阅读说明：本技术 可调节灵敏度的三轴型光纤光栅应变测量传感器 (Three spindle-type fiber grating strain measurement sensors of adjustable sensitivity ) 是由 薛飞 王红珂 陈志林 徐德城 林磊 余伟炜 周帅 于 2019-09-04 设计创作，主要内容包括：本发明公开了一种可调节灵敏度的三轴型光纤光栅应变测量传感器,述应变测量传感器包括圆形环状的传感器基底、沿所述传感器基底内周向内延伸形成的安装臂以及安装在所述安装臂上的应变传感光纤光栅,所述安装臂上开设有用于容纳所述应变传感光纤光栅的光纤安装槽,所述光纤安装槽上设置有用于固定所述应变传感光纤光栅的光纤固定点和光纤固定卡扣,所述传感器基底上开设有用于将所述应变测量传感器固定于被测件上的安装孔。本发明的可调节灵敏度的三轴型光纤光栅应变测量传感器,能够实现调节应变测量传感器的应变测量灵敏度,且采用按照不同方向布置的3根应变传感光纤光栅,可同时实现对测点处三个方向的应变测量,提高了传感器的测量准确度。(The invention discloses a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity, state the sensor base that strain gauge sensors include circular annular form, the installing arm extended inwardly to form along the sensor base inner circumferential and the strain sensing fiber grating being mounted in the installing arm, the optical fiber mounting groove for accommodating the strain sensing fiber grating is offered in the installing arm, the optical fiber fixed point and optical fiber fixed card buckle for fixing the strain sensing fiber grating are provided on the optical fiber mounting groove, the mounting hole for being fixed on the strain gauge sensors on measured piece is offered in the sensor base.Three spindle-type fiber grating strain measurement sensors of adjustable sensitivity of the invention, it can be realized the strain measurement sensitivity for adjusting strain gauge sensors, and using the 3 strain sensing fiber gratings arranged according to different directions, the strain measurement to three directions at measuring point can be achieved at the same time, improve the accuracy of measurement of sensor.)

1. a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity, which is characterized in that the strain measurement The installing arm and peace that sensor includes the sensor base of circular annular form, extends inwardly to form along the sensor base inner circumferential Strain sensing fiber grating in the installing arm is offered for accommodating the strain sensing optical fiber in the installing arm The optical fiber mounting groove of grating, the optical fiber being provided with for fixing the strain sensing fiber grating on the optical fiber mounting groove are fixed Point and optical fiber fixed card buckle are offered for the strain gauge sensors to be fixed on measured piece in the sensor base Mounting hole.

2. a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity according to claim 1, special Sign is that the installing arm arranges that one end of the installing arm is fixed on the biography along the diametrical direction of the sensor base On base of sensilla bottom and corresponding with the mounting hole, the other end of the installing arm prolongs to the center of circle direction of the sensor base It stretches.

3. a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity according to claim 2, special Sign is that a pair of installing arm is arranged symmetrically in the two of the sensor base center of circle along the diametrical direction of the sensor base Side.

4. a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity according to claim 1, special Sign is that diametrical direction of three strain sensing fiber gratings respectively with different angle along the sensor base is arranged, Three strain sensing fiber gratings intersect at the center of circle of the sensor base.

5. a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity according to claim 4, special Sign is that the strain sensing fiber grating is including 0 ° of direction strain sensing fiber grating and is symmetrically disposed on 0 ° of direction Strain sensing fiber grating two sides and with 0 ° of direction strain sensing optical fiber be in 45 ° of angles+45 ° of direction strain sensing optical fiber Grating and -45 ° of direction strain sensing fiber gratings.

6. a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity according to claim 5, special Sign is, is serially connected with temperature compensation optical fiber grating at least one described strain sensing fiber grating.

7. a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity according to claim 6, special Sign is that the temperature compensation optical fiber grating is serially connected in one end of 0 ° of direction strain sensing fiber grating.

8. a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity according to claim 1, special Sign is, 3 optical fiber fixed points are evenly distributed in each installing arm.

It is passed 9. a kind of three spindle-type fiber grating strains of adjustable sensitivity according to any one of claims 1 to 8 measure Sensor, which is characterized in that the side of the sensor base is offered for the perforative optical fiber peace of the strain sensing fiber grating Fill through-hole.

10. a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity according to claim 9, special Sign is that the mounting hole is uniformly distributed in the sensor base, and the optical fiber installation through-hole corresponds to the mounting hole and opens If.

Technical field

The invention belongs to sensor designs and strain measurement technique field, and in particular to a kind of three axis of adjustable sensitivity Type fiber grating strain measurement sensor.

