JP2002001832A - How to repair a sandwich structure - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a repair method for a sandwich structure that can be easily repaired. SOLUTION: The sandwich structure 1 has a sandwich structure sandwiched between face plates 2 and 3 made of a composite material in which a closed-cell foamed plastic material is used as a core material 4 and inorganic fibers having no affinity for water are reinforced fibers. No water seeps in. In the case of damage, first, an opening 10 is formed in the face plate 2 in a region including the damaged portion, and the blast material is sprayed on the core material 4 to remove the core material 4 around the opening. Next, the radial support plate 16 is joined to the face plate 2 from the back side of the face plate 2 by rivets 25, the opening 10 is covered by a disc-shaped cover plate 40, and the cover plate 40 and the support plate 16 are joined by the rivets 25. . Finally, the filler 4 is formed in the recess formed by removing the core 4.
Inject 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a sandwich structure used for structures such as aircraft, railway vehicles, automobiles, and ships.

[0002]

2. Description of the Related Art Conventionally, lightweight metal reinforcing plate structures such as aluminum alloys have been used as structures for aircrafts and the like. In recent years, however, composite reinforcing plate structures and honeycomb cores have been used as core materials. A sandwich structure whose surface is covered with a composite face plate has been used. If the composite skin is damaged and needs to be repaired, the damaged area must first be scraped off, and then the prepreg and adhesive pre-impregnated with fiber resin are laminated on the damaged area to fill the damaged area, and then Repairs in which the prepreg is cured by heating and pressing are common.

[0003]

When a prepreg is to be repaired by laminating it at a damaged portion, it is necessary to heat and press the laminated prepreg to cure it. However, a special device is required for this purpose. In addition, the heating and pressurization of the prepreg has a problem that the temperature and the pressure must be strictly controlled, which requires much time and effort. Further, after curing, it is necessary to inspect the adhesion state between the mother structure at the repaired portion and the additional laminated portion. As described above, there is a problem that repair of the composite material requires a special device and requires much labor and time.

[0004] An object of the present invention relates to a method for repairing a sandwich structure which can be repaired by simple operations.

[0005]

According to the present invention, there is provided a method for repairing a sandwich structure in which a closed-cell foamed plastic material is used as a core, and both surfaces of the core are covered with a face plate made of a fiber-reinforced composite material. A method for repairing a sandwich structure, characterized in that an outer support plate is joined to a back side of a damaged portion of an outer surface side plate by a rivet.

According to the present invention, since the outer support plate for reinforcing the damaged portion is attached from the inside of the face plate on the outer surface side, the outer surface can be repaired in a smooth state. In addition, we do not perform time-consuming and time-consuming adhesive repair for repair,
The use of a simple rivet connection greatly reduces the labor and time involved in repairing the composite.

According to a second aspect of the present invention, the inner surface side plate and the core material at the lower part of the region including the damaged portion of the outer surface side plate are removed, and the outer support plate is joined to the back side of the damaged portion by rivets, and the core material is removed. The removal portion is filled with a filler, the opening is covered with an inner support plate larger than the opening of the inner side surface plate, and attached around the opening of the inner side surface plate with rivets.

According to the present invention, when an operator can repair from the inner surface side of the sandwich structure and the face plate is slightly damaged, the outer support plate is applied to the inside of the face plate from the inner surface side to the outer surface side and joined by rivets. In addition, it is also possible to easily inject the filler in the core material removing portion and attach the inner support plate for the inner side surface plate.

According to a third aspect of the present invention, an opening is formed in a region including a damaged portion of the outer surface side plate, and the core material and the inner side surface plate in a region larger than the opening below the opening are removed.
The outer support plate is rivet-bonded to the back side around the opening of the outer surface side plate, a cover plate having the same size as the opening and the same thickness as the outer surface side plate is fitted into the opening, and rivets are attached to the outer support plate. And filling the core material removing portion with a filler, covering the opening with an inner support plate larger than the opening of the inner side surface plate, and attaching the opening around the opening of the inner side surface plate with rivets.

According to the present invention, when an operator can repair from the inner surface side of the sandwich structure, an opening is formed in a region including a damaged portion of the outer surface side plate, and an outer support plate is provided on the back side of the outer surface side plate. The outer surface can be repaired in a smooth state by injecting a filler into the mounting and core removing parts and mounting the cover plate having the same size and thickness as the opening.
Also, since the rivet is repaired, a repair that reduces labor and time can be realized.

