Multi-parameter sensing optical cable based on ultra-weak fiber grating array

Abstract

The utility model relates to a multi-parameter sensing optical cable based on an ultra-weak fiber grating array. The multi-parameter sensing optical cable comprises a strain reinforcing rib, wherein the center of the strain reinforcing rib is compounded with the ultra-weak fiber grating array; the vibration type ultra-weak fiber grating array is embedded in the casing pipe, and the casing pipe is filled with ointment; the fiber reinforced resin reinforcing ribs are symmetrically arranged relative to the strain reinforcing ribs and the sleeve; and the strain reinforcing ribs, the sleeve and the reinforcing ribs are subjected to hot extrusion molding through a mold to form the flat sheath. According to the ultra-weak fiber bragg grating multi-parameter sensing optical cable provided by the utility model, the fiber reinforced resin strain sensing optical fibers and the fiber reinforced resin reinforcing ribs are compounded on the two sides, and the high-density polyethylene flat sheath is wrapped outside, so that the ultra-weak fiber bragg grating multi-parameter sensing optical cable has good mechanical tensile property and flattening resistance.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of fiber grating strain sensing, especially relates to a multi-parameter sensing optical cable based on ultra-weak fiber grating array. BACKGROUND

[0002] In the field of structural health monitoring, although the traditional monitoring method can meet most of the monitoring needs, it also exposes corresponding problems. Some technologies can only measure the structure point by point, and the measurement data density is small; some technologies are easily affected by environmental factors; some technologies cannot be integrated with automation to meet the needs of digital monitoring. In recent years, optical fiber sensing technology has developed rapidly. Optical fiber grating sensors, with their advantages of distributed, high precision, environmental interference resistance, and low cost, have been widely used in perimeter security, aerospace, rail transportation, and large-scale structure health monitoring. However, the engineering accidents of such large-scale engineering applications are often accompanied by changes in vibration, strain, temperature, and other physical quantities. The change of a single physical quantity is not reliable enough, so it is necessary to obtain multiple parameter indicators such as strain, temperature, and vibration of the measured structure to comprehensively evaluate the structural safety state.

[0003] Traditional optical fiber grating sensors can usually only demodulate one of the parameters such as strain, temperature, and strain, which cannot meet the monitoring needs of modern engineering structures for multiple parameters of their own structures, and cannot comprehensively evaluate the structure health. Multi-parameter optical fiber grating sensing cable is the development direction of modern sensing cable. It not only easily integrates FBG and distributed sensing optical fiber to realize state information extraction and damage identification, but also has the advantages of multiple sensing parameters, small sensing head volume, easy remote sensing, cost reduction, and high system integration. In 2017, Jiang Youhua et al. proposed and made a transverse pressure and temperature dual-parameter optical fiber sensor, but the structure design was too simple, and only laboratory performance tests were conducted, so further improvement is still needed for actual engineering application. In 2021, Ye Shaomin et al. established a multi-parameter optical fiber sensing system on the Jingxiong intercity tunnel to monitor tunnel temperature, deformation, vibration, and other physical quantities, which can reflect the tunnel safety status in real time and provide real-time warning. However, the arrangement of optical fiber sensors is complex and cannot form a single optical fiber multi-parameter sensing, which increases the construction difficulty and economic burden. In 2022, Feng Qian et al. laid multi-core optical fiber security engineering in the protective fence of Wuhan Earthquake Engineering Research Institute to realize distributed strain, temperature, frequency, and other multi-parameter sensing, but it is only applied to small-scale fence engineering monitoring, and the traditional FBG has limited multiplexing capability, so its large-scale structure monitoring capability needs to be improved. UTILITY MODEL CONTENT

[0004] The utility model discloses in view of the shortage of prior art, specifically, is in view of the problem that the prior art arrayed fiber grating sensor can not monitor multiple parameters simultaneously, the prior art multi-core multi-parameter sensing optical cable is difficult to adapt to the harsh working condition, and the monitoring capacity of large structure is limited, the utility model provides a kind of flat multi-parameter sensing optical cable based on ultra-weak fiber grating array, vibration signal can be demodulated simultaneously when strain signal is demodulated;Built-in strain sensing fiber and reinforcing rib greatly improve the mechanical tensile, compression flat performance of optical cable;External through mould hot extrusion flat jacket, compared with traditional vibration fiber, the special shape structure can be better combined with measured object, and sense vibration signal;Embedded strain type, vibration type ultra-weak fiber grating array can monitor measured object at long distance, and it is more suitable for large structure health monitoring such as rail transit.

