| CN202141546U (en) | High pressure sensor having fiber Bragg grating based on carbon fiber lamination composite material | |
| Wei et al. | High pressure sensor based on fiber Bragg grating and carbon fiber laminated composite | |
| KR101529610B1 (en) | Apparatus and Sensing System for Fiber Bragg Grating Probes Having Controlled Sensitivity and Method for Sensing and Manufacturing thereof | |
| Li et al. | A diaphragm-type highly sensitive fiber Bragg grating force transducer with temperature compensation | |
| CN105890533A (en) | Material surface strain fiber grating reverse differential detection sensing device | |
| Baoxi et al. | Humidity influence on embedded fiber Bragg grating strain sensors | |
| Zhu et al. | Analysis of strain transfer in FBG-based embedded optical fiber 3-D shape sensor | |
| Luyckx et al. | Three-dimensional strain and temperature monitoring of composite laminates | |
| Davidi et al. | The importance of fiber coating and bonding process in accurate high spatial resolution strain measurements | |
| Montero et al. | Influence of humidity on fiber Bragg grating sensors | |
| Li et al. | The study of enhancing temperature sensitivity for FBG temperature sensor | |
| Lesiak et al. | Polarimetric and bragg optical fiber sensors for stress distribution and temperature measurements in composite materials | |
| Li et al. | FBG strain sensor based on thermal stress mechnism | |
| Wang et al. | Coiling an optical fiber for long-range dynamic displacement and force sensing | |
| Goossens et al. | Dynamic 3D strain measurements with embedded micro-structured optical fiber Bragg grating sensors during impact on a CFRP coupon | |
| Guo et al. | A novel fiber Bragg grating pressure sensor with the smart metal structure based on the planar diaphragm |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |