Panel member

Abstract

The purpose of the invention is to provide a highly versatile panel member that can be reduced in weight and improved in mechanical strength, and can be used for various applications.　A panel member (100) comprises: a first skin member (1) and a second skin member (2) that are sheet-like and include a thermoplastic resin; and an intermediate member (3) that includes continuous fibers and is disposed between the first skin member (1) and the second skin member (2). The intermediate member (3) has intermediate forming members (M1, M2, M3). The intermediate forming members (M1, M2, M3) respectively include: first portions (M11, M23, M33) joined to the first skin member (1); second portions (M13, M21, M31, M35) joined to the second skin member (2); and third portions (M12, M22, M24, M32, M34) connecting the first portions (M11, M23, M33) and the second portions (M13, M21, M31, M35).

Description

Panel material

[0001] The present invention relates to a panel member having skin members comprising a thermoplastic resin and an intermediate member comprising continuous fibers.

[0002] Conventionally, panel members have been known in which a low-density intermediate member such as a honeycomb, polymer foam, or corrugated sheet is sandwiched between sheet-like skin members. Such panel members have excellent properties in terms of strength and rigidity. For this reason, such panel members are used in a variety of fields and applications, such as aircraft fuselage parts.

[0003] Panel members having a corrugated intermediate member have superior bending strength compared to panel members having a honeycomb intermediate member. When such panel members contain a thermoplastic resin that can be molded by applying heat, this is advantageous in terms of forming a shape suited to the application. Recently, there have been known panel members in which the mechanical strength is improved by devising a continuous fiber arrangement (see, for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2019-130695

[0005] For panel members having a skin member containing a thermoplastic resin and an intermediate member containing continuous fibers as described above, it is expected that the range of application will be expanded (i.e., versatility will be improved) by simultaneously reducing the weight and improving the mechanical strength. Therefore, the inventors of the present invention have focused on a configuration that can achieve these two goals simultaneously through intensive research.

[0006] Panel members can be used in a variety of applications, and are expected to offer both weight reduction and improved mechanical strength. However, achieving both weight reduction and improved mechanical strength is not always easy. For example, reducing the area occupied by the intermediate member in a panel member can reduce the weight of the panel member. However, this can easily result in a decrease in the strength of the panel member. For example, depending on the application of the panel member, loads may not be applied uniformly, and the required strength may vary from part to part. Furthermore, if the panel member is not placed on a flat surface or the panel member itself does not have a flat shape, loads may not be applied evenly to each part of the panel member. Considering the various environments in which panel members are used, localized mechanical strength deficiencies may occur. On the other hand, attempting to compensate for this deficiency by uniformly increasing the thickness or other strength enhancements may hinder weight reduction. Therefore, simply having a uniform shape or homogeneous configuration of panel members leaves room for improvement in various practical applications.

[0007] The present invention has been made in consideration of these points, and aims to provide a highly versatile panel member that can be made lighter and has improved mechanical strength, and that can be used for a variety of purposes.

[0008] The panel member disclosed herein includes first and second skin members each having a sheet shape and containing a thermoplastic resin, and an intermediate member containing continuous fibers and disposed between the first and second skin members. The first skin member has a plurality of first bonded portions joined to the intermediate member and a plurality of first non-bonded portions not joined to the intermediate member. The second skin member has a plurality of second bonded portions joined to the intermediate member and a plurality of second non-bonded portions not joined to the intermediate member. The first bonded portions and the first non-bonded portions are alternately arranged along a first direction. The second bonded portions and the second non-bonded portions are alternately arranged along the first direction. The intermediate member includes a plurality of intermediate forming members. Each of the plurality of intermediate forming members includes a first portion joined to at least a portion of the first joint portion of the first skin member, a second portion joined to at least a portion of the second joint portion of the second skin member, and a third portion connecting the first portion and the second portion and not joined to the first joint portion or the second joint portion.

[0009] The panel member has a sandwich structure with a corrugated intermediate member, which allows it to achieve lightweight and sufficient compressive strength. Furthermore, since the intermediate member has multiple intermediate forming members, appropriate selection of the intermediate forming members allows for a configuration suited to the product to which it is applied. This results in high versatility. For example, when the panel member is used as a compound curvature surface member (a member having a curved surface with multiple curvatures), the desired strength can be achieved by arranging the intermediate forming members in a position and orientation that matches the overall shape of the compound curvature surface member. Therefore, while maintaining the expected lightweight and compressive strength, the panel member can be effectively applied to products of various shapes.

[0010] At least one of the plurality of intermediate forming members may have a first intermediate forming portion formed by a first number of layers of the continuous fibers and a second intermediate forming portion formed by a second number of layers of the continuous fibers, the first number being greater than the second number. With such a panel member, since the first number is greater than the second number, the first intermediate forming portion has greater strength than the second intermediate forming portion. Strength can be increased in areas requiring locally high strength without increasing the weight of other areas. At least one of the intermediate forming members may have three or more portions with different numbers of layers of continuous fibers.

[0011] The first bonded portion, the first non-bonded portion, the second bonded portion, and the second non-bonded portion may extend in a second direction different from the first direction. The first intermediate formation portion and the second intermediate formation portion may be aligned in the first direction or the second direction.

[0012] The first skin member and / or the second skin member may have a first skin forming portion formed by a third number of layers of continuous fibers and a second skin forming portion formed by a fourth number of layers of continuous fibers, the third number being greater than the fourth number. This allows the strength of the first skin member and / or the second skin member in a portion requiring locally high strength to be higher than the strength of the other portions. Note that the first skin member and / or the second skin member may have three or more portions with different numbers of layers of continuous fibers.

