Patent Description:
In the related art, as a repair method for repairing a part to be repaired such as a damaged part which is a repair target of a composite material, there is known a method for repairing a composite material, in which a truncated cone-shaped area which is increased in diameter from a back surface side toward a surface side of the composite material is removed, and a repair material is bonded to a recessed portion which is formed by the removal (for example, refer to PTL <NUM> below).

<CIT>, also published as <CIT>, is designated as PTL <NUM> and describes a method of repairing a composite material, in which a frustum-shaped portion of a composite material is removed and the composite material and repair material are bonded with each other while evacuating. Also described is a plate shaped composite material formed of fibers and resin. However, PTL <NUM> does not disclose the features forming the characterising portion of either Claim <NUM> or Claim <NUM> below.

Here in PTL <NUM>, as the repair material to be bonded to a counterbore hole such as a recessed portion, for example, there is a repair patch disclosed. The repair patch has a truncated cone shape, and has a bottom surface, a top surface, and an inclined surface. Fiber reinforced preforms having circular shapes of different diameters are concentrically laminated to mold the repair patch having a truncated cone shape.

However, when the fiber reinforced preforms are laminated to form the repair patch, fiber meandering (wrinkle) is generated in an end portion of the fiber reinforced preform of each layer, which is a problem. When the part to be repaired is repaired with such a repair patch, it is difficult to sufficiently recover the strength of the part to be repaired as compared to the strength before damage.

United States patent publication no. <CIT> describes a process for patching a crack or other defect in a thick-walled steel component. Stacked sheets of preimpregnated carbon fiber-reinforced epoxy are bonded together and cured by interposed layers of a second resin. However, this publication does not disclose the features forming the characterising portion of either of claim <NUM> or claim <NUM> below.

Therefore, an object of the present invention is to provide a repair patch that suppresses the generation of fiber meandering and is molded in an appropriate shape, a method for molding a repair patch, and a method for repairing a composite material.

In a first aspect of the present invention, there is provided a repair patch for a composite material to repair a part to be repaired which is a repair target of the composite material, the patch comprising: a patch main body that is a laminate of a plurality of fiber reinforced preforms in a thickness direction, and has a bonding surface to be bonded to the part to be repaired; and a removal layer that is provided on the bonding surface to be peelable off from the patch main body, wherein the bonding surface includes an inclined surface that is inclined with respect to the thickness direction of the patch main body, the removal layer includes a processed portion that causes the removal layer to have a shape complementary to a shape of the inclined surface of the patch main body, characterised in that the processed portion is formed of slits that are formed at positions to face end portions of the plurality of fiber reinforced preforms in the thickness direction of the patch main body, the end portions being located in the inclined surface.

According to the configuration, since end portions of the plurality of fiber reinforced preforms, the end portions forming the inclined surface of the patch main body, can be pressed by the removal layer having a shape complementary to the shape of the inclined surface, fiber meandering can be suppressed from being generated in the end portions of the fiber reinforced preforms. For this reason, the patch main body can be shaped into an appropriate shape. In addition, the removal layer can protect the bonding surface of the patch main body.

The processed portion is formed of slits that are formed at positions to face end portions of the plurality of fiber reinforced preforms in the thickness direction of the patch main body, the end portions being located in the inclined surface.

According to the configuration, since the slits are formed in the removal layer, the end portions of the fiber reinforced preforms can be appropriately pressed by the removal layer.

In a second aspect of the present invention, there is provided a repair patch for a composite material to repair a part to be repaired which is a repair target of the composite material, the patch comprising: a patch main body that is a laminate of a plurality of fiber reinforced preforms in a thickness direction, and has a bonding surface to be bonded to the part to be repaired; and a removal layer that is provided on the bonding surface to be peelable off from the patch main body, wherein the bonding surface includes an inclined surface that is inclined with respect to the thickness direction of the patch main body, the removal layer includes a processed portion that causes the removal layer to have a shape complementary to a shape of the inclined surface of the patch main body, characterised in that the processed portion is formed of a plurality of through-holes that penetrate through the removal layer at positions to face end portions of the plurality of fiber reinforced preforms in the thickness direction of the patch main body, the end portions being located in the inclined surface.

