JP2004308065A - High-strength fiber composite material cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-strength fiber composite material cable having good and stable strength, having uniform shaft force and stable shape to bending, enabling winding without causing deformation of a reel and hardly causing buckling when inserting into a hole or a cylinder. <P>SOLUTION: The high-strength fiber composite material cable is obtained by forming a cable obtained by singly twisting a high-strength fiber composite material as a strand and twisting a plurality of strands together in a direction which is reverse to twisting direction of the strand at 2-12° twist angle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-strength woven composite cable having a multiple twist structure.
[0002]
[Prior art]
High-strength fiber composite cable is an alternative to steel wire rope, strand cable, PC tendon, etc. due to its high strength, low elongation, light weight, high corrosion resistance and high fatigue resistance. Its application is expanding.
In such a high-strength fiber composite material cable, when it is applied to a large structure requiring a high tension, a ground anchor, or the like, conventionally, as shown in FIG. And a plurality of strands k obtained by twisting strands s composed of a composite of high-strength fiber and resin as shown in FIG. 1 (b). A cable that is configured to be bundled in parallel while maintaining an interval is used.
[0003]
However, such a conventional high-strength woven composite cable has the following problems.
1. Multi-layer stranded structure cable (1) Since the wires are in line contact with each other, the cross section is almost circular and the surface area is small, the resin or cement is injected into the sleeve at the time of use to integrate the sleeve and the cable. In order to obtain sufficient adhesion, it is necessary to separate the terminals for each wire.
{Circle around (2)} Since the multi-layer twisted structure cable has a form in which the strands are collectively twisted in a predetermined direction, as the number of strands increases, the size of the equipment to be twisted becomes large, and the investment cost thereof is enormous.
[0004]
2. When using a cable composed of a plurality of strands bundled in parallel (1), when tension is applied to the cable, the length of each of the constituting strands is not uniform, or the cable is bent and arranged by a deflection part. In some cases, the tension may not be transmitted evenly to each cable, and the original design tension of the cable may not be achieved.
(2) If the cable is wound around a reel to transport the cable, the cable will lose its shape, making it difficult to handle. In addition, the difference in diameter between the inside and outside of the cable may cause bending stress and damage the cable. is there.
[0005]
{Circle over (3)} Since the cable merely aligns the strands in parallel, the cable is vulnerable to torsion. In particular, the twisting and twisting of the strand in a direction opposite to the twisting direction of the strand may cause the strand to open and break.
(4) Vulnerable to axial compression (buckling).
(5) Attach the cylinder to the outer periphery of the cable and fill the inside of the cylinder with resin or cement to integrate the cable and the cylinder, or at the ground anchor, fill the sheath tube around the cable with a specific gravity adjuster. In such a case, since the filler flows out from the gap between the strands, a process of filling the gap at the time of manufacturing or construction is required.
[0006]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above-mentioned problems, and has an object to have good and stable strength, and to have a uniform axial force with respect to bending and a stable shape. To provide a high-strength fiber composite material cable that can be wound on a reel without breaking its shape, does not easily buckle even when inserted into a hole or a cylinder, and can obtain a sufficient terminal fixing force. .
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a single strand cable of a high-strength fiber composite material as a strand, and twisting a plurality of the strands at a twist angle of 2 to 12 ° in a direction opposite to the strand twist direction. Features.
[0008]
Further, the present invention is characterized in that, in addition to the above configuration, a resinous intervening layer is arranged between the strands.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
2 to 6 show an embodiment of the high-strength fiber composite cable according to the present invention, wherein 1 indicates the entire high-strength fiber composite cable, and 2 indicates each of the high-strength low elongation fiber and the thermosetting fiber. It is a strand consisting of a single twisted structure composed of a resin.
The high-strength fiber composite material cable 1 is obtained by twisting a plurality of strands (seven in the drawing) at a long twist pitch, that is, at a twist angle α of 2 to 12 °, into a single cable. It is.
