CN205139433U - A distributing type optical cable of meeting an emergency for monitoring of structure surface strain - Google Patents

Abstract

The utility model relates to a distributing type optical cable of meeting an emergency for monitoring of structure surface strain, including a temperature optic fibre that is used for measuring meet an emergency optic fibre and the measure the temperature that meet an emergency, the two constitutes circular platykurtic, and its moderate temperature optic fibre is placed in the metal spiral pipe, and the metal spiral pipe is the tubular structure that adopts the steel band coiling to form, the optic fibre of meeting an emergency is equipped with the strengthening rib outward and is used for the protection, and metal spiral pipe and temperature optic fibre are provided with the oversheath outward. The utility model discloses profitable effect: this optical cable can be used to the distributed strain monitoring on structure surface, and elimination temperature optic fibre that can be good produces residual strain's influence to improving the tensile and the compressive capacity of the optic fibre of meeting an emergency, having improved the survival ability of optical cable and the pliability of cable configuration, messenger's optical cable can be followed crooked uneven structure surface and is laid, good experiences the surperficial change of meeting an emergency of structure. This optical cable design simple structure, it is reliable and stable, with low costs, the practical valence of engineering has.

Description

A kind of distributed strain optical cable for body structure surface strain monitoring

Technical field

The utility model relates to optical cable field, mainly a kind of distributed strain optical cable for body structure surface strain monitoring.

Background technology

In recent years, the Distributed Optical Fiber Sensing Techniques (BOTDA) based on Brillouin scattering is widely used, and utilizes stimulated Brillouin scattering effect, measures the frequency information of the stokes light of backscattering, and its frequency shift amount meets:

f＝2nv/λ

Wherein, n is the refractive index of optical fiber, and v is the velocity of sound in optical fiber, and λ is the wavelength of laser pulse.

Because velocity of sound v is relevant with temperature with the strain of optical fiber, therefore optical fiber fabrication can be become optical cable and measured object to paste, utilize the deformation suffered by Brillouin shift amount indirect inspection measured object in optical fiber and temperature, therefore, it is possible to realization strain or thermometric sensing optic cable are core contents of the distributing optical fiber sensing based on Brillouin scattering.

Domestic also have relevant research in this regard, but all there is different defects and not enough disclose a kind of metal-based cable distributed optical fiber sensor as patent 2011110212087.5.Its technical scheme is a built-in tight tube fiber in the middle of optical cable; Metal Substrate cord structures is adopted to protect around optical fiber; although this optical cable substantially increases the tensile strength of sensor; may be used for the strain monitoring of xoncrete structure; but there is no temperature compensation unit in optical cable; so measurement result can be acted upon by temperature changes, make measurement result inaccurate.Patent 201220335164.6 discloses a kind of distributed strain of laying along body surface and temperature monitoring optical cable, what its technical scheme adopted equally is the scheme that the isolation of temperature optical cable strains, what but isolation adopted is stainless-steel tube, what steel pipe was filled is ointment material, so cause the hardness of optical cable to be difficult to very greatly bend, larger along body structure surface laying difficulty, and the interior filling of steel pipe is ointment material, when can cause optical cable generation strain variation, filler produces viscous force to temperature optical cable, produce overstrain, can not the impact of completely isolated strain.

Utility model content

The purpose of this utility model is exactly to overcome above-mentioned problems of the prior art, and a kind of distributed strain optical cable for body structure surface strain monitoring is provided, mainly be pasted onto structure surface, experience the strain variation of body structure surface, use as sensor.

The purpose of this utility model has been come by following technical solution.This distributed strain optical cable for body structure surface strain monitoring, comprise one for the strain optical fiber of monitor strain and the optical fiber temperature of measuring tempeature, the two forms circular flat, wherein optical fiber temperature is positioned in metallic coil, and metallic coil is the tubular structure adopting steel band coiling; Strain optical fiber outside be provided with reinforcement for the protection of, metallic coil and optical fiber temperature are outside equipped with oversheath.