[0013] The first bonded portion, the first non-bonded portion, the second bonded portion, and the second non-bonded portion may extend in a second direction different from the first direction. The first skin forming portion and the second skin forming portion may be aligned in the first direction or the second direction.

[0014] In this way, by varying the number of layers in each direction, a panel member can be realized that has the necessary strength for each part, depending on the shape and use of the product. For example, unlike panel members that have a uniform thickness and strength, sufficient strength can be obtained by increasing the number of continuous fiber layers in parts that require strength, and the effect of weight reduction can be achieved by decreasing the number of continuous fiber layers in parts that require fewer layers. This makes it possible to create a panel member that can flexibly provide strength suitable for practical use and also achieve weight reduction.

[0015] The first joint portion, the first non-joint portion, the second joint portion, and the second non-joint portion may extend in a second direction different from the first direction. The panel member may include a cover member attached to ends of the first skin member, the second skin member, and the intermediate member in the second direction or the opposite direction to the second direction, and covering an area defined by the first skin member, the second skin member, and the intermediate member. The cover member may have a plurality of fixing surfaces fixed to at least two of the first skin member, the second skin member, and the intermediate member. In this way, by providing the plurality of fixing surfaces of the cover member, peeling of the intermediate member and the like can be effectively suppressed. As a result, the quality of the panel member can be maintained for a long period of time.

[0016] At least one of the intermediate forming members may have a hat-shaped cross section. At least one of the intermediate forming members may have a substantially Z-shaped, substantially C-shaped, or substantially U-shaped cross section.

[0017] At least one of the first skin member and the second skin member may be a compound curvature surface member. A plurality of intermediate forming members may be arranged to fit the shape of the first skin member and / or the second skin member, which are compound curvature surface members.

[0018] According to the present invention, it is possible to provide a panel member that is lightweight and has improved mechanical strength, and is highly versatile and can be used for a variety of purposes.

[0019] FIG. 1( a) is a perspective view of a panel member according to a first embodiment, and FIG. 1( b) is a cross-sectional view of the panel member as viewed in the X1-X1 direction in FIG. 1( a). FIG. 2 is an exploded cross-sectional view of the panel member according to the first embodiment. FIG. 3 is a perspective view showing the longitudinal direction of the continuous fibers in the outermost layer of a portion of the panel member according to the first embodiment. FIG. 4 is a schematic plan view showing each section of the panel member according to the first embodiment. FIG. 5 is a cross-sectional view of a different example of the panel member according to the first embodiment. FIG. 6( a) is a schematic view showing the arrangement of a panel member according to a second embodiment, FIG. 6( b) is a rear view of the panel member, FIG. 6( c) is a cross-sectional view taken along line P1-P1 in FIG. 6( b), and FIG. 6( d) is a cross-sectional view taken along line P2-P2 in FIG. 6( b). Figure 7(a) is a perspective view of a panel member according to the third embodiment, Figure 7(b) is a side view of the same panel member, Figure 7(c) is a cross-sectional view taken along line P3-P3 in Figure 7(b), and Figure 7(d) is a cross-sectional view taken along line P4-P4 in Figure 7(b).

[0020] Hereinafter, an embodiment of a panel member will be described with reference to the drawings. FIG. 1( a) is a schematic perspective view of a panel member 100 according to a first embodiment. The panel member 100 according to this embodiment constitutes part of an aircraft wing. X, Y, and Z in the figure represent three mutually orthogonal directions. In the following description, the Y direction may be referred to as rearward, and the direction opposite the Y direction as forward. Furthermore, the Z direction may be referred to as upward, and the direction opposite the Z direction as downward.

[0021] The panel member 100 includes a first skin member 1, a second skin member 2, and an intermediate member 3 disposed between the first skin member 1 and the second skin member 2. The first skin member 1 and the second skin member 2 are sheet-like members containing thermoplastic resin. The first skin member 1 and the second skin member 2 are spaced apart from each other in the Z direction. The intermediate member 3 contains continuous fibers.

[0022] The length L1 of the end of the panel member 100 opposite the X direction is greater than the length L2 of the end in the X direction. Note that the lengths L1 and L2 referred to here are lengths in the Y direction. The first skin member 1 and the second skin member 2 have main surfaces extending in the X direction and the Y direction. The main surfaces of the first skin member 1 and the second skin member 2 are curved and have multiple curvatures. The curvatures of the main surfaces of the first skin member 1 and the second skin member 2 vary from part to part. The upper main surface (first skin member 1) and the lower main surface (second skin member 2) of the panel member 100 are compound curvature surface members with curvature anisotropy.

[0023] As shown in FIG. 1( b), the intermediate member 3 has a corrugated shape that fits the compound curvature surfaces of the first skin member 1 and the second skin member 2. The intermediate member 3 extends in the X direction. The first skin member 1, the second skin member 2, and the intermediate member 3 form a sandwich structure in which the intermediate member 3 serves as the core member. The first skin member 1, the second skin member 2, and the intermediate member 3 have a highly durable structure against stress changes that occur on the main surfaces of the first skin member 1 and the second skin member 2.

