A cambered high-strength high-precision low-density composite profile

Abstract

This utility model relates to the field of materials processing technology, and in particular to a high-strength, high-precision, low-density composite profile with an arc surface; it includes a hollow profile structure and a solid profile structure, which are bonded together by a mortise and tenon structure to form an alternating continuous profile structure; the hollow profile structure has an extruded arc-shaped hollow outer wall, filled with glass microspheres, and mortise and tenon grooves and overlapping surfaces at both ends; the solid profile structure has an arc-shaped solid body, with mortise and tenon blocks and overlapping grooves at the ends that match the trapezoidal mortise and tenon grooves. This composite profile, through the alternating splicing design of the hollow and solid profile structures combined with the trapezoidal interlocking structure of the mortise and tenon grooves and blocks, significantly improves the connection reliability and assembly efficiency.

Description

Technical Field

[0001] This utility model relates to the field of material processing technology, and in particular to a high-strength, high-precision, low-density composite profile with curved surfaces. Background Technology

[0002] Curved composite profiles are structural materials manufactured using fiber-reinforced resin as the matrix through a pultrusion process. They possess characteristics such as high strength, lightweight, and customizable cross-sections. These materials are widely used in aerospace, rail transportation, and other fields. Their core performance lies in the optimized fiber arrangement and synergy with the resin matrix to meet the mechanical and weight requirements under complex working conditions.

[0003] Traditional pultruded composite profiles face significant technical bottlenecks. Firstly, they suffer from severe shortcomings in mechanical properties: unidirectional fiber arrangement results in transverse strength less than 30% of longitudinal strength. When applied to multi-directional load-bearing structures such as building dome nodes or aircraft wing spars, uneven load distribution can easily lead to interlaminar delamination or even fracture. Simultaneously, weak resin-fiber interfacial bonding and low interlaminar shear strength further weaken overall reliability. Secondly, achieving both lightweight and precision is difficult: while high fiber content ensures strength, it results in high density, forcing performance sacrifices in weight-sensitive fields such as aircraft. Inaccurate temperature control during curing leads to excessive air bubbles and tolerance issues, and straightness deviations necessitate additional correction processes, significantly increasing production costs. More critically, structural design is rigid: traditional molds cannot directly form variable-thickness hollow sections. For example, lightweight cavity structures required for satellite supports rely on post-assembly bonding or welding, which not only introduces stress concentration points but also accumulates dimensional deviations at joints, compromising assembly consistency. Of particular note is that bolted connections suffer from stress concentration due to drilling, which significantly reduces fatigue life, while the heat-affected zone of welding induces deformation and oxidation, posing a risk of loosening in long-term vibration environments. These defects collectively restrict the widespread application of composite profiles in high-end industrial settings.

[0004] Therefore, this application provides a high-strength, high-precision, low-density composite profile with curved surfaces to solve the problems mentioned in the background art. Utility Model Content

[0005] The purpose of this utility model is to provide a high-strength, high-precision, low-density composite profile with curved surfaces, which solves the core defects of traditional pultruded profiles, such as insufficient mechanical properties that make them prone to delamination and breakage, high density that affects the lightweight effect, difficulty in forming complex cross sections, and stress concentration and vibration loosening risks caused by bolt welding connection.

[0006] To solve the above-mentioned technical problems, this utility model provides a high-strength, high-precision, low-density composite profile with curved surface, including a hollow profile structure and a solid profile structure. The hollow profile structure and the solid profile structure are bonded together by a tenon and mortise structure to form an alternating continuous profile structure. The hollow profile structure includes an extruded curved hollow outer wall, filled with glass microspheres, and tenon and mortise grooves and overlapping surfaces at both ends; The solid profile structure includes a rectangular curved solid body, with mortise and tenon blocks and overlapping grooves at the ends that match the trapezoidal mortise and tenon grooves.

[0007] The further improvement of this utility model technical solution is as follows: the hollow profile structure is formed by machining mortise and tenon grooves on the cross section of the hollow profile, the cross section of the hollow profile has an upper arc surface and a lower arc surface, and the wall thickness is 3±0.5mm; the solid profile structure is formed by machining mortise and tenon blocks on the cross section of the solid profile, the cross section of the solid profile has a width of 119±0.5mm and a thickness of 20±0.5mm; the upper length of the mortise and tenon structure is 15mm, the lower length is 35mm, and the height is 25mm.