Described oversheath cross section is two toroidals, adopts PE material package.

Described reinforcement adopts GFRP or steel wire.

Described strain optical fiber and optical fiber temperature are single-mode fiber of the same race.

The beneficial effects of the utility model are:

A. sensing optic cable adopts temperature unit and strain unit independently structure, measures while can meeting strain and temperature;

B. sensing optic cable adopts the oversheath of PE material, and overall elastic modulus is suitable with concrete, and strain transfer is effective, and PE material can resist the materials such as acid, alkali, oiliness simultaneously, and have good water proofing property and environmental suitability, long-time stability are good;

C. straining unit adopts GFPR (or steel wire) reinforcement to protect, and can improve tension and the compressive strength of optical cable, can resist the tension and compression in work progress and impact failure, improve the survival rate of optical cable in work progress.

D. temperature unit adopts metallic coil to carry out armouring protection; tension and the compressive strength of optical cable can be improved on the one hand; the impact of extraneous strain on optical fiber temperature can be isolated in addition on the one hand, harmony and the pliability of optical cable can also be improved, facilitate sensing optic cable to lay along body structure surface.

Accompanying drawing explanation

Fig. 1 is structural profile schematic diagram of the present utility model.

Description of reference numerals: optical fiber temperature 1; Metallic coil 2; Reinforcement 3; Strain optical fiber 4; Oversheath 5.

Embodiment

Below in conjunction with drawings and Examples, the utility model is described further:

The utility model provides a kind of distributed strain optical cable for object structures surface strain monitoring, with solve temperature and strain simultaneously, distributed measurement, optical cable and tested body structure surface install technique additional, cable strength strengthens, the easy enforcement of optical cable and the problem of engineering protection.The distributed strain optical cable combined by the extraordinary finer wire reinforcement protection strain unit of tight tube fiber and the tight tube fiber of metal spiral protection of pipe can be used in conjunction with BOTDA/BOTDR technology advanced at present; directly can carry out distributed sensing test being pasted onto tested structural objects surface, be widely used in the monitorings such as the temperature of the structures such as bridge, tunnel, dam, strain and damage.

As shown in the figure, this distributed strain optical cable for body structure surface strain monitoring, the two forms circular flat for the strain optical fiber 4 of monitor strain and the optical fiber temperature 1 of measuring tempeature to comprise one, and described strain optical fiber 4 and optical fiber temperature 1 are single-mode fiber of the same race.Wherein optical fiber temperature 1 is positioned in metallic coil 2, and metallic coil 2 is the tubular structures adopting steel band coiling; Strain optical fiber 4 outside be provided with reinforcement 3 for the protection of, described reinforcement 3 adopts GFRP or steel wire.Metallic coil 2 and optical fiber temperature 1 are outside equipped with oversheath 5, and described oversheath 5 cross section is two toroidals, adopt PE material package.

This patent one-piece construction is circular flat, and sheath material is PE encapsulation, and diameter is about 4mm.Optical cable is divided into two parts from centre, and optical cable left-hand component comprises the strain optical fiber for monitor strain, and right-hand component is an optical fiber temperature for measuring tempeature, and concrete implementation process is:

(1) the 0.6mm tightly packaged fiber of the G652B fibre core of optical fiber temperature employing; the metallic coil of outside diameter 2mm is protected; metallic coil is the tubular structure adopting steel band coiling; possesses certain compressive strength; and there is good bending changeability; can lay along by geodesic structure march face after making optical cable, compressive property is good.

(2) compared with distributed surperficial sensing optic cable before, the optical fiber temperature of spiral pipe encapsulation is adopted not have filling material, so when optical cable produces bending strain, strain viscous force can not be produced to optical fiber temperature, temperature optical cable can be in free state to carry out bending change and not to produce overstrain, can the impact that brings of good compensates; Adopting the method for metallic coil package temperature optical fiber to compare metal tube package temperature optical fiber in addition can make optical cable one-piece construction have good pliability, lays easily simple along body structure surface.

