CN203479265U - Metal armored distributed sensitive optical cable for monitoring surface strain of object - Google Patents

Abstract

The utility model relates to a distributed strain-monitoring optical cable which is mounted along the surface of an object. The optical cable includes a slice band-shaped copper substrate, a groove is formed in the surface of the metal substrate, a four-core optical fiber ribbon which includes two types of fibers is laid in the groove, hollowed circular holes are symmetrically formed at the two sides of a metal sheet, and hollowed strip-shaped holes vertical to the groove are formed in the groove. The slice band-shaped structure of the metal substrate enables that the contact area between the optical cable and the tested object is enough, the hollowed holes further reduce the deformation modulus of the fibers, and the groove is used for matching and protecting the fibers. The optical cable of the utility model is characterized by good coupling performance, high sensitivity, convenience in installation and distributed monitoring.

Description

A kind of metal armouring distributed sensing optical cable for body surface strain monitoring

Technical field

The utility model relates to optical cable field, is specifically related to a kind of distributed strain monitoring optical cable mounting along body surface.

Background technology

In recent years, the Distributed Optical Fiber Sensing Techniques based on Brillouin scattering (BOTDA) 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, the refractive index that n is optical fiber, v is the velocity of sound in optical fiber, the wavelength that λ is laser pulse.

Because velocity of sound v is relevant with strain and the temperature of optical fiber, therefore optical fiber fabrication can be become to optical cable and measured object pastes, therefore utilize the Brillouin shift amount in optical fiber indirectly to measure the suffered deformation of measured object and temperature, can realize strain or thermometric sensing optic cable is a core of the distributing optical fiber sensing based on Brillouin scattering.

Here we utilize two optical fiber with the different frequency displacement coefficients of strain and frequency displacement temperature coefficient, build matrix of coefficients, realize the separating and measuring of strain and temperature, and corresponding computing formula is as follows:

$\left[\begin{array}{c}\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="v\; B"\; filenames="HDA0000376610170000012.png"\; state="\{\{state\}\}">v</figure-callout>}}_B\\ \mathrm{\&Delta;}{\mathrm{\&nu;}}_{B2}\end{array}\right]=\left[\begin{array}{cc}{C}_{T1}& C_{\mathrm{\&epsiv;}1}\\ C_{T2}& C_{\mathrm{\&epsiv;}2}\end{array}\right]\left[\begin{array}{c}\mathrm{\&Delta;T}\\ \mathrm{\&Delta;\&epsiv;}\end{array}\right]$

$\mathrm{\&Delta;\&epsiv;}=\frac{{\mathrm{<figure-callout\; id="1"\; label="C\; T"\; filenames="HDA0000376610170000012.png"\; state="\{\{state\}\}">C</figure-callout>}}_T\mathrm{\&Delta;}{v}_{B2}-C_{T2}\mathrm{\&Delta;}{v}_{B1}}{C_{\mathrm{\&epsiv;}2}{C}_{T1}-C_{\mathrm{\&epsiv;}1}{C}_{T2}}$

$\mathrm{\&Delta;T}=\frac{C_{\mathrm{\&epsiv;}2}\mathrm{\&Delta;}{v}_{B1}-C_{\mathrm{\&epsiv;}1}\mathrm{\&Delta;}{v}_{B2}}{C_{\mathrm{\&epsiv;}2}{C}_{T1}-C_{\mathrm{\&epsiv;}1}{C}_{T2}}$

Domestic also have relevant research in this regard, part utility model has also formed patent, but all exist different defects and not enough as utility model 201020686743.6 to disclose a kind of temperature strain optical cable for sensing, its technical scheme is to solve optical cable and by the technique for sticking problem of geodesic structure at sheath Bottomattached gluing layer.This technical scheme does not solve the engineering protection of optical cable, and optical cable part and technique for sticking problem by geodesic structure except gluing layer, patent 201110160135.0 discloses a kind of metal strain optical cable, because its metal cables adopts double recess, and be optical fiber of the same race, so may cause optical fiber and determinand Surface Contact bad, strain transfer is inhomogeneous, can not separated strain and the problem such as temperature coupling.