[0005] The technical purpose of the utility model is realized through the following technical schemes: provide a kind of multi-parameter sensing optical cable based on ultra-weak fiber grating array, including the strain reinforcing rib that the ultra-weak fiber grating array is compounded in the center;The sleeve of vibration type ultra-weak fiber grating array is embedded, and the sleeve is also filled with ointment;Fiber reinforced resin reinforcing rib is symmetrically laid relative to the strain reinforcing rib and the sleeve;The strain reinforcing rib, the sleeve and the reinforcing rib are formed into flat jacket by mould hot extrusion.

[0006] Preferably, the strain reinforcing rib is hot-pultruded from high-strength glass fiber, polymer matrix and the ultra-weak fiber grating array, for coupling the strain transmitted on the flat jacket.

[0007] Preferably, the vibration type ultra-weak fiber grating array is used to couple the micro-vibration transmitted on the flat jacket through the ointment and the sleeve.

[0008] Preferably, the fiber reinforced resin reinforcing rib is hot-pultruded from glass fiber and polymer matrix, for improving the mechanical tensile and compression resistance.

[0009] Preferably, the flat jacket is trapezoidal.

[0010] Preferably, glue is added between the strain reinforcing rib and the jacket for bonding.

[0011] Compared with the prior art, the utility model has the following beneficial effects:

[0012] 1. The utility model provides a kind of multi-parameter sensing optical cable based on ultra-weak fiber grating array, and the ultra-weak fiber grating multi-parameter sensing optical cable is compounded fiber reinforced resin strain sensing fiber and fiber reinforced resin reinforcing rib on both sides, is wrapped with high-density polyethylene flat jacket outside, and has good mechanical tensile, compression flat performance.

[0013] 2. The ultra-weak fiber optic grating multi-parameter sensing optical cable provided by this utility model can simultaneously monitor strain and vibration signals, meeting the monitoring needs of multi-parameter sensors for large structures.

[0014] 3. The ultra-weak fiber optic grating multi-parameter sensing optical cable provided by this utility model can better integrate with the ground due to its special shape and structure, and can better sense vibration signals compared with traditional vibration optical cables.

[0015] 4. The ultra-weak fiber optic grating multi-parameter sensing optical cable provided by this utility model has fiber-reinforced resin strain sensing optical fiber part bonded to the sheath with adhesive, which enhances the sensor's ability to sense strain signal transmission. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] Figure 2 The strain-wavelength curve of the multi-parameter sensing optical cable provided by this utility model.

[0018] Figure 3 Temperature-wavelength curve of the multi-parameter sensing optical cable provided by this utility model.

[0019] Figure 4 The present invention provides a multi-parameter sensing optical cable, and compares the frequency-phase curves of bare optical fiber and circular vibrating optical cable under the action of a vibration table.

[0020] In the above figures: 1. Ultra-weak fiber Bragg grating array; 2. Strain stiffener; 3. Vibration-type ultra-weak fiber Bragg grating array; 4. Sleeve; 5. Stiffener; 6. Flat sheath. Detailed Implementation

[0021] The present invention will now be described in detail with reference to specific embodiments.

[0022] This embodiment provides a multi-parameter sensing optical cable based on an ultra-weak fiber grating array, such as... Figure 1 As shown, it includes: a strain reinforcing rib 2 with an ultra-weak fiber grating array 1 at its center; a sleeve 4 with an embedded vibrating ultra-weak fiber grating array 3, the sleeve 4 being filled with grease; fiber-reinforced resin reinforcing ribs 5 symmetrically arranged relative to the strain reinforcing rib 2 and the sleeve 4; the strain reinforcing rib 2, the sleeve 4 and the reinforcing ribs 5 are formed into a flat sheath 6 by hot extrusion through a mold.

[0023] In the above embodiments, the strain reinforcing rib 2 is formed by hot pultrusion of high-strength glass fiber, polymer matrix and ultra-weak fiber grating array 1, and is used to couple the strain transmitted on the flat sheath 6.

[0024] The vibration type ultra-weak fiber grating array 3 is used for coupling micro-vibration transmitted on the flat sheath 6 through the oil cream and the sleeve 4.

[0025] In some embodiments, the fiber reinforced resin reinforcing rib 5 is made of glass fiber and polymer matrix by thermal pultrusion, for improving mechanical tensile and compression performance.