According to a fourth aspect of the present invention, an opening is formed in a region including a damaged portion of the outer surface side plate, a core material at a lower portion of the opening and around the opening is removed, and the outer support plate has an area larger than the opening. The outer support plate is inserted from the opening, attached to the back of the outer surface side plate with rivets, and a cover plate having the same size as the opening and the same thickness as the outer surface side plate is fitted into the opening, and the outer support plate is inserted. It is characterized in that it is connected to the plate by rivets, and the core material removing portion is filled with a filler.

According to the present invention, by using the extensible outer support plate, repair can be performed with the outer surface kept smooth even when work can be performed only from the outside of the sandwich structure.

According to a fifth aspect of the present invention, there is provided a plurality of the outer support plates, wherein an opening is formed in a region including a damaged portion of the outer surface side plate, and a core material at a lower portion of the opening and a peripheral portion of the opening is removed.
The plurality of outer support plates are inserted, arranged on the inner surface of the periphery of the opening, attached with rivets inside the outer surface side plate, and a cover plate having the same size as the opening and the same thickness as the outer surface side plate is opened. It is characterized by being fitted, connected to the outer support plate with a rivet, and filled with a filler in the core material removing portion.

According to the present invention, since a plurality of outer support plates are inserted in place of the extensible outer support plates, complicated processing of the outer support plates becomes unnecessary, and the processing labor is further reduced. Can be.

According to a sixth aspect of the present invention, a core material is removed from a foamed plastic material by spraying a blast material.

According to the present invention, since the sandwich structure uses a foamed plastic core as a core material, the core material can be easily removed by a method of spraying a blast material, and labor and time for repair are reduced. Can be reduced.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention.
2 is an exploded perspective view showing the sandwich structure 50 of FIG. The sandwich structure 50 is used, for example, as an outer skin of an aircraft. The core 51 is made of a closed-cell foamed plastic material, and both surfaces of the core are made of a fiber-reinforced composite material.
2 and 53. The foamed plastic material is, for example, polymethacrylimide (PMI) or polyvinyl chloride (PVC), which is a closed-cell foamed plastic material. The face plates 52 and 53 are made of a fiber reinforced composite material using inorganic fibers having no affinity for water, for example, carbon fibers as reinforced fibers. It is configured by lamination.

When the core members 51 of the sandwich structure 50 are joined to each other, a film-like adhesive 54 that does not foam at the joining portion, for example, Cytec FM300K (trade name) is used. The face plates 52 and 53 and the core material 51 are formed of a film-like adhesive 55 containing no carrier, for example, Cy.
TEC FM300U (trade name). By bonding with a film-like adhesive containing no carrier, no gap is formed between the face plates 52 and 53 and the core material 51, so that water can be prevented from entering. In addition, the core material 51 and the face plates 52, 53 are not bonded by using a film-like adhesive, but the face plates 52, 5 which are a composite material.
The third resin may be used. That is, the prepregs to become the face plates 52 and 53 are directly attached to both surfaces of the core material 51, and the prepreg is cured by heating under pressure, and the face plates 52 and 53 and the core material 51 are bonded.

Since the core 51 is made of a closed-cell foamed plastic material, water is prevented from penetrating into the core. In addition, since the adhesive between the core materials uses a film-like adhesive 54 that does not foam, the face plates 52 and 53 are damaged,
Even if water invades, it is possible to prevent the water that has entered along the joint surface of the core material 51 from spreading into the sandwich structure 50.

FIG. 2 is an exploded perspective view showing a second sandwich structure 60 on which the present invention is based. The sandwich structure 60 of the present embodiment is made of a honeycomb core 66 as a core material 67 and a foamed plastic material surrounding the honeycomb core 66, and the face plates 62 and 63 have an affinity for water similarly to the sandwich structure 50 described in FIG. It is a composite material using inorganic fibers having no reinforcement as reinforcing fibers, and is a film-like adhesive 64 containing no carrier, or composite material face plates 62 and 6.
3 is bonded with the resin contained in the resin.

The core 67 has a honeycomb core 66 on the inside as shown in FIG. 2, and a foamed plastic material 61 is arranged around the periphery of the honeycomb core 66 in a frame shape.