Utility model content

The purpose of this utility model is to overcome the deficiency that prior art exists, for solving the bonding problem of temperature and strain while, distributed measurement and optical cable and tested body structure surface, make optical cable strength-enhanced, easily construction and easily protection, a kind of metal armouring distributed sensing optical cable for body surface strain monitoring is provided.

The utility model adopts following technical scheme to realize:

A kind of metal armouring distributed sensing optical cable for body surface strain monitoring, it is characterized in that: with metal material, do substrate, and be that thin slice is banded, by banded structure, can reduce optical cable volume, obtain more contact area to promote coupling, by flaky texture, reduce the deformation modulus of optical fiber to improve compatibility of deformation; Metal substrate surface is opened fiber grooves, and optical fiber is placed in fiber grooves, fills glue-line in groove, makes fiber grooves agree with optical fiber to promote strain transfer and protection optical fiber; Metallic substrates bottom be on adhesive tape protective seam for the protection of optical cable lower surface, adhesive tape protective seam, also have the matrix of one deck for the protection of optical fiber at the bottom of; In metallic substrates, along fiber grooves both sides, have equally spacedly symmetrical hollow out circular hole, in fiber grooves, perpendicular to groove, have equally spacedly hollow out cylindrical void, hollow out circular hole and hollow out cylindrical void are all in order to reduce modulus deformation; Described optical fiber adopts four-core fiber band, is two kinds of different single-mode fibers, by two naked fibres of G657 and two, with the naked fibre of G652, is combined.

The beneficial effects of the utility model are:

1, metallic substrates has certain width, adopts metal band-shaped structure can obtain more contact area to promote the transitivity of coupling and deformation;

2, Metal Substrate tail band is laminar and has the hollow hole of symmetrical structure, can reduce the compatibility of deformation performance that base metal band deformation modulus improves sensor;

3, the groove that has special coupling agrees with sensor fibre band to promote strain transfer and protection sensor fibre band, makes the work of sensor more reliable;

4, groove has hollow out cylindrical void to meet, the curved surface of detected object to be laid at a certain distance;

5, adopt four-core fiber band, can improve the consistance of the fibre ribbon environment of living in of measuring fiber intensity and temperature, strain decoupling zero, and redundancy backup is provided.

Accompanying drawing explanation:

Fig. 1 cable configuration figure;

Fig. 2 optical cable sectional view;

Description of reference numerals: at the bottom of copper strips substrate 1, hollow out circular hole 2, fiber grooves 3, hollow out cylindrical void 4, matrix 5, four-core fiber band 6, adhesive tape protective seam 7, fill glue-line 8.

Embodiment

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

Referring to Fig. 1, Fig. 2; metal armouring optical cable selects copper as band-shaped substrate 1; fiber grooves 3 is opened on copper strips substrate 1 surface; four-core fiber band 6 for monitor strain and temperature is placed on fiber grooves 3; in fiber grooves 3, using silica gel as fill glue-line 8, copper strips substrate 1 bottom be on adhesive tape protective seam 7 for the protection of optical cable lower surface, adhesive tape protective seam 7, also have one deck for the protection of the matrix of four-core fiber band 6 at the bottom of 5, in copper strips substrate 1, have reduce modulus deformation hollow out circular hole 2, in fiber grooves 3, have the hollow out cylindrical void 4 that reduces modulus deformation.

Copper strips substrate 1, has certain width, and width size is 9.6mm, and gross thickness is 0.72mm, and fiber grooves 3 width in the middle of are wherein 1.1mm, and the degree of depth of fiber grooves 3 is 0.3mm, and the degree of depth of fiber grooves 3 and width be take and suited four-core fiber band 6 as standard.Along groove line direction, every 10mm, have hollow out cylindrical void 4, hollow out cylindrical void 4 is perpendicular to groove line direction, and its width is 0.3mm, at the right and left of copper strips substrate 1, every 5mm, has symmetrical hollow out circular hole 2, and the diameter of circular hole is 1.5mm.

Four-core fiber band 6 adopts two naked fibres of G657 and two to combine with the naked fibre of G652, and the diameter of naked fibre is 0.25mm.It is larger that the frequency displacement-temperature coefficient of the G657 selecting and the naked fibre of G652 and frequency displacement-coefficient of strain will differ.

