TWM578387U - Fiber grating smart steel strand - Google Patents

Abstract

The present invention provides a fiber grating smart steel strand, comprising: a center wire, and a side wire twisted with the center wire; the center wire is provided with at least one groove, and the fiber is placed in the groove At least one grating is engraved on the fiber. This creation can solve the technical problems of the survival rate of the laying process and the low monitoring range when the existing fiber Bragg grating monitors the stress state of the steel strand.

Description

Fiber grating wisdom steel strand

This creation is about a field of monitoring technology, especially with regard to a fiber grating smart steel strand.

Steel strands such as tie rods, suspension bridges, cable-stayed bridges, internal and external prestressing tendons, and anchors in rock and soil are the key members of the structure. The working state during use is directly related to the structure. Safety. Due to the coupling of environmental erosion, material aging and long-term load effects during use, it is inevitable that damage accumulation will occur, resulting in lowering of various functions, threatening the safety of the structural service period, and even in extreme cases. Catastrophic consequences. It is therefore necessary to monitor the above components.

The traditional monitoring methods are mainly acceleration test, corrosion detection, magnetic flux monitoring and other technologies. There are defects such as low precision, poor operability, large influence by disturbance, large influence on structural members, difficulty in real-time monitoring, and stress of key components. Strain monitoring requires reliable testing tools and techniques. Fiber Bragg Grating technology senses small changes in external physical quantities by reflecting wavelengths and movements of the grid. It has the advantages of high linearity, good repeatability, and high-precision, absolute, quasi-dispersive digital measurement of stress and strain. It has strong anti-electromagnetic interference capability, high temperature resistance, small sensor volume, simple wiring and long-distance transmission of data. It is suitable for stress and strain monitoring of steel strands of key stressed components.

However, due to the inherent glass fragility of the fiber material, its shear and bending resistance is poor, and special protection is required for application. At the same time, the ultimate tensile strain of the fiber is about 5000 micro strain, and the ultimate tensile strain of the steel wire can reach or exceed 10,000. Micro-strain, so that the fiber grating sensor monitors the range is not enough. Therefore, the application of fiber Bragg grating to monitor the stress condition of the steel strand needs to solve the key technical problems such as the survival rate and the monitoring range of the layout process.

In view of this, the technical problem to be solved by this creation is the technical problem of the survival rate of the layout process and the low monitoring range when the fiber grating is used to monitor the stress state of the steel strand.

In order to solve the above technical problem, the present invention provides a fiber grating smart steel strand, comprising: a center wire, and a side wire twisted with the center wire; the center wire is provided with at least one groove, An optical fiber is placed in the recess, and the optical fiber is engraved with at least one grating.

Further, the optical fiber is adhered to the groove by an adhesive.

Further, the groove has a depth of 0.1 to 0.8 mm and a width of 0.1 to 1.5 mm.

Further, the groove is a longitudinal groove.

Further, the number of the grooves is 1 to 6.

Compared with the prior art, the technical solution of the present embodiment has the following technical effects: (1) by directly bonding the grating into the groove provided by the center wire, the adhesion degree between the grating and the fiber grating smart steel strand is ensured, so that The deformation is kept in harmony, so that the strain measured by the grating can not truly reflect the actual strain of the fiber grating smart steel strand; (2) the longitudinal groove provided on the center wire and the glue for protecting the optical fiber Adhesive agent, avoiding the fracture caused by the direct contact of the optical fiber with other hard surfaces, and improving the survival rate and service life of the optical fiber in the fiber grating smart steel strand under the extensive construction conditions and the harsh environment; (3) Pulling the center wire, holding the bonded fiber, and after the strength of the adhesive is stabilized, the method of manufacturing the center wire, changing the tensile force of the center wire according to the strain range of the fiber grating smart steel strand, and serving in the fiber grating smart steel strand Applying compressive strain to the fiber beforehand to expand the monitoring range of the grating, avoiding the disadvantages of limiting the monitoring range due to the glass fragility of the fiber material itself; (4) making multiple groups by a plurality of longitudinal grooves provided in the center wire The grating works at the same time, and can perform multiple data comparisons, which greatly improves the accuracy and persuasiveness of the monitoring results. (5) The strain of different parts of the fiber grating smart steel strand can be monitored through multiple gratings engraved on the optical fiber. situation.

Of course, any product that implements this creation necessarily does not necessarily need to achieve all of the technical effects described above at the same time.

1‧‧‧ fiber grating smart steel strand

2‧‧‧Center wire

21‧‧‧ Groove

22‧‧‧ fiber

23‧‧‧Raster

24‧‧‧Adhesive

The drawings described herein are provided to provide a further understanding of the present invention and constitute a part of the present invention. The illustrative embodiments of the present invention and the description thereof are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings: FIG. 1 is a perspective view of a fiber grating smart steel strand of the present embodiment; FIG. 2 is a cross-sectional structural view of a fiber grating smart steel strand of the present embodiment; FIG. The longitudinal direction of the center wire of the fiber grating smart steel strand of the creation example Cross-sectional schematic view; Fig. 4 is a schematic cross-sectional view of the center wire of the fiber grating smart steel strand of the present embodiment.