The honeycomb core 66 has high strength and rigidity in the thickness direction, but has low strength and rigidity in the horizontal direction perpendicular to the thickness direction. Therefore, in a sandwich structure using only a honeycomb core as a core material, a frame-shaped metal locator jig surrounds the sandwich structure or forms a gently tapered periphery of the sandwich structure to withstand the side pressure during heating and pressing However, in the present embodiment, by disposing the foamed plastic material 61 in a frame shape at the peripheral portion,
The lateral strength and rigidity of the periphery of the sandwich structure can be increased, and the taper angle of the periphery of the sandwich structure can be increased.

The foamed plastic material 6 of the present embodiment
Similarly to the sandwich structure shown in FIG. 1, the foamed plastic material 61 uses a film-like adhesive 65 that does not foam as in the sandwich structure shown in FIG.

FIG. 3 is a sectional view showing a third sandwich structure 70 on which the present invention is based. The core material 77 of the sandwich structure 70 is formed by sandwiching both surfaces of a honeycomb core 71 between foamed plastic materials 72, 73, and via a honeycomb core 71, a foamed plastic material 72, 73, and a film-like adhesive 78 that does not include a carrier. Joined.
Further, the core material 77 and the face plates 75 and 76 are also bonded via a film-like adhesive 79 containing no carrier.
The face plates 75 and 76 are a composite material using inorganic fibers having no affinity for water as reinforcing fibers, as described above.

By sandwiching both surfaces of the honeycomb core 71 between the foamed plastic materials 72 and 73 in this manner, the face plate 7 is formed.
Even if 5,76 is damaged and cracked, no water will penetrate into the sandwich structure. In addition, by disposing the foamed plastics 72, 73 that easily absorb the impact directly below the face plates 75, 76, the sandwich structure 70 that is less likely to be damaged can be realized.

FIG. 4 is a sectional view showing a fourth sandwich structure 80 on which the present invention is based. In this embodiment,
The core material 86 is made of the honeycomb core 81 and the foamed plastic material 8.
The sandwich structure 80 uses a foamed plastic material 85 for a portion where the plate thickness changes greatly, and a honeycomb core 81 for a portion where the plate thickness changes gradually.

In the case of a sandwich structure having a large change in plate thickness, it is necessary to machine the honeycomb core. However, since machining of the honeycomb core is a time-consuming operation, in the present embodiment, the portions where the plate thickness change is large are: By using the foamed plastic material 85 that is easy to machine and using the honeycomb core 81 in the portion where the thickness changes gradually, the processing of the core material 86 becomes easy. The face plates 83 and 84 are made of prepreg and are formed by being laminated on a core material 86. The bonding between the face plates 83 and 84 and the core material 86 uses a film-like adhesive 87 that does not include a carrier. Also, face plates 83, 8
As the reinforcing fiber of No. 4, an inorganic fiber having no affinity for water is used as described above.

Next, an embodiment of a method for repairing a sandwich structure according to the present invention will be described. FIG. 5 is a cutaway perspective view showing the damaged sandwich structure 1. The sandwich structure 1 is a composite material having a sandwich structure in which both surfaces of a plate-like core material 4 having a thickness of 12.7 mm are covered with face plates 2 and 3. The core material 4 is made of a closed-cell foamed plastic material, and the face plates 2 and 3 are fiber-reinforced composite materials using inorganic fibers having no affinity for water as reinforcing fibers. The sandwich structure 1 of the present embodiment is used, for example, as an outer plate of a passenger transport device such as an aircraft or a high-speed railway vehicle.

The face plate 2 of the sandwich structure 1 is on the outer surface side, and the face plate 3 is on the inner surface side. The outer face plate 2
A fiber-reinforced composite material formed by laminating eight prepregs in which a resin is impregnated in a cloth material made of reinforcing fibers,
The inner face plate 3 is thinner than the face plate 2 and is a fiber reinforced composite material in which four prepregs are laminated.

