CN110865443A

CN110865443A - Bamboo joint type stress sensing optical cable

Info

Publication number: CN110865443A
Application number: CN201810984934.1A
Authority: CN
Inventors: 杜兵
Original assignee: Xian Genher Optical Tech Co
Current assignee: Xian Genher Optical Tech Co
Priority date: 2018-08-28
Filing date: 2018-08-28
Publication date: 2020-03-06

Abstract

The invention discloses a bamboo joint type stress sensing optical cable which comprises a plurality of micro-bending units and a binding layer, wherein the micro-bending units are formed by connecting sensing optical fibers in series, the binding layer is arranged on the outer side of each micro-bending unit, each micro-bending unit consists of an A side part and a B side part, the opposite surfaces of the two sides are respectively provided with deformation teeth in a staggered and corresponding mode, the sensing optical fibers are clamped between the deformation teeth on the two sides, and a gap is reserved between the adjacent micro-bending units. When the sensing optical cable is subjected to axial tension, the binding layer contracts in the radial direction of the sensing optical cable, so that the bending state of the sensing optical fiber is changed, and the sensing optical cable can be detected by a testing instrument arranged at the tail end of the sensing optical fiber.

Description

Bamboo joint type stress sensing optical cable

Technical Field

The invention relates to an optical fiber cable for sensing, in particular to a sensing optical cable based on the bending effect of optical fibers.

Background

The landslide hazard is the third geological hazard second to earthquake and flood, and due to the difference of geological structures, the forming and development process of landslide is complex, so that how to monitor the change of a landslide body in real time is a research hotspot, particularly, the monitoring of the deep displacement of the landslide body is one of key parameters, and the optical fiber sensing is one of the most potential sensing systems applied to landslide monitoring. However, the optical fiber is very thin, the outer diameter of the optical fiber is usually between 0.25 mm and 0.90 mm, and the optical fiber can be damaged by a small sand in practical engineering; in addition, the protection of the optical fiber cannot be excessive, otherwise, the sensing performance of the optical fiber is reduced, which is a contradiction problem and is an obstacle that always hinders the large-scale application of optical fiber sensing. In the existing slope and landslide examples monitored by adopting a distributed optical fiber sensing technology, most of the examples are that a groove is formed in a plastic pipe or a steel bar, an optical fiber is fixedly embedded into the groove through an adhesive, then the optical fiber is embedded into a slope or a landslide body, and finally the strain of the sensing optical fiber is monitored through a Brillouin Optical Time Domain Reflectometer (BOTDR).

The microbending loss optical fiber sensing device is the sensing device with the simplest structure, the typical structure is shown in fig. 1, the sensing device comprises two opposite toothed plates and sensing optical fibers clamped between the two toothed plates, when the two toothed plates move relatively, the change of the bending state of the sensing optical fibers is caused, so that the optical fibers generate additional bending loss, and the change of the loss of the sensing optical fibers is detected by a testing unit connected with the tail ends of the sensing optical fibers, so that the change of the physical quantity to be detected acting on the toothed plates is monitored. However, the typical structure cannot be bent, so that construction is difficult when a distributed or quasi-distributed optical fiber sensing system is constructed, and the large-length microbend optical fiber sensing device is not beneficial to production, storage, transportation, installation and maintenance, so that popularization and use of the structural sensing device are limited.

Disclosure of Invention

The invention discloses a sensing optical cable based on a microbend principle, wherein a plurality of short-section microbend units are connected in series in the sensing optical cable, so that the aim of quasi-distributed sensing can be fulfilled, and the sensing optical cable is relatively soft and easy to bend and is convenient to produce, store, transport and install; instruments which can be connected by the sensing optical fiber in the optical cable comprise a light source-power meter, an optical time domain reflectometer, an optical fiber Brillouin scatterometer or an optical fiber interferometer and the like, and the constructed optical fiber sensing system has the advantages of simple structure, low cost, high precision and better application prospect.

In order to solve the technical problems, the invention adopts the technical scheme that:

a bamboo joint type stress sensing optical cable is characterized by comprising a plurality of micro-bending units and a binding layer, wherein the micro-bending units are formed by connecting sensing optical fibers in series, the binding layer is arranged on the outer side of each micro-bending unit, each micro-bending unit is composed of an A side part and a B side part, deformation teeth which correspond to the A side part and the B side part in a staggered mode are respectively distributed on the opposite surfaces of the A side part and the B side part, the sensing optical fibers are clamped between the deformation teeth on the two sides, and gaps are reserved between the adjacent micro-bending units.

Preferably, said constraining layer is radially contractible under axial tension.

Preferably, the tie layer is a helically shaped reinforcement. Such as steel wire, aramid fiber.

Preferably, the binding layer is a fiber net sleeved on the microbend unit. Such as nylon woven mesh, steel wire mesh, etc.

Preferably, the binding layer is a polymer material layer. Such as polyethylene layers, nylon layers.

Preferably, a protective tube is arranged on the outer side of the sensing optical fiber between the adjacent microbending units.

Preferably, the binding layer is a plastic tube with an opening arranged in the longitudinal direction.

Preferably, the adjacent slightly-bent units are connected with each other through the arranged connecting ropes.

Preferably, an outer protective layer is arranged outside the binding layer.

