FRP sandwich structure, manufacturing method of FRP sandwich structure

Abstract

This provides an FRP sandwich structure with edges that maintain flatness and strength. [Solution] The FRP sandwich structure 10 is manufactured by a process comprising: a lower fiber cloth placement step of placing a lower fiber cloth 11B on a base plate P1; a core material placement step of placing a core material 12 on the lower fiber cloth 11B; a reinforcing member placement step of placing a reinforcing member 13 on the lower fiber cloth 11B along the end 12a of the core material 12; an upper fiber cloth placement step of placing an upper fiber cloth 14B on the core material 12 and the reinforcing member 13; a film covering step of covering the upper fiber cloth 14B on the base plate P1 with a film P2; and a resin supply / degassing step of degassing the space between the base plate P1 and the film P2 and supplying resin. The reinforcing member 13 is molded by the impregnated resin to have three connecting surfaces 13a, 13b, and 13c that are connected to each other and are all connected along the lower fiber cloth 11B, the end 12a of the core material 12, and the upper fiber cloth 14B.

Description

Technical Field

[0001] The present invention relates to an FRP sandwich structure and a method for manufacturing the FRP sandwich structure.

Background Art

[0002] The FRP (Fiber Reinforced Plastics) sandwich structure is a structure in which reinforcing fiber cloth materials are arranged on both sides of a core material and integrated by resin impregnation. FRP sandwich structures are widely used in various fields such as watercraft, railway vehicles, plant equipment, buildings, and aircraft. Among FRP sandwich structures, large-sized ones with a length of 3 m or more are generally molded by the VARTM (Vacuum Assisted Resin Transfer Molding) method (Patent Documents 1 and 2).

[0003] The FRP sandwich structure molded by the VARTM method is difficult to process at its end portions.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of Invention

Problems to be Solved by the Invention

[0005] As described in Patent Document 1, it is difficult to manufacture the FRP sandwich structure molded by the VARTM method while maintaining flatness over the entire panel-shaped main surface. As described in Patent Document 2, FRP sandwich structures molded using the VARTM method are difficult to process at their edges. In particular, when fixing the edges with bolts or the like, it was necessary to separately install sleeves or the like to prevent the foam core from being crushed.

[0006] Thus, panels produced by the VARTM method have not been able to fully satisfy the requirements for main surface flatness near the edges, formability sufficient for use as a sheet material, and strength to withstand fastening with bolts, etc. Therefore, when forming an FRP sandwich structure using the VARTM method, it was necessary to join the upper and lower FRP sections at the edges with additional FRP. Alternatively, after forming the FRP sandwich structure using the VARTM method, it was necessary to process the edges separately. This led to a demand for reducing the amount of material used, the number of manufacturing steps, and the manufacturing time.

[0007] This invention has been made in view of the above circumstances and aims to achieve the following objectives. 1. To enable manufacturing while maintaining the flatness of the edges in the FRP sandwich structure. 2. To enable manufacturing without requiring separate processing of the edges in the FRP sandwich structure. 3. To enable manufacturing with sufficient strength at the edges of the FRP sandwich structure. [Means for solving the problem]

[0008] (1) A method for manufacturing an FRP sandwich structure according to one aspect of the present invention is: The lower fiber cloth placement process involves placing the lower fiber cloth on a surface plate, A core material placement step in which the core material is placed on the lower fiber cloth, A reinforcing member placement step involves placing a reinforcing member on the lower fiber cloth along the end of the core material, An upper fiber cloth placement step in which the upper fiber cloth is placed on the core material and the reinforcing member, A film covering step in which the lower fiber cloth on the base plate, the core material, the reinforcing member, and the upper fiber cloth are covered with a film, A resin supply and degassing step is performed to degas the space between the surface plate and the film and to supply resin, It has, Each of the reinforcing members is formed to have three connecting surfaces that are connected along the lower fiber fabric, the end of the core material, and the upper fiber fabric, and that are interconnected with each other. This resolved the above issues. (2) The method for manufacturing the FRP sandwich structure of the present invention is as described in (1) above, The process includes a cutting step in which the reinforcing member is cut along the end of the core material after the resin supply and degassing step. It is possible. (3) The method for manufacturing the FRP sandwich structure of the present invention is as described in (1) above, The reinforcing member is a hollow, columnar FRP profile having at least three connecting surfaces. It is possible. (4) The method for manufacturing the FRP sandwich structure of the present invention is as described in (1) above, The reinforcing member is a shaped fiber fabric in which at least three connecting surfaces of fiber fabric are formed along a hollow shape. It is possible. (5) The method for manufacturing the FRP sandwich structure of the present invention is as described in (1) above, The core material placement step involves placing a plurality of core materials on the lower fiber fabric with the reinforcing member in between. It is possible. (6) Another aspect of the present invention is an FRP sandwich structure, An FRP sandwich structure in which a plate-shaped core material is sandwiched between FRP panels along both main surfaces of the core material, The aforementioned core material, A reinforcing member along the end of the core material, The core material and the reinforcing member sandwiched between FRP panels, It has, The reinforcing member is an FRP material having three connecting surfaces that are connected along the ends of the FRP panels on both sides and the core material, and that are interconnected with each other. This resolved the above issues. (7) The method for manufacturing the FRP sandwich structure of the present invention is as described in (6) above, The reinforcing member has a U-shaped cross-section with three connecting surfaces. It is possible.

[0009] In the configuration described in (1) above, degassing and resin impregnation can be performed with the reinforcing member positioned in contact with the end, so that the end of the core material does not sink towards the base plate. As a result, a plate-shaped FRP sandwich structure can be formed in which the surfaces of the upper and lower FRP panels are flat without unevenness. Because a reinforcing member is provided at the end, a plate-shaped FRP sandwich structure with sufficient strength at the end can be formed without forming unnecessary fiber cloth layers at the end. A plate-shaped FRP sandwich structure with sufficient strength at the end can be formed in just one degassing and impregnation step, without the need for additional processing.