Background technique

Fiber grating be in fiber core specific position medium refraction index at a kind of fiber optic passive device of mechanical periodicity.It is logical The variation for crossing measurement raster center wavelength, may be implemented the measurement to multi-parameters such as temperature, strain, pressure.

Currently, the strain measurement to single direction at measured piece measuring point may be implemented in fiber grating strain measurement sensor. When it needs to be determined that measuring point principal direction of stress when, need to arrange according to certain angle at least three fiber grating strain measurement sensing Device not only installs installation accuracy that is time-consuming and laborious, but also not can guarantee sensor.

Summary of the invention

In view of this, in order to overcome the drawbacks of the prior art, the object of the present invention is to provide a kind of adjustable sensitivity Three spindle-type fiber grating strain measurement sensors, can be realized the strain measurement to three directions at measuring point, and adjustable Its sensitivity measured.

In order to achieve the above object, the invention adopts the following technical scheme:

A kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity, the strain gauge sensors include The sensor base of circular annular form, the installing arm extended inwardly to form along the sensor base inner circumferential and it is mounted on the peace The strain sensing fiber grating on arm is filled, the optical fiber for accommodating the strain sensing fiber grating is offered in the installing arm Mounting groove is provided with optical fiber fixed point and and optical fiber for fixing the strain sensing fiber grating on the optical fiber mounting groove Fixed point matched optical fiber fixed card buckle is offered for being fixed on the strain gauge sensors in the sensor base Mounting hole on measured piece.Installing arm and optical fiber mounting groove extend along strain sensing fiber grating axial direction, by adjusting Strain sensing fiber grating is fixed on the fixation position in installing arm, to realize the strain measurement for adjusting strain gauge sensors Sensitivity, accuracy that is simple, convenient and fast and not interfering with measurement.And optical fiber mounting groove is open groove body, facilitates peace Dress and fixed strain sensing fiber grating.

Preferably, the installing arm arranges that one end of the installing arm is fixed along the diametrical direction of the sensor base In the sensor base and corresponding with the mounting hole, the other end of the installing arm is to the center of circle of the sensor base Direction extends.

It is further preferred that a pair of installing arm is arranged symmetrically in sensor base along the diametrical direction of the sensor base The two sides in the bottom center of circle.That is corresponding two installing arms of a strain sensing fiber grating, the two installing arms are along sensor base One diametrical direction, and it is symmetrically disposed on the center of circle of sensor base.The grid region of strain sensing fiber grating is located at two installations Region between arm.

Preferably, three strain sensing fiber gratings are respectively with different angle along the diameter side of the sensor base To arrangement, for measuring the strain in 3 directions at measuring point, three strain sensing fiber gratings intersect at the sensor base The center of circle at bottom, the center point are at the measuring point of sensor.In other some embodiments, the strain sensing fiber grating packet Three strain sensing fiber gratings at an angle to each other are included, the difference is that three strain sensing fiber gratings are not along sensor base Diametrical direction arrangement, three strain sensing fiber gratings form the distribution form of triangle in sensor base, and three strains pass Feeling tool between fiber grating, there are three intersection points.

In some embodiments, the strain sensing fiber grating includes 0 ° of direction strain sensing fiber grating and symmetrical It is set to 0 ° of direction strain sensing fiber grating two sides and is in+45 ° of 45 ° of angles with 0 ° of direction strain sensing fiber grating Direction strain sensing fiber grating and -45 ° of direction strain sensing fiber gratings, 0 ° of direction strain sensing fiber grating ,+ The grid region of 45 ° of direction strain sensing fiber gratings and -45 ° of direction strain sensing fiber gratings is located in the sensor base The heart.It can be achieved at the same time according to 0 ° ,+45 °, -45 ° of direction arrangements to 0 ° of side at measuring point using 3 strain sensing fiber gratings To, the strain measurement in+45 ° of directions and -45 ° of directions.Compared with traditional resistance-type strain rosette measurement method, this method has anti- The advantages that electromagnetic interference, high, corrosion-resistant measurement stability, while also solving and three uniaxially fiber gratings are installed at measuring point The disadvantages of installation effectiveness existing for strain gauge sensors is low and accuracy of measurement is poor.

It is further preferred that being serially connected with temperature compensation optical fiber grating at least one described strain sensing fiber grating, it is used for Compensation temperature changes the drift of bring grating wavelength, eliminates the measurement error that temperature change is come, so that the result of measurement is more Accurately.Temperature compensation optical fiber grating is preferably serially connected in this section that strain sensing fiber grating is located on optical fiber mounting groove, only right Temperature is sensitive, and not experiencing strain bring influences.