In FIG. 5, reference numeral 5 indicates a damaged portion,
In order to repair the damaged portion 5, the face plate 2 in the area including the damaged portion 5 is first cut out. For this purpose, a hole saw 11 shown in FIG. 6 is used. The hole saw 11 has a cylindrical shape, and has a sawtooth 12 formed at the distal end thereof over the entire outer circumference. The saw 12 can be hollowed out by rotating at high speed around an axis. Therefore, by using the hole saw 11 having a diameter larger than the damaged portion 5, the face plate 2 in the region including the damaged portion can be hollowed out. By digging out the damaged portion in a circular shape in this way, the concentration of stress can be suppressed low. In the present embodiment, the diameter of the hole saw 11 is, for example, 50 mm. Also, as shown in FIG.
Are also cut out in a circle. Thus, a circular opening 10 is formed in the face plate 2.

Next, the lower part of the opening 10 of the face plate 2 and the opening 10
The core material 4 at the periphery is removed. Since the core material 4 is a foamed resin as described above and the face plates 2 and 3 are a fiber-reinforced composite material, only the core material 4 can be efficiently removed by using a blast shot.

FIG. 7 is a perspective view showing a core material removing operation.
FIG. 8 is a sectional view at that time. As blast material,
For example, walnut powder, alumina, cone, or the like is used. By injecting such a blast material from the blast injection nozzle 15 toward the core material 4, only the core material 4 can be scraped.

As shown in FIG. 8, the core material 4 attached to the back side of the face plate 2 is removed by using a blast jet nozzle 15 whose tip end is bent by 180 ° as shown in FIG.
0 to easily insert the blast nozzle 15
Can be removed.

After removing the core material 4, the support plate 16 is mounted. FIG. 9 is a plan view showing a state where the support plate 16 is mounted, and FIG. 10 is a cross-sectional view thereof. The support plate 16 can be extended in a radial or petal shape as shown in FIG.
Made of titanium alloy. The support plate 16 includes a circular support portion 17 at a central portion, and a plurality of rectangular, and radially outwardly extending from the support portion 17, and in the present embodiment, eight support pieces 18. And formed from a titanium alloy plate. The central circular support portion 17 has a smaller diameter than the opening 10. The entire size of the support plate 16 including the support pieces 18 is formed sufficiently larger than the opening 10.

The support plate 16 is inserted from the opening 10, and each support piece 18 is attached to the rivet 2 on the back side of the face plate 2 around the opening 10.
Linked by 5. When the support plate 16 is inserted from the opening 10, each support piece 18 is inserted into the opening 10 with the support piece 18 being curved inward, and the support piece 18 is spread within the opening 10.
Next, a through hole 24 for inserting the rivet 25 is formed by drilling from the face plate 2 to the support piece 18.
The through holes 24 may be separately formed in the support plate 16 and the face plate 2 in advance.

Next, each support piece 18 of the support plate 16 and the face plate 2 are fixed by rivets 25. FIG. 11 shows rivet 2
It is sectional drawing explaining the fastening method of No. 5. Rivet 25
Is a blind rivet that can be swaged from one side, and the head 26 has a dish shape and is smooth without protruding above the outer surface of the face plate 2.

The rivet 25 has a hollow shaft portion 27, and a drawing bar 28 is inserted into the shaft portion 27. Shaft 2
A sleeve 30 is attached to the tip of the extraction rod 28 projecting from
Is inserted, and the distal end of the extraction rod 28 is connected to the solid core bolt 31 at the distal end of the sleeve 30. Also,
A coiled washer 32 is provided at the base end of the sleeve 30, and the tip of the shaft 27 is tapered.

As shown in FIG. 11A, such a rivet 25 is inserted into the through hole 24 from the front side of the face plate 2. Next, when the pull-out bar 28 is pulled out with a tool, the coiled washer 32 is guided by the tapered portion at the tip of the shaft portion 27 to be unwound and expanded as shown in FIG. When the pullout rod 28 is further pulled out, the coiled washer 32 comes into contact with the back surface of the support plate 16 and is completely swaged. Finally, withdrawal rod 2
8, and the rivet caulking operation is completed. In this way, the eight support pieces 18 of the support plate 16 are connected to the face plate 2 by the rivets 25, respectively.

Next, the opening 10 is closed by the cover plate 40. The cover plate 40 is made of a fiber-reinforced composite material having the same thickness as the face plate 2, and is formed to have the same size as the opening 10. Therefore,
Using the hole saw 11 used to form the opening 10, a fiber-reinforced composite material having the same thickness as the face plate 2 is cut out in a circular shape.