[0026] In some preferred embodiments, the flat sheath 6 is in a trapezoidal shape, and the special shape of the flat sheath in the embodiments can better combine with the ground, so that the vibration type ultra-weak fiber grating array in the sleeve can more sensitively sense vibration.

[0027] In some preferred embodiments, the strain reinforcing rib 2 is glued and combined with the sheath 4, so as to enhance the ability of the sensor to perceive strain signal transmission.

[0028] The ultra-weak fiber grating array multi-parameter sensing optical cable is placed into a tension machine, strain calibration experiments are carried out, and a strain-wavelength curve diagram of the flat type multi-parameter sensing optical cable is as shown in Figure 2 The abscissa is strain applied on the optical cable, and the ordinate is the central wavelength of the grating. Test results show that the ultra-weak fiber grating array multi-parameter sensing optical cable provided by the utility model has a linear relationship between strain and wavelength, a strain sensitivity of 0.9996, and a high strain transmission efficiency.

[0029] The ultra-weak fiber grating array multi-parameter sensing optical cable is placed into a high-low temperature cycle box, connected to an ultra-weak fiber grating demodulator, temperature calibration experiments are carried out, and a temperature-wavelength curve diagram of the flat type multi-parameter sensing optical cable is as shown in Figure 3 The abscissa is temperature, and the ordinate is the central wavelength of the grating. Test results show that the ultra-weak fiber grating array multi-parameter sensing optical cable provided by the utility model has a linear relationship between temperature and wavelength, a temperature sensitivity of 0.9991, and a high strain transmission efficiency.

[0030] The ultra-weak fiber grating array multi-parameter sensing optical cable is fixed on a vibration table, under the action of a vibration table 1A, 0.6V amplitude, the vibration table is given an excitation of 100HZ, the flat type multi-parameter sensing optical cable is connected to an ultra-weak fiber grating DAS demodulator, and the same operation is carried out on bare vibration optical fiber and circular vibration optical cable for comparison, and a time-phase curve diagram of the three is as shown in Figure 4 The abscissa is time, and the ordinate is the phase change of the optical fiber and the optical cable. Test results show that the phase change of the ultra-weak fiber grating array multi-parameter sensing optical cable provided by the utility model is close to that of bare optical fiber, the phase change of the circular optical cable is weaker than that of the two, and the flat type optical cable can better sense vibration.

[0031] In summary, the utility model provides a kind of multi-parameter sensing optical cable based on ultra-weak fiber grating array, its flat special shape structure effectively promotes the ability of optical cable sensing vibration signal.This optical cable simultaneously composite fiber reinforced resin strain sensing fiber and the sleeve of embedded vibration type ultra-weak fiber grating array, can simultaneously monitor strain and vibration signal, meet the monitoring demand of large structure multi-parameter.This sensing optical cable two sides symmetrically arrange fiber reinforced resin reinforcing rib and fiber reinforced resin strain sensing fiber, and outer wrapping high-density polyethylene, so that the optical cable also has good tensile, anti-pressing flat characteristics, provide a kind of extremely potential solution for large structure monitoring.

[0032] Finally, it is explained that the above examples are only used to illustrate the technical solutions of the utility model and are not limited. Although the utility model has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the utility model can be modified or replaced equivalently without departing from the spirit and scope of the utility model technical solutions, which should be covered in the scope of the claims of the utility model.

Claims

1. A multi-parameter sensing optical cable based on ultra-weak fiber grating array, characterized in that, The strain reinforcement rib (2) comprises a central composite ultra-weak fiber grating array (1); a sleeve (4) in which a vibration type ultra-weak fiber grating array (3) is embedded, and the sleeve (4) is also filled with ointment; a fiber reinforced resin reinforcement rib (5) symmetrically arranged relative to the strain reinforcement rib (2) and the sleeve (4); the strain reinforcement rib (2), the sleeve (4) and the reinforcement rib (5) are formed into a flat sheath (6) by mold hot extrusion.

2. The multi-parameter sensing optical cable based on ultra-weak fiber grating array according to claim 1, characterized in that, The vibration type ultra-weak fiber grating array (3) is used to couple the micro-vibration transmitted on the flat sheath (6) through the ointment and the sleeve (4).

3. The multi-parameter sensing optical cable based on ultra-weak fiber grating array according to claim 1, characterized in that, The flat sheath (6) is in the shape of a trapezoid.

4. The multi-parameter sensing optical cable based on ultra-weak fiber grating array according to claim 1, characterized in that, The strain reinforcement rib (2) and the sleeve (4) are glued and bonded.

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