It is further preferred that the temperature compensation optical fiber grating is serially connected in the one of 0 ° of direction strain sensing fiber grating End.

Preferably, 0 ° of direction strain sensing fiber grating ,+45 ° of direction strain sensing fiber gratings and -45 ° of sides It needs to carry out a degree of pre-stretching to grid region part when installing fixed to strain sensing fiber grating, it can be real with guarantee Now the two-way strain at measuring point is monitored.The optical fiber that the fixed bit of optical fiber is set to outside strain sensing fiber grating grid region is fixed Point, i.e. both ends outside sensor fibre grid region carry out installation fixation by the optical fiber fixed point in the installing arm.

Preferably, 3 optical fiber fixed points are evenly distributed in each installing arm.It is equidistant between optical fiber fixed point From setting, the position of the optical fiber fixed point in installing arm can be fixed on by adjusting strain sensing fiber grating, to adjust The strain measurement sensitivity of strain gauge sensors.

Preferably, the side of the sensor base is offered for the perforative optical fiber installation of the strain sensing fiber grating Through-hole.

It is further preferred that the mounting hole is uniformly distributed in the sensor base, the optical fiber installation through-hole is corresponding The mounting hole opens up.8 circular mounting holes, strain gauge sensors are evenly distributed in the sensor base of circular annular form It is fixed on measured piece by the mounting hole, realizes the compression and elongation strain measurement at measuring point.And the strain sensing optical fiber The grid region of grating does not have glued dose of encapsulation, eliminates the influence that bonding agent transmits fiber grating strain, improves sensor Measurement accuracy.

Compared with prior art, the invention has the beneficial effects that: three spindle-type optical fiber of adjustable sensitivity of the invention Installing arm is arranged in grating strain measurement sensor in the sensor base of circular annular form, and multiple use are provided in installing arm In the optical fiber fixed point of fixed strain sensing fiber grating, consolidating in installing arm is fixed on by adjusting strain sensing fiber grating Positioning is set, thus realize the strain measurement sensitivity for adjusting strain gauge sensors, it is simple, convenient and fast and do not interfere with survey The accuracy of amount；And the present invention uses the 3 strain sensing fiber gratings arranged according to different directions, can be achieved at the same time to measuring point The strain measurement for locating three directions improves the accuracy of measurement of sensor.

Detailed description of the invention

To describe the technical solutions in the embodiments of the present invention more clearly, make required in being described below to embodiment Attached drawing is briefly described.It should be evident that drawings in the following description are only some embodiments of the invention, for this For the those of ordinary skill of field, without creative efforts, it can also be obtained according to these attached drawings others Attached drawing.

Fig. 1 is the master that three spindle-type fiber grating strain measurement sensors of sensitivity are adjusted in the preferred embodiment of the present invention View；

Fig. 2 is the perspective view of preferred embodiment of the present invention sensor base；

Fig. 3 is preferred embodiment of the present invention strain sensing fiber grating adjustment of sensitivity principle and temperature bring sensor Strain measurement error analyzes schematic diagram；

In attached drawing: annular sensor substrate -10, sensor mounting hole -11, the strain of optical fiber installation through-hole -12,0 ° direction pass Feel fiber grating -20 ,+45 ° of directions strain sensing fiber grating -21, -45 ° of directions strain sensing fiber grating -22, temperature benefit Repay fiber grating -23, strain sensing fiber grating grid region -24, installing arm -30, optical fiber fixed point -31, optical fiber mounting groove -32.

Specific embodiment

In order that those skilled in the art will better understand the technical solution of the present invention, implement below in conjunction with the present invention Attached drawing in example, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment It is only the embodiment of a part of the invention, instead of all the embodiments.Based on the embodiments of the present invention, the common skill in this field Art personnel every other embodiment obtained without making creative work all should belong to what the present invention protected Range.

Reference attached drawing 1-3, a kind of three spindle-type fiber grating strain measurement sensors of adjustable sensitivity of the present embodiment, Including annular sensor substrate 10, strain sensing fiber grating and installing arm 30.

Strain sensing fiber grating includes 0 ° of direction strain sensing fiber grating 20 and is symmetrically disposed in the present embodiment The two sides of 0 ° of direction strain sensing fiber grating and with 0 ° of direction strain sensing fiber grating be in 45 ° of angles+45 ° of directions Strain sensing fiber grating 21 and -45 ° of direction strain sensing fiber gratings 22,3 mutual angled strain sensing optical fiber Grating can be realized simultaneously to 0 ° at measuring point, the strain measurement in+45 °, -45 ° three directions.

