Composite material workpiece
The mixed layup structure with carbon and polyimide fibers in composite fan blades addresses the weight and detachment issues of metal reinforcement, enhancing edge strength and reliability.
Patent Information
- Application Number
- CN202421959999.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-13
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-08-13
AI Technical Summary
The tail edges of existing composite fan blades are easily delaminated and broken in accidents such as bird collisions. The manufacturing of special-shaped metal reinforced edges is complex and costly, and there is a risk of falling off.
The mixed laying structure is introduced into the composite material parts. By setting high-strength second type of laying and transition zones in the edge area, combining the higher-strength PI fiber epoxy resin prepreg and the carbon fiber epoxy resin prepreg to form a gradient transition to improve edge strength and bond strength.
It effectively improves the strength of the edges of composite materials, prevents breakage and delamination, enhances the blade's bird-resistant ability, and reduces manufacturing complexity and cost.
Smart Images
Figure CN223100019U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the field of composite materials, and particularly relates to a composite material part. Background Art
[0002] More than 80% of the thrust of a high bypass ratio aero-engine comes from the fan blades. With the increasing requirements for the economy of aero-engines, using lightweight and high-strength composite materials to manufacture fan blades has become an important development trend in the design and manufacture of new aero-engines. The trailing edge of the fan blade is the thinnest area of the composite fan blade. When an accident such as a bird strike occurs to the engine, delamination and fracture are most likely to occur in the trailing edge area, causing blade failure. Currently, composite fans mainly adopt the method of introducing metal reinforcement edges to improve strength and reduce the risk of failure. However, on the one hand, the manufacturing process of special-shaped metal reinforcement edges is complex, costly, and heavy in weight. On the other hand, in some accident conditions, the metal reinforcement edges themselves also have the risk of falling off and failing. Therefore, providing a composite material part that improves mechanical properties by optimizing the ply structure has positive significance for improving the reliability of composite material blades of aero-engines. Summary of the Utility Model
[0003] The purpose of the utility model is to provide a composite material part, which improves the edge strength of the composite material part by forming a mixed ply structure in the composite material part.
[0004] An embodiment of the utility model provides a composite material part, which includes a matrix area, a mixed ply area, and a transition area; wherein, the matrix area is covered by a first type of ply; the mixed ply area is covered by the first type of ply and a second type of ply, and only the first type of ply or the second type of ply is included in the same ply, and the mixed ply area forms at least part of the edge of the composite material part; the transition area is covered by the first type of ply and the second type of ply, and at least part of the ply is configured as a mixed layer, and the mixed layer includes the first type of ply and the second type of ply; the first type of ply and the second type of ply in the mixed layer are arranged in butt joint, and a butt joint gap is arranged between the first type of ply and the second type of ply, and the mixed layer is arranged between two layers of the first type of ply; in the transition area, the lengths of the second type of ply in different mixed layers are set in a gradient, and the length of the second type of ply closer to the surface of the composite material part is longer; the strength of the second type of ply is greater than that of the first type of ply.
[0005] By arranging the second type of ply with higher strength in the mixed ply area, the strength of the edge area of the part is effectively improved, and the fracture, cracking, or delamination at the edge of the composite material part can be prevented. Further, by arranging the transition area, the bonding strength between the first type of ply and the second type of ply can be effectively improved, and the separation of the mixed ply area from the matrix area can be avoided.
[0006] Further, in some embodiments, the docking gap is 0.2 mm - 0.3 mm.
[0007] Further, in some embodiments, the projection distance of two adjacent docking gaps in the laying plane is not less than 20 mm. The distance between the docking gaps should not be too close to avoid being a weak area in the composite part.
[0008] Further, in some embodiments, the length of the transition zone along the gradient direction is not less than 70 mm. Sufficient length is reserved in the transition zone to ensure the bonding strength between the hybrid laying area and the matrix area.
[0009] Further, in some embodiments, the second type of ply is laid at the same laying angle.