According to the configuration, since the plurality of through-holes are formed in the removal layer, the end portions of the fiber reinforced preforms can be appropriately pressed by the removal layer.

In addition, it is preferable that the removal layer is a peel ply.

According to the configuration, since the peel ply can be peeled off to activate the bonding surface of the patch main body, the bondability of the bonding surface to the part to be repaired can be enhanced.

In a third aspect of the present invention, there is provided a method for repairing a composite material, which repairs a part to be repaired that is a repair target of the composite material, the method comprising: preparing the repair patch according to either of the first or second aspects of the invention in advance; a peeling step of peeling the removal layer off from the patch main body; an adhesive agent disposition step of disposing an adhesive agent on a surface to be bonded of the part to be repaired; a patch disposition step of disposing the bonding surface of the patch main body to face the surface to be bonded with the adhesive agent interposed therebetween; and a bonding step of bonding the patch main body to the part to be repaired.

According to the configuration, the removal layer is peeled off from the patch main body to cause the bonding surface of the patch main body to be exposed, the bonding surface being protected, so that the patch main body can be bonded to the part to be repaired. For this reason, while foreign matter is suppressed from adhering to the bonding surface, the patch main body having an appropriate shape can be bonded to the part to be repaired, so that the part to be repaired can be suitably repaired.

In a fourth aspect of the present invention, there is provided a method for molding a repair patch for a composite material to repair a part to be repaired which is a repair target of the composite material, the method comprising: a laminate forming step of laminating a plurality of fiber reinforced preforms in a thickness direction such that a bonding surface to be bonded to the part to be repaired is an upper surface, to form a laminate, the bonding surface including an inclined surface that is inclined with respect to the thickness direction of the laminate; a removal layer disposition step of disposing a removal layer, which is peelable off from the laminate, to cover the bonding surface of the laminate, a processed portion being provided in the removal layer to cause the removal layer to have a shape complementary to a shape of the inclined surface of the laminate, the processed portion being formed of slits that are formed at positions to face end portions of the plurality of fiber reinforced preforms in the thickness direction, the end portions being located in the inclined surface; and a molding step of heating the laminate and the removal layer to be integrated to mold the laminate and the removal layer and to deform the removal layer according to the shape of the inclined surface of the laminate due to the processed portion.

According to the configuration, since end portions of the plurality of fiber reinforced preforms, the end portions forming the inclined surface of the laminate, can be pressed by the removal layer that is deformed to have a shape complementary to the shape of the inclined surface, fiber meandering can be suppressed from being generated in the end portions of the fiber reinforced preforms. For this reason, the repair patch having an appropriate shape can be molded.

In addition, in the molding step, it is preferable that a covering member which follows the deformation of the removal layer is disposed to cover the removal layer to mold the laminate and the removal layer.

According to the configuration, the removal layer can be appropriately deformed without interruption in the deformation of the removal layer. Incidentally, the covering member may be a bag film having good followability, or may be a film adhesive provided between a bag film and the removal layer, and is not particularly limited.

In a fifth aspect of the invention, there is provided a method for molding a repair patch for a composite material to repair a part to be repaired which is a repair target of the composite material, the method comprising: a laminate forming step of laminating a plurality of fiber reinforced preforms in a thickness direction such that a bonding surface to be bonded to the part to be repaired is an upper surface, to form a laminate, the bonding surface including an inclined surface that is inclined with respect to the thickness direction of the laminate; a removal layer disposition step of disposing a removal layer, which is peelable off from the laminate, to cover the bonding surface of the laminate, a processed portion being provided in the removal layer to cause the removal layer to have a shape complementary to a shape of the inclined surface of the laminate, the processed portion being formed of a plurality of through-holes that penetrate through the removal layer at positions to face end portions of the plurality of fiber reinforced preforms in the thickness direction, the end portions being located in the inclined surface; and a molding step of heating the laminate and the removal layer to be integrated to mold the laminate and the removal layer and to deform the removal layer according to the shape of the inclined surface of the laminate due to the processed portion.