(3) strain the 0.6mm tightly packaged fiber that optical fiber adopts same G652B fibre core, outside GFRP (or steel wire) reinforcement of 6 diameter 0.6mm that adopts is protected.GFRP (or steel wire) reinforcement has higher physical strength and thermotolerance, and plasticity is strong, easy construction.

(4) in order to solve the problem of body structure surface Strain Distribution formula monitoring, measure while realizing temperature strain, the frequency displacement-coefficient of strain of assumed temperature optical fiber and strain optical fiber is C respectively _t1and C _t2, the frequency displacement-temperature coefficient of optical fiber temperature and strain optical fiber is C respectively _{ε 1}and C _{ε 2}.Because optical fiber temperature has the effect of strain isolating, so the frequency displacement-coefficient of strain of optical fiber temperature is C _{ε 1}=0, the frequency shift amount Δ v of optical fiber temperature and strain optical fiber so can be obtained by (FBG) demodulator _b1with Δ v _b2, formula is as follows:

$\left[\begin{array}{c}{\mathrm{\Δv}}_{B1}\\ {\mathrm{\Δv}}_{B2}\end{array}\right]=\left[\begin{array}{cc}{C}_{T1}& 0\\ C_{T2}& C_{\mathrm{\ϵ}2}\end{array}\right]\left[\begin{array}{c}\mathrm{\Δ}T\\ \mathrm{\Δ}\mathrm{\ϵ}\end{array}\right]$

Wherein Δ T and Δ ε is unknown quantity, and frequency shift amount Δ v _b1with Δ v _b2can be obtained by (FBG) demodulator, and the frequency displacement-coefficient of strain of the frequency displacement-temperature coefficient of optical fiber temperature, strain optical fiber and strain optical fiber is all obtained by rating test, temperature, the strain information that just can obtain environment by solving an equation:

$\mathrm{\Δ}T=\frac{{\mathrm{\Δv}}_{B1}}{C_{T1}}$

$\mathrm{\Δ}\mathrm{\ϵ}=\frac{{\mathrm{\Δv}}_{B2}-\frac{{\mathrm{\Δv}}_{B1}}{C_{T1}}{C}_{T2}}{C_{\mathrm{\ϵ}2}}$

By this kind of structural design, the impact of elimination optical fiber temperature generation overstrain that can be good, and improve tension and the anti-pressure ability of strain optical fiber, improve the viability of optical cable and the pliability of cable configuration, the optical cable made can be laid along the body structure surface of bending injustice, the strain variation of good impression body structure surface.

The distributed fiberoptic sensor of this structure can adopt BOTDR, BOTDA, ROTDR and OTDR distributed optical fiber sensing technology to carry out demodulation, be for the object such as concrete, steel structure body surface strain, Temperature Distribution formula monitoring.There is the features such as coupling is good, highly sensitive, installation facility, distributed monitoring.

In addition to the implementation, the utility model can also have other embodiments, and all employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of the utility model requirement.

Claims (4)

1. the distributed strain optical cable for body structure surface strain monitoring, it is characterized in that: comprise one for the strain optical fiber (4) of monitor strain and the optical fiber temperature (1) of measuring tempeature, the two forms circular flat, wherein optical fiber temperature (1) is positioned in metallic coil (2), and metallic coil (2) is the tubular structure adopting steel band coiling; Be provided with outside strain optical fiber (4) reinforcement (3) for the protection of, metallic coil (2) and optical fiber temperature (1) are outside equipped with oversheath (5).

2. the distributed strain optical cable for body structure surface strain monitoring according to claim 1, is characterized in that: described oversheath (5) cross section is two toroidals, adopts PE material package.

3. the distributed strain optical cable for body structure surface strain monitoring according to claim 1, is characterized in that: described reinforcement (3) adopts GFRP or steel wire.

4. the distributed strain optical cable for body structure surface strain monitoring according to claim 1, is characterized in that: described strain optical fiber (4) and optical fiber temperature (1) are single-mode fiber of the same race.