[0010] Further, in some embodiments, the laying angle of the second type of ply is 0°.
[0011] Further, in some embodiments, in the hybrid laying area and the transition zone, the laying method of at least part of the plies from the surface layer inward is [A0 / A45 / A0 / A - 45 / B0 / A45 / B0 / A - 45 / B0 / A45 / B0 / A - 45 / A0 / A45 / A0], where A represents the first type of ply, B represents the second type of ply, A0 is the first type of ply laid along the 0° direction, A45 is the first type of ply laid along the 45° direction, A - 45 is the first type of ply laid along the - 45° direction, and B0 is the second type of ply laid along the 0° direction.
[0012] Further, in some embodiments, the laying method of the matrix area is [0 / 45 / 0 / -45]2s.
[0013] Further, in some embodiments, the composite part is configured as a fan blade of an aeroengine.
[0014] Further, in some embodiments, the hybrid laying area is configured as the trailing edge of the fan blade of the aeroengine. Description of the Drawings
[0015] Figure 1 It is a schematic diagram of the partial cross-sectional structure of a composite fan blade in an embodiment;
[0016] Figure 2 It is a schematic diagram of the ply structure of the transition zone in an embodiment.
[0017] The purpose of the above-mentioned drawings is to illustrate the present utility model in detail so that those skilled in the art can understand the technical concept of the present utility model, rather than to limit the present utility model. For the sake of brevity, the above-mentioned drawings only schematically show the structures related to the technical features of the present utility model, and do not strictly draw the complete structure and all details according to the actual proportion. Detailed Description of the Embodiment
[0018] The following further elaborates on the present utility model through specific embodiments in conjunction with the drawings.
[0019] The mention of "embodiment" in this article means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of this article. The phrase appearing in various positions in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive independent or alternative embodiments. Those skilled in the art should be able to understand that the embodiments in this article can be combined with other embodiments without structural conflicts.
[0020] In the description of this article, terms indicating orientation or positional relationships such as "upper", "lower", "left", "right", "horizontal", "vertical", "height", "length", "width", etc. are intended to accurately describe the embodiment and simplify the description, rather than to limit that the parts or structures involved must have a specific orientation, be installed or operated in a specific orientation, and should not be construed as a limitation to the embodiments in this article.
[0021] In the description of this article, terms such as "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating relative importance or limiting the quantity, specific order or primary-secondary relationship of the described technical features. In the description of this article, the meaning of "a plurality" is at least two.
[0022] The composite fan blade with a metal edging has better trailing edge strength. However, the manufacturing process of the special-shaped metal edging is complex, the cost is high, and it will also cause an increase in the weight of the fan blade and a change in the center of gravity. In the accident conditions such as when foreign objects are inhaled by the engine, it may also be damaged and detached, causing more serious additional damage to the engine. To overcome these difficulties, the embodiments of the present utility model provide a composite fan blade with a hybrid layup structure, which improves the resistance of the weak trailing edge area of the blade to fracture and delamination by setting a hybrid zone with a higher-strength ply material in the blade edge area.
[0023] In one embodiment, the original fan blade is manufactured by laying carbon fiber epoxy prepreg. In order to enhance the strength of its blade trailing edge, a hybrid zone needs to be set in the fan blade.
[0024] The design method of the fan blade includes the following steps:
[0025] First, through simulation calculations, obtain the stress-strain diagram under the accident conditions of the blade (for example, the bird strike accident condition), and simulate and analyze to obtain the weakest area under the accident conditions. In one embodiment, assuming that a 540g bird strikes the blade at a speed of 315m / s, the maximum strain occurs at the trailing edge position, and the peak tensile and compressive stresses generated at this position will cause delamination failure at the trailing edge. Through simulation calculations, the size of the delamination area at the trailing edge is approximately 300mm in radial length, 235mm in spanwise length, 3mm in the thickness of the area where it is located, and the ply layup is [0 / 45 / 0 / -45]2s.
