Crystalline autoclave composite molding die for bionic lotus root and tuna skin structures

Abstract

The present invention discloses a lattice autoclave composite material forming mold of a bionic lotus root and tuna skin structure, comprising a molding surface layer, a frame layer, and a guide plate; the frame layer is composed of a partition plate and a lotus root-like support plate; each adjacent lotus root-like support plate is fixedly connected by two upper and lower partition plates; the molding surface layer, each lotus root-like support plate, and each partition plate enclose an upper and lower hexagonal vent group to form a lattice structure; a guide plate is fixed to the bottom surface of each hexagonal vent; the guide plate is composed of a tuna skin-like structure and a wedge-shaped bottom plate; the tuna skin-like structure is evenly spread over the upper surface of the bottom plate. The lotus root-like support plate and the guide plate of the present invention both improve the heat transfer efficiency of the mold, and the lotus root-like support plate and the lattice structure both improve the rigidity of the mold. Thus, while ensuring the rigidity of the mold, the heating efficiency of the entire mold is improved, the mold temperature rises more evenly, and the problems of low mold temperature rise efficiency and molding surface deformation during the molding process are effectively reduced.

Description

Technical Field

[0001] The invention belongs to the field of aerospace technology, and in particular relates to a crystalline autoclave composite material forming die having a bionic lotus root and tuna skin structure applied to composite wing skins. Background Art

[0002] As a wing component in direct contact with the airflow, the quality of its manufacturing process directly impacts the aircraft's flight performance. Composite components produced through autoclave molding have low porosity, stable and reliable performance, and high dimensional accuracy. Therefore, autoclave molding is commonly used to manufacture complex wing skin structures on aircraft with demanding manufacturing requirements. Currently, most autoclave molds are frame-type structures, which feature simple construction, light weight, easy transportation, and rapid heating through forced convection heat transfer. However, this type of mold still needs improvement. For one thing, the mold at the air inlet is always heated before the mold at the air outlet. This results in the mold temperature at the air inlet being much higher than that at the air outlet during the heating phase. This asynchronous heating can cause residual material in the composite component, leading to deformation and significantly impacting component performance. Furthermore, to ensure overall rigidity, frame-type molds incorporate support plates in both the horizontal and vertical directions. A support plate perpendicular to the hot airflow direction impedes the flow of the fluid medium and creates vortices, significantly reducing the fluid velocity and, in turn, the efficiency of forced convection heat transfer. This not only slows down the mold heating rate but also further widens the temperature difference between the two ends of the mold. These issues are significant for high-precision wing skin components, making structural design optimization of the frame-type mold essential. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems of low mold heating efficiency and surface deformation caused by uneven heating when using autoclave molding technology to prepare composite wing skins. A crystalline autoclave composite molding mold with a bionic lotus root and tuna skin structure is provided. While ensuring the overall rigidity of the mold, the mold's heating rate and temperature uniformity are improved.

[0004] The technical solution adopted in the present invention is:

[0005] The present invention discloses a lattice-shaped autoclave composite material forming mold for a bionic lotus root and tuna skin structure, comprising a molding layer, a frame layer, and a guide plate. The top surface of the molding layer serves as a molding surface; the side surface of the molding layer, perpendicular to the airflow direction, is provided with a plurality of air distribution ports arranged equidistantly along the molding surface line; the air distribution ports are semicircular through-holes.

[0006] The frame layer is composed of a partition and an imitation lotus-shaped support plate; a plurality of imitation lotus-shaped support plates are arranged at equal distances, and the imitation lotus-shaped support plates are arranged parallel to the airflow direction; the imitation lotus-shaped support plate is composed of an upper support plate and a lower support plate formed in one piece; the cross sections of the upper support plate and the lower support plate are both imitation lotus-shaped surfaces; the imitation lotus-shaped surfaces are composed of an upper inverted trapezoid and a lower upright trapezoid of the same shape; each upper support plate is fixedly connected to the profile layer; each adjacent two imitation lotus-shaped support plates are fixedly connected by two upper and lower partitions; the partition is perpendicular to the imitation lotus-shaped support plate, and the length of the partition is equal to the length of the imitation lotus-shaped support plate; the connection position of the upper partition and the imitation lotus-shaped support plate is located at the upper support The intersection of the plate and the lower support plate; the connection position of the lower partition and the imitation lotus-shaped support plate is located at the bottom of the side of the lower support plate; the profile layer, each imitation lotus-shaped support plate and each partition enclose an upper and lower hexagonal vent group, and the hexagonal vent group is composed of a plurality of hexagonal vents equidistantly arranged in a direction perpendicular to the airflow and horizontally; the sides of the upper support plate and the lower support plate are provided with a plurality of square vents equidistantly arranged in the direction of airflow; the length of each part separated by the square vents on the upper support plate or the lower support plate is greater than the maximum width of the cross section of the upper support plate or the lower support plate; a guide plate is fixed to the bottom of each hexagonal vent.