[0024] The distance between the first skin member 1 and the second skin member 2 decreases toward the front and decreases toward the rear. A solid (e.g., solid rod-shaped) trailing edge member 4 is provided at the rear end of the panel member 100. A spar member 5 is provided at the front end of the panel member 100. The trailing edge member 4 and the spar member 5 extend in the X direction. Note that in this specification, extending in the X direction, Y direction, and Z direction does not only mean extending in a direction that strictly coincides with the X direction, Y direction, and Z direction, respectively, but also includes extending in a direction slightly inclined from those directions. The spar member 5 has a substantially C-shaped cross section. These members 1, 2, 3, 4, and 5 are welded to each other at their contact portions.

[0025] As shown in FIG. 1( a), a plurality of cover members 6 are provided at the end of the panel member 100 opposite the X direction. The cover members 6 support the first skin member 1, the second skin member 2, the intermediate member 3, the trailing edge member 4, and the spar member 5. The cover members 6 also divide the panel member 100 into an inner region and an outer region. The rearmost cover member 6 is a filler member 6a that covers the region S1 (see FIG. 1( b)) surrounded by the trailing edge member 4, the intermediate member 3, and the second skin member 2. Like the other cover members 6, this filler member 6a has a supporting function for the panel member 100.

[0026] As shown in FIG. 1B , the first skin member 1 is used as the upper skin member of the panel member 100. The first skin member 1 is a carbon fiber reinforced composite material made of a thermoplastic resin (e.g., polyphenylene sulfide or ketone-based resin) containing carbon fiber (e.g., PAN-based carbon fiber). The second skin member 2 is also a carbon fiber reinforced composite material made of a thermoplastic resin containing carbon fiber. The intermediate member 3 has a corrugated structure with multiple projections and depressions arranged in the Y direction. Like the first skin member 1 and the second skin member 2, the intermediate member 3 is a carbon fiber reinforced composite material made of a thermoplastic resin containing carbon fiber. Because the panel member 100 according to this embodiment is formed from the above composite material, it is lightweight and has excellent strength and rigidity. Furthermore, the panel member 100 contains carbon fiber, which gives it excellent flame retardancy.

[0027] The first skin member 1 has joint portions C11, C12, and C13 that are joined to the intermediate member 3, and non-joined portions NC11, NC12, and NC13 that are not joined to the intermediate member 3. The intermediate member 3 is fixed to the joint portions C11, C12, and C13 by welding. The non-joined portions NC11, NC12, and NC13 are spaced apart from the intermediate member 3. The joint portions C11, C12, and C13 and the non-joined portions NC11, NC12, and NC13 are arranged alternately and continuously with each other along the curved main surface of the first skin member 1. The joint portions C11, C12, and C13 and the non-joined portions NC11, NC12, and NC13 are arranged side by side in the Y direction. The bonded portions C11, C12, and C13 and the non-bonded portions NC11, NC12, and NC13 all extend in the X direction (see FIG. 1A). The thickness of the first skin member 1 is not uniform but varies partially in both the juxtaposition direction (Y direction) and the extension direction (X direction). Although not particularly limited, the thickness of the first skin member 1 here is approximately 0.4 to 2.2 mm.

[0028] The second skin member 2 has non-bonded portions NC21, NC22, and NC23 that are not bonded to the intermediate member 3, and bonded portions C21, C22, and C23 that are bonded to the intermediate member 3. The intermediate member 3 is fixed to the bonded portions C21, C22, and C23 by welding. The non-bonded portions NC21, NC22, and NC23 are spaced apart from the intermediate member 3. The bonded portions C21, C22, and C23 and the non-bonded portions NC21, NC22, and NC23 are arranged alternately and continuously along the curved main surface of the second skin member 2. The bonded portions C21, C22, and C23 and the non-bonded portions NC21, NC22, and NC23 are arranged side by side in the Y direction. The bonded portions C21, C22, and C23 and the non-bonded portions NC21, NC22, and NC23 all extend in the X direction. The thickness of the second skin member 2 is not uniform but varies partially in both the juxtaposition direction and the extension direction. Although not particularly limited, the thickness of the second skin member 2 is approximately 0.4 to 2.2 mm.

[0029] The intermediate member 3 includes a plurality of separate members (hereinafter referred to as intermediate members). In this embodiment, the intermediate member 3 includes three intermediate members M1, M2, and M3. The intermediate members M1, M2, and M3 are separately molded members and have different shapes. As shown in FIG. 1( b), the intermediate members M1, M2, and M3 have lengths LM1, LM2, and LM3, respectively, along the main surface of the second skin member 2. Each of the intermediate members M1, M2, and M3 has a portion that contacts the first skin member 1 and a portion that contacts the second skin member 2. For example, the rearmost intermediate forming member M1 includes a portion M1a (first skin contact surface portion) that contacts the joining portion C11 of the first skin member 1, a portion M1c (second skin contact surface portion) that contacts the joining portion C21 of the second skin member 2, and a portion M1b (inclined surface portion) that connects these two portions M1a and M1c and is not joined to the joining portions C11 and C21. The portion M1b is inclined with respect to the Y direction and the Z direction.