Using the cover plate 40, the opening 10 is closed as shown in FIG. As shown in FIG. 9, the support plate 16 has a central circular support portion 17 exposed at the center of the opening 10 and a peripheral support piece 18 formed on the support plate 2.
, The cover plate 40 is arranged on the central support portion 17. Next, insertion holes for inserting the rivets 25 are formed by drilling the cover plate 40 from the cover plate 40 to the support plate 16 at eight positions, for example, corresponding to the support pieces 18. And, as before, blind rivet 2
5, the support plate 26 and the cover plate 40 are connected. Since the cover plate 40 has the same thickness as the face plate 2, the support plate 16
The surface of the face plate 2 becomes smooth by fixing it on the upper side.

After joining the cover plate 40 with the rivets 25, two through holes 41 and 42 are formed on the cover plate 40, and a filler 43 is injected from one of the through holes 41. Filler 43
Is a liquid foamed resin containing fine bubbles, and is injected from the through hole 41 by an injection gun. Filled filler 43
Is filled with a recess formed by removing the core material 4, and FIG.
When completely filled as shown in FIG.
Come out of two. This makes it possible to confirm that the filling has been completed. After injecting the filler, the filler 43 is completely cured by being left for a predetermined time. The filling material 43
Cures at room temperature.

In this way, the sandwich structure 1 can be easily repaired using rivets without using any special device. Further, the support plate 16 is made of a titanium alloy, and the titanium alloy and the fiber reinforced composite material of the face plates 2 and 3 have a thermal expansion coefficient closer to that of an aluminum alloy or the like. Therefore, even if they are joined with the rivets 25, it is possible to prevent the occurrence of excessive thermal stress during use.

In the present embodiment, the radial support plate 16 is used as the support plate 16. However, the present invention is not limited to this. For example, a plurality of support plates are connected to the back side of the periphery of the opening 10 by rivets to support the support plate. The plate may be partially exposed to the opening 10, the cover plate 40 may be placed on the exposed support plate, and the cover plate and the support plate may be joined by rivets.

Although the present embodiment has been described on the assumption that the repair is performed only from the damaged front side, when the repair work can be performed from the back side of the outer plate, the outer plate is pierced by the hole saw 11, that is, the inner surface is repaired. An opening is formed through the face plate 3. As a result, the work can be performed not only from the front side but also from the back side, so that the work of removing the core material 4 can be easily performed. Further, since the back side is not noticeable and does not need to be smoothed, a cover plate larger than the opening may be directly connected to the face plate 3 by rivets without using a support plate.

FIG. 14 is a sectional view showing a method of repairing the sandwich structure 1 according to still another embodiment of the present invention. In addition,
In the configurations corresponding to FIGS. 5 to 13 described above, the same reference numerals are given, and the description is omitted.

The repair method according to the present embodiment is a repair method in the case where repair can be performed from the face plate 3 inside the sandwich structure 1. The inner face plate 3 and the core 4 corresponding to the back side of the damaged portion 5 are removed in the same manner as described above by spraying the hole saw 11 and the blast material. Next, the upper support plate 45 is brought into contact with the back side of the face plate 2 so as to cover the damaged portion 5 on the back side of the face plate 2 on the outer surface side, and is joined with the rivets 25. The upper support plate 45 is made of a titanium alloy or a fiber-reinforced composite material similar to the face plate 2. Next, the core removing portion is filled with the filler 43, and then the opening of the inner face plate 3 opened by the hole saw 11 is
6 and is connected to the face plate 3 by rivets 25. By repairing in this manner, it is possible to repair without forming an opening in the outer surface side plate 2.

In the repair method of this embodiment, the sandwich structure is made of only the foamed plastic material as the core material. However, the present invention is not limited to such a form. As shown in FIGS. The repair method of the present invention can also be applied to a sandwich structure having a core material. Further, for the sandwich structure, a film-like adhesive as described in FIGS. 1 to 4 may be used.

[0048]

According to the present invention, the outer support plate is connected to the back side of the damaged portion by rivets and repaired.
The labor and time can be greatly reduced as compared with the case of performing the adhesive repair.

According to the present invention, an opening is formed at a damaged portion, an outer support plate is connected with a rivet from the back side, a cover plate is fitted into the opening and connected to the outer support plate with a rivet, thereby providing an outer surface. Can be repaired in a smooth condition.

Further, according to the present invention, by spraying the blast material, the core material made of the foamed plastic material can be easily removed, and the repair time can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a sandwich structure 50. FIG.