[0007] The deflector is composed of a tuna skin-like structure and a bottom plate; the bottom plate is wedge-shaped, and its height increases from the middle of the hexagonal vent to the air outlet; the tuna skin-like structure is evenly spread over the upper surface of the bottom plate.

[0008] The simulated tuna skin structure consists of a simulated hard fish scale layer and a simulated flexible skin layer; the simulated hard fish scale layer is fan-shaped, with the arc portion embedded in and fixed to the bottom plate, and the triangular portion exposed outside the bottom plate; the simulated hard fish scale layer is inclined toward the air outlet of the hexagonal vent, and the angle between each simulated hard fish scale layer and the upper surface of the bottom plate is equal; the portion of the simulated hard fish scale layer exposed outside the bottom plate and the upper surface of the bottom plate are both covered with the simulated flexible skin layer.

[0009] Preferably, the diameter of the air distribution port is 18-20 mm.

[0010] Preferably, the thickness of the partition is 2-4 mm.

[0011] Preferably, the lower base size of the lower upright trapezoid is 20-22 mm, and the ratio of the upper base size to the lower base size is 1:3.

[0012] Preferably, the height of the lotus root-shaped support plate is 230 mm-240 mm.

[0013] Preferably, the ratio of the length of the guide plate to the length of the hexagonal vent is 2:3, and the guide plate is closer to the air outlet position of the hexagonal vent.

[0014] Preferably, the inclination angle of the upper surface of the bottom plate is 3-5°.

[0015] Preferably, the tuna-like skin structure is evenly spread over the upper surface of the bottom plate. Specifically, a plurality of tuna-like skin structure groups are provided along the length direction of the bottom plate. Each tuna-like skin structure group is composed of a plurality of tuna-like skin structures arranged along the width direction of the bottom plate. The tuna-like skin structures of adjacent tuna-like skin structure groups are staggered along the length direction of the bottom plate.

[0016] Preferably, the included angle between the imitation hard fish scale layer and the upper surface of the bottom plate is 8-10°, the central angle of the imitation hard fish scale layer is 120-130°, and the radius is 30-35 mm.

[0017] Preferably, the two straight sides of the fan-shaped imitation hard fish scale layer are replaced with arcs, and the length of the arc is 40 mm.

[0018] The present invention has the following beneficial effects:

[0019] 1. The present invention reduces the cross-section of the lotus-shaped support plate of the frame layer perpendicular to the airflow direction, thereby reducing the obstruction of the support plate to the airflow and improving the heat transfer efficiency of the mold. However, the loss of rigidity is compensated by the lotus-shaped structural design of the cross-section of the lotus-shaped support plate. In this way, while ensuring the rigidity of the mold, the flow speed of the fluid medium in the frame layer is increased, thereby improving the heating efficiency of the entire mold and making the mold heat up more evenly.

[0020] 2. Each lotus root-shaped support plate, each partition plate and the mold surface layer enclose an upper and lower layer of hexagonal vent groups. The hexagonal vent groups are composed of multiple hexagonal vents equidistantly arranged in a direction perpendicular to the airflow and horizontally, so that the upper and lower layers of the hexagonal vent groups form a lattice structure, further improving the overall rigidity of the mold and reducing the degree of deformation of the mold surface layer. In addition, the hexagonal vents are firm, reliable and not prone to deformation.

[0021] 3. The present invention incorporates a guide plate positioned between the center and the outlet of each hexagonal vent. The upper surface of the guide plate is coated with a tuna-skin-like structure, which reduces friction and increases flow velocity. The wedge-shaped guide plate gradually reduces the area over which air flows while also increasing the contact area between the airflow and the outer surface of the tuna-skin-like structure. These two mechanisms gradually increase fluid velocity, thereby reducing the temperature difference between the mold inlet and outlet, resulting in a more uniform temperature distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0023] Figure 2 Schematic diagram of the medium-sized surface layer of the present invention.