[0026] Next, calculate and determine the mechanical properties that the fan blade needs to improve. Before the fan blade delaminates after being struck, the stress caused by the bending moment on the blade cross-section is determined by the following formula:
[0027] M = 2 / 3σh 2 ,
[0028] where M is the bending moment, σ is the tensile or compressive strength of the material, and h is the thickness of the cross-sectional area. By increasing the strength of the material (tensile strength or compressive strength), the anti-bird strike ability of the structure can be improved. The following formula can be used to determine that the hybrid laminate structure of multi-fiber reinforced composites can improve the strength of the material:
[0029] M Hybrid / M CFRP = [(1 - β)(1 - α) 3 + β](1 - α) -1 ,
[0030] where α = h2 / h1, β = E2 / E1, h1 and h2 are the half-thicknesses of the two ply materials with different layups, and E1 and E2 are the moduli of the two ply materials with different layups.
[0031] Screen common materials. The fracture strain of carbon fiber is 2.0% - 2.2%, while the fracture strain of PI (polyimide) fiber is 3.5%. The strength performance of PI fiber is better than that of carbon fiber. Replacing part of the carbon fiber with PI fiber can improve the delamination resistance of the trailing edge. Using carbon fiber pre-impregnated epoxy resin as the first type of ply and PI fiber epoxy resin pre-impregnated material as the second type of ply, manufacture a composite fan blade.
[0032] Next, design the ply laying structure of the composite fan blade. As Figure 1As shown in the figure, the area near the trailing edge of the fan blade is divided into a matrix area 1, a hybrid laying area 2, and a transition area 3, where: the matrix area 1 is made by laying carbon fiber epoxy prepreg; the inner layer of the hybrid laying area 2 is a core part 4 made by laying carbon fiber epoxy prepreg, and the outer layer is a composite laying layer 5 made by laying 75% carbon fiber epoxy prepreg and 25% PI fiber epoxy prepreg; the transition area 3 is the junction area between PI fiber epoxy prepreg and carbon fiber epoxy prepreg, and the composite laying layer transitions to a carbon fiber prepreg laying layer. Specifically, in the hybrid laying area 2, the composite laying layer 5 includes alternately laid carbon fiber epoxy prepreg (C prepreg) and PI fiber epoxy prepreg (PI prepreg), and there is only one of C prepreg or PI prepreg in each laying layer; the PI prepreg in the composite layer 5 extends into the transition area 3 and changes from a pure PI prepreg layer to a mixed layer, and transitions to C prepreg in the same laying layer. The PI prepreg and C prepreg in the same laying layer are transitioned in a butting manner, and there is a butting gap reserved between the ends, and the PI prepreg and C prepreg are not connected by overlapping. As Figure 2 shown, the laying layers 8, 10, 12 are pure C prepreg layers, the laying layers 9, 11 are mixed layers, with PI prepreg on the left side and transitioning to C prepreg on the right side. The mixed layer 9 is arranged between the C prepreg layers 8, 10, and the mixed layer 11 is arranged between the C prepreg layers 10, 12. In the transition area 3, the lengths of the PI prepreg in different mixed layers are distributed in a gradient. The closer to the surface layer ( Figure 2 the lower part in
[0033] is the surface layer), the longer the length of the PI prepreg. The lengths of the PI prepreg on the left side in the mixed layers 9, 11, 13, 14 increase in sequence, forming a gradient section 6. Such a structure can improve the bonding strength between the hybrid laying area 2 and the matrix area 1 and avoid failure caused by the stress and strain incoordination between the PI prepreg and C prepreg.
[0034] In a preferred embodiment, each PI prepreg laying layer is laid at the same laying angle. AsFigure 2 As shown, the PI prepregs in the hybrid layers 9, 11, 13, and 14 are all laid at a laying angle of 0°.