[0030] As shown in FIG. 1B, the area surrounded by the first skin member 1, the second skin member 2, the trailing edge member 4, and the spar member 5 is divided into six areas S1, S2, S3, S4, S5, and S6 by three intermediate forming members M1, M2, and M3. The cover member 6 (see FIG. 1A) includes a first cover member 6a, a second cover member 6b, a third cover member 6c, a fourth cover member 6d, a fifth cover member 6e, and a sixth cover member 6f, which cover these areas S1 to S6, respectively. The sixth cover member 6f is provided in the forwardmost area S6. The sixth cover member 6f has an upright surface portion whose principal surface is the YZ plane and four fixed surface portions bent from the upright surface portion toward the front side of FIG. 1B (in the direction opposite to the X direction). The upright surface portion has a shape that is substantially the same as the shape of area S6 shown in FIG. 1B. Each of the four fixing surfaces faces and contacts the non-joint portion NC13 of the first skin member 1, the inclined surface portion M34 of the intermediate member M3, the joint portion C23 of the second skin member 2, and the upright surface portion 53 of the spar member 5. These four fixing surfaces are fixed to the corresponding portions by welding or via fasteners. The sixth cover member 6f covers the region S6 by being fixed to multiple different portions in this manner. By providing the six cover members (the first to sixth cover members 6a to 6f) for the six regions S1 to S6, peeling of the components of the panel member 100 (the first skin member 1, the second skin member 2, and the intermediate member 3) can be prevented. In the panel member 100 according to this embodiment, as described above, the filler member 6a is used as the first cover member. However, depending on the size and shape of the above-mentioned region, the first cover member 6a may have a configuration similar to at least one of the other cover members 6b to 6f.

[0031] As described above, the panel member 100 according to this embodiment has a compound curvature surface member, and the lengths L1, L2 of the ends in the X direction and the opposite direction are different from each other. Therefore, the strength required of the panel member 100 varies from part to part. In this embodiment, the intermediate forming members M1 to M3 are provided as shown in the schematic cross-sectional view of Figure 2 so as to fit the shape of the panel member 100.

[0032] As described above, the first intermediate forming member M1 has a first upper surface portion M11 that contacts the joint portion C11, a first lower surface portion M13 that contacts the joint portion C21, and a first inclined surface portion M12 that connects the first upper surface portion M11 and the first lower surface portion M13. The first intermediate forming member M1 has a substantially Z-shaped cross section. The first upper surface portion M11 is welded to the first skin member 1, and the first lower surface portion M13 is welded to the second skin member 2. In addition, the rear ends of the first skin member 1, the second skin member 2, and the first intermediate forming member M1 are welded to the trailing edge member 4.

[0033] The second intermediate forming member M2 has a second rear lower surface portion M21 in contact with the joint portion C21, a second upper surface portion M23 in contact with the joint portion C12, a second front lower surface portion M25 in contact with the joint portion C22, a second rear inclined surface portion M22 connecting the second rear lower surface portion M21 and the second upper surface portion M23, and a second front inclined surface portion M24 connecting the second upper surface portion M23 and the second front lower surface portion M25. In this embodiment, the second rear lower surface portion M21 is spaced from the first lower surface portion M13, and a gap is formed between the second rear lower surface portion M21 and the first lower surface portion M13. The second intermediate forming member M2 has a hat-shaped cross-sectional shape. The second rear lower surface portion M21 and the second front lower surface portion M25 are welded to the second skin member 2, and the second upper surface portion M23 is welded to the first skin member 1.

[0034] The third intermediate forming member M3 has a third rear lower surface portion M31 in contact with the joint portion C22, a third upper surface portion M33 in contact with the joint portion C13, a third front lower surface portion M35 in contact with the joint portion C23, a third rear inclined surface portion M32 connecting the third rear lower surface portion M31 and the third upper surface portion M33, and a third front inclined surface portion M34 connecting the third upper surface portion M33 and the third front lower surface portion M35. In this embodiment, the third rear lower surface portion M31 is spaced from the second front lower surface portion M25, and a gap is formed between the third rear lower surface portion M31 and the second front lower surface portion M25. The third intermediate forming member M3 has a hat-shaped cross-sectional shape. The third rear lower surface portion M31 and the third front lower surface portion M35 are welded to the second skin member 2, and the third upper surface portion M33 is welded to the first skin member 1. A spar member 5 is interposed between the third front lower surface portion M35 and the first skin member 1. The first skin member 1, the second skin member 2, and the third intermediate forming member M3 are supported by the spar member 5.

[0035] In the panel member 100 having a compound curvature surface member as in this embodiment, the intermediate member 3 has portions that contact the first skin member 1 and the second skin member 2 (i.e., upper and lower surfaces) and a bridging portion (i.e., an inclined surface portion) that connects these portions. This allows the panel member 100 to have the desired strength against compressive loads. Furthermore, by combining multiple intermediate forming members M1, M2, and M3, the panel member 100 can be formed into a desired shape and obtain strength that matches its overall shape. In this embodiment, the intermediate forming member M1 has a generally Z-shaped cross-section, and the intermediate forming members M2 and M3 have hat-shaped cross-sections. However, the combination of the cross-sectional shapes of the intermediate forming members M1 to M3 can be changed as appropriate, and it is also possible to use only one of the shapes. Naturally, the intermediate forming members M1 to M3 may have other cross-sectional shapes (e.g., a generally C-shaped or U-shaped cross-section) as long as the same effect is achieved. Furthermore, the number of intermediate forming members can be changed as appropriate to match the overall shape of the panel member 100. For example, instead of a configuration in which multiple intermediate forming members having a hat-shaped cross-sectional shape are spaced apart from each other, a configuration in which multiple intermediate forming members are arranged continuously without gaps to match the overall shape of the panel member 100 is also possible.

[0036] Next, the orientation of the carbon fibers (continuous fibers) in the panel member 100 will be described with reference to Fig. 3. Here, the third intermediate forming member M3 will be described as a representative example. Fig. 3 is an exploded perspective view of the first skin member 1, the third intermediate forming member M3, and the second skin member 2.