FIG. 2 is an exploded perspective view showing the sandwich structure 60.

FIG. 3 is a sectional view showing a sandwich structure 70.

FIG. 4 is a sectional view showing a sandwich structure 80.

FIG. 5 is a perspective view showing a damaged sandwich structure 1.

FIG. 6 is a perspective view showing a method for hollowing out a damaged portion.

FIG. 7 is a perspective view showing a method of removing a core material 4;

FIG. 8 is a cross-sectional view of the sandwich structure 1 showing a method of removing the core material 4;

FIG. 9 is a plan view of the sandwich structure 1 showing a state where the support plate 16 is attached.

FIG. 10 is a cross-sectional view of the sandwich structure 1 showing a state where the support plate 16 is attached.

FIG. 11 is a sectional view showing a method of caulking the rivet 25.

FIG. 12 is a perspective view of the sandwich structure 1 showing a state where the cover plate 40 is attached.

FIG. 13 is a cross-sectional view showing the sandwich structure 1 in a state where the filler 43 is injected.

FIG. 14 is a sectional view showing another embodiment of the sandwich structure repair method of the present invention.

[Explanation of symbols]

1,50,60,70,80 sandwich structure 2,3,52,53,62,63,75,76,83,
84 face plate 4, 51, 67, 77, 86 core material 5 damaged portion 10 opening 11 hole saw 12 sawtooth 16 support plate 25 rivet 40 cover plate 43 filler 45 upper support plate 46 lower support plate 54, 55, 64, 65, 78, 79,87 Film adhesive 61,72,73,85 Foamed plastic material 66,71,81 Honeycomb core

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F213 AD16 AD17 AD20 AG03 WA02 WA15 WA52 WA53 WA56 WA67 WA94 WB01 WM02

Claims (6)

[Claims] 1. A method for repairing a sandwich structure in which a closed cell foamed plastic material is used as a core material and both surfaces of the core material are covered with a face plate made of a fiber reinforced composite material, wherein an outer support plate is provided on the back side of the damaged portion of the outer surface side plate. Repairing the sandwich structure, characterized in that the rivets are joined with rivets. 2. The inner side plate and the core below the area including the damaged portion of the outer side plate are removed, the outer support plate is rivet-bonded to the back side of the damaged portion, and the core material removing portion is filled with filler. The method for repairing a sandwich structure according to claim 1, wherein the opening is covered with an inner support plate larger than the opening of the inner side surface plate, and attached around the opening of the inner side surface plate with rivets. 3. An opening is formed in a region including a damaged portion of the outer surface side plate, a core material and an inner side surface plate in an area larger than an opening below the opening are removed, and an area around the opening of the outer surface side plate is removed. The outer support plate is connected to the back side by rivets, a cover plate having the same size as the opening and having the same thickness as the outer surface side plate is fitted into the opening, connected to the outer support plate with rivets, and filled in the core material removing portion. 2. The method for repairing a sandwich structure according to claim 1, wherein an agent is filled, the opening is covered with an inner support plate larger than the opening of the inner side surface plate, and attached around the opening of the inner side surface plate with rivets. 4. An opening is formed in a region including a damaged portion of the outer surface side plate, and a core material at a lower portion of the opening and a peripheral portion of the opening is removed, and the outer support plate is expandable in a region larger than the opening. Insert the support plate from the opening and attach it with rivets to the back side of the outer surface side plate, fit a cover plate of the same size as the opening and the same thickness as the outer surface side plate into the opening, and rivet it to the outer support plate, The method for repairing a sandwich structure according to claim 1, wherein a filler is filled in the core material removing portion. 5. An outer support plate comprising a plurality of outer support plates, wherein an opening is formed in a region including a damaged portion of an outer surface side plate, a core material at a lower portion of the opening and a periphery of the opening is removed, and the plurality of outer support plates are provided. Insert and place it on the inner surface of the periphery of the opening, attach it with rivets inside the outer surface side plate, fit a cover plate of the same size as the opening and the same thickness as the outer surface side plate into the opening, and attach it to the outer support plate The method for repairing a sandwich structure according to claim 1, wherein the core material removing portion is filled with a filler by rivets. 6. The method for repairing a sandwich structure according to claim 1, wherein a core material of the foamed plastic material is removed by spraying a blast material.