For solving the mounting problem on metal armouring optical cable and measured object surface; first before construction, to go out adhesive tape protective seam 7; then measured object surface finish is clean; by spot welding mode, metal armouring optical cable and measured object point are welded into one; then with epoxide-resin glue E-44, carrying out surface uniform smears; after 24 hours solidify, can measure.

In order to solve the problem of strain and temperature cross sensitivity, distributed measurement when realizing temperature strain, adopts the not fibre ribbon of optical fiber of the same race, and frequency displacement-coefficient of strain of setting G652 optical fiber and G657 optical fiber is respectively C _{ε 1}and C _{ε 2}; Frequency displacement-temperature coefficient is respectively C _t1and C _t2, because two kinds of optical fiber are in the middle of same environment, thus can experience identical temperature and strain variation, but because frequency displacement-coefficient of strain is different with frequency displacement temperature coefficient, so the Brillouin shift producing is different, can obtain following formula:

$\left[\begin{array}{c}\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="v\; B"\; filenames="HDA0000376610170000012.png"\; state="\{\{state\}\}">v</figure-callout>}}_B\\ \mathrm{\&Delta;}{\mathrm{\&nu;}}_{B2}\end{array}\right]=\left[\begin{array}{cc}{C}_{T1}& C_{\mathrm{\&epsiv;}1}\\ C_{T2}& C_{\mathrm{\&epsiv;}2}\end{array}\right]\left[\begin{array}{c}\mathrm{\&Delta;T}\\ \mathrm{\&Delta;\&epsiv;}\end{array}\right]$

Wherein Δ T and Δ ε are unknown quantity, and Δ v _b1with Δ v _b2brillouin shift amount for BOTDA apparatus measures obtains, by separating linear equation in two unknowns, just can obtain temperature and the strain information of environment:

$\mathrm{\&Delta;\&epsiv;}=\frac{{\mathrm{<figure-callout\; id="1"\; label="C\; T"\; filenames="HDA0000376610170000012.png"\; state="\{\{state\}\}">C</figure-callout>}}_T\mathrm{\&Delta;}{v}_{B2}-C_{T2}\mathrm{\&Delta;}{v}_{B1}}{C_{\mathrm{\&epsiv;}2}{C}_{T1}-C_{\mathrm{\&epsiv;}1}{C}_{T2}}$

$\mathrm{\&Delta;T}=\frac{C_{\mathrm{\&epsiv;}2}\mathrm{\&Delta;}{v}_{B1}-C_{\mathrm{\&epsiv;}1}\mathrm{\&Delta;}{v}_{B2}}{C_{\mathrm{\&epsiv;}2}{C}_{T1}-C_{\mathrm{\&epsiv;}1}{C}_{T2}}$

So distributed measurement when the utility model can be realized temperature and strain, focuses on the demarcation of G652 optical fiber and G657 fiber optic frequency shifter-coefficient of strain and frequency displacement-temperature coefficient.

To description of the present utility model, do not have restricted above; if those of ordinary skill in the art is enlightened by it; in the situation that does not depart from the protection of the utility model claim, make other malformation of the present utility model and embodiment, all belong to protection domain of the present utility model.

Claims (1)

1. the metal armouring distributed sensing optical cable for body surface strain monitoring, it is characterized in that: with metal material, do substrate, and be that thin slice is banded, by banded structure, can reduce optical cable volume, obtain more contact area to promote coupling, by flaky texture, reduce the deformation modulus of sensing optic cable to improve the compatibility of deformation of sensing optic cable; Metal substrate surface is opened fiber grooves, and optical fiber is placed in fiber grooves, fills glue-line in groove, makes fiber grooves agree with optical fiber to promote strain transfer and protection optical fiber; Metallic substrates bottom be on adhesive tape protective seam for the protection of optical cable lower surface, adhesive tape protective seam, also have the matrix of one deck for the protection of optical fiber at the bottom of; In metallic substrates, along fiber grooves both sides, have equally spacedly symmetrical hollow out circular hole, in fiber grooves, perpendicular to groove, have equally spacedly hollow out cylindrical void, hollow out circular hole and hollow out cylindrical void are all in order to reduce modulus deformation; Described optical fiber adopts four-core fiber band, is two kinds of different single-mode fibers, by two naked fibres of G657 and two, with the naked fibre of G652, is combined.

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