[0037] The first skin member 1 has multiple layers stacked in the Z direction. Each layer of the first skin member 1 contains carbon fibers 11. As shown in FIG. 3, the top layer of the first skin member 1 contains multiple carbon fibers 11 extending in the Y direction. The curvature of each portion of the first skin member 1 varies. The number of layers of the first skin member 1 varies depending on the portion so that the first skin member 1 has a desired shape that matches the overall shape of the panel member 100. For example, in the range shown in FIG. 3, the portion that becomes the non-bonded portion NC13 (see FIG. 1(b)) has 12 layers. In the stacked multiple layers, the carbon fibers 11 are oriented in a pattern such as 45 degrees, 0 degrees, −45 degrees, 90 degrees, 90 degrees, −45 degrees, 0 degrees, and 45 degrees. The first skin member 1 has multiple layers stacked quasi-isotropically. Furthermore, the portion that becomes the bonded portion C13 has six layers. Similarly, in these six layers, the carbon fibers 11 are appropriately oriented to form a quasi-isotropic lamination. The non-bonded portion NC12 has nine layers. In these layers, the carbon fibers 11 are also oriented to form a quasi-isotropic lamination. The longitudinal direction of the carbon fibers 11 in the top layer of the first skin member 1 is at a 45-degree angle. In this embodiment, the content of carbon fibers 11 in the first skin member 1 is 60% by mass, but this can be changed as appropriate between 40 and 70% by mass, with 55 to 70% by mass being particularly preferred. The orientation of the carbon fibers 11 in multiple layers may be in combinations other than those described above. Furthermore, even when the above-described angle combinations are used, the lamination order may be different from that described above.

[0038] The second skin member 2 has multiple layers stacked in the Z direction. Each layer of the second skin member 2 contains carbon fibers 12. As with the first skin member 1, the number of layers of the second skin member 2 varies from one portion to another. For example, in the area shown in FIG. 3 , the portion that will become the joining portion C23 has eight layers. In these layers, the carbon fibers 12 are oriented at angles of 45 degrees, 0 degrees, −45 degrees, 90 degrees, 90 degrees, −45 degrees, 0 degrees, and 45 degrees. The second skin member 2 has multiple layers stacked quasi-isotropically. The portion that will become the non-joining portion NC23 has 12 layers. In these layers, the carbon fibers 12 are also oriented to form a quasi-isotropic stack. The portion that will become the joining portion C22 has four layers, and the carbon fibers 12 are oriented in the same way in these layers. The longitudinal direction of the carbon fibers 12 in the bottom layer of the second skin member 2 is 45 degrees. The content of carbon fibers 12 in the second skin member 2 is 60% by mass, but can be changed as appropriate within the range of 40 to 70% by mass, with 55 to 70% by mass being particularly preferred. The orientation of the carbon fibers 12 in the multiple layers may be a combination other than the above-mentioned angles. Even with the above-mentioned angle combinations, the lamination order may be different from that described above.

[0039] The top layer of the intermediate member 3 includes multiple carbon fibers 13 extending in the Y direction. Similar to the first skin member 1 and the second skin member 2, the number of layers in the intermediate member 3 varies from portion to portion. For example, in the range illustrated in FIG. 3 , the third rear lower surface portion M31 of the third intermediate forming member M3 has four layers, the third rear inclined surface portion M32 has eight layers, the third upper surface portion M33 has four layers, the third front inclined surface portion M34 has eight layers, and the third front lower surface portion M35 has four layers. In all of the surface portions M31 to M35, the longitudinal direction of the carbon fibers 13 in the top layer is at a 45-degree angle. In all of the surface portions M31 to M35, multiple layers are quasi-isotropically laminated. The intermediate member 3 according to this embodiment includes multiple hat-shaped members and Z-shaped members each having multiple quasi-isotropically laminated layers. This allows the panel member 100 to exhibit high strength against external compression. In particular, aircraft wings require favorable performance against compressive stress, bending stress, shear stress, and tensile stress not only in one direction but also in multiple directions. The intermediate member 3 according to this embodiment is suitable in that it provides favorable performance in these areas. The content of carbon fiber 13 in the intermediate member 3 is 60% by mass, but can be changed as appropriate within the range of 40 to 70% by mass, with 55 to 70% by mass being particularly preferred. As with the first skin member 1 and the second skin member 2, the orientation of the carbon fibers 13 in the multiple layers of the intermediate member 3 may be a combination other than the angles described above. Furthermore, even with the combination of angles described above, the layering order may be different from the layering order described above.

[0040] As described above, the first skin member 1, the second skin member 2, and the intermediate member 3 each have a plurality of layers, with the number of layers varying from section to section. The first skin member 1, the second skin member 2, and the intermediate member 3 can be formed by producing a desired number of laminates of carbon fibers 11, 12, and 13 for each section and impregnating the spaces formed between the carbon fibers 11, 12, and 13 with a thermoplastic resin.

[0041] To produce the first skin member 1 and the second skin member 2, substrates with different numbers of layers of carbon fiber 11, 12 are prepared, and sheet materials are formed by impregnating the substrates with thermoplastic resin. The sheet materials are then shaped as needed. To produce the intermediate forming members M1, M2, and M3 of the intermediate member 3, substrates with different numbers of layers of carbon fiber 13 are prepared, and sheet materials are formed by impregnating the substrates with thermoplastic resin. The sheet materials are then shaped into the above-mentioned shapes using a press.