[0024] Figure 3 Schematic diagram of the framework layer in the present invention.

[0025] Figure 4 Schematic diagram of the guide plate in the present invention.

[0026] Figure 5 Schematic diagram of the structure of the imitation tuna skin in the present invention.

[0027] Figure 6 This is a schematic structural diagram of the imitation hard fish scale layer of the present invention.

[0028] Figure 7 Schematic diagram of another structure of the imitation hard fish scale layer in the present invention. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] like Figure 1 As shown, the bionic lotus root and tuna skin structure lattice autoclave composite material forming mold includes a molding surface layer 1, a frame layer 2 and a guide plate 3.

[0031] like Figure 1 and Figure 2 As shown, the top surface of the profile layer 1 is profile 101, designed to fit the composite wing skin. Profile 101 directly contacts the composite prepreg, providing the necessary shaping. The side of the profile layer 1, perpendicular to the airflow direction, is provided with multiple air distribution ports 102, spaced evenly along the profile of profile 101. These ports 102 are semicircular through-holes.

[0032] like Figure 1 and Figure 3As shown, the frame layer 2 is composed of a partition 201 and a lotus-shaped support plate 202; a plurality of lotus-shaped support plates 202 are arranged at equal intervals, and the lotus-shaped support plates 202 are set parallel to the airflow direction; the lotus-shaped support plates 202 are composed of an upper support plate and a lower support plate formed in one piece; the cross-sections of the upper support plate and the lower support plate are both lotus-shaped surfaces; the lotus-shaped surfaces are composed of an upper inverted trapezoid and a lower upright trapezoid of the same shape, forming a lotus-shaped structure, which reduces material while improving the compressive resistance of the entire mold. Each upper support plate is fixedly connected to the profile layer 1; each adjacent two imitation lotus root-shaped support plates 202 are fixedly connected by upper and lower partitions 201; the partition 201 is perpendicular to the imitation lotus root-shaped support plate 202, and the length of the partition 201 is equal to the length of the imitation lotus root-shaped support plate 202; the connection position of the upper partition 201 and the imitation lotus root-shaped support plate 202 is located at the intersection of the upper support plate and the lower support plate; the connection position of the lower partition 201 and the imitation lotus root-shaped support plate 202 is located at the bottom of the side of the lower support plate; the profile layer 1, each imitation lotus root-shaped support plate 202 and each partition 201 enclose an upper and lower hexagonal vent group, and the hexagonal vent group consists of a plurality of hexagonal vents 203 arranged equidistantly in a direction perpendicular to the airflow and horizontally. The upper and lower layers of hexagonal vents form a lattice structure, further improving the overall rigidity of the mold. The hexagonal vents 203 are the main channels for hot air to enter. The sides of the upper and lower support plates are both provided with multiple square vents 204 arranged equidistantly along the airflow direction to improve the fluidity of the airflow in the mold. The length of each part separated by the square vents 204 on the upper or lower support plate is greater than the maximum width of the cross section of the upper or lower support plate. In this way, the surface area of ​​each part separated by the square vents 204 on the upper or lower support plate perpendicular to the heat flow (airflow) is small, and the surface area parallel to the heat flow is large, thereby ensuring good support without significantly hindering the heat flow. A guide plate 3 is fixed from the middle position of each hexagonal vent 203 to the air outlet position.

[0033] like Figure 4 As shown, the guide plate 3 is composed of a tuna-like skin structure 301 and a bottom plate 302; the bottom plate 302 is wedge-shaped, and its height increases from the middle of the hexagonal vent 203 to the air outlet; the tuna-like skin structure 301 is evenly spread over the upper surface of the bottom plate 302. Since the bottom plate 302 is wedge-shaped, the space through which the airflow flows in the hexagonal vent becomes smaller and smaller, and the contact area between the airflow and the tuna-like skin structure 301 becomes larger and larger.

[0034] like Figure 4 、 Figure 5 and Figure 6As shown, the simulated tuna skin structure 301 consists of a simulated hard fish scale layer 3011 and a simulated flexible skin layer 3012; the simulated hard fish scale layer 3011 is fan-shaped, with the arc portion embedded in the bottom plate 302 and fixed to the bottom plate 302, and the triangular portion exposed outside the bottom plate 302; the simulated hard fish scale layer 3011 is inclined toward the air outlet of the hexagonal vent 203, and the angle between each simulated hard fish scale layer 3011 and the upper surface of the bottom plate 302 is equal; the portion of the simulated hard fish scale layer 3011 exposed outside the bottom plate 302 and the upper surface of the bottom plate 302 are both covered with the simulated flexible skin layer 3012.