[0035] In one embodiment, in combination with Figure 1 and Figure 2 , in the composite ply 5 and the gradient section 6, from the surface layer inwards, the laying method of the plies is:
[0036] [C0 / C45 / C0 / C-45 / PI0 / C45 / PI0 / C-45 / PI0 / C45 / PI0 / C-45 / C0 / C45 / C0], where C represents the C prepreg, PI represents the PI prepreg, and 0, 45, -45 respectively represent the laying angles of the prepregs. The matrix region 1 and the core 4 are laid by the C prepreg according to [0 / 45 / 0 / -45]2s.
[0037] After the prepregs are laid according to the above method and the laying of other regions is completed according to the laying diagram of the fan blade, the preform of the fan blade is loaded into a vacuum bag and cured according to the corresponding curing regime to obtain a finished composite aeroengine fan blade. The trailing edge region of the fan blade is a hybrid structure composed of the PI prepreg and the C prepreg. Through the reinforcement of the PI fibers, its trailing edge region has higher strength and toughness, and has better resistance to delamination and fracture in accidents such as bird strikes, effectively improving the performance and reliability of the fan blade.
[0038] In other embodiments, the fan blade can also be replaced by other composite parts, such as a fan containment casing, etc. Among them, the carbon fiber in the prepreg can also be replaced by other materials such as glass fiber or Kevlar fiber, and the PI fiber can also be replaced by other strengthening fiber materials with a strength higher than that of the matrix fiber, such as ceramic fiber.
[0039] The purpose of the above embodiments is to further elaborate on the present invention in combination with the accompanying drawings so that those skilled in the art can understand the technical concept of the present invention. Within the scope disclosed by the present invention, optimizing or equivalently replacing the part structures involved, and combining the implementation manners in different embodiments without conflict in structure and principle all fall within the protection scope of the present invention.
Claims
1. A composite material component, characterized in that, It includes a matrix region, a hybrid laying region, and a transition region; Among them, the matrix region is covered by the first type of ply; The hybrid laying region is covered by the first type of ply and the second type of ply, and only the first type of ply or the second type of ply is included in the same ply. The hybrid laying region forms at least part of the edge of the composite part; The transition region is covered by the first type of ply and the second type of ply, and at least part of the plies are configured as hybrid plies. The hybrid ply includes the first type of ply and the second type of ply; the first type of ply and the second type of ply in the hybrid ply are arranged in butt joint, and there is a butt joint gap between the first type of ply and the second type of ply. The hybrid ply is arranged between two layers of the first type of ply; within the transition region, the lengths of the second type of ply in different hybrid plies are set in a gradient manner, and the length of the second type of ply closer to the surface of the composite part is longer; The strength of the second type of ply is greater than that of the first type of ply.
2. The composite part according to claim 1, characterized in that, The butt joint gap is 0.2 mm - 0.3 mm.
3. The composite part according to claim 2, characterized in that, The projected distance of adjacent two butt joint gaps in the ply plane is not less than 20 mm.
4. The composite part according to claim 3, characterized in that, The length of the transition region along the gradient direction is not less than 70 mm.
5. The composite part according to claim 3, wherein The second type of ply is laid at the same laying angle.
6. The composite part according to claim 5, characterized in that, The laying angle of the second type of ply is 0°.
7. The composite part according to claim 6, characterized in that, In the hybrid laying region and the transition region, the laying method of at least part of the plies from the surface layer inward is [A0 / A45 / A0 / A - 45 / B0 / A45 / B0 / A - 45 / B0 / A45 / B0 / A - 45 / A0 / A45 / A0], where A represents the first type of ply, B represents the second type of ply, A0 is the first type of ply laid along the 0° direction, A45 is the first type of ply laid along the 45° direction, A - 45 is the first type of ply laid along the - 45° direction, and B0 is the second type of ply laid along the 0° direction.
8. The composite part according to claim 5, characterized in that, The laying method of the matrix region is [0 / 45 / 0 / -45]2s.
9. The composite part according to any one of claims 1 to 8, characterized in that, The composite part is configured as an aeroengine fan blade.
10. The composite part according to claim 9, characterized in that, The hybrid laying region is configured as the trailing edge of the aeroengine fan blade.