[0010]
In this example, since seven single-stranded cables 2 are used, one single-stranded cable 2a is arranged at the center as a core strand, and six strands 2b are arranged as side strands around it. An intervening layer 3 is provided around the core strand 2a.
[0011]
More specifically, as shown in FIG. 3, the strand 2 (2a, 2b) is made of a high-strength low-elongation fiber selected from carbon fiber, aramid fiber, silicon carbide fiber, and the like, as well as an epoxy resin, an unsaturated polyester resin, and a polyurethane resin. It is composed of a large number of composite strands 20 impregnated with a thermosetting resin selected from the above. The composite strand 20 is formed by converging a large number of high-strength low-elongation fiber prepregs 200 or twisting them at a long twist pitch, and wrapping a synthetic fiber yarn 202 such as a high-strength low-elongation fiber or a polyester fiber around the outer periphery. Covered in form.
[0012]
The twist direction of the strand 2 (2a, 2b) and the twist direction of the high-strength fiber composite cable 1 are opposite to each other. That is, if the twist direction of the strand 2 (2a, 2b) is, for example, the S direction, the twist direction of the high-strength fiber composite cable 1 is the Z direction. This is to reduce the rotation property and make it hard to be twisted and collapse.
[0013]
The reason for limiting the twist angle α when twisting the strand 2 (2a, 2b) to the cable 1 is to achieve a target tensile strength without causing damage or shape loss, as described later. This is because the twisting step can be easily performed by an existing twisting machine, and furthermore, as will be described later, there is an advantage that the curing step of the thermosetting resin is not limited to the final step. A more preferred twist angle α is 2 to 8 °.
[0014]
The reason why the lower limit of the twist angle is set to 2 ° is that when the twist angle is less than this, although the tensile strength is high, it approaches parallel, so that the above-mentioned drawback of the conventional cable, that is, the cable collapses when wound on a reel, and handling is difficult. Difficulty, bending stress may be caused by the difference in diameter between the inside and outside of the cable, which may damage the cable, and weakness to twisting, especially lifting twisted in the opposite direction to the twisting direction of the cable This is because it is not possible to eliminate the point where the element wire opens and breaks.
[0015]
The reason why the upper limit of the twist angle is set to 12 ° is that the tensile strength decreases. In other words, high-strength fiber composite materials are vulnerable to bending, shear, and torsion, and are completely brittle.When twisted at a large twist angle, the angle difference between the tensile direction and the fiber direction increases, resulting in a decrease in strength due to shearing. It is.
In a normal case, the twist pitch P when twisted to the cable 1 is set larger than the twist pitch P1 when the strand 2 (2a, 2b) is obtained.
[0016]
The intervening layer 3 may be omitted, but is preferably provided. The reason is that when each strand comes in contact, if the cable is tensioned or bent, the strands will be damaged due to rubbing and side pressure between the strands, and sufficient strength will not be exhibited However, the presence of the intervening layer 3 can alleviate the contact between the core strand and the side strand, and the presence of the intervening layer 3 reduces the contact between the side strands due to the diameter-expanding action. This is because a decrease in strength (twist loss) can be reduced.
Further, when the high-strength fiber composite material cable 1 is put in a hole or a tube and a filler such as cement milk or resin is injected, the filler does not flow out from the inside of the cable (a gap between the strands).
[0017]
As the intervening layer 3, a linear body 30 made of a synthetic resin or the like may be arranged between the outer peripheral valleys of the strand 2 a as shown in FIG. This method has an advantage that it can be implemented when the strand 2 (2a, 2b) is twisted to the cable. Alternatively, as shown in FIG. 6B, a resin coating 31 may be applied to the outer periphery of the strand 2a in advance by extruding a molten resin or the like. The linear body 30 and the coating resin 31 are preferably made of a thermoplastic resin such as polyethylene.
[0018]
The present invention is not limited to the illustrated example.
1) The number of composite strands 20 constituting the strand 2 may be three or more, and is not limited to seven as shown in FIG. As shown in FIGS. 4B and 4C, the number may be 19 or the like.