[0035] As a preferred embodiment, the diameter of the air balancing port 102 is 19 mm.

[0036] As a preferred embodiment, the thickness of the partition 201 is 3 mm.

[0037] As a preferred embodiment, the bottom base size of the lower upright trapezoid is 21 mm, and the height of the lotus root-shaped support plate 202 is 235 mm.

[0038] As a preferred embodiment, the inclination angle of the upper surface of the bottom plate 302 is 4°.

[0039] As a preferred embodiment, the tuna-like skin structure 301 is evenly spread over the entire upper surface of the bottom plate 302. Specifically, the bottom plate 302 is provided with a plurality of tuna-like skin structure groups along its length. Each tuna-like skin structure group is composed of a plurality of tuna-like skin structures 301 arranged along its width. The tuna-like skin structures 301 of adjacent tuna-like skin structure groups are staggered along its length.

[0040] As a preferred embodiment, Figure 6 As shown, the central angle of the imitation hard fish scale layer 3011 is 124° and the radius is 34 mm; the angle between the imitation hard fish scale layer 3011 and the upper surface of the base plate is 10°.

[0041] As a preferred embodiment, Figure 7 As shown, the two straight sides of the fan-shaped imitation hard fish scale layer 3011 are replaced with arcs, and the length of the arc is 40 mm.

[0042] As a preferred embodiment, the simulated flexible skin layer 3012 is formed by curing epoxy resin on the portion of the simulated hard fish scale layer 3011 exposed outside the bottom plate 302 and the upper surface of the bottom plate 302.

[0043] The working principle of the present invention is as follows:

[0044] The present invention is placed in an autoclave, and a release agent, a layer of polytetrafluoroethylene release cloth, a composite wing skin blank (composite prepreg), and another layer of polytetrafluoroethylene release cloth are placed on the mold surface layer in sequence. The composite wing skin blank, the release agent, and the polytetrafluoroethylene release cloth are then wrapped with a vacuum bag and sealed with a sealing strip. When heat flow is introduced into the autoclave, the heat flow mainly flows from around the composite wing skin blank, the uniform air vent 102, and each hexagonal vent 203 ( Figure 1 The middle arrow indicates the direction of heat flow) flows through, causing the composite wing skin blank and the mold layer 1 to heat up, wherein the mold layer 1 heats the bottom of the composite wing skin blank to soften the composite wing skin blank, and finally forms a composite wing skin with the same shape as the mold surface 101 of the mold layer 1 through hot pressing. When the heat flow flows through the hexagonal vents 203, the cross-section of the imitation lotus-shaped support plate perpendicular to the airflow direction is smaller, which can reduce the support plate's obstruction to the airflow, improve the heat transfer efficiency of the mold, and make the mold heat up more evenly. The cross-section of the imitation lotus-shaped support plate imitates the lotus-shaped structure and the lattice structure formed by the upper and lower layers of hexagonal vents further improve the overall rigidity of the mold, thereby improving the heat transfer efficiency without reducing the rigidity of the mold. In addition, when the heat flow flows through the middle and rear sections of the hexagonal vents 203, it will flow through the guide plate. The upper surface of the guide plate is paved with a tuna skin-like structure. This bionic structure can reduce the friction of the airflow when it flows through and increase the flow rate. The guide plate is set to be wedge-shaped, which can gradually reduce the area through which the airflow flows and gradually increase the contact area between the airflow and the outer surface of the tuna skin-like structure, thereby gradually increasing the fluid velocity, greatly reducing the temperature difference between the mold inlet and outlet, and further improving the uniformity of temperature distribution.