In order that the invention will be more readily understood, embodiments thereof will now be described, by way of example only, with reference to the drawings, and in which:-.

Incidentally, the claimed invention is not limited by the embodiments. In addition, components in the following embodiments include those that can be easily replaced by those skilled in the art, or those that are substantially the same. Furthermore, the components described below can be combined as appropriate, and when there are a plurality of embodiments, the embodiments can be combined.

A repair patch <NUM> according to the present embodiment is a repair material used to repair a composite material. A method for repairing a composite material using the repair patch <NUM> is a method in which a defect part that is formed in a composite material by damage or the like is a repair target, and a part to be repaired which is the repair target is repaired.

<FIG> is a cross-sectional view schematically illustrating one example of the repair patch according to the first embodiment. <FIG> is a plan view illustrating a removal layer of the repair patch. <FIG> is a view describing a method for molding a repair patch according to the first embodiment. <FIG> is a view describing the method for repairing a composite material using the repair patch according to the first embodiment. <FIG> is a graph relating to the repair result of the part to be repaired which is repaired with the repair patch according to the first embodiment.

First, the repair patch <NUM> will be described with reference to <FIG>. The repair patch <NUM> is made of a composite material, and includes a patch main body <NUM> and a removal layer <NUM>.

The patch main body <NUM> has a truncated cone shape having a bottom surface <NUM>, a top surface <NUM>, and a side surface (inclined surface) <NUM>. In the patch main body <NUM>, the top surface <NUM> and the side surface <NUM> form a bonding surface <NUM> to be bonded to the part to be repaired, and the bottom surface <NUM> is a surface opposite to the bonding surface <NUM>.

The patch main body <NUM> is produced by laminating and precuring a plurality of prepregs P as fiber reinforced preforms in a thickness direction. Incidentally, a direction along a plane orthogonal to the thickness direction is referred to as an in-plane direction. The prepreg is produced by infiltrating reinforcing fibers with a resin. For example, carbon fibers are used as the reinforcing fibers; however, the reinforcing fibers are not limited to the carbon fibers, and may be plastic fibers, glass fibers, natural fibers, or metallic fibers. A thermosetting resin is preferable as the resin; however, the resin may be a thermoplastic resin. The thermosetting resin is, for example, an epoxy resin. Examples of the thermoplastic resin are polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and polyphenylenesulfide (PPS). Incidentally, the resin is not limited to the above-described resins, and other resins may be used. In addition, in addition to molding using the prepregs, methods such as hand layup, resin infusion, and RTM may be applied.

Specifically, the plurality of prepregs P which are cut in a circular shape are used to produce the patch main body <NUM>, and the plurality of prepregs P are cut in a circular shape such that the diameters of the prepregs P are increased at a constant ratio. In a state where the central axes of the prepregs P are aligned, the prepregs P are concentrically laminated in order of size to form the patch main body <NUM> having a truncated cone shape. For this reason, intervals between outer end portions of the prepregs P which are adjacent to each other in the thickness direction are predetermined intervals that are concentric in a radial direction of the patch main body <NUM> having a circular shape.

The bonding surface <NUM> includes the top surface <NUM> and the side surface <NUM>. In the bonding surface <NUM>, the side surfaces <NUM> are located on both sides in the in-plane direction, the top surface <NUM> being interposed between both the sides, in a cross section that is illustrated in <FIG> and is cut in the thickness direction of the patch main body <NUM> along a central axis of the patch main body <NUM> having a truncated cone shape. Each of the side surfaces <NUM> is a surface that is straight inclined with respect to the thickness direction. Namely, in the cross section illustrated in <FIG>, the side surfaces <NUM> on both the sides are inclined with respect to the thickness direction to spread out as the side surfaces <NUM> extend from the removal layer <NUM> toward the patch main body <NUM>. The bottom surface <NUM> is a surface extending in the in-plane direction, and is a surface serving as the surface of a part <NUM> to be repaired after repair.