0 ° of direction strain sensing fiber grating, 20 ,+45 ° of direction strain sensing fiber gratings 21 and -45 ° of direction strain sensings Fiber grating 22 arranges that temperature compensation optical fiber grating 23 is serially connected in 0 ° of direction strain and passes along annular sensor basal diameter direction One end for feeling fiber grating 20, for compensation temperature variation bring grating wavelength drift.Sensor base 10 is along strain sensing 6 installing arms 30 are respectively set in optical fiber axial direction, and one end of installing arm 30 and sensor base 10 connect, and the other end is free end. Installing arm 30 offers open optical fiber mounting groove 32 along strain sensing optical fiber axial direction, is equidistantly positioned light in optical fiber mounting groove Fine fixed point 31 will be answered by the way that optical fiber fixed card buckle (not shown) engaged therewith is arranged in optical fiber fixed point 31 Become sensor fibre grating to be fixed in installing arm 30.It is uniform along annulus in the sensor base of circular annular form 10 in the present embodiment 8 mounting holes 11 are set, for fixing with test specimen.In sensor base side, 30 corresponding position of installing arm offers light Fine installation through-hole 12.As shown in Figure 1-3, installing arm 30 setting position and optical fiber installation through-hole 12 open up position with peace It is corresponding to fill hole 11.Strain sensing fiber grating needs to carry out certain pre-stretching during installation.

3 optical fiber fixed points 31 are evenly distributed in the present embodiment in each installing arm 30.Between optical fiber fixed point 31 It is equidistantly positioned, the fixation position in installing arm 30 can be fixed on by adjusting strain sensing fiber grating, answered to adjust Become the strain measurement sensitivity of measurement sensor.And the fixed bit of strain sensing fiber grating is set to grating grid region in the present embodiment Outer both ends, the grid region of strain sensing fiber grating do not have glued dose of encapsulation, eliminate bonding agent and pass to fiber grating strain The influence passed improves the measurement accuracy of sensor.Intersection position at measuring point, three strain sensing fiber gratings have thickness Superposition on direction can be modified by correction.

Sensor may be implemented in three spindle-type fiber grating strain measurement sensors of the adjustable sensitivity of the present embodiment Strain sensitivity adjusts and temperature-compensating.It is specific as follows:

Transducer sensitivity is adjusted:

The reflection that three spindle-type fiber grating strain measurement sensors of adjustable sensitivity pass through detection sensor fibre grating Wavelength realizes the measurement to strain, the reflected wavelength lambda of fiber grating_BMeet bragg's formula λ_B=2n_effΛ.Wherein, n_effFor light The effective refractive index of fine grating, Λ are screen periods.

By taking Fig. 3 as an example, when deformation occurs for testee, the mounting hole 11 in annular sensor substrate stretches or compression peace Arm 30 is filled, installing arm 30 acts on+45 ° of direction strain sensing fiber gratings 21 by optical fiber fixed point 31, brings it about Δ_L's Deformation quantity.

The then deformation quantity that strain sensing fiber grating grid region 24 occurs are as follows:

So additional strain for being subject to of strain sensing fiber grating grid region 24 are as follows:

Strain stress is measured according to strain gauge sensors are as follows:

It can be obtained by formula (2) and formula (3), the central wavelength drift value of strain sensing fiber grating are as follows:

In formula (4), λ_BFor the central wavelength of strain sensing fiber grating, meet bragg's formula λ_B=2n_effΛ.Wherein, n_effFor the effective refractive index of fiber grating, Λ is screen periods.K_εFor strain-responsive coefficient, l_fFor the grid region of sensor fibre grating Length, l_sThe distance of free end, l are arrived for fiber grating fixed point 31 in installing arm 30₂For the mounting hole 10 of annular sensor substrate To the distance of fiber grating fixed point 31.

By deriving above it is found that when the grid length of sensor base size and strain sensing fiber grating determines, by changing Become l_sWith l₂Ratio adjust sensor strain measurement sensitivity.I.e. through this embodiment in device, can be by adjusting answering Become sensor fibre grating and be fixed on the fixation position in installing arm 30, so that the strain measurement for adjusting strain gauge sensors is sensitive Degree.

Refering to what is shown in Fig. 3 ,+45 ° of direction strain sensing fiber gratings 21 use pure vitreous silica bragg grating, light The central wavelength of grid is 1560nm, and grid region length is l_f=5mm, installation arm lengths are 10mm, fiber grating strain response coefficient For K_ε=0.784, then have:

(1) when optical fiber fixed point is at installing arm midpoint, l₂=l_s=5mm, strain transducer sensitivity are 1.31；

(2) when optical fiber fixed point is when close to 1/4 position of installing arm free end, l₂=7.5mm, l_s=2.5mm, sensor Strain sensitivity is 1.96；

(3) when optical fiber fixed point is when close to 3/4 position of installing arm free end, l₂=2.5mm, l_s=7.5mm, sensor Strain sensitivity is 0.98.