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and embodiments, so that the implementation of the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented.

As shown in FIGS. 1 to 4, the fiber grating smart steel strand 1 of the present embodiment includes a center wire 2 and a side wire 3 twisted with the center wire 2; the center wire 2 is provided with at least one groove 21, an optical fiber 22 is placed in the recess 21, and at least one grating 23 is engraved on the optical fiber 22.

The groove 21 is a longitudinal groove, and the number of the grooves 21 is 1 to 6. The groove 21 has a depth of 0.1 to 0.8 mm and a width of 0.1 to 1.5 mm, and the optical fiber 22 is adhered to the groove 21 by the adhesive 24.

The present invention also provides a method for fabricating a fiber grating smart steel strand, comprising the following steps: Step 1: mechanically breaking the steel strand to take out the center wire 2 or take the center wire 2 without twisting into a steel strand; Step 2: The groove 21 in the longitudinal direction of the center wire 2 is 0.1-0.8 mm and the width is 0.1-1.5 mm; Step 3: Tensioning the center wire 2, the tensile stress is between 0 and 1860 MPa; Step 4 : maintaining the tension is unchanged, the optical fiber 22 engraved with the grating 23 is adhered to the groove 21 with the adhesive 24; Step 5: when the strength of the adhesive is stable, the center wire 2 is placed; Step 6: twisting the prepared center wire 2 and the edge wire 3 wound around the center wire 2 into a fiber grating smart steel strand.

The number of the grooves 21 in the present embodiment is 1 to 6, and may of course be other numbers.

The number of the gratings 23 engraved in the optical fiber 22 in the present embodiment may be one or more, depending on the required measurement site.

In the present embodiment, the stress of the center wire 2 is between 0 and 1860 MPa, and when the tensile stress is 0, the center wire 2 is not stretched, and whether the tension and the tensile stress are required to be determined are specifically determined. It can be determined according to the range of strain change of the tested steel strand.

Compared with the prior art, the technical solution of the present embodiment has the following technical effects: (1) by directly attaching the grating 23 to the groove 21 provided in the center wire 2, ensuring the grating 23 and the fiber grating intelligent steel strand 1 The degree of bonding is such that the deformation remains consistent, so that the strain measured by the grating 23 does not truly reflect the actual strain of the fiber grating smart steel strand 1; (2) the longitudinal groove 21 provided on the center wire 2 and the protective fiber The adhesive 24 avoids the breakage caused by the direct contact of the optical fiber 22 with other hard surfaces, and improves the survival rate and service life of the optical fiber 22 in the fiber grating smart steel strand 1 under the extensive construction conditions and the harsh use environment; 3) By tensioning the center wire 2, the holding adhesive 24 is attached to the optical fiber 22. After the strength of the adhesive 24 is stabilized, the method of manufacturing the center wire 2 is performed, and the center wire is changed according to the strain range of the fiber grating smart steel strand 1. 2 tensile force, before the fiber grating smart steel strand 1 is serviced, the pressure strain is applied to the optical fiber 22 in advance, and the monitoring range of the grating 23 is enlarged, thereby avoiding the material of the optical fiber 22 itself. The brittleness of the glass limits the unfavorable factors of the monitoring range; (4) the plurality of sets of gratings 23 are simultaneously operated by the plurality of longitudinal grooves 21 provided in the center wire 2, so that a plurality of data comparisons can be performed, and the monitoring result is greatly improved. The accuracy and persuasiveness; (5) the strain condition of different parts of the fiber grating smart steel strand 1 can be monitored by a plurality of gratings 23 engraved on the optical fiber 22.

The above description illustrates and describes several preferred embodiments of the present invention, but as described above, it should be understood that the present invention is not limited to the forms disclosed herein, and should not be construed as being excluded from the other embodiments. Other combinations, modifications, and environments are possible and can be modified by the teachings or related art or knowledge within the scope of the inventive concept described herein. All changes and modifications made by those skilled in the art are intended to be within the scope of the appended claims.

Claims (5)

A fiber grating smart steel strand comprising: a center wire, and a side wire twisted with the center wire; and the center wire is provided with at least one groove in which an optical fiber is placed, the fiber At least one grating is engraved on it. The fiber grating smart steel strand according to claim 1, wherein the optical fiber is adhered to the groove by an adhesive. The fiber grating smart steel strand according to claim 1, wherein the groove has a depth of 0.1 to 0.8 mm and a width of 0.1 to 1.5 mm. The fiber grating smart steel strand according to claim 1, wherein the groove is a longitudinal groove. The fiber grating smart steel strand according to claim 1, wherein the number of the grooves is 1 to 6.