[0042] The impregnated thermoplastic resin facilitates bonding between the skin member 1 and the intermediate member 3, and between the skin member 2 and the intermediate member 3. A mold suitable for the desired shape of the panel member 100 is placed on the upper side of the first skin member 1 and the lower side of the second skin member 2, and a pressing process is performed using this mold. During this pressing process, the mold is also heated and cooled. For the intermediate member 3, abutting members (cores) suitable for the shapes of the respective regions S1 to S6 (see FIG. 1(b)) are placed in the regions S1 to S6, respectively, and the above-mentioned joining process is performed. In particular, in this embodiment, the intermediate forming members M1, M2, and M3 each have a different shape. Furthermore, each portion of each intermediate forming member M1, M2, and M3 has a different shape, number of layers, and thickness. Therefore, multiple abutting members suitable for each portion are placed. Furthermore, the abutting members are individually removed.

[0043] As shown in the plan view of Figure 4, the first skin member 1 has multiple divided portions, such as portions S11, S12, S13, ..., S31, S32, S33, ..., S61, S62, S63, ..., and each portion has a desired number of layers. The first skin member 1 has at least two portions with different numbers of layers in the direction (X direction) in which the bonded portions C11, C12, C13 and the non-bonded portions NC11, NC12, NC13 are arranged side by side. The first skin member 1 also has at least two portions with different numbers of layers in the direction (Y direction) in which the bonded portions C11, C12, C13 and the non-bonded portions NC11, NC12, NC13 extend. The number of layers in a given portion of the first skin member 1 is greater than the number of layers in another given portion. Although not shown, the second skin member 2 and the intermediate member 3 also have at least two or more sections with different numbers of layers in the juxtaposition direction and / or the extension direction, but the number and size of the sections of the second skin member 2 and the intermediate member 3 differ from those of the first skin member 1.

[0044] The carbon fibers 11, 12, and 13 are continuous fibers (long fibers) extending in one direction. For example, when continuous fibers are included in a panel member with a constant surface curvature or in a panel member with end lengths that are the same, the crossing angles between the carbon fibers are constant from portion to portion. On the other hand, the panel member 100 according to this embodiment is anisotropic, and the end lengths L1 and L2 are different from one another (see FIG. 1(a)). Therefore, the crossing angles between the carbon fibers are not uniform and vary from portion to portion. However, the intermediate member 3 includes multiple intermediate forming members M1, M2, and M3. The orientation and position of the intermediate forming members M1, M2, and M3 can be flexibly set, thereby minimizing the effects of differences in the crossing angles. Specifically, the variation in the crossing angles between portions can be made substantially uniform. Differences in the crossing angles due to factors such as differences in surface curvature can be reduced. Alternatively, the intermediate forming members M1, M2, and M3 can be set in different states so that the difference in crossing angle is a predetermined amount according to the desired shape and strength of the panel member 100. In other words, the intermediate forming members M1, M2, and M3 can be positioned according to the desired strength and required panel shape. The posture and position of each intermediate forming member M1, M2, and M3 can be adjusted as appropriate.

[0045] Furthermore, because the intermediate forming members M1, M2, and M3 are individually positioned, their shapes, sizes, and number of layers can be individually set. It is easy to appropriately vary the number of layers in the extension direction of the intermediate forming members M1, M2, and M3. As shown in FIG. 4 , by setting the number of layers of each of the first skin member 1, the second skin member 2, and the intermediate member 3 to the appropriate number, the panel member 100 including the compound curvature surface member can be formed into a desired shape and can achieve the desired strength. Furthermore, its variations can be diversified (generalized). The desired strength is set depending on the compatibility with the curvature of the compound curvature surface member and the compatibility based on the connection structure with the main wing section.

[0046] Figure 5 shows different examples of intermediate forming members. As shown in Figure 5, the intermediate member 3 may include intermediate forming members M10, M20, and M30 that are butted against each other. The intermediate forming members M10 and M20 are in contact with each other, and the intermediate forming members M20 and 30 are in contact with each other. Although not shown, the intermediate member 3 may include intermediate forming members that are butted against each other and intermediate forming members that are spaced apart from each other (see Figure 1(a)). By skillfully combining multiple intermediate forming members, it is possible to realize a suitable panel member 100 that meets the requirements of various uses and shapes.

[0047] The panel member 100 according to this embodiment has high durability against out-of-plane compression. When a pressure load is applied to the first skin member 1 from above, the panel member 100 is compressed in its thickness direction (Z direction). In this case, the continuous carbon fibers 11 are oriented as described above, thereby achieving high durability. Furthermore, compressive loads are applied to the first skin member 1 from various directions. Supporting the first skin member 1 by the intermediate member 3 having a quasi-isotropic laminated structure significantly enhances durability. Furthermore, various concentrated stresses may occur in the corners of the intermediate member 3 (e.g., portions R1 and R2, which transition from a portion joined to the first skin member 1 to a portion not joined to the first skin member 1, as shown in FIG. 1( b) ) in response to pressure loads from various directions. However, the quasi-isotropic laminated structure described above effectively counteracts these concentrated stresses. As a result, the shape of the first skin member 1 is stably maintained for a long period of time. Furthermore, the overall shape of the panel member 100 is well maintained. Therefore, the strength against the out-of-plane compression described above is improved. The laminated layers contain carbon fibers 11, 12, and 13 oriented at 45 degrees. This improves the strength against shear forces within the panel surface. The panel member 100 also exhibits the same effect when a pressure load is applied to the second skin member 2 from below. The arrangement direction of the panel member 100 can be changed as appropriate. The panel member 100 can be effectively applied to specifications and applications in which a pressure load is applied to the first skin member 1 and / or in which a pressure load is applied to the second skin member 2. In other words, the panel member 100 according to this embodiment is a highly versatile panel member.