As illustrated in <FIG>, the removal layer <NUM> is provided on a bonding surface <NUM> side of the patch main body <NUM> in the thickness direction, and is peelably joined to the patch main body <NUM>. The removal layer <NUM> is formed of, for example, a peel ply. In addition, a processed portion is formed in the removal layer <NUM> to cause the removal layer <NUM> to have a shape complementary to that of the side surface <NUM> of the patch main body <NUM>. Specifically, the processed portion is formed of a plurality of slits <NUM>.

The plurality of slits <NUM> are formed at positions to face the outer end portions of the plurality of prepregs P in the thickness direction. For this reason, the slit <NUM> is formed in a circular shape, and the plurality of slits <NUM> are concentrically formed at predetermined intervals in the radial direction. In addition, the slit <NUM> is formed in a C shape where a part in a circumferential direction of the slit <NUM> is connected to not be separated when the removal layer <NUM> is peeled off.

Since the plurality of slits <NUM> are formed in the removal layer <NUM>, as illustrated in <FIG>, the removal layer <NUM> has a step shape which is complementary to those of the outer end portions of the prepregs P having a step shape in the side surface <NUM> of the patch main body <NUM>.

Next, the method for molding the repair patch <NUM> in which the repair patch <NUM> of <FIG> is molded will be described with reference to <FIG>. In the method for molding the repair patch <NUM>, the repair patch <NUM> is molded using a molding tool <NUM>. Incidentally, <FIG> illustrates a part of the repair patch <NUM>.

Specifically, in the method for molding the repair patch <NUM>, the plurality of prepregs P are laminated on the molding tool <NUM> in the thickness direction to form a laminate <NUM> (step <NUM>: laminate forming step). In the laminate forming step S11, the prepreg P having a circular shape with a large diameter is laminated on the molding tool <NUM>, and the prepregs P having a circular shape are laminated, the prepregs P being reduced in diameter as the prepregs P are disposed closer to an upper side. In addition, in the laminate forming step S11, vacuum suction is performed whenever a predetermined number of the prepregs P are laminated. Namely, when the prepregs P are laminated, there is a possibility that a gap between the layers of the prepregs P laminated is formed. Therefore, vacuum suction is periodically performed to remove the gap formed between the layers of the prepregs P. In the laminate <NUM> formed on the molding tool <NUM>, the bonding surface <NUM> is an upper surface.

Subsequently, the removal layer <NUM> is disposed to cover the bonding surface <NUM> of the laminate <NUM> formed on the molding tool <NUM> (step S12: removal layer disposition step). In the removal layer disposition step S12, the removal layer <NUM> is disposed on the laminate <NUM> such that the slit <NUM> of the removal layer <NUM> faces the outer end portion of the prepreg P of the laminate <NUM>.

Next, the laminate <NUM> and the removal layer <NUM> are heated to be integrated to mold the repair patch <NUM> (step S13: molding step). In the molding step S13, first, a film adhesive <NUM> is disposed to cover the removal layer <NUM>. The film adhesive <NUM> is a covering member that follows deformation of the removal layer <NUM> during molding, and allows the removal layer <NUM> to be deformed. The film adhesive <NUM> is, for example, a thermosetting resin that melts when heated, and at least a part of the film adhesive <NUM> is infiltrated into the prepregs P to be heat cured. Subsequently, in the molding step S13, a shield film <NUM> made of fluororesin such as FEP is disposed to cover the film adhesive <NUM>. The shield film <NUM> suppresses the resin, which melts during molding, from flowing into a breather <NUM> to be described later.

In addition, in the molding step S13, the breather <NUM> is disposed to cover the shield film <NUM>. The breather <NUM> forms an air flow path during vacuum suction. Then, in the molding step S13, a bag film <NUM> is disposed to cover the breather <NUM>, and a sealing member <NUM> seals a space between the molding tool <NUM> and the bag film <NUM>, so that a sealed space is formed inside the bag film <NUM>.

In the molding step S13, the sealed space which is formed inside the bag film <NUM> is vacuum suctioned via a vacuum suction port (unillustrated) to bring the inside of the bag film <NUM> into a vacuum state. Then, in the molding step S13, in the vacuum state, the laminate <NUM>, the removal layer <NUM>, and the film adhesive <NUM> are heated to mold the repair patch <NUM> that is precured.