[0010] Furthermore, since the reinforcing member is molded sandwiched between the upper and lower FRP panels, no steps are created due to the lamination overlap, and a flat, plate-like FRP sandwich structure can be formed with smooth, even surfaces on the upper and lower FRP panels. A plate-like FRP sandwich structure with sufficient strength at the edges can be formed without requiring any additional processing.

[0011] Furthermore, the upper FRP panel, in which the upper fiber cloth is impregnated with resin, and the connecting surface of the reinforcing member are molded together in close contact, the lower FRP panel, in which the lower fiber cloth is impregnated with resin, and the connecting surface of the reinforcing member are molded together in close contact, the connecting surface of the reinforcing member, in which the fiber cloth is impregnated with resin, and the end of the core material are molded together in close contact, and since the connecting surfaces of these reinforcing members are connected to each other and the reinforcing member is located at the end, a plate-shaped FRP sandwich structure with sufficient strength at the end can be formed.

[0012] In the configuration described in the above (2), by cutting the reinforcing member, the end portion that forms the contour of the plate-shaped FRP sandwich structure is formed by the two FRP panels that are the both ends in the thickness direction formed integrally by the reinforcing member and the upper and lower FRP panels. As a result, since the core material having lower strength than the FRP panel is not exposed at the contour, shear deformation in the core material of the FRP sandwich structure is suppressed, and the overall deformation can be reduced.

[0013] Further, even when the end portion of the FRP sandwich structure is fixed in the thickness direction thereof with a bolt or the like, there is no need to add a sleeve or the like to prevent the foam core material from being crushed, and a fixing member such as a bolt can be disposed to penetrate the FRP panel formed integrally by the reinforcing member and the upper and lower FRP panels. This makes it possible to more easily perform clamping with bolts or the like. As a result, at the end portion of the plate-shaped FRP sandwich structure, bending deformation becomes dominant as the deformation, and shear deformation can be ignored.

[0014] In the configuration described in the above (3), at the end portion of the plate-shaped FRP sandwich structure, the upper FRP panel formed by impregnating the upper fiber cloth with resin and the connection surface of the reinforcing member are integrally molded in a closely attached state, the lower FRP panel formed by impregnating the lower fiber cloth with resin and the connection surface of the reinforcing member are integrally molded in a closely attached state, the connection surface of the reinforcing member formed by impregnating the fiber cloth with resin and the end portion of the core material are integrally molded in a closely attached state, and further, since the reinforcing member whose connection surfaces are connected to each other to be integrated is located at the end portion, a plate-shaped FRP sandwich structure whose end portion has sufficient strength can be molded.

[0015] Because one connecting surface of the reinforcing member, which is in close contact with the end of the core material, is positioned in the thickness direction at the end of the core material, the core material will not collapse in the thickness direction even when a load is applied that compresses the core material in the thickness direction. As a result, when fixing the ends of a plate-shaped FRP sandwich structure with bolts, etc., there is no need to insert sleeves or the like to prevent the core material from collapsing when using a foamed core material, and tightening with bolts, etc. can be performed more easily.

[0016] In the configuration described in (4) above, resin is prevented from entering the hollow interior, and the fiber cloth that serves as the reinforcing member can be made to form a connection surface for the reinforcing member that is tightly attached to the upper FRP panel, the lower FRP panel, and the end of the core material, thus enabling the formation of a plate-shaped FRP sandwich structure with sufficient strength at the ends in just one degassing and impregnation step. At the same time, since resin cannot be allowed to enter the hollow interior, it is possible to reduce resin consumption and prevent damage caused by heat generation during curing by preventing large amounts of resin from penetrating the hollow interior.

[0017] In the configuration described in (5) above, multiple FRP sandwich structures can be formed in the same process using reinforcing members, allowing for the simultaneous formation of sandwich plates with reinforced ends. Furthermore, when cutting the reinforcing members, the FRP sandwich structures on both sides of the cutting position can be formed in such a way that the ends are covered by the reinforcing members where they are sandwiched between the upper and lower FRP panels, thus reducing material waste.

[0018] In the configuration described in (6) above, the upper FRP panel, in which the upper fiber cloth is impregnated with resin, and the connecting surface of the reinforcing member are molded together in close contact, the lower FRP panel, in which the lower fiber cloth is impregnated with resin, and the connecting surface of the reinforcing member are molded together in close contact, and the connecting surface of the reinforcing member, in which the fiber cloth is impregnated with resin, and the end of the core material are molded together in close contact, and moreover, the connecting surfaces of these reinforcing members are connected to each other, and the reinforcing member is located at the end, thereby enabling the formation of a plate-shaped FRP sandwich structure with sufficient strength at the end. As a result, the end of the core material does not become concave in the thickness direction. A plate-shaped FRP sandwich structure can be provided in which the flatness of the upper and lower FRP panels is not lost due to overlapping. Because a reinforcing member is provided at the end, the amount of resin used can be reduced without forming unnecessary fiber cloth layers at the end, and a plate-shaped FRP sandwich structure with sufficient strength at the end can be formed.

[0019] Furthermore, since the reinforcing member is molded sandwiched between the upper and lower FRP panels, and one connecting surface of the reinforcing member that is in close contact with the end of the core material is positioned in the thickness direction at the end of the core material, even when a load is applied that compresses the core material in the thickness direction, the core material will not collapse in the thickness direction. As a result, even when fixing the ends of a plate-shaped FRP sandwich structure with bolts, etc., in the case of a foamed core material, there is no need to insert sleeves or the like to prevent the core material from collapsing, and tightening with bolts, etc. can be performed more easily. This makes it possible to provide a plate-shaped FRP sandwich structure in which there are no steps near the ends and the surfaces of the upper and lower FRP panels are flat without any bumps or unevenness.