[0048] The shapes of the intermediate forming members M1, M2, and M3 also contribute to improving strength against out-of-plane compression. For example, each of the intermediate forming members M1, M2, and M3 has at least a portion (upper surface) that joins to the first skin member 1, a portion (lower surface) that joins to the second skin member 2, and a portion (inclined surface) that connects the two portions. These three portions are integrally molded. Therefore, the intermediate forming members M1, M2, and M3 can easily change shape in response to pressure loads. The intermediate forming members M1, M2, and M3 can exhibit high durability when subjected to the above-mentioned pressure loads. In particular, the durability is improved because these three portions contain the same continuous carbon fiber 13.

[0049] The panel member 100 includes a corrugated intermediate member 3, which provides high compressive strength during flight and minimal deterioration over time. The panel member 100 allows for flexible configuration of the thicknesses of the first skin member 1, the second skin member 2, and the intermediate member 3, depending on the combination of these members. The panel member 100 as a whole allows for optimal combinations of the members 1, 2, and 3. When used as an aileron connected to a main wing, the panel member 100 can be adapted to ensure a predetermined strength for the connecting member. In this embodiment, the first skin member 1, the second skin member 2, and the intermediate member 3 all have the above-described quasi-isotropic layered structure, enabling a synergistic effect based on their respective characteristics. This synergistic effect is further enhanced by the panel member 100 having a compound curvature surface member, which is preferable. However, depending on various design conditions, only one of the first skin member 1, the second skin member 2, and the intermediate member 3 may have a quasi-isotropic layered structure. These features and effects are significant differences compared to panel members having a uniform thickness or panel members with a single curvature surface. The panel member 100 offers greater design freedom and improved versatility.

[0050] Furthermore, the panel member 100 can ensure smoothness of its outer surface because the intermediate member 3 is welded to the first skin member 1 and the second skin member 2. Furthermore, the panel member 100 has high durability against out-of-plane compression, so the smoothness can be maintained for a long period of time. Furthermore, the provision of the cover member 6 improves the peel strength of the panel member 100 assembled by welding.

[0051] The configurations and shapes are not limited to those described above, and similar effects can be achieved with other configurations and shapes. For example, in the above embodiment, the shapes of the intermediate forming members M1, M2, and M3 are all different, but they may all be the same shape if the desired shape, strength, durability, etc. for the panel member 100 can be achieved. Also, only some of the multiple intermediate forming members may have the same shape. Another embodiment will be described using Figure 6. The following description will mainly focus on differences from the above embodiment.

[0052] 6A is a schematic diagram showing a panel member 200 according to a second embodiment. The panel member 200 is used in a pressure bulkhead provided at the rear of an aircraft. The panel member 200 has a dome-shaped surface containing a thermoplastic resin.

[0053] 6(b) is a rear view of the panel member 200. The panel member 200 has a first skin member 201 that forms the outer surface, a second skin member 202 that forms the inner surface, and an intermediate member 203 that is interposed between the first and second skin members and contains continuous fibers. The first skin member 201 and the second skin member 202 have curved main surfaces with multiple curvatures. A plurality of intermediate members 203 are provided along the main surfaces.

[0054] In this embodiment, the intermediate member 203 has seven intermediate forming members 2031, 2032, 2033, 2034, 2035, 2036, and 2037 arranged radially (see FIG. 6(b)). The first intermediate forming member 2031 is the longest member. The second intermediate forming member 2032 and the third intermediate forming member 2033 are provided so as to intersect with the first intermediate forming member 2031. The fourth intermediate forming member 2034 to the seventh intermediate forming member 2037 are provided between the first intermediate forming member 2031 and the second intermediate forming member 2032, and between the first intermediate forming member 2031 and the third intermediate forming member 2033. As can be seen from FIGS. 6(c) and 6(d), each of the intermediate forming members 2031 to 2037 has a hat-shaped cross section.

[0055] The panel member disclosed in this specification is suitable for use as a compound curvature surface member. The panel member 200 is used in pressure bulkheads and helps to maintain stable air pressure inside an aircraft. In particular, the panel member 200 has high durability against out-of-plane pressure, making it suitable as a member that can suppress deterioration over time and maintain stable performance over a long period of time.

[0056] As described above, the panel members 100, 200 according to the first and second embodiments have been described. The type of thermoplastic resin contained in the first skin member 1, 201 and the second skin member 2, 202 is not particularly limited, and polyphenylene sulfide, ketone resin, or other resins may be used. Materials with high melting points are primarily used as the thermoplastic resin. Materials with high melting points are advantageous in terms of forming high-strength resins. However, the thermoplastic resin is not limited to these materials, and other materials may also be used. The same type of thermoplastic resin may also be used for the intermediate member 3, 203.

[0057] Examples of carbon fibers that can be used include PAN-based carbon fibers and pitch-based carbon fibers. However, the carbon fibers are not limited to the above, and continuous fibers such as glass fibers (e.g., E-glass fibers) can also be used. The longitudinal direction of these continuous fibers may coincide with the X direction or the Y direction. Note that "coinciding with the X direction" and "coinciding with the Y direction" does not only mean that the longitudinal direction coincides exactly with the X direction and the Y direction, respectively, but also includes that the longitudinal direction is slightly tilted from the X direction and the Y direction, respectively. Even when the longitudinal direction is slightly tilted, the same effect can be obtained.