[0008] The further improvement of this utility model is that the mortise and tenon structure is a trapezoidal design with an upper length of 15mm, a lower length of 35mm, and a height of 25mm; the contact surface of the lap joint and the lap groove and the contact surface of the mortise and tenon structure are the bonding area, and the adhesive thickness is controlled at 0.2±0.05mm.

[0009] A further improvement of this utility model is that: the glass microsphere filling density is 60wt%, and the overall profile density after filling is 1.2~1.3g / cm³; the glass microsphere particle size is 20~100μm, and it is surface modified by silane coupling agent, with the amount of modifier added being 1.5% of the mass of the microspheres.

[0010] A further improvement of this utility model is that both the hollow profile structure and the solid profile structure contain reinforcing fibers; the reinforcing fibers include: Fiberglass: 80% by volume; ±45° glass fiber braided layer: 10% of volume, 200g / m²; Seam edge felt: 10% of the volume, placed on the outermost edge of the profile, with a weight of 150g / m².

[0011] A further improvement of this utility model is that the ±45° glass fiber braided layer makes the transverse strength of the profile reach more than 60% of the longitudinal strength, and the interlayer shear strength ≥30MPa.

[0012] A further improvement of this utility model is that both the hollow profile structure and the solid profile structure contain a resin matrix; The resin matrix is ​​composed of 100 parts modified epoxy resin, 115 parts 2-ethyl-4-methylimidazolium, 10 parts polyetherimide, and 2 parts tributyl phosphate. The resin matrix was subjected to vacuum degassing treatment with a vacuum degree of -0.095MPa and a degassing time of 30min, and the viscosity was controlled at 300±50mPa·s.

[0013] A further improvement of the present invention is that: the hollow profile section is reinforced with fibers arranged by a hollow threading plate, the hollow threading plate comprising, in sequence, an upper seam edge felt opening, a glass fiber mesh, an upper axial fabric opening, a lower axial fabric opening, and a lower seam edge felt opening. The solid profile section is reinforced with fibers arranged through a solid yarn-threading plate. The solid yarn-threading plate includes, in sequence, upper seam edge felt openings, upper axial fabric openings, fiberglass yarn eyes, lower axial fabric openings, and lower seam edge felt openings.

[0014] A further improvement of this utility model is that the upper axial holes and the lower axial holes constrain the position of the axial glass fiber, so that it is fixed in the outermost bearing area of ​​the profile section. The fiberglass mesh ensures that the fiberglass is spread evenly, and a ±45° fiberglass braided layer is superimposed on the fiberglass. The fiberglass mesh provides a non-crossing matrix for the superimposed ±45° oblique braided layer. The openings in the upper and lower seam edge felts are interspersed with the seam edge felt, precisely positioned to the edge of the profile, thus suppressing delamination failure.

[0015] A further improvement to the technical solution of this utility model lies in the fact that the glass microsphere filling process includes: Fill in multiple quantitative portions, with each portion containing 25±2g. Hydraulic compaction, pressure 0.6MPa, compaction time 15±2s; The material is pushed into the hollow profile structure cavity at a uniform speed of 2 mm / s. Gradient curing: 30℃-60℃-90℃-100℃-120℃.

[0016] By adopting the above technical solution, this utility model has the following beneficial effects: 1. This utility model provides a high-strength, high-precision, low-density composite profile with an arc surface. This composite profile significantly improves connection reliability and assembly efficiency through an alternating splicing design of hollow and solid profile structures combined with a trapezoidal interlocking structure of mortise and tenon grooves and blocks. The trapezoidal design of the mortise and tenon structure ensures more even load distribution, completely avoiding stress concentration problems caused by traditional bolt connections, and maintaining zero loosening in the vibration environment of rail transit. Simultaneously, the precise fit between the lap surface and the lap groove allows the adhesive to form a continuous sealing layer, greatly improving the fatigue life of the connection parts.

[0017] 2. This utility model provides a high-strength, high-precision, low-density composite profile with an arc surface. This composite profile achieves a synergistic breakthrough in lightweighting and functional enhancement through an innovative design that fills the interior of a hollow profile with glass microspheres. The glass microspheres are uniformly filled in the arc-shaped cavity, significantly reducing the overall weight of the profile due to their ultra-low density characteristics. Simultaneously, the rigid support of the microspheres enhances the crush resistance and suppresses thin-wall deformation, increasing the bending stiffness of the profile by more than 40% in load-bearing scenarios such as aircraft wing spars, and imparting excellent thermal and sound insulation performance.

