JP7279250B1 - Fiber-reinforced resin cable and wire with damage detection function - Google Patents

Abstract

Kind Code: A1 A fiber-reinforced resin cable used as a reinforcing material for overhead power transmission lines is provided. A wire (1) comprises a wire core (10) and conductive layers (20, 30) surrounding the wire core (10). The electric wire core 10 consists of a total of seven cables, one long coated CFRP cable 11 (core wire) located in the center and six long coated CFRP cables 11 (side wires) twisted around it. It is composed of a coated CFRP cable 11 . The CFRP cable 12 includes one long tungsten wire 16, a large number of long carbon fibers bundled in a circular cross section so as to surround the tungsten wire 16, and epoxy resin impregnated in the carbon fibers. consists of [Selection drawing] Fig. 1

Description

The present invention relates to a fiber-reinforced resin cable and electric wire with a damage detection function.

Overhead transmission lines that are stretched over long distances between steel towers are required to be lightweight, have high tensile strength, and be able to carry large currents. Aluminum Conductor Steel Reinforced (ACSR), in which a single or stranded wire (steel wire core) of galvanized steel wire is placed in the center and multiple aluminum wires are twisted around it, is an overhead power transmission line. However, in recent years, in order to further reduce weight and increase tensile strength, aluminum conductor fiber reinforced (ACFR), in which fiber reinforced composite members are placed in the center instead of steel wires, has been used. are also used as overhead transmission lines.

When the aluminum wire is twisted around the fiber-reinforced composite member, it becomes difficult to tell from the outside whether the fiber-reinforced composite member is damaged. Therefore, there is a need for a method of detecting the state of a fiber-reinforced composite member by means other than visual confirmation. Patent Literature 1 discloses a fiber-reinforced composite member in which optical fibers are arranged. For example, by observing the backscattered light signal through the optical fiber, the condition of the fiber reinforced composite member covered with the aluminum wire is detected.

U.S. Patent Publication US2022/0146563 A1

In order to observe the optical signal passing through the optical fiber in Patent Document 1, the aluminum wire is removed at the end of the electric wire to expose the fiber-reinforced composite member, and the fiber-reinforced composite member is removed to expose the optical fiber. A light source, measuring instrument, etc. shall be connected to the exposed end of the optical fiber. Especially when the wire is actually used as an overhead transmission line, it is not easy to process the ends of the wire as described above.

The present invention provides a method for easily detecting the state, typically the state of damage, of a fiber-reinforced resin cable used as a reinforcing material for an overhead power transmission line, even when the cable is used as an overhead power transmission line. intended to

A fiber reinforced resin cable with a damage detection function according to the present invention includes a fiber reinforced resin cable composed of a fiber bundle obtained by bundling a plurality of fibers continuous in the longitudinal direction and a resin impregnated in the fiber bundle, and the fiber reinforced A heavy metal wire is arranged in the resin cable and extends in the longitudinal direction of the fiber reinforced resin cable while being surrounded by the fiber bundle and the hardened resin.

Fibers constituting the fiber-reinforced resin cable with damage detection function include carbon fiber, glass fiber, boron fiber, aramid fiber, polyethylene fiber, PBO (poly p-phenylenebenzobisoxazole) fiber, and other fibers. These fibers are very fine and can be impregnated with resin by bundling multiple fibers.

The resin constituting the fiber-reinforced resin cable with damage detection function may be either a thermosetting resin or a thermoplastic resin. Epoxies, saturated polyesters, vinyl esters, phenols, polyamides, polycarbonates, and the like can be used.

If a fiber-reinforced resin cable with a damage detection function is damaged, for example, by being bent, the fibers that make up the fiber bundle may break, or the resin impregnated in the fiber bundle may crack. Since the surrounding (restraint) of the heavy metal wire is weakened (for example, a gap is generated) at the location where disconnection and cracking occur, deformation (plastic deformation) occurs in the heavy metal wire.

Since the heavy metal wire is arranged in the fiber-reinforced resin cable, it cannot be visually recognized from the outside, but the shape of the heavy metal wire can be confirmed with an X-ray transmission image. This is because heavy metals have a high density and a high X-ray shielding rate (that is, they are clearly reflected in an X-ray transmission image). That is, the fiber-reinforced resin cable with a damage detection function according to the present invention has therein heavy metal wires whose shape can be clearly recognized in an X-ray transmission image. If deformation of the heavy metal wire is confirmed in the X-ray transmission image, there is a high possibility that fiber disconnection and resin cracking have occurred around the deformation point, and the X-ray transmission image shows the broken fiber and crack state. Even if the resin does not appear at all (conversely, it is easier to see the shape of the heavy metal wire clearly if it does not appear), the fiber reinforced resin cable with damage detection function is damaged or may be damaged. I understand. It is possible to prevent the erroneous use of a cable whose tensile strength has decreased due to the presence of broken fibers or cracks in the resin.