[0020] In the configuration described in (7) above, a reinforcing member is provided at the end, which has a connecting surface that tightly connects to the upper FRP panel, a connecting surface that tightly connects to the lower FRP panel, and a connecting surface that tightly connects to the end of the core material, and these are integrally molded together. This provides a plate-shaped FRP sandwich structure with sufficient strength at the end. As a result, the end of the core material does not collapse in the thickness direction. A plate-shaped FRP sandwich structure is provided in which the flatness of the upper and lower FRP panels is not lost due to overlapping. Because a reinforcing member is provided at the end, the amount of resin used can be reduced without forming unnecessary fiber cloth layers at the end, and a plate-shaped FRP sandwich structure with sufficient strength at the end can be molded.

[0021] Furthermore, since the reinforcing member is molded sandwiched between the upper and lower FRP panels, and one connecting surface of the reinforcing member that is in close contact with the end of the core material is positioned in the thickness direction at the end of the core material, even when a load is applied that compresses the core material in the thickness direction, the core material will not collapse in the thickness direction. As a result, even when fixing the ends of a plate-shaped FRP sandwich structure with bolts, etc., in the case of a foamed core material, there is no need to insert sleeves or the like to prevent the core material from collapsing, and tightening with bolts, etc. can be performed more easily. This makes it possible to provide a plate-shaped FRP sandwich structure in which there are no steps near the ends and the surfaces of the upper and lower FRP panels are flat without any bumps or unevenness. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a plate-shaped FRP sandwich structure that has sufficient edge strength, maintains surface flatness, and reduces the amount of resin used, while also reducing the number of manufacturing steps. [Brief explanation of the drawing]

[0023] [Figure 1] This is a schematic cross-sectional view showing a first embodiment of the FRP sandwich structure according to the present invention. [Figure 2]This is a cross-sectional view showing the manufacturing process in the first embodiment of the method for manufacturing an FRP sandwich structure according to the present invention. [Figure 3] This is a cross-sectional view showing the manufacturing process in the first embodiment of the method for manufacturing an FRP sandwich structure according to the present invention. [Figure 4] This is a cross-sectional view showing the manufacturing process in the first embodiment of the method for manufacturing an FRP sandwich structure according to the present invention. [Figure 5] This is a cross-sectional view showing the manufacturing process in the first embodiment of the method for manufacturing an FRP sandwich structure according to the present invention. [Figure 6] This is a cross-sectional view showing the manufacturing process in the first embodiment of the method for manufacturing an FRP sandwich structure according to the present invention. [Figure 7] This is a flowchart showing the manufacturing process in the first embodiment of the method for manufacturing an FRP sandwich structure according to the present invention. [Figure 8] This is a cross-sectional view showing the manufacturing process in a second embodiment of the method for manufacturing an FRP sandwich structure according to the present invention. [Figure 9] This is a cross-sectional view showing the manufacturing process in a third embodiment of the method for manufacturing an FRP sandwich structure according to the present invention. [Modes for carrying out the invention]

[0024] Hereinafter, a first embodiment of the FRP sandwich structure and the method for manufacturing the FRP sandwich structure according to the present invention will be described with reference to the drawings. Figure 1 is a schematic cross-sectional view showing the FRP sandwich structure in this embodiment. In the figure, reference numeral 10 denotes the FRP sandwich structure.

[0025] As shown in Figure 1, the FRP sandwich structure 10 according to this embodiment includes a lower FRP panel (FRP panel) 11, a core material 12, a reinforcing member 13, and an upper FRP panel (FRP panel) 14. Note that the terms "upper" and "lower" in the lower FRP panel 11 and the upper FRP panel 14 are used for convenience to distinguish them, and do not represent the actual vertical direction.

[0026] The lower FRP panel 11, the core material 12, and the upper FRP panel 14 are all roughly flat. The lower FRP panel 11, the core material 12, and the upper FRP panel 14 are laminated in this order. The lower FRP panel 11, the core material 12, and the upper FRP panel 14 are bonded together as a single unit. The main surfaces of the lower FRP panel 11, the core material 12, and the upper FRP panel 14 are all parallel. The core material 12 is sandwiched between the lower FRP panel 11 and the upper FRP panel 14 in the thickness direction. The lower FRP panel 11, the core material 12, and the upper FRP panel 14 may have a rectangular outline when viewed from above.

[0027] The lower FRP panel 11 and the upper FRP panel 14 have almost the same contour shape when viewed from above. The lower FRP panel 11 and the upper FRP panel 14 have larger contours than the core material 12 when viewed from above. The peripheral edges of the lower FRP panel 11 and the upper FRP panel 14, when viewed from above, extend beyond the contour of the core material 12 all around. The lower FRP panel 11 and the upper FRP panel 14 both have the same thickness dimension across their entire surface when viewed from above. The core material 12 has the same thickness dimension across its entire surface when viewed from above. The core material 12 can be thicker than the lower FRP panel 11 and the upper FRP panel 14. The lower FRP panel 11 and the upper FRP panel 14 can have the same thickness dimension as each other. The lower FRP panel 11 and the upper FRP panel 14 may have different thickness dimensions as each other. Furthermore, the lower FRP panel 11 and the upper FRP panel 14 may have the same thickness dimension distribution in each region when viewed from above. The lower FRP panel 11 and the upper FRP panel 14 may each have different thickness dimension distributions in each region when viewed from above. Also, the lower FRP panel 11 and the upper FRP panel 14 may have different thickness dimension distributions as each other.