Sensor Temperature Compensation:

When fiber Bragg grating strain sensor is only affected by temperature, strain sensing fiber grating is affected by temperature bring center Wavelength shift are as follows:

Δλ_B,T=λ_B*K_T*ΔT (5)

In formula (5), λ_BFor the central wavelength of strain sensing fiber grating, Δ T is temperature variation, K_TFor fiber grating Temperature coefficient.The drift of optic fiber grating wavelength caused by waveguiding effect, K are not considered_T=∝+ζ, wherein ∝ is the line of optical fiber The property coefficient of expansion, ζ is thermo-optical coeffecient.

Specifically, by taking Fig. 3 as an example, due to temperature change, two optical fiber fixed points 31 in installing arm 30 are opposed, inwardly directed swollen Swollen Δ l₂, according to the thermalexpansioncoefficientα of base material₁Fiber grating fixed point 31 is arrived with annular sensor substrate mounting hole 11 Distance l₂, available Δ l₂Length are as follows:

Δl₂=2* α₁*l₂*ΔT (6)

So, the grid region deformation quantity of strain sensing fiber grating are as follows:

Then, according to formula (6) and formula (7), the additional strain that the grid region of strain sensing fiber grating is subject to are as follows:

In turn, the drift value of strain sensing fiber bragg grating center wavelength caused by additional strain are as follows:

According to formula (5) and formula (9), it can be deduced that: due to temperature change, total drift value of strain sensing optic fiber grating wavelength Are as follows:

Since temperature compensation optical fiber grating 23 is only by temperature change, do not influenced by substrate deformation.Therefore, temperature variation Δ T can be acquired by the wavelength shift of temperature compensation optical fiber grating, it may be assumed that

In formula (11), Δ λ_B,23For the wavelength shift of temperature compensation optical fiber grating 23 in strain gauge sensors.

It, can be total in the hope of optic fiber grating wavelength of the strain gauge sensors after by temperature-compensating according to formula (10) and formula (11) Drift value Δ λ_B.At this point, obtained Δ λ_BIt is temperature independent for caused by the structural strain that is subject at measuring point.

Due to each strain gauge sensors include 3 strain sensing fiber gratings (0 ° of direction strain sensing fiber grating, + 45 ° of direction strain sensing fiber gratings, -45 ° of direction strain sensing fiber gratings), then 3 strain sensing optical fiber light can be obtained The wavelength shift of grid is respectively Δ λ_B,0、Δλ_B,+45、Δλ_B,-45。

Then, it measuring point can be obtained by formula (4) is in the structural strain in 0 ° of direction ,+45 ° of directions and -45 ° of directions and be respectively as follows:

Wherein, in formula (12)~(14),

When test, guarantee that 0 ° of direction fiber grating is consistent with the main deformation direction of measuring point, obtains at measuring point three according to measurement The strain in direction (0 ° ,+45 °, -45 °), the principal stress calculation formula of measuring point are as follows:

In formula (15),For the maximum principal stress and minimum principal stress at certain moment measuring point, E and μ are respectively tested knot The elasticity modulus and Poisson's ratio of structure material.ε_-45、ε₀、ε₊₄₅Respectively -45 ° at measuring point, 0 ° and+45 ° of dynamic strain.

The present invention realizes the sensitivity of sensor by the fixed position of difference of strain sensing fiber grating in installing arm It adjusts；The present invention, by certain angle arrangement, can be achieved at the same time to three directions at measuring point using 3 strain sensing fiber gratings Strain measurement improves the installation effectiveness and accuracy of measurement of sensor；The present invention analyzes temperature change to strain measurement knot The influence of fruit, and be modified by temperature compensation optical fiber grating, eliminate the measurement error that temperature change is come；Present invention strain The fixed bit of sensor fibre grating is set to the both ends outside sensor fibre grid region, and grating grid region does not have glued dose of encapsulation, eliminates The influence that bonding agent transmits fiber grating strain improves the measurement accuracy of sensor.

The above embodiments merely illustrate the technical concept and features of the present invention, and its object is to allow person skilled in the art Scholar cans understand the content of the present invention and implement it accordingly, and it is not intended to limit the scope of the present invention, it is all according to the present invention Equivalent change or modification made by Spirit Essence, should be covered by the protection scope of the present invention.