2) The high-strength fiber composite cable 1 is not necessarily limited to having the core strand 2a. 4A and 4B, a structure using three strands 2 may be used. In this example, a 3 × 7 structure and a 3 × 19 structure are employed. When there is no such core strand, the intervening layer 3 is interposed between the strands 2 and 2 as typically shown in FIG. As the intervening layer 3, a strip formed of a resin or the like into a polygonal or similar shape can be used.
3) In the case of having the core strand 2a, a 7 × 19 structure can be adopted as illustrated in FIG. 4C. In this figure, the intervening layer 3 is omitted.
[0019]
Next, the manufacturing process of the high-strength fiber composite cable according to the present invention will be described. FIGS. 7 and 8 show two examples of the manufacturing process.
The first method is to fabricate a single-stranded structure strand in which the resin is uncured in the layering process-wrapping process-primary closing process, and twist a plurality of the uncured strands into the cable 1 in the secondary closing process. Together, and finally the whole is cured by a curing process.
The second method is to fabricate a strand having a single twist structure in which the resin is cured by a layering process, a wrapping process, a primary closing process, and a curing process, and to apply a plurality of the obtained strands to the cable 1 in a secondary closing process. Twist.
[0020]
Note that there is a third method applied when there is a core strand. This is one strand of single twisted structure in which the resin is cured by the layering process-wrapping process-primary closing process-curing process, and the resin is uncured separately in the layering process-wrapping process-primary closing process A single-strand structure strand in a state is manufactured, a resin-cured strand is used as a core strand, and a resin-uncured single-strand structure strand is arranged around the strand as a side strand, and twisted to the cable 1 in a secondary closing step. Finally, the side strands in which the resin is not cured are cured by a curing process.
[0021]
In the layering process, as shown in FIG. 8 (a), a large number of prepregs 200 impregnated with a thermosetting resin, for example, 10 to 20, each are sent from a bobbin to a twisting machine 5 and twisted at a predetermined pitch, and the strand Get 20 '.
In the lapping step, as shown in FIG. 8B, a plurality of, for example, seven strands 20 'are sent out, and the synthetic fiber yarn 202 is fed out from the lapping machine 6 and wound around the strand 20' in a spiral shape.
In the primary closing step, as shown in FIG. 8 (c), for example, seven wrapped strands 20 are unreeled from bobbins, respectively, and twisted by the closing machine 7 at a predetermined pitch, for example, 100 to 200 mm. As a result, a strand 2 ′ having an uncured one-strand structure in which the resin is uncured is obtained.
[0022]
In the first method, the wrapped strand 20 is twisted at a predetermined pitch, for example, 100 to 200 mm by the closing machine 7 to obtain the uncured strand 2 'of the resin. As described above, the twisting angle is set in the range of 2 to 12 ° by the closing machine 9, the twisting direction is opposite to the twisting direction in the strand twisting step, and the untwisted resin cable 1 ′ is obtained. The cable 1 of the present invention is obtained by passing through a heat treatment furnace 8 having a shape of FIG. 1 and heating at 120 to 135 ° C. to cure the resin.
[0023]
In the second method, as shown in FIG. 8 (e), the strand 2 ′ where the resin is uncured is passed through a tunnel-shaped heat treatment furnace 8 and heated at 120 to 135 ° C. to cure the strand 2 where the resin is cured. obtain. Then, the resin cured strands 2 are twisted by the closing machine 9 to obtain the cable 1 of the present invention. At this time, the twist angle is in the range of 2 to 12 °, and the twist direction is opposite to the twist direction in the strand twisting step. In the first and second methods, the curing process is sufficient once, so that the process is simple.
[0024]
In the case where the intervening layer 3 is provided, in a cable structure having no core strand, the secondary closing step may be performed by arranging a strip or a striatum to be the intervening layer at the center and arranging the strands around the center. .
In the case of a cable structure having a core strand, an intervening layer may be applied to the outer periphery of one strand, and the other strands 2b may be arranged around the outer layer to perform the secondary closing step. The strands may be cured or uncured.