[0028] The upper surface 11a of the lower FRP panel 11 is connected to the main surface of the core material 12. The lower surface 14a of the upper FRP panel 14 is connected to the main surface of the core material 12. The upper surface 11a of the lower FRP panel 11 and the lower surface 14a of the upper FRP panel 14 face each other. The upper surface 11a of the lower FRP panel 11 and the lower surface 14a of the upper FRP panel 14 face inward in the thickness direction of the FRP sandwich structure 10. The upper surface 11a of the lower FRP panel 11 and the lower surface 14a of the upper FRP panel 14 are parallel to each other.

[0029] Both the lower FRP panel 11 and the upper FRP panel 14 are molded from resin-impregnated fiber cloth material. Both the lower FRP panel 11 and the upper FRP panel 14 are molded by impregnating the fiber cloth material along the main surface with resin. The fibrous fabric material may be woven, matted, or knitted fabric made from glass fiber, aramid fiber, carbon fiber, etc. The fibrous fabric material may also be a reinforced fibrous fabric made by laminating multiple layers. The resin used for impregnation is preferably a thermosetting resin. Examples of thermosetting resins include vinyl ester, unsaturated polyester, and epoxy. The core material 12 can be made of lightweight balsa wood, polyvinyl chloride foam, urethane foam, or other plastic foams, but the material is not particularly limited.

[0030] The reinforcing member 13 is an FRP panel (FRP profile), similar to the lower FRP panel 11 and the upper FRP panel 14. The reinforcing member 13 is connected to the lower FRP panel 11, the core material 12, and the upper FRP panel 14. The reinforcing member 13 is positioned around the entire circumference of the core material 12, as viewed from above. The reinforcing member 13 is connected to the lower FRP panel 11 and the upper FRP panel 14 that protrude from the core material 12, as viewed from above. The reinforcing member 13 is positioned along the contour of the core material 12. If the contour of the core material 12, as viewed from above, is rectangular, the reinforcing member 13 may be positioned on each side of the contour of the core material 12. The reinforcing member 13 has a connecting surface 13a, a connecting surface 13b, and a connecting surface 13c.

[0031] The reinforcing member 13 has connecting surfaces 13a and 13b, and connecting surface 13a and 13c connected to each other. The end of connecting surface 13a and the end of connecting surface 13b, and the end of connecting surface 13a and the end of connecting surface 13c are connected to each other. The reinforcing member 13 has connecting surfaces 13a, 13b, and 13c along the entire length in the direction in which it extends. The cross section of the reinforcing member 13 perpendicular to the direction of extension is formed in a U shape by connecting surfaces 13a, 13b, and 13c. The direction of the U-shaped opening of the reinforcing member 13 is outward along the main surface of the core material 12.

[0032] The connecting surface 13a extends in the thickness direction of the core material 12. The connecting surface 13a connects to the end (end face) 12a of the core material 12. The connecting surface 13a is parallel to the end (end face) 12a of the core material 12. The connecting surface 13a has the same length as the end (end face) 12a in the thickness direction of the core material 12. The connecting surface 13a is in close contact with the end (end face) 12a along its entire length in the thickness direction of the core material 12. The connecting surface 13a is in close contact with the end (end face) 12a along its entire length in the direction along the contour of the core material 12. When viewed from above, the connecting surface 13a is positioned along the contour of the core material 12.

[0033] The connecting surface 13b extends along the main surface of the lower FRP panel 11. The connecting surface 13b connects to the upper surface 11a of the lower FRP panel 11. When viewed from above, the connecting surface 13b is in close contact with the upper surface 11a of the lower FRP panel 11 that extends beyond the core material 12. The connecting surface 13b is parallel to the upper surface 11a of the lower FRP panel 11. The connecting surface 13b is in close contact with the entire surface of the upper surface 11a in the direction along the main surface of the lower FRP panel 11. When viewed from above, the connecting surface 13b has the same length as the upper surface 11a of the lower FRP panel 11 that extends beyond the core material 12 in the radial direction. When viewed from above, the connecting surface 13b may have a different length than the upper surface 11a of the lower FRP panel 11 that extends beyond the core material 12 in the radial direction. When viewed from above, the connecting surface 13b is in close contact with the entire length of the lower FRP panel 11 that extends beyond the core material 12 in the radial direction. The connecting surface 13b is in close contact with the entire length of the lower FRP panel 11 that protrudes from the core material 12 in the circumferential direction when viewed from above.

[0034] The connecting surface 13c extends along the main surface of the upper FRP panel 14. The connecting surface 13c is connected to the lower surface 14a of the upper FRP panel 14. When viewed from above, the connecting surface 13c is in close contact with the lower surface 14a of the upper FRP panel 14 that extends beyond the core material 12. The connecting surface 13c is parallel to the lower surface 14a of the upper FRP panel 14. The connecting surface 13c is in close contact with the entire surface of the lower surface 14a in a direction along the main surface of the upper FRP panel 14. When viewed from above, the connecting surface 13c has the same length as the lower surface 14a of the upper FRP panel 14 that extends beyond the core material 12 in the radial direction. When viewed from above, the connecting surface 13c may have a different length than the lower surface 14a of the upper FRP panel 14 that extends beyond the core material 12 in the radial direction. When viewed from above, the connecting surface 13c is in close contact with the entire length of the upper FRP panel 14 that extends beyond the core material 12 in the radial direction. The connecting surface 13c is in close contact with the entire length of the upper FRP panel 14 that protrudes from the core material 12 in the circumferential direction when viewed from above.