[0058] The thermoplastic resins and continuous fibers used in the first skin members 1, 201, the second skin members 2, 202, and the intermediate members 3, 203 may be different for some or all of the members. In the above-described embodiment, the first skin members 1, 201 and the intermediate members 3, 203 are welded together. The second skin members 2, 202 and the intermediate members 3, 203 are also welded together. Therefore, forming these members from the same material is a significant feature. According to the above-described embodiment, high recyclability and shortened manufacturing lead time are achieved, and the more similar materials (same materials) are used, the greater the effect.

[0059] Furthermore, the panel member disclosed herein is not limited to the panel members 100 and 200 of the above-described embodiments, which are used as components of ailerons and pressure bulkheads. It can also be applied to other aircraft components, such as the skin of an aircraft fuselage F as shown in FIG. 7 . The skin of the aircraft fuselage F is composed of an annular panel member 300. The annular panel member 300 has high strength (rigidity) against out-of-plane compression. The panel member 300 includes an outer skin member 301, an inner skin member 302, and a corrugated intermediate member 303 as shown in the figure, thereby achieving weight reduction and manufacturing cost reduction due to fewer components compared to conventional aircraft fuselages. Furthermore, the panel member 300 includes two types of skin members, the outer skin member (first skin member) 301 and the inner skin member (second skin member) 302, thereby achieving a pressurization fail-safe function. Furthermore, the intermediate member 303 includes multiple intermediate forming members, as in the other embodiments. This allows the aircraft fuselage F to have uniform strength throughout the annular area. By appropriately setting the shape and number of layers of the intermediate member (note that different numbers of layers result in different thicknesses), and the number of layers of the outer skin member 301 and the inner skin member 302, a configuration can be achieved in which desired portions have different strengths from other portions. Therefore, strength and other factors can be flexibly set according to the specifications required for the aircraft fuselage F. This can improve the durability and reduce weight of the aircraft fuselage F, increasing versatility. Furthermore, the panel member disclosed herein can also be applied to other aircraft components, such as the upper skin of a main wing. Because the panel member disclosed herein has high compressive strength during flight, it achieves weight reduction and reduced manufacturing costs. Furthermore, the panel member disclosed herein can be similarly effective not only in aircraft but also in other fields where applications as composite curvature surface members are required, such as vehicles, railways, and underwater vehicles, as well as structures such as offshore wind power plants and disaster prevention infrastructure such as shelters.

[0060] REFERENCE SIGNS LIST 1 First skin member 2 Second skin member 3 Intermediate member 4 Trailing edge member 5 Spar member 6 Cover member C11, C12, C13 Joined portion (first joined portion) NC11, NC12, NC13 Non-joined portion (first non-joined portion) C21, C22, C23 Joined portion (second joined portion) NC21, NC22, NC23 Non-joined portion (second non-joined portion) M1, M2, M3 Intermediate forming member 11, 12, 13 Carbon fiber 100 Panel member

Claims

1. A composite material comprising: a first skin member and a second skin member in the form of sheets each including a thermoplastic resin; and an intermediate member including continuous fibers and disposed between the first skin member and the second skin member; the first skin member has a plurality of first bonding portions bonded to the intermediate member and a plurality of first non-bonding portions not bonded to the intermediate member; the second skin member has a plurality of second bonding portions bonded to the intermediate member and a plurality of second non-bonding portions not bonded to the intermediate member; the first bonding portions and the first non-bonding portions are alternately arranged along a first direction; the second bonding portions and the second non-bonding portions are alternately arranged along the first direction; the intermediate member has a plurality of intermediate forming members; Each of the multiple intermediate forming members is a panel member including a first portion joined to at least a portion of the first joint portion of the first skin member, a second portion joined to at least a portion of the second joint portion of the second skin member, and a third portion connecting the first portion and the second portion and not joined to the first joint portion or the second joint portion.

2. A panel member as described in claim 1, wherein at least one of the plurality of intermediate forming members has a first intermediate forming section formed by laminating the continuous fibers a first number of times and a second intermediate forming section formed by laminating the continuous fibers a second number of times, and the first number is greater than the second number.

3. A panel member as described in claim 2, wherein the first joint portion, the first non-joint portion, the second joint portion, and the second non-joint portion extend in a second direction different from the first direction, and the first intermediate forming portion and the second intermediate forming portion are aligned in the first direction or the second direction.

4. A panel member as described in any one of claims 1 to 3, wherein the first skin member and / or the second skin member has a first skin forming portion formed by laminating a third number of continuous fibers and a second skin forming portion formed by laminating a fourth number of the continuous fibers, and the third number is greater than the fourth number.

5. A panel member as described in claim 4, wherein the first joint portion, the first non-joint portion, the second joint portion and the second non-joint portion extend in a second direction different from the first direction, and the first skin forming portion and the second skin forming portion are aligned in the first direction or the second direction.

6. A panel member as described in any one of claims 1 to 5, wherein the first joint portion, the first non-joint portion, the second joint portion, and the second non-joint portion extend in a second direction different from the first direction, and a cover member is attached to ends of the first skin member, the second skin member, and the intermediate member in the second direction or in the direction opposite to the second direction, and covers an area defined by the first skin member, the second skin member, and the intermediate member, and the cover member has a plurality of fixing surface portions fixed to at least two of the first skin member, the second skin member, and the intermediate member.

7. A panel member according to any one of claims 1 to 6, wherein at least one of said plurality of intermediate forming members has a hat-shaped cross-sectional shape.

8. A panel member according to any one of claims 1 to 7, wherein at least one of said first skin member and said second skin member is a compound curvature surface member.

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