[0018] 3. This utility model provides a high-strength, high-precision, low-density composite profile with an arc surface. This composite profile overcomes the core challenge of anisotropic mechanical properties through the precise control of a multi-layered fiber-reinforced structure and a fiber-threaded plate. Hollow and solid fiber-threaded plates lock the main load-bearing fibers in the outermost area of ​​the profile through axially arranged perforations. The glass fiber mesh ensures that the glass fibers are evenly spread and do not tangle. The ±45° glass fiber woven layer and seam felt suppress edge delamination, making the transverse strength close to two-thirds of the longitudinal strength, thus meeting the multi-directional load requirements of building dome nodes.

[0019] 4. This utility model provides a high-strength, high-precision, low-density composite profile with an arc surface. This composite profile achieves zero-defect precision manufacturing through a gradient-cured resin matrix and segmented microsphere filling process. Resin degassing treatment ensures matrix purity, and zoned temperature-controlled molds reduce the bubble rate to less than one-quarter of the industry standard. The phased quantitative filling of glass microspheres, combined with uniform-speed propulsion technology, ensures no voids within the cavity. Combined with gradient curing to eliminate shrinkage deformation, this allows the profile's straightness and wall thickness tolerances to meet aerospace assembly precision requirements. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overlapping of a high-strength, high-precision, low-density composite profile with an arc surface; Figure 2 This is a structural schematic diagram of the hollow profile structure of this utility model; Figure 3 This is a structural schematic diagram of the solid profile structure of this utility model; Figure 4 This is a structural schematic diagram of the hollow profile cross-section of this utility model; Figure 5 This is a structural schematic diagram of the solid profile cross-section of this utility model; Figure 6 This is a schematic diagram of the hollow yarn threading plate of this utility model; Figure 7 This is a schematic diagram of the solid yarn threading plate of this utility model.

[0022] Reference numerals: 1. Hollow profile structure; 11. Curved hollow outer wall; 12. Glass microspheres; 13. Mortise and tenon groove; 14. Overlap surface; 2. Solid profile structure; 21. Curved solid body; 22. Mortise and tenon block; 23. Overlap groove; 3. Hollow profile section; 4. Solid profile section; 5. Hollow threaded board; 6. Solid threaded board; 61. Opening of upper seam edge felt; 62. Glass fiber mesh; 63. Opening of upper axial fabric; 64. Opening of lower axial fabric; 65. Opening of lower seam edge felt. Detailed Implementation

[0023] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0024] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] The present invention will be further explained below with reference to specific embodiments.

[0027] like Figures 1-7As shown in this embodiment, a high-strength, high-precision, low-density composite profile with an arc surface is provided. Its core innovation lies in the mortise and tenon joint design of the hollow profile structure 1 and the solid profile structure 2. The hollow profile structure 1 uses an extruded arc-shaped hollow outer wall 11, filled internally with glass microspheres 12 modified with a silane coupling agent. The filling density of the glass microspheres 12 is strictly controlled at 60 wt%, with a particle size range of 20~100 μm. The modifier addition ratio is 1.5% of the microsphere mass, significantly enhancing the interfacial bonding force between the microspheres and the resin. This design reduces the overall profile density to 1.2~1.3 g / cm³, while the rigid support of the microspheres effectively suppresses thin-wall buckling deformation. The hollow profile structure 1 has trapezoidal mortise and tenon grooves 13 and overlapping surfaces 14 precisely machined at both ends. The solid profile structure 2 has mortise and tenon blocks 22 and overlapping grooves 23 with matching dimensions at its ends. The two are connected by an epoxy resin adhesive, forming a continuous load-bearing structure with alternating hollow and solid sections.

[0028] like Figures 1-5 As shown, in this embodiment, the mortise and tenon structure is key to achieving high-precision assembly: the mortise and tenon structure adopts a trapezoidal interlocking design, with specific dimensions of 15mm upper side length, 35mm lower side length, and 25mm height. The top-narrow, bottom-wide geometric shape achieves three functions: the 15mm narrow side guides rapid and accurate positioning, avoiding assembly deviations; the 35mm wide side provides a large contact surface for evenly distributing loads; and the 25mm height forms a mechanical interlock to resist vibration and shear forces. The contact area dimensions between the overlapping surface 14 and the overlapping groove 23 are 120mm × 50mm × 20mm, and the adhesive thickness is strictly controlled at 0.2 ± 0.05mm, ensuring a bonding strength ≥ 200MPa while avoiding excessive thickness that could lead to curing shrinkage and cracking.