[0035] The connecting surfaces 13b and 13c overlap each other when viewed from above. The connecting surfaces 13b and 13c may have equal lengths in the radial direction of the panel when viewed from above. The connecting surfaces 13b and 13c may have different lengths in the radial direction of the panel when viewed from above. The connecting surfaces 13b and 13c may have equal lengths in the circumferential direction of the panel when viewed from above. The connecting surfaces 13b and 13c may be formed to a thickness smaller than the lower FRP panel 11 and the upper FRP panel 14. The connecting surfaces 13b and 13c may be formed to the same thickness as the lower FRP panel 11 and the upper FRP panel 14. The connecting surfaces 13a, 13b, and 13c may be formed to the same thickness. Alternatively, the connecting surfaces 13a, 13b, and 13c may be formed to different thicknesses.

[0036] According to the FRP sandwich structure 10 of this embodiment, the end can be reinforced by the reinforcing member 13. Therefore, there is no need to laminate fiber cloth to reinforce the end, and the amount of resin used in manufacturing can be reduced. Furthermore, since the panels between the parallel connecting surfaces 13b and the lower FRP panel 11, and the panels between the connecting surface 13c and the upper FRP panel 14 are formed around the entire circumference of the end, when fixing the end of the FRP sandwich structure 10 with bolts or the like in the thickness direction, there is no need to make through holes in the soft core material 12, and there is no need to provide a separate sleeve or the like, thus reducing the number of work steps and making the fixing work easier.

[0037] The FRP sandwich structure 10 can ensure flatness on its surface by having a reinforcing member 13 positioned between the lower FRP panel 11 and the upper FRP panel 14 in the thickness direction. Furthermore, since the reinforcing member 13 is positioned between the lower FRP panel 11 and the upper FRP panel 14 in the thickness direction and is arranged along the contour of the core material 12 in a plan view, even when a compressive load is applied in the thickness direction, there is no need to provide a separate sleeve or the like, and the core material 12 can be prevented from collapsing.

[0038] The manufacturing method of the FRP sandwich structure according to this embodiment will be described below with reference to the drawings.

[0039] Figures 2 to 6 are schematic cross-sectional views showing the steps of the manufacturing method for the FRP sandwich structure in this embodiment. Figure 7 is a flowchart showing the manufacturing method for the FRP sandwich structure in this embodiment. The manufacturing method for the FRP sandwich structure in this embodiment, as shown in Figure 7, includes a preparation step S00, a lower fiber cloth placement step S01, a core material placement step S02, a reinforcing member placement step S03, an upper fiber cloth placement step S04, a film coating step S05, a resin supply and degassing step S06, a curing step S07, and a cutting step S08.

[0040] In preparation step S00, a base plate P1, a lower fiber cloth 11B, a core material 12, a reinforcing member 13, an upper fiber cloth 14B, and a film (vacuum film) P2 are prepared. In preparation step S00, a base plate P1 with an area larger than the FRP sandwich structure 10 to be manufactured is prepared. Also, a core material 12 with a predetermined contour when viewed from above is prepared. A lower fiber cloth 11B and an upper fiber cloth 14B that are larger than the core material 12 when viewed from above are prepared. Reinforcement members 13 in the same number as the number of sides of the core material 12 with a predetermined contour when viewed from above are prepared. A film P2 with an area the same as or larger than the base plate P1 when viewed from above is prepared.

[0041] In the preparation step S00 of this embodiment, a columnar FRP panel is prepared as the reinforcing member 13. This reinforcing member 13 can be a die-cut material. That is, the reinforcing member 13 has at least three surfaces corresponding to the connecting surface 13a, connecting surface 13b, and connecting surface 13c. The reinforcing member 13 can be an FRP panel formed in a columnar shape with a rectangular cross-section. The reinforcing member 13 has a constant cross-sectional shape and dimensions of each part of this cross-sectional shape along its entire length in the direction extending along the columnar axis. In other words, the width dimensions of the connecting surface 13a, connecting surface 13b, and connecting surface 13c of the reinforcing member 13 are all constant along its entire length in the direction extending along the columnar axis in the direction perpendicular to the columnar axis. Furthermore, the thickness dimensions of the connecting surface 13a, connecting surface 13b, and connecting surface 13c of the reinforcing member 13 are all constant along its entire length in the direction extending along the columnar axis. The connecting surface 13a and connecting surface 13b can be perpendicular to each other, and the connecting surface 13a and connecting surface 13c can be perpendicular to each other.

[0042] In the lower fiber cloth placement process S01, as shown in Figure 2, multiple lower fiber cloths 11B are placed on top of each other on a flat surface plate P1. The lower fiber cloths 11B are arranged parallel to the surface of the surface plate P1. The area around the lower fiber cloths 11B is arranged so that the surface of the surface plate P1 is exposed. One lower fiber cloth 11B may be used, but it is preferable to use multiple cloths to achieve sufficient thickness and strength. The material of the base plate P1 is not particularly limited and can be steel, FRP, wood, etc. The lower fiber cloth 11B can be a woven fabric, mat, knit, etc. made of glass fiber, aramid fiber, carbon fiber, etc. The lower fiber cloth 11B is placed on the base plate P1 so as to form the contour of the FRP sandwich structure 10.

[0043] Next, in the core material placement process S02, as shown in Figure 3, the core material 12 is placed on the lower fiber cloth 11B. The main surface of the core material 12 is positioned parallel to the lower fiber cloth 11B. The main surface of the core material 12 is positioned parallel to the surface of the base plate P1. At this time, the core material 12 is placed such that, when viewed from above, the edge of the lower fiber cloth 11B is left over all around, and the center of the lower fiber cloth 11B and the center of the core material 12 coincide. The core material 12 is a panel made of lightweight materials such as balsa wood, polyvinyl chloride foam, or plastic foam such as urethane foam.