Note that the third method has an advantage that the twisting process is easy because the rigid strand 2a obtained by curing the resin is present at the center when the uncured side strand 2b is twisted.
[0025]
【Example】
Example 1
The cable of the present invention was manufactured using the second method as a manufacturing method.
Twenty fifteen prepregs, each of which is a carbon fiber impregnated with epoxy resin and having a diameter of 7 μm and having a diameter of 12,000 bundled together, are twisted in a twisting direction Z at a pitch of 90 mm, and then wrapped to obtain a strand having an outer diameter of 4.2 mm. Was.
Seven strands were twisted in a twisting direction S at a pitch of 160 mm to obtain a strand having a 1 × 7 structure. The strand was heated in a heat treatment furnace at 130 ° C. for 90 minutes to cure the resin.
[0026]
Of these seven strands, one outer circumference is coated with polyethylene to form a core strand, and six non-coated strands are used as side strands, and the twisting direction Z and the twisting angle α are in the range of 2 to 18 °. Together, a 7 × 7 double twist cable was obtained. Incidentally, the twist pitch at the twist angle α: 2 ° is 2200 mm, the twist pitch at the twist angle α: 4.1 ° is 1100 mm, and the twist pitch at the twist angle α: 5 ° is 900 mm.
[0027]
FIG. 9 shows the results of nine levels of tensile tests performed on the obtained multi-stranded cable. From this result, it can be seen that when the twist angle is in the range of 2 to 12 °, particularly 2 to 8 °, a decrease in the breaking load is hardly observed.
[0028]
For comparison, a twisted cable having a 7 × 7 structure was manufactured at a twist angle α = 4 ° and α = 4 ° without coating the core strand, and a tensile test was performed. As a result, the breaking load was 1100 kN, the twist angle α was 4 °, and the multi-stranded cable coated with the core strand was 1250 kN, so that a higher breaking load was obtained.
The breaking load was also compared for a conventional cable (referred to as Conventional Example 2) in which seven of the strands were bundled in parallel. As a result, Conventional Example 2 was 1070 kN, which was inferior to the present invention.
[0029]
Regarding the cable of Example 1, the relationship between the body diameter of the reel and the twist length was investigated by a winding experiment. As a result, when the twist angle α is in the range of 2 to 18 °, if the twist length P / reel body diameter D is 0.73 or less, normal winding can be performed as shown in FIG. It was confirmed that there was. When the twist angle α was 1.6 °, that is, when the twist pitch was 2800 mm, when the P / D was 0.93, the cable was damaged or out of shape during winding.
For comparison, a winding test was also performed on Conventional Example 2, but as a result, the shape collapsed as shown in FIG. 10B, and lap winding could not be performed.
[0030]
As shown in FIG. 11 (a), for a cable of the present invention (7 × 7 structure) having a core strand with a polyethylene coating and a twist angle α: 4 °, the bending angle 2θ is 0 ° to 8 as shown in FIG. A bending tensile test was performed in the range of ° C.
For comparison, the same bending-tensile test was performed on a 1 × 37 structure having the same cross-sectional area (conventional example 1) and a cable in which seven strands were bundled (conventional example 2). The result is shown in FIG. As can be seen from this figure, the cable of the present invention exhibited good bending performance, whereas Conventional Example 2 showed the greatest decrease in breaking load due to bending.
[0031]
As shown in FIG. 12, a cylindrical body was put on the outer periphery of a 7 × 7 structure cable in which a core strand was covered with polyethylene, and both ends of the cylindrical body were filled with epoxy clay and sealed, and provided at the lower part of the cylindrical body. When the cement milk was injected from the injection hole, the filling was successful without the cement flowing out of the cable. This result indicates that the intervening layer is effective.