Compared with the prior art, the invention has the following advantages:

1. because the stress sensing optical cable adopts the bamboo joint type structure, the sensing optical cable still has good bending property while ensuring the quasi-distributed sensing, thereby being capable of adapting to the requirements of production, storage and transportation and installation.

2. Because the bamboo joint type micro-bending structure is adopted by the stress sensing optical cable, the sensing precision is ensured while the convenience in use is ensured, and the cost is reduced.

In conclusion, the bamboo joint type stress sensing optical cable has the characteristics of simple structure, low cost and good use performance.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

Fig. 1 is a schematic structural diagram of a conventional microbend fiber sensing device.

Fig. 2 is a microbend unit of the bamboo joint type stress sensing optical cable.

Fig. 3 is a schematic side view of the microbend unit shown in fig. 2.

FIG. 4 is a schematic structural diagram of the bamboo joint type stress sensing optical cable.

Description of reference numerals:

1-sensing optical fiber; 2-part A; 3-the B-side portion; 5, a first microbending unit;

6, a second microbending unit; 8-a constraining layer; 21-deformation tooth one; and 22, forming a second tooth.

Detailed Description

The implementation scheme is as follows: as shown in fig. 2, 3 and 4, the bamboo joint type stress sensing optical cable comprises a plurality of microbend units connected in series by a sensing optical fiber 1, and a binding layer 8 arranged outside the microbend units, each microbend unit is composed of an a-side part 2 and a B-side part 3, staggered and corresponding deformation teeth including a first deformation tooth 21 and a second deformation tooth 22 are respectively arranged on the opposite surfaces of the a-side part 2 and the B-side part 3, the sensing optical fiber 1 is clamped between the deformation teeth on the two sides, and a gap is formed between the adjacent microbend units. Preferably, said constraining layer 8 is radially contractible under axial tension. For example, in fig. 3, a microbend unit i 5 and a microbend unit ii 6 are arranged inside a binding layer 8, a sensing optical fiber 1 is clamped inside the microbend unit i 5 and the microbend unit ii 6, and a gap is arranged between the microbend unit i 5 and the microbend unit ii 6, so that the cable has good bending property, when the binding layer 8 is subjected to an axial force, the binding layer 8 starts to contract radially, so that an a-side part 2 and a B-side part 3 forming the microbend unit i 5 and the microbend unit ii 6 are close to each other, so that the bending radius of the sensing optical fiber 1 between two deformed teeth is changed, and an optical signal transmitted in the sensing optical fiber 1 is changed and is detected by a testing device arranged at the tail end of the sensing optical fiber 1, and the purpose of monitoring a physical quantity to be measured is achieved.

Preferably, the tie layer 8 is a helically shaped reinforcement. Such as steel wire, aramid fiber. The reinforcement is wound around the outside of the microbend unit.

Preferably, the binding layer 8 is a fiber net sleeved on the microbend unit. Such as nylon woven mesh, steel wire mesh, etc.

Preferably, the binding layer 8 is a polymer material layer. Such as polyethylene layers, nylon layers.

Preferably, a protective tube is arranged outside the sensing optical fiber 1 between adjacent microbend units, and the protective tube is positioned inside the binding layer 8.

Preferably, the binding layer 8 is a plastic tube with an opening arranged in the longitudinal direction. Of course, the binding layer 8 may be formed by combining multiple layers of materials, such as nylon woven net arranged outside the plastic pipe to form the binding layer 8.

Preferably, an outer protective layer is arranged outside the binding layer 8. Such as polyethylene sheath, can make the sensing optical cable adapt to the field environment condition.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A bamboo joint type stress sensing optical cable is characterized in that: the sensor comprises a plurality of microbend units connected in series by sensing fibers (1) and a binding layer (8) arranged on the outer side of each microbend unit, wherein each microbend unit consists of an A-side part (2) and a B-side part (3), deformation teeth corresponding to the A-side part (2) and the B-side part (3) in a staggered mode are respectively distributed on the opposite surfaces of the A-side part and the B-side part, the sensing fibers (1) are clamped between the deformation teeth on the two sides, and a gap is reserved between the adjacent microbend units.

2. The bamboo joint type stress sensing optical cable according to claim 1, wherein the binding layer (8) is radially contracted under the action of axial tension.

3. The bamboo joint type stress sensing optical cable according to claim 1 or 2, wherein the tie layer (8) is a spiral-shaped reinforcing member.

4. The bamboo joint type stress sensing optical cable according to claim 1 or 2, wherein the binding layer (8) is a fiber mesh sleeved on the microbend unit.

5. The bamboo joint type stress sensing optical cable according to claim 1 or 2, wherein the binding layer (8) is a polymer material layer.

6. The bamboo joint type stress sensing optical cable according to claim 1 or 2, wherein a protective tube is arranged on the outer side of the sensing optical fiber (1) between the adjacent micro-bending units, and the protective tube is positioned on the inner side of the binding layer (8).

7. The bamboo joint type stress sensing optical cable according to claim 1 or 2, wherein the binding layer (8) is longitudinally provided with an open plastic tube.

8. The bamboo joint type stress sensing optical cable according to claim 1 or 2, wherein the adjacent micro-bending units are connected with each other through the arranged connecting ropes.

9. The bamboo joint type stress sensing optical cable according to claim 1 or 2, wherein an outer protective layer is arranged outside the binding layer (8).