In the molding step S13, since the slits <NUM> are formed in the removal layer <NUM>, when the inside of the bag film <NUM> is vacuum suctioned, portions of the removal layer <NUM> between the slits <NUM> press the outer end portions of the prepregs P of the laminate <NUM> in the thickness direction, and in this state, the laminate <NUM> and the removal layer <NUM> are heat cured. For this reason, in the molding step S13, the removal layer <NUM> is deformed according to the side surface <NUM> of the laminate <NUM> having a step shape due to the slits <NUM>.

Next, the method for using the repair patch <NUM> to repair a composite material having a part to be repaired will be described with reference to <FIG>.

In the method for repairing a composite material, the repair patch <NUM> and a resin sheet <NUM> as an adhesive agent are used. The resin sheet <NUM> is produced by forming a resin in a sheet shape, and is made of a material that can be bonded to the resin used as the material of the repair patch <NUM>. Incidentally, the resin sheet <NUM> may be made of the same resin as or a different resin from that used as the material of the repair patch <NUM>, and the resin material is not particularly limited. In addition, a plurality of types of the repair patches <NUM> having different diameters are prepared, and the repair patch <NUM> is appropriately selected and used according to the shape (size) of a counterbore hole <NUM> to be formed which will be described later.

First, a defect part formed in a composite material is processed by cutting or the like to form the counterbore hole <NUM> having a shape illustrated in <FIG> (step S21). An opening portion of the counterbore hole <NUM> is formed in a circular shape, and a bottom surface of the counterbore hole <NUM> is formed in a circular shape that is smaller than the opening portion. In addition, a side surface of the counterbore hole <NUM> is a surface that is inclined to spread as the surface extends from the bottom surface toward the opening portion. The bottom surface and the side surface of the counterbore hole <NUM> form a surface to be bonded to which the repair patch <NUM> is to be bonded.

Subsequently, the resin sheet <NUM> is disposed on an inner surface including the bottom surface and the side surface of the counterbore hole <NUM> that is formed as a recess (step S22: adhesive agent disposition step). Specifically, in the adhesive agent disposition step S22, the resin sheet <NUM> is disposed in contact with the inner surface of the counterbore hole <NUM> to cover the inner surface.

The repair patch <NUM> is prepared almost at the same time as steps S21 and S22 (step S23). Then, the removal layer <NUM> is peeled off from the patch main body <NUM> of the repair patch <NUM> (step S24: peeling step).

Next, the repair patch <NUM> is disposed on the resin sheet <NUM> such that the bonding surface <NUM> of the patch main body <NUM> faces the inner surface which is the surface to be bonded of the counterbore hole <NUM> (step S25: patch disposition step). Incidentally, in the patch disposition step S25, a marking is applied to the bottom surface (surface) of the patch main body <NUM>, a marking is applied to a surface of the composite material, the surface being the part <NUM> to be repaired, and the patch main body <NUM> may be disposed in the counterbore hole <NUM> such that the position of the patch main body <NUM> is an appropriate position with respect to the counterbore hole <NUM>.

Thereafter, the resins of the patch main body <NUM> and the resin sheet <NUM> are melted to bond the patch main body <NUM> to the counterbore hole <NUM> (step S26: bonding step). Incidentally, in the bonding step S26, although unillustrated, the patch main body <NUM> and the resin sheet <NUM> are sealed with the bag film or the like, and the patch main body <NUM> and the resin sheet <NUM> are heated while the sealed space is vacuumed, so that the repair patch <NUM> and the resin sheet <NUM> are completely cured. Then, finishing is performed on the surface of the composite material, the surface being the part to be repaired, and the bottom surface <NUM> of the patch main body <NUM> (step S26) to repair the part <NUM> to be repaired.

Next, the repair result of the part <NUM> to be repaired which is repaired with the repair patch <NUM> will be described with reference to <FIG>. In <FIG>, the vertical axis is the fracture strain. Incidentally, in a repair patch of the related art which is used to repair a part to be repaired, fiber meandering is generated in outer end portions of the prepregs P. When the fracture strains of the related art and the first embodiment were compared, it was confirmed that the fracture strain of the first embodiment was larger than the fracture strain of the related art. Namely, it was confirmed that the recovery of the strength in the first embodiment was larger than that of the related art since the part <NUM> to be repaired was repaired with the repair patch <NUM> of the first embodiment.