In one embodiment, the fiber-reinforced resin cable includes a plurality of resin-impregnated fiber bundles, each having a plurality of resin-impregnated fibers, each bundled into a bundle, and the resin-impregnated fiber The heavy metal wire is embedded in each of the bundles. Flexibility can be imparted to the fiber-reinforced resin cable by bundling a plurality of resin-impregnated fiber bundles into the fiber-reinforced resin cable.

Preferably, the plurality of resin-impregnated fiber bundles includes a centrally arranged core wire and a plurality of side wires twisted around the core wire. In addition to flexibility, high tensile strength and excellent fatigue resistance can be imparted to the fiber-reinforced resin cable.

The present invention provides a fiber reinforced resin cable composed of a fiber bundle obtained by bundling a plurality of fibers continuous in the longitudinal direction and a resin impregnated in the fiber bundle, arranged in the fiber reinforced resin cable, and having a circumference of A heavy metal wire extending in the longitudinal direction of the fiber reinforced resin cable surrounded by the fiber bundle and the hardened resin, and an electric wire comprising a plurality of light metal conductive wires twisted around the fiber reinforced resin cable. also provide. Since heavy metals (e.g. tungsten) have a higher density than light metals (e.g. aluminum), the deformation of heavy metal wires can be clearly confirmed in X-ray transmission images, enabling the detection of wire damage that cannot be seen from the outside. can be done.

It is a perspective view of an electric wire. 1 is a cross-sectional view of a length of coated CFRP cable; FIG. 1 is a schematic diagram of an X-ray inspection apparatus; FIG. FIG. 2 is a schematic vertical cross-sectional view of a normal coated CFRP cable; FIG. 2 is a schematic vertical cross-sectional view of a coated CFRP cable that has been bent; FIG. 3 is a schematic vertical cross-sectional view of the coated CFRP cable that has been unbent. 1 is an X-ray CT image of a wire core containing a damaged coated CFRP cable;

FIG. 1 shows an electric wire 1 with portions of an electric wire core 10 located in the center of the electric wire 1 and a conductive layer 20 around the electric wire core 10 exposed. FIG. 2 is a cross-sectional view of a covered CFRP (Carbon Fiber Reinforced Plastics) cable 11 that constitutes the wire core 10 shown in FIG. For convenience of illustration, the scales of FIGS. 1 and 2 are different.

Referring to FIG. 1, an electric wire 1 is composed of an electric wire core 10 and conductive layers 20 and 30 surrounding the electric wire core 10 . The electric wire core 10 is used as a reinforcing material for the electric wire 1 . Current flows through conductive layers 20 , 30 around wire core 10 .

The electric wire core 10 consists of a total of seven cables, one long coated CFRP cable 11 (core wire) located in the center and six long coated CFRP cables 11 (side wires) twisted around it. It is composed of a coated CFRP cable 11 .

Referring to FIG. 2, each of the coated CFRP cables 11 includes a CFRP cable 12 having a tungsten wire 16 in the center and a protective layer 15 coated on the surface of the CFRP cable 12, such as a polyethylene terephthalate (PET) resin layer. It is configured. The CFRP cable 12 includes one long tungsten wire 16, a large number of long carbon fibers 13 bundled in a circular cross section so as to surround the tungsten wire 16, and the carbon fibers 13 impregnated with Consists of epoxy resin 14 . The epoxy resin 14 impregnated in the carbon fiber 13 is hardened, and the CFRP cable 12 including the tungsten wire 16 is composed of the tungsten wire 16, the carbon fiber 13, and the epoxy resin 14. The coated CFRP cable 11 is constructed by coating the surface of the CFRP cable 12 with the protective layer 15 as described above.

The CFRP cable 12 contains tens of thousands to hundreds of thousands of long carbon fibers 13, and the entire wire core 10 contains hundreds of thousands to millions of carbon fibers 13. can be done. The diameter of the wire core 10 can be arbitrarily adjusted by the number of carbon fibers 13 or the number of coated CFRP cables 11 . By forming the electric wire core 10 using the coated CFRP cable 11 as a core wire and the coated CFRP cable 11 as a plurality of side wires twisted around it, it has high breaking strength and excellent flexibility. The electric wire core 10 having excellent fatigue resistance can be obtained. However, the electric wire core 10 may be formed by bundling or twisting a plurality of covered CFRP cables 11 without distinguishing between the core wire and the side wire. Furthermore, if the diameter of the electric wire 1 is particularly small, the single coated CFRP cable 11 may be used as the electric wire core 10 as it is.