Claims

1. A bionic lotus root and tuna skin structured lattice autoclave composite material forming mold, comprising a molding surface layer and a frame layer, characterized by: It also includes a guide plate; the top surface of the profile layer is a profile; the side surface of the profile layer perpendicular to the airflow direction is provided with a plurality of air distribution ports arranged equidistantly along the profile line; the air distribution ports are semicircular through holes; The frame layer is composed of a partition and an imitation lotus-shaped support plate; a plurality of imitation lotus-shaped support plates are arranged at equal distances, and the imitation lotus-shaped support plates are arranged parallel to the airflow direction; the imitation lotus-shaped support plate is composed of an upper support plate and a lower support plate formed in one piece; the cross sections of the upper support plate and the lower support plate are both imitation lotus-shaped surfaces; the imitation lotus-shaped surfaces are composed of an upper inverted trapezoid and a lower upright trapezoid of the same shape; each upper support plate is fixedly connected to the profile layer; each adjacent two imitation lotus-shaped support plates are fixedly connected by two upper and lower partitions; the partition is perpendicular to the imitation lotus-shaped support plate, and the length of the partition is equal to the length of the imitation lotus-shaped support plate; the connection position of the upper partition and the imitation lotus-shaped support plate is located at the upper support The intersection of the plate and the lower support plate; the connection position of the lower partition plate and the imitation lotus-shaped support plate is located at the bottom of the side of the lower support plate; the profile layer, each imitation lotus-shaped support plate and each partition plate enclose the upper and lower layers of hexagonal vent groups, and the hexagonal vent groups are composed of a plurality of hexagonal vents arranged equidistantly in the direction perpendicular to the airflow and horizontally; the sides of the upper support plate and the lower support plate are each provided with a plurality of square vents arranged equidistantly in the direction of airflow; the length of each part of the upper support plate or the lower support plate separated by the square vents is greater than the maximum width of the cross section of the upper support plate or the lower support plate; a guide plate is fixed to the bottom surface of each hexagonal vent; The deflector is composed of a tuna skin-like structure and a bottom plate; the bottom plate is wedge-shaped, and its height increases from the middle of the hexagonal vent to the air outlet; the tuna skin-like structure is evenly spread over the upper surface of the bottom plate; The simulated tuna skin structure consists of a simulated hard fish scale layer and a simulated flexible skin layer; the simulated hard fish scale layer is fan-shaped, with the arc portion embedded in and fixed to the bottom plate, and the triangular portion exposed outside the bottom plate; the simulated hard fish scale layer is inclined toward the air outlet of the hexagonal vent, and the angle between each simulated hard fish scale layer and the upper surface of the bottom plate is equal; the portion of the simulated hard fish scale layer exposed outside the bottom plate and the upper surface of the bottom plate are both covered with the simulated flexible skin layer.

2. The bionic lotus root and tuna skin structure lattice autoclave composite material forming mold according to claim 1, characterized in that: The diameter of the air distribution port is 18-20 mm.

3. The lattice autoclave composite material forming mold of the bionic lotus root and tuna skin structure according to claim 1, characterized in that: The thickness of the separator is 2-4 mm.

4. The bionic lotus root and tuna skin structure lattice autoclave composite material forming mold according to claim 1, characterized in that: The lower base size of the lower upright trapezoid is 20-22 mm, and the ratio of the upper base size to the lower base size is 1:

3.

5. The bionic lotus root and tuna skin structure lattice autoclave composite material forming mold according to claim 1, characterized in that: The height of the lotus root-shaped support plate is 230 mm to 240 mm.

6. The bionic lotus root and tuna skin structure lattice autoclave composite material forming mold according to claim 1, characterized in that: The ratio of the length of the guide plate to the length of the hexagonal vent is 2:3, and the guide plate is closer to the air outlet position of the hexagonal vent.

7. The bionic lotus root and tuna skin structure lattice autoclave composite material forming mold according to claim 1, characterized in that: The inclination angle of the upper surface of the bottom plate is 3-5°.

8. The bionic lotus root and tuna skin structure lattice autoclave composite material forming mold according to claim 1, characterized in that: The tuna-like skin structure is evenly spread over the upper surface of the base plate. Specifically, a plurality of tuna-like skin structure groups are provided along the length direction of the base plate. Each tuna-like skin structure group is composed of a plurality of tuna-like skin structures arranged along the width direction of the base plate. The tuna-like skin structures of adjacent tuna-like skin structure groups are staggered along the length direction of the base plate.

9. The bionic lotus root and tuna skin structure lattice autoclave composite material forming mold according to claim 1, characterized in that: The included angle between the imitation hard fish scale layer and the upper surface of the bottom plate is 8-10 degrees, the central angle of the imitation hard fish scale layer is 120-130 degrees, and the radius is 30-35 mm.

10. The bionic lotus root and tuna skin structure lattice autoclave composite material forming mold according to claim 1, characterized in that: The two straight sides of the fan-shaped imitation hard fish scale layer are replaced with arcs, and the length of the arc is 40 mm.

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