[0044] Next, in the reinforcing member placement step S03, as shown in Figure 3, the reinforcing member 13 is placed on the lower fiber cloth 11B so as to be adjacent to the core material 12. At this time, the reinforcing member 13 is positioned along the contour of the core material 12 and in contact with the end portion 12a of the core material 12. The columnar axis of the reinforcing member 13 is positioned along the contour edge of the core material 12 when viewed from above. The reinforcing member 13 is positioned such that its connecting surface 13a contacts the end 12a of the core material 12. The reinforcing member 13 is positioned such that its connecting surface 13b contacts the edge of the lower fiber fabric 11B. The reinforcing member 13 is positioned so that its connecting surface 13b is parallel to the lower fiber fabric 11B. The reinforcing member 13 is placed on the lower fiber fabric 11B at the same height as the core material 12. When viewed from above, the reinforcing member 13 is positioned along the contour of the lower fiber fabric 11B. Furthermore, the columnar reinforcing members 13 may be configured such that the openings at both ends are closed by covers. In addition, at the corners of the core material 12 when viewed from above, of two reinforcing members 13 that are close together and intersect each other, the opening of one reinforcing member 13 can be positioned so that it abuts against the outer surface of the other reinforcing member 13, thereby closing the opening of one of the reinforcing members 13.

[0045] Next, in the upper fiber cloth placement step S04, as shown in Figure 4, the upper fiber cloth 14B is placed on the reinforcing member 13 and the core material 12. The upper fiber cloth 14B is positioned parallel to the main surface of the core material 12. The upper fiber cloth 14B is positioned parallel to the surface of the base plate P1. The upper fiber cloth 14B is positioned so that its top-view contour approximately matches the contour of the lower fiber cloth 11B. Note that even if the lower fiber cloth 11B and the upper fiber cloth 14B are slightly misaligned, this can be corrected in a later process by cutting or other processing. The upper fiber cloth 14B is positioned so that its top-view contour follows the reinforcing member 13. The upper fiber cloth 14B is positioned so that its edge contacts the connecting surface 13c of the reinforcing member 13. The upper fiber cloth 14B is positioned parallel to the connecting surface 13c. The laminated lower fiber cloth 11B, reinforcing member 13 and core material 12, and upper fiber cloth 14B form a laminate.

[0046] Next, in the film coating process S05, as shown in Figure 5, the film (packing film) P2 is placed on the upper fiber cloth 14B. The film P2 covers the laminated lower fiber cloth 11B, reinforcing member 13 and core material 12, and upper fiber cloth 14B. When viewed from above, the contour of the film P2 is larger than that of the upper fiber cloth 14B. When viewed from above, the film P2 extends beyond the upper fiber cloth 14B. The portion of the film P2 that extends beyond the periphery of the upper fiber cloth 14B contacts the exposed surface of the base plate P1. The film P2 then houses the laminated lower fiber cloth 11B, reinforcing member 13 and core material 12, and upper fiber cloth 14B in the internal space formed between it and the base plate P1. Furthermore, in the film coating process S05, a resin supply tube P3 and a degassing tube P4 are inserted into the film P2.

[0047] The resin supply tube P3 is connected to a resin supply mechanism (not shown). The resin supply mechanism can supply a predetermined resin to the interior covered by the film P2 via the resin supply tube P3. Examples of thermosetting resins include vinyl esters, unsaturated polyesters, and epoxy. The degassing tube P4 is connected to a vacuum generating mechanism (not shown). The vacuum generating mechanism can reduce the pressure by evacuating the inside covered by the film P2 through the degassing tube P4 to a predetermined pressure.

[0048] Next, in the resin supply and degassing process S06, the vacuum generation mechanism sucks air from inside the film P2 through the degassing tube P4, reducing the pressure, while the resin supply mechanism supplies thermosetting resin from the resin supply tube P3. As a result, the laminate formed by the lower fiber cloth 11B, reinforcing member 13, core material 12, and upper fiber cloth 14B is impregnated with the thermosetting resin while being subjected to a compressive action. In this case, very little resin penetrates into the interior of the reinforcing member 13.

[0049] In the resin supply and degassing process S06, by supplying thermosetting resin into the film P2, the supplied thermosetting resin moves along the main surface of the core material 12 and diffuses within the film P2, while simultaneously penetrating in the thickness direction of the core material 12. The thermosetting resin permeates the lower fiber cloth 11B and the upper fiber cloth 14B along the main surface of the core material 12, and the thermosetting resin is uniformly distributed across the entire laminate between the film P2 and the base plate P1. Therefore, even if the lower fiber cloth 11B and the upper fiber cloth 14B cover a large area, the thermosetting resin is distributed uniformly without any unevenness in the resin.

[0050] Next, in the curing process S07, the thermosetting resin is impregnated into the entire laminate and then cured. Once curing is complete, the film P2 is removed. As a result, the FRP structure that will become the FRP sandwich structure 10 is molded as a single unit, as shown in Figure 6. The lower FEP panel 11 is formed from the lower fiber cloth 11B. The upper FRP panel 14 is formed from the upper fiber cloth 14B. The lower FEP panel 11, the core material 12 and reinforcing member 13, and the upper FRP panel 14 are molded together as a single unit. In this state, a plate-shaped FRP structure can also be used.