The conductive layers 20, 30 are formed by a plurality of aluminum wires 21, 31 arranged around the wire core 10 described above. The electric wire 1 shown in FIG. It has a two-layer structure of a conductive layer 30 that Both of the aluminum wires 21 and 31 extend in the longitudinal direction of the electric wire 1 and are gently twisted, and are spirally wound around the electric wire core 10 . The number of conductive layers surrounding the wire core 10 and the number and shape of the aluminum wires 21, 31 forming each layer of the conductive layers 20, 30 can be changed as appropriate. For example, the cross-sectional shape of the aluminum wires 21, 31 may be circular.

FIG. 3 schematically shows an X-ray examination apparatus.

The X-ray inspection apparatus 40 is used by being attached to the wire 1 so as to enclose a part of the wire 1 which is suspended by the housing 41, and a plurality of X-ray generation sources (illustrated not shown) and a plurality of X-ray detection panels (not shown). For example, the X-ray image data is picked up from three ranges obtained by dividing the electric wire 1 in the circumferential direction (angle ranges of approximately 60 degrees each). The X-ray inspection device 40 has a motor (not shown) and can move along the electric wire 1 . By picking up a plurality of X-ray image data while moving the X-ray inspection device 40 along the electric wire 1, the X-ray image data over a desired range of the electric wire 1 can be picked up.

4 to 6 schematically show longitudinal sections of the coated CFRP cable 11. FIG. 4 shows a normal coated CFRP cable 11 that is not damaged, and FIG. FIG. 6 shows the coated CFRP cable 11 straightened after being damaged. 4 to 6 the protective layer 15 is drawn with considerable emphasis. 4 to 6, illustration of the epoxy resin 14 impregnated in the carbon fiber 13 is omitted. Also, for the sake of clarity, only a small number of carbon fibers 13 are drawn. Furthermore, the tungsten wire 16 is highlighted by a thick line.

Referring to FIG. 4, if the wire 1 is not damaged, the wire core 10 forming the wire 1 is not damaged, and the coated CFRP cable 11 forming the wire core 10 is also not damaged. A tungsten wire 16 contained in the coated CFRP cable 11 extends along the length of the coated CFRP cable 11 . Of course, if the coated CFRP cable 11 is twisted (see FIG. 1), the tungsten wire 16 will also spiral along the coated CFRP cable 11 .

Referring to FIG. 5, when electric wire 1 is strongly bent, for example, by being stepped on by a worker's foot, electric wire core 10 and conductive layers 20, 30 constituting electric wire 1 are also bent. The coated CFRP cable 11 forming the electric wire core 10 is also bent.

As described above, the multiple carbon fibers 13 forming the coated CFRP cable 11 are impregnated with the epoxy resin 14 and hardened. If the coated CFRP cable 11 is strongly bent due to the electric wire 1 being strongly bent, the epoxy resin 14 at the bent portion is likely to crack. In addition, the carbon fiber 13 has a lower compressive strength than a tensile strength, and is likely to break when a force is applied in the compressive direction. In FIGS. 5 and 6, a crack generated in the epoxy resin 14 and a disconnection (damage) generated in the carbon fiber 13 constituting the coated CFRP cable 11 are schematically indicated by symbol C. As shown in FIG.

The carbon fiber 13 impregnated with the epoxy resin 14 exists around the tungsten wire 16 as described above, and the tungsten wire 16 is restrained at its periphery by the carbon fiber 13 and the epoxy resin 14, so to speak. state. As described above, when the epoxy resin 14 cracks and the carbon fiber 13 breaks, a gap (small space) is created at the cracked wire C. On the other hand, a stress is applied to the tungsten wire 16, and the tungsten wire 16 undergoes plastic deformation toward the location of the crack break C (FIG. 5). In FIG. 5, the portion of tungsten wire 16 that has undergone plastic deformation is indicated by reference numeral 16A.

Referring to FIG. 6, when the electric wire 1 that has been bent once is then straightened again, the protective layer 15 constituting the coated CFRP cable 11 is highly elastic and returns to its original shape. The aluminum wires 21 and 31 are also the same. From the appearance, it is not clear whether the electric wire 1 and the coated CFRP cable 11 have been subjected to strong bending. On the other hand, the crack breakage C of the epoxy resin 14 and the carbon fiber 13 and the plastic deformation 16A of the tungsten wire 16 generated inside the coated CFRP cable 11 straighten the electric wire 1 (coated CFRP cable 11) again. Even if you let it go, it will never come back.