Further, in order to examine the fixing property, the cable 1 of the present invention was inserted into a sleeve 15 made of a steel pipe as shown in FIG. For comparison, as shown in FIG. 14, the wires of Conventional Example 1 were separated and inserted into a sleeve, and cement milk was injected. As a result, the cable 1 of the present invention obtained a high fixing strength despite the fact that the strands were not separated. This is because, in the cable of the present invention, since the strands are in point contact with each other, the outer periphery of the cable has large irregularities and a large adhesion surface area, and the helix of the strand has a draw resistance.
[0032]
【The invention's effect】
According to the first aspect of the present invention described above, the following excellent effects can be obtained.
1) Since the lengths of the respective strands are almost non-uniform, the tension applied to the respective strands or the individual wires becomes uniform, and the design strength can be reliably realized.
2) By twisting the strands, even if the cable is bent, the axial force applied to each strand becomes equal, and the shape is stable, so the shape collapses when the cable is wound on a reel or deployed. Less likely to occur and can be wound up again.
[0033]
3) When a cable is inserted into a tube or a hole, it is hardly damaged by buckling.
4) Since the surface area of the outer periphery of the cable is large, it is possible to obtain a sufficient fixing force without performing the end balancing like a multilayer stranded cable when performing the terminal fixing process.
5) Since the twisting direction of the cable is opposite to the twisting direction of the strand, the cable has low rotation, is hardly twisted, and does not collapse.
6) Twisting can be easily performed with an existing stranded wire machine, and a desired tensile tension can be obtained only by increasing or decreasing the number of strands (single stranded cables) to be stranded.
[0034]
According to the second aspect, the filler does not flow out from the inside of the cable (the gap between the strands) due to the intervening layer 3. Further, since the contact between the strands can be alleviated and internal abrasion can be prevented, excellent effects such as a reduction in tensile strength can be obtained.
[Brief description of the drawings]
FIGS. 1A and 1B are partial perspective views of a conventional high-strength fiber composite cable. FIG.
FIG. 2 is a partial perspective view showing an example of a high-strength fiber composite cable according to the present invention.
FIG. 3 is a partial perspective view showing a composite strand according to the present invention.
FIGS. 4A, 4B and 4C are cross-sectional views showing another example of the cable of the present invention.
5A is an explanatory diagram showing a twist angle of the cable of the present invention, and FIG. 5B is an explanatory diagram showing a twist length.
FIGS. 6A and 6B are side views illustrating an intervening layer of the cable of the present invention.
FIGS. 7A and 7B are explanatory views showing an example of a manufacturing process of the cable of the present invention.
8A is an explanatory view of a layering step, FIG. 8B is an explanatory view of a lapping step, FIG. 8C is an explanatory view of a primary closing step, FIG. 8D is an explanatory view of a secondary closing step, and FIG. () Is an explanatory view of a curing step.
FIG. 9 is a diagram showing a relationship between a twist angle and a breaking load.
10A is a plan view showing a winding test state of the cable of the present invention, and FIG. 10B is a plan view showing a winding test state of a conventional cable.
11A is an explanatory view showing an outline of a bending-tensile test, and FIG. 11B is a diagram showing a bending angle and a breaking load of the cable of the present invention and a conventional cable.
FIG. 12 is a perspective view showing a filling test state.
FIG. 13A is a longitudinal sectional side view showing a state of the terminal fixing processing of the cable of the present invention, and FIG. 13B is a transverse sectional view.
FIG. 14A is a longitudinal side view showing a state of terminal fixing processing of a conventional multilayer stranded cable, and FIG. 14B is a transverse sectional view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 High-strength fiber composite material cable 2 of the present invention 2 Strand 2a composed of single-stranded cable Core strand 2b Side strand 3 Interposed layer 20 Composite strand

Claims (2)

A high-strength fiber composite cable characterized in that a single-strand cable of a high-strength fiber composite is used as a strand, and a plurality of the strands are twisted at a twist angle of 2 to 12 ° in a direction opposite to the strand twist direction. 2. The high-strength fiber composite cable according to claim 1, wherein an intervening layer of resin is disposed between the strands.

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