[0051] Next, in cutting step S08, the columnar reinforcing member 13 is cut in the lamination thickness direction along the contour that will form the FRP sandwich structure 10. In cutting step S08, the reinforcing member 13 is cut parallel to the direction along the columnar axis. At this time, the cutting position of the connecting surface 13b is set so that there is no part that connects to the upper surface 11a of the lower FRP panel 11. The cutting position of the connecting surface 13b is set so that there is no part that connects to the upper surface 11a of the lower FRP panel 11. The connecting surface 13a maintains a state of connection with the end (end face) 12a of the core material 12. Furthermore, it is possible to perform cutting on only some of the reinforcing members 13 along the contour edges of the core material 12 as viewed from above, while leaving some of the reinforcing members 13 uncut. It is also possible to perform cutting on all of the reinforcing members 13 along the contour edges of the core material 12 as viewed from above. This completes the manufacturing of the FRP sandwich structure 10, as shown in Figure 1.

[0052] According to this embodiment, by using a foamed core material 12 and a reinforcing member 13 made of FRP extruded material, it is possible to manufacture the structure more easily while reducing weight. By using the reinforcing member 13 made of FRP extruded material at the ends of the FRP sandwich structure 10, the ends can be reinforced. By using the reinforcing member 13 made of FRP extruded material at the ends of the FRP sandwich structure 10, it is possible to avoid forming a lamination that reinforces the ends, which are a weak point in terms of strength.

[0053] By not forming reinforcing layers at the ends of the FRP sandwich structure 10, steps caused by overlapping layers are avoided, and the flatness of the upper and lower surfaces of the FRP sandwich structure can be maintained. When using hollow FRP extruded material as the reinforcing member 13 and forming the sandwich by vacuum impregnation, the amount of resin that penetrates the hollow portion of the reinforcing member 13 can be prevented from increasing resin consumption and preventing damage due to heat generation during curing.

[0054] By using FRP extruded material as the reinforcing member 13, shear deformation of the core material 12 in the FRP sandwich structure 10 can be suppressed, making bending deformation dominant and thus suppressing the overall amount of deformation. By using reinforcing member 13 made of FRP extruded material at the ends of the FRP sandwich structure 10, joining can be easily carried out by clamping with bolts or the like, which was not possible with foamed core materials such as PVC or PET.

[0055] The FRP sandwich structure 10 prevents damage to the end interface between the core material 12 and the FRP panels 11 and 14 without directly joining the ends of the lower FRP panel 11 and the upper FRP panel 14, by placing reinforcing members 13 at the end interface between the core material 12 and the FRP panels 11 and 14 where stress is concentrated.

[0056] Even when fixing the end of the FRP sandwich structure 10 with bolts or the like, there is no need to insert sleeves or the like to prevent the foam core material 12 from being crushed. Since the connection surface 13b of the reinforcing member 13 and the lower FRP panel 11 are made of a single FRP sheet, and the connection surface 13c and the upper FRP panel 14 are also made of a single FRP sheet, tightening with bolts or the like becomes easier.

[0057] Therefore, in the FRP sandwich structure 10, it becomes unnecessary to consider the shape of the fixing part, and the degree of freedom in fixing the end can be improved. Furthermore, when shaping the ends, only the FRP panels 11 and 14 connected to the reinforcing member 13 and its connecting surfaces 13b and 13c need to be cut, thus reducing the amount of material wasted during manufacturing.

[0058] Hereinafter, a second embodiment of the FRP sandwich structure and the method for manufacturing the FRP sandwich structure according to the present invention will be described with reference to the drawings. Figure 8 is a cross-sectional view showing the manufacturing method of the FRP sandwich structure in this embodiment. In this embodiment, the difference from the first embodiment described above is in the reinforcing member 13, and other components corresponding to the first embodiment described above are denoted by the same reference numerals and their descriptions are omitted.

[0059] In this embodiment, in preparation step S00, a reinforcing fiber cloth 13B and a hollow mold 13A are prepared in relation to the reinforcing member 13. The reinforcing fiber cloth 13B is a reinforcing fiber cloth equivalent to the lower fiber cloth 11B and the upper fiber cloth 14B. The hollow mold 13A has an outer shape that corresponds to the hollow portion of the reinforcing member 13 to be molded. The hollow mold 13A only needs to have an outer shape that corresponds to the hollow portion of the reinforcing member 13, and may be filled or hollow inside. It is preferable that the hollow mold 13A is closed at the position corresponding to the end opening of the reinforcing member 13. It is preferable that the hollow mold 13A has a structure that prevents resin from entering the interior.

[0060] In the reinforcing member placement step S03 of this embodiment, as shown in Figure 8, the reinforcing fiber cloth 13B, which is wrapped around the hollow mold 13A, is placed on the lower fiber cloth 11B, corresponding to the reinforcing member 13 which is molded to be adjacent to the core material 12. The reinforcing fiber cloth 13B and the hollow mold 13A are arranged to take on a shape corresponding to the reinforcing member 13 after being impregnated and solidified with resin in the resin supply / degassing step S06 and the curing step S07. Here, the reinforcing fiber cloth 13B is a molded fiber cloth.

[0061] In other words, the reinforcing fiber cloth 13B is arranged on the outer surface of the columnar hollow type 13A so as to correspond to the connecting surfaces 13a, 13b, and 13c. The portion of the reinforcing fiber cloth 13B corresponding to the connecting surface 13a is arranged so as to contact the end 12a along the contour of the core material 12. The portion of the reinforcing fiber cloth 13B corresponding to the connecting surface 13b is arranged so as to contact the lower fiber cloth 11B.

[0062] Furthermore, in the upper fiber cloth placement step S04, as shown in Figure 8, the upper fiber cloth 14B is positioned so that its edge contacts the reinforcing fiber cloth 13B corresponding to the connecting surface 13c of the reinforcing member 13. Furthermore, after the hardening process S07 is completed, the hollow mold 13A is pulled out and removed from the molded reinforcing member 13. The hollow mold 13A may be pulled out before the cutting process S08 or after the cutting process S08 is completed. Furthermore, in the cutting process S08, the reinforcing fiber cloth 13B may not be placed at the position corresponding to the outer surface of the hollow type 13A, which is parallel to and outward from the end face 12a of the core material 12 that is cut. This allows the reinforcing fiber cloth 13B to be placed on three sides of the hollow type 13A. In this case, the amount of fiber cloth used can be reduced.