[0029] like Figures 2-7 As shown, in this embodiment, both the hollow profile structure 1 and the solid profile structure 2 are made of reinforcing fibers; the reinforcing fibers include glass fibers, ±45° glass fiber woven layers, and edge felt. Glass fibers, as the main load-bearing layer, account for 80% of the volume and are precisely positioned by the threading plate perforation system: the hollow threading plate 5 locks the axial glass fibers to the outermost side of the curved outer wall 11 through the upper axial perforation 63 and the lower axial perforation 64, maximizing the bending stiffness; the glass fiber mesh 62 ensures that the glass fibers are evenly spread and untangled, providing a flat substrate for the superimposed ±45° oblique woven layers, making the transverse strength reach more than 60% of the longitudinal strength; the edge felt, positioned at the edge of the profile through the upper edge felt perforation 61 and the lower edge felt perforation 65, accounts for 10% of the volume and has a basis weight of 150g / m², significantly improving the interlaminar shear strength to ≥30MPa.

[0030] The resin matrix consists of 100 parts modified epoxy resin, 115 parts 2-ethyl-4-methylimidazolium, 10 parts polyetherimide, and 2 parts tributyl phosphate. Before pultrusion, the mixed resin is treated in a vacuum degassing device for 30 minutes, with the vacuum level strictly maintained at -0.095 MPa and the viscosity controlled at 300±50 mPa·s. After degassing, the resin is thoroughly impregnated with fibers in a constant-temperature impregnation bath, and then enters a zoned temperature-controlled mold. Inlet section: Pre-gelation at 145℃ initiates initial cross-linking of the resin; Mid-stage: Primary curing at 185℃ to achieve complete polymerization of molecular chains; Export section: Cured at 185℃ to eliminate internal stress.

[0031] The microbead filling process achieves void-free filling through staged precision operations: Multi-stage quantitative filling: Each time, take 25±2g of microbead mixture and compact it with 0.6MPa hydraulic pressure for 15s to eliminate the initial voids; Uniform speed advancement: The filling rod is pushed into the cavity 1 of the hollow profile structure at a uniform speed of 2mm / s to avoid local accumulation; Gradient curing: Maintaining 30℃ for 40 minutes to achieve initial resin impregnation → Maintaining 60℃ for 60 minutes to enhance bonding strength → Segmented curing from 90℃ to 120℃ to suppress microbead floating and ensure uniform and seamless cavity filling.

[0032] The resulting composite profile remains completely stable in the vibration environment of rail transit, improving assembly efficiency by 50%, while also possessing excellent thermal and sound insulation performance, with a thermal conductivity as low as 0.05 W / m·K.

[0033] This utility model also provides a working principle for a high-strength, high-precision, low-density composite profile with curved surfaces: At the assembly site, operators first sandblast the mortise and tenon grooves 13 and overlapping surfaces 14 of the hollow profile structure 1, and the mortise and tenon blocks 22 and overlapping grooves 23 of the solid profile structure 2 to remove surface impurities. Then, epoxy resin adhesive is evenly applied to the trapezoidal contact surfaces of the mortise and tenon grooves 13 and mortise and tenon blocks 22, with the thickness strictly controlled at 0.2±0.05mm. The mortise and tenon blocks 22 of the solid profile structure 2 are precisely embedded into the mortise and tenon grooves 13 of the hollow profile structure 1, and mechanical interlocking is achieved by utilizing the self-locking effect of the trapezoidal inclined surface. At the same time, the overlapping grooves 23 and overlapping surfaces 14 are tightly fitted to form a double seal. After being alternately spliced ​​into a continuous structure, it is left to cure statically, and finally an integral profile with high connection strength and resistance to vibration and loosening is formed, which can be directly applied to rail transit track bases or building dome support beams.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A high-strength, high-precision, low-density composite profile with an arc surface, characterized in that: It includes hollow profile structure (1) and solid profile structure (2). The hollow profile structure (1) and solid profile structure (2) are bonded together by mortise and tenon structure to form an alternating continuous profile structure. The hollow profile structure (1) includes an extruded curved hollow outer wall (11), filled with glass microspheres (12), and tenon and mortise grooves (13) and overlapping surfaces (14) respectively at both ends; The solid profile structure (2) includes an arc-shaped solid body (21) formed by bending a rectangle, and the ends are provided with mortise and tenon blocks (22) that match the trapezoidal mortise and tenon groove (13) and overlapping grooves (23).