As described above, according to the first embodiment, since the outer end portions of the plurality of prepregs P, the outer end portions forming the side surface <NUM> of the patch main body <NUM>, can be pressed by the removal layer <NUM> having a shape complementary to that of the side surface <NUM>, fiber meandering can be suppressed from being generated in the outer end portions of the prepregs P. For this reason, the patch main body <NUM> can be shaped into an appropriate shape. In addition, the removal layer <NUM> can protect the bonding surface <NUM> of the patch main body <NUM>.

In addition, according to the first embodiment, since the slits <NUM> are formed in the removal layer <NUM>, the outer end portions of the prepregs P can be appropriately pressed by the removal layer <NUM>.

In addition, according to the first embodiment, since the removal layer <NUM> which is a peel ply can be peeled off to activate the bonding surface <NUM> of the patch main body <NUM>, the bondability of the part <NUM> to be repaired to the counterbore hole <NUM> can be enhanced.

In addition, according to the first embodiment, since the removal layer <NUM> is covered with the film adhesive <NUM>, the removal layer <NUM> can be appropriately deformed without interruption to the deformation of the removal layer <NUM>. Incidentally, in the first embodiment, the film adhesive <NUM> is applied; however, as long as the bag film <NUM> has good followability, the film adhesive <NUM> may be omitted. Namely, the bag film <NUM> may be applied as a covering member that follows deformation of the removal layer <NUM>.

In addition, according to the first embodiment, the removal layer <NUM> is peeled off from the patch main body <NUM> to cause the bonding surface <NUM> of the patch main body <NUM> to be exposed, the bonding surface <NUM> being protected, so that the patch main body <NUM> can be bonded to the counterbore hole <NUM> of the part <NUM> to be repaired. For this reason, while foreign matter is suppressed from adhering to the bonding surface <NUM> of the patch main body <NUM>, the patch main body <NUM> having an appropriate shape can be bonded to the counterbore hole <NUM>, so that the part <NUM> to be repaired can be appropriately repaired.

Incidentally, in the first embodiment, the patch main body <NUM> has a truncated cone shape; however, the patch main body <NUM> is not particularly limited to having the shape, and may have any shape as long as having the side surface <NUM> which is inclined.

Next, a removal layer <NUM> of a repair patch according to a second embodiment will be described with reference to <FIG> is a plan view illustrating the removal layer of the repair patch according to the second embodiment. In the second embodiment, in order to avoid duplicated description, portions different from the first embodiment will be described, and while portions have the same configurations as those of the first embodiment are denoted with the same reference signs, description will be given.

In the removal layer <NUM> of the repair patch <NUM> in the second embodiment, a plurality of through-holes <NUM> are formed instead of the slits <NUM> of the first embodiment. The plurality of through-holes <NUM> are formed at positions to face the outer end portions of the plurality of prepregs P in the thickness direction. Namely, the plurality of through-holes <NUM> are formed side by side along the circumferential direction to form a circular shape, and are concentrically formed at predetermined intervals in the radial direction.

Claim 1:
A repair patch (<NUM>) for a composite material to repair a part (<NUM>) to be repaired which is a repair target of the composite material, the patch comprising:
a patch main body (<NUM>) that is a laminate of a plurality of fiber reinforced preforms (P) in a thickness direction, and has a bonding surface (<NUM>) to be bonded to the part (<NUM>) to be repaired; and
a removal layer (<NUM>) that is provided on the bonding surface to be peelable off from the patch main body,
wherein the bonding surface includes an inclined surface (<NUM>) that is inclined with respect to the thickness direction of the patch main body,
the removal layer includes a processed portion that causes the removal layer to have a shape complementary to a shape of the inclined surface of the patch main body,
characterised in that the processed portion is formed of slits (<NUM>) that are formed at positions to face end portions of the plurality of fiber reinforced preforms in the thickness direction of the patch main body, the end portions being located in the inclined surface.