[0063] In this embodiment, the same effects as those of the above-described embodiment can be achieved. Furthermore, since the same fiber fabric as the lower fiber fabric 11B and upper fiber fabric 14B can be applied to the reinforcing fiber fabric 13B and impregnated with the same resin, in this case, it is possible to integrate it more closely compared to the case in which a reinforcing member 13 composed of different fiber fabrics and different resins is used, thus providing the effect of an even more advantageous configuration in terms of strength.

[0064] Hereinafter, a second embodiment of the FRP sandwich structure and the method for manufacturing the FRP sandwich structure according to the present invention will be described with reference to the drawings. Figure 9 is a cross-sectional view showing the manufacturing method of the FRP sandwich structure in this embodiment. In this embodiment, the only difference from the first and second embodiments described above is the number of core material 12 and reinforcing members 13. Other components corresponding to those in the first and second embodiments described above are denoted by the same reference numerals and their descriptions are omitted.

[0065] In the core material placement step S02 of this embodiment, as shown in Figure 9, multiple core materials 12 are placed spaced apart. Also, in the reinforcing member placement step S03, as shown in Figure 9, multiple reinforcing members 13 are placed parallel to each other. The reinforcing members 13, sandwiched on both sides by the core materials 12, all have their connecting surfaces 13a in contact with the end surfaces 12a of adjacent core materials 12. After the resin is impregnated and solidified in the resin supply / degassing process S06 and the curing process S07, multiple core materials 12 are sandwiched between an upper FRP panel 14 and a lower FRP panel 11 with reinforcing members 13 in between. The reinforcing members 13, sandwiched on both sides by the core materials 12, have their connecting surfaces 13a all connected to the end faces 12a of adjacent core materials 12.

[0066] This makes it possible to manufacture large-area FRP panels by connecting multiple FRP sandwich structures 10 as shown in Figure 1. Furthermore, in the cutting process S08, the reinforcing member 13 sandwiched between the core material 12 is cut along its axis. In the cutting process S08, the reinforcing member 13 sandwiched between the core material 12 is cut along the center position in the width direction at the connecting surface 13b and connecting surface 13c. This makes it possible to manufacture panels with the same structure as the FRP sandwich structure 10 shown in Figure 1 in a single resin supply / degassing process S06 and curing process S07.

[0067] In this embodiment, multiple reinforcing members 13 are installed so as to be in contact with the opposing end faces 12a of the multiple foam core materials 12, and by simply cutting the reinforcing members 13, multiple FRP sandwich structures 10 with protected ends can be formed.

[0068] In this embodiment, the same effects as those of the above-described embodiment can be achieved.

[0069] Furthermore, in the present invention, it is also possible to individually select and combine each of the configurations in the above-described embodiments. [Explanation of Symbols]

[0070] 10…FRP sandwich structure 11…Lower FRP panel 11a…Top surface 11B...Lower fiber cloth 12…Core material (foamed core material) 12a...End (end face) 13…Reinforcement member 13A…Hollow type 13B…Reinforced fiber cloth 14…Upper FRP panel 14a…Bottom surface 14B…Upper fiber cloth 13a, 13b, 13c… connection surfaces P1... Surface plate P2... Film (vacuum film, packing film)

Claims

1. The lower fiber cloth placement process involves placing the lower fiber cloth on a surface plate, A core material placement step in which the core material is placed on the lower fiber cloth, A reinforcing member placement step involves placing a reinforcing member on the lower fiber cloth along the end of the core material, An upper fiber cloth placement step in which the upper fiber cloth is placed on the core material and the reinforcing member, A film covering step in which the lower fiber cloth on the base plate, the core material, the reinforcing member, and the upper fiber cloth are covered with a film, A resin supply and degassing process that degasss the space between the surface plate and the film and supplies resin, It has, The reinforcing member is molded with impregnated resin so that it has three connecting surfaces that are connected to each other along the lower fiber cloth, the end of the core material, and the upper fiber cloth. A method for manufacturing an FRP sandwich structure characterized by the following.

2. The process includes a cutting step in which the reinforcing member is cut along the end of the core material after the resin supply and degassing step. A method for producing an FRP sandwich structure according to claim 1, characterized in that it is the same as described in claim 1.

3. The reinforcing member is a hollow, columnar FRP profile having at least three of the aforementioned connecting surfaces. A method for producing an FRP sandwich structure according to claim 1, characterized in that it is the same as described in claim 1.

4. The reinforcing member is a shaped fiber fabric in which at least three connecting surfaces of fiber fabric are formed along a hollow shape. A method for producing an FRP sandwich structure according to claim 1, characterized in that it is the same as described in claim 1.

5. The core material placement step involves placing a plurality of core materials on the lower fiber fabric with the reinforcing member in between. A method for producing an FRP sandwich structure according to claim 1, characterized in that it is the same as described in claim 1.

6. An FRP sandwich structure in which a plate-shaped core material is sandwiched between FRP panels along both main surfaces of the core material, The aforementioned core material, A reinforcing member along the end of the core material, The FRP panel sandwiching the core material and the reinforcing member, It has, The reinforcing member is an FRP material having three connecting surfaces that are connected along the ends of the FRP panels on both sides and the core material, and that are interconnected with each other. A FRP sandwich structure characterized by the following features.

7. The reinforcing member has a U-shaped cross-section with three connecting surfaces. The FRP sandwich structure according to claim 6.

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