FIG. 7 shows an X-ray CT (Computed Tomograph) image of the damaged electric wire 1 . The X-ray CT image shown in FIG. 7 is created by computer processing the X-ray image data of the wire core 10 . As will be explained below, only the tungsten wire 16 is clearly emphasized in the X-ray CT image. For clarity, the portion of tungsten wire 16 undergoing plastic deformation 16A is circled in FIG.

As described above, the wire core 10 forming the wire 1 has seven coated CFRP cables 11, each of which includes one tungsten wire 16. As shown in FIG. The density of the tungsten wire 16 (approximately 19.1 g/cm ³ ) is much higher than the densities of the other materials constituting the wire 1 (aluminum: 2.7 g/cm ³ , carbon fiber 13: 1.8 g/cm ³ ). high, and the X-ray shielding rate is large. That is, the tungsten wire 16 is difficult to transmit X-rays, and only the tungsten wire 16 can be clearly imaged in the X-ray image. As shown in FIG. 7, the shape of seven tungsten wires 16 can be clearly seen in the X-ray CT image of the wire 1 .

If it is found that the tungsten wire 16 is plastically deformed 16A, it will cause the carbon fiber 13 and the epoxy resin 14 around the portion of the tungsten wire 16 where the plastic deformation 16A has occurred, such as cracks and disconnections as described above. It means that damage has occurred. That is, by observing the shape of the tungsten wire 16 (presence or absence of plastic deformation 16A) using an X-ray image (X-ray CT image), the presence and extent of damage to the wire core 10 (coated CFRP cable 11) can be known. be able to.

In the above-described embodiment, an example in which the coated CFRP cable 11 containing tungsten wires 16 is used as the electric wire 1 has been described, but the coated CFRP cable 11 containing tungsten wires 16 (or the CFRP cable 12 containing tungsten wires 16) It can also be used for civil engineering applications such as tendons for prestressed concrete.

Also, in the above-described embodiment, the covered CFRP cable 11 using the carbon fiber 13 has been described, but glass fiber, Kevlar fiber, or other fibers (synthetic fibers) may be used instead of the carbon fiber. As the resin with which the carbon fiber is impregnated, saturated polyester, vinyl ester, phenol, polyamide, polycarbonate, or the like may be used instead of the epoxy described above. In any event, the density of these fibers and resins is lower than that of tungsten.

Iron (steel) wire (iron has a density of 7.86 g/cm ³ ) and molybdenum wire (molybdenum has a density of 10.2 g/cm ³ ) are used instead of the tungsten wire 16, although the density is slightly lower than that of tungsten. , and other heavy metal wires may be used. Heavy metals have a higher density than aluminum and carbon fiber 13 (aluminum is classified as a light metal and carbon fiber 13 as a non-metal), so their shape (plastic deformation 16A presence or absence) can be observed.

1 electric wire
10 wire core
11 Covered CFRP cable
12 CFRP cable
13 carbon fiber
14 epoxy resin
15 protective layer
16 tungsten wire
20, 30 conductive layer
21, 31 aluminum wire
40 X-ray inspection device C crack breakage

Claims (4)

A fiber reinforced resin cable composed of a fiber bundle that bundles a plurality of fibers continuous in the longitudinal direction and resin impregnated in the fiber bundle, and a fiber reinforced resin cable that is arranged in the fiber reinforced resin cable and surrounds the fiber bundle and a tungsten or molybdenum wire having a higher density than the fibers and extending in the longitudinal direction of the fiber reinforced resin cable surrounded by the cured resin.
Fiber reinforced resin cable with damage detection function. The fiber reinforced resin cable is
each having a plurality of resin-impregnated fibers, each having a plurality of resin-impregnated fiber bundles, each of which is bundled together;
The tungsten or molybdenum wire is embedded in each of the resin-impregnated fiber bundles,
The fiber-reinforced resin cable with a damage detection function according to claim 1. The plurality of resin-impregnated fiber bundles are
A core wire arranged in the center,
a plurality of side wires twisted around the core wire,
The fiber-reinforced resin cable with a damage detection function according to claim 2. A fiber reinforced resin cable composed of a fiber bundle obtained by bundling a plurality of fibers continuous in the longitudinal direction and a resin impregnated in the fiber bundle,
Made of tungsten or molybdenum, which has a density higher than that of the fibers, is arranged in the fiber reinforced resin cable and extends in the longitudinal direction of the fiber reinforced resin cable while being surrounded by the fiber bundle and the hardened resin. wire, and a plurality of light metal conductive wires twisted around the fiber reinforced resin cable,
Electric wire with damage detection function.

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