2. The high-strength, high-precision, low-density composite profile with curved surface according to claim 1, characterized in that: The hollow profile structure (1) is formed by machining tenon and mortise grooves (13) from the hollow profile section (3). The hollow profile section (3) has an upper arc surface and a lower arc surface, and the wall thickness is 3±0.5mm. The solid profile structure (2) is formed by machining tenon and mortise blocks (22) from the solid profile section (4). The solid profile section (4) has a width of 119±0.5mm and a thickness of 20±0.5mm. The upper length of the tenon and mortise structure is 15mm, the lower length is 35mm, and the height is 25mm.

3. The high-strength, high-precision, low-density composite profile with curved surface according to claim 2, characterized in that: The mortise and tenon structure is a trapezoidal design with a top length of 15mm, a bottom length of 35mm, and a height of 25mm. The contact surfaces of the lap joint (14) and lap groove (23) and the mortise and tenon structure are bonding areas, and the adhesive thickness is controlled at 0.2±0.05mm.

4. The high-strength, high-precision, low-density composite profile with curved surface according to claim 1, characterized in that: The glass microspheres (12) have a filling density of 60wt%, and the overall profile density after filling is 1.2~1.3g / cm³. The glass microspheres (12) have a particle size of 20~100μm and are surface modified by silane coupling agent. The amount of modifier added is 1.5% of the mass of the microspheres.

5. The high-strength, high-precision, low-density composite profile with curved surface according to claim 1, characterized in that: Both the hollow profile structure (1) and the solid profile structure (2) contain reinforcing fibers; the reinforcing fibers include: Fiberglass: 80% by volume; ±45° glass fiber braided layer: 10% of volume, 200g / m²; Seam edge felt: 10% of the volume, placed on the outermost edge of the profile, with a weight of 150g / m².

6. The high-strength, high-precision, low-density composite profile with curved surface according to claim 5, characterized in that: The ±45° glass fiber braided layer enables the profile's transverse strength to reach more than 60% of its longitudinal strength, and the interlaminar shear strength to be ≥30MPa.

7. The high-strength, high-precision, low-density composite profile with curved surface according to claim 1, characterized in that: Both the hollow profile structure (1) and the solid profile structure (2) contain a resin matrix; The resin matrix is ​​composed of 100 parts modified epoxy resin, 115 parts 2-ethyl-4-methylimidazolium, 10 parts polyetherimide, and 2 parts tributyl phosphate. The resin matrix was subjected to vacuum degassing treatment with a vacuum degree of -0.095MPa and a degassing time of 30min, and the viscosity was controlled at 300±50mPa·s.

8. The high-strength, high-precision, low-density composite profile with curved surface according to claim 2, characterized in that: The hollow profile section (3) is reinforced with fibers arranged through the hollow yarn-threading plate (5). The hollow yarn-threading plate (5) includes an upper seam edge felt opening (61), a glass fiber yarn eye (62), an upper axial fabric opening (63), a lower axial fabric opening (64), and a lower seam edge felt opening (65) arranged in sequence. The solid profile section (4) is reinforced with fibers arranged through a solid threading plate (6). The solid threading plate (6) includes an upper seam edge felt opening (61), an upper axial fabric opening (63), a glass fiber yarn eye (62), a lower axial fabric opening (64), and a lower seam edge felt opening (65) arranged in sequence.

9. The high-strength, high-precision, low-density composite profile with curved surface according to claim 8, characterized in that: The upper axial holes (63) and lower axial holes (64) constrain the position of the axial glass fiber, fixing it to the outermost load-bearing area of ​​the profile section; Glass fiber mesh (62) ensures that the glass fiber is spread evenly, and a ±45° glass fiber braided layer is superimposed in the glass fiber. Glass fiber mesh (62) provides a non-cross matrix for superimposing the ±45° oblique braided layer. The upper seam edge felt opening (61) and the lower seam edge felt opening (65) are inserted into the seam edge felt and precisely positioned to the edge of the profile to suppress delamination failure.

10. The high-strength, high-precision, low-density composite profile with curved surface according to claim 1, characterized in that: The glass microsphere (12) filling process includes: Fill in multiple quantitative portions, with each portion containing 25±2g. Hydraulic compaction, pressure 0.6MPa, compaction time 15±2s; The material is pushed into the cavity of the hollow profile structure (1) at a constant speed of 2 mm / s. Gradient curing: 30℃-60℃-90℃-100℃-120℃.

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