Anisotropic stiffness-adjustable carbon fiber composite elastic ring

Abstract

The application discloses a carbon fiber composite material elastic ring with adjustable anisotropic rigidity, and belongs to the technical field of composite material elastic elements. In order to solve the problem of interface fatigue risk caused by internal lattices or cavities in the existing elastic ring, and the problem of affecting the structural reliability, the application comprises a basic laminated ring body, the inner circumferential side and the outer circumferential side of the basic laminated ring body are fixedly connected with an inner ring structure and an outer ring structure respectively, the inner ring structure comprises a plurality of inner ring structure bearing areas and a plurality of inner ring structure non-bearing areas, the plurality of inner ring structure bearing areas and the plurality of inner ring structure non-bearing areas are sequentially and alternately arranged in the circumferential direction; the outer ring structure comprises a plurality of outer ring structure bearing areas and a plurality of outer ring structure non-bearing areas, the plurality of outer ring structure bearing areas and the plurality of outer ring structure non-bearing areas are sequentially and alternately arranged in the circumferential direction; the junctions of the inner ring structure bearing areas and the inner ring structure non-bearing areas and the junctions of the outer ring structure bearing areas and the outer ring structure non-bearing areas are all provided with transition areas, and the application is used in scenes such as elastic support of an aero-engine.

Description

Technical Field

[0001] This invention belongs to the field of composite material elastic element technology, specifically relating to an anisotropic stiffness adjustable carbon fiber composite elastic ring. Background Technology

[0002] Elastic rings are widely used elastic support elements in rotating machinery. Their basic function is to provide radial elastic support while maintaining reliable circumferential positioning accuracy. Traditional elastic rings are mostly made of isotropic metal materials such as alloy steel or titanium alloy, and their radial stiffness is equal to their circumferential stiffness, making it difficult to meet the specific requirements for stiffness in a particular direction. To obtain differentiated stiffness characteristics, complex geometric features such as bosses and notches are usually required on the elastic ring, but the design methods are limited and stress concentration occurs.

[0003] Carbon fiber reinforced resin matrix composites possess high specific strength, high specific modulus, and excellent fatigue resistance. Furthermore, the stiffness and strength of a single layer differ significantly along the fiber direction and perpendicular to the fiber direction, exhibiting typical anisotropic characteristics. By rationally designing the fiber angle, layup ratio, and layup sequence of each layer, customized designs for stiffness in different directions can be achieved at the macroscopic structural level.

[0004] In the prior art, CN115628275A discloses an elastic ring and its stiffness adjustment method, which uses a cavity with a lattice structure inside the boss to adjust the radial stiffness. This approach introduces a complex ordered lattice structure, and under alternating loads, the interface between the lattice and the ring body may become a fatigue weak point, making it difficult to guarantee long-term structural integrity. Therefore, there is an urgent need for an elastic ring that does not require a complex internal lattice and achieves circumferential variable stiffness through integrated structural design. Summary of the Invention

[0005] This application aims to address the problem of interfacial fatigue risk caused by internal lattice or cavities in existing elastic rings, which affects structural reliability, and provides an anisotropic stiffness adjustable carbon fiber composite elastic ring.

[0006] An anisotropic stiffness adjustable carbon fiber composite elastic ring, the elastic ring includes a base ply ring body, an inner ring structure is fixed to the inner circumference of the base ply ring body, and an outer ring structure is fixed to the outer circumference of the base ply ring body.

[0007] The inner ring structure includes multiple load-bearing areas and multiple non-load-bearing areas, which are alternately arranged along the circumference.

[0008] The outer ring structure includes multiple load-bearing areas and multiple non-load-bearing areas, which are alternately arranged along the circumference.

[0009] Transition zones are provided at the junction of the load-bearing zone and the non-load-bearing zone of the inner ring structure, and at the junction of the load-bearing zone and the non-load-bearing zone of the outer ring structure.

[0010] Furthermore, the inner ring structure bearing area includes an inner ring convex shell that protrudes radially inward and an inner cavity filler. The inner ring convex shell is fixed to the inner circumferential side of the base ply ring and forms an inner filling gap with the base ply ring. The inner cavity filler fills the inner filling gap.

[0011] The outer ring structure bearing area includes an outer ring convex shell that protrudes radially outward and an outer cavity filler. The outer ring convex shell is fixed to the outer peripheral side of the base ply ring and forms an outer filling gap with the base ply ring. The outer cavity filler fills the outer filling gap.

[0012] Furthermore, the central angles corresponding to the load-bearing area of ​​the inner ring structure and the load-bearing area of ​​the outer ring structure are both 8°~12°, and the wall thickness of the inner ring convex shell is equal to the wall thickness of the non-load-bearing area of ​​the inner ring structure everywhere, and the wall thickness of the outer ring convex shell is equal to the wall thickness of the non-load-bearing area of ​​the outer ring structure everywhere.

[0013] Furthermore, the base ply ring is constructed by layering and integrally curing carbon fiber reinforced resin matrix composite material. The base ply ring adopts symmetrical plying, and the ply sequence is [90°]. m / (0° / +45° / -45°) n ]s, where m and n are both positive integers, and n is an integer ≥3. In the basic ply ring, the sum of the number of ply with fiber orientation ±45° accounts for 60%~65% of the total number of ply rings, the number of 0° ply accounts for 25%~35% of the total number of ply rings, and the number of 90° ply accounts for 5%~10% of the total number of ply rings.

[0014] Furthermore, both the inner and outer ring non-load-bearing regions are constructed from carbon fiber reinforced resin matrix composites through layer-by-layer layup and integral curing. Both the inner and outer ring non-load-bearing regions employ symmetrical layup, with a layup sequence of [0°]. p / (+45° / -45°) q ]s, where p and q are both positive integers, in the non-load-bearing areas of the inner ring structure and the outer ring structure, the number of layups with the fiber orientation at 0° accounts for 60% to 80% of the total number of local layers in this area;

[0015] Furthermore, both the inner and outer ring convex shells are constructed from carbon fiber reinforced resin matrix composites through layer-by-layer layup and integral curing. Both the inner and outer ring convex shells employ symmetrical layup, with a layup sequence of [90°]. e / (+45° / -45°)f ]s, where e and f are both positive integers, in the layup of the inner and outer ring convex shells, the number of layups with fiber orientation at 90° accounts for 50% to 80% of the total number of layers in the local area;

[0016] Furthermore, the circumferential range of the transition zone is 5°~15°. The ends of each layer in the non-load-bearing zone of the transition zone are processed into a slope shape, and the slopes at the ends of adjacent ply groups are staggered in the circumferential direction to form an overlapping step. The non-load-bearing zone in the transition zone is erected on the load-bearing zone in the transition zone through the overlapping step.

[0017] Furthermore, in the non-load-bearing zone of the transition zone, the circumferentially offset distance between the end slopes of adjacent ply groups is 15% to 30% of the circumferential arc length of the transition zone, and is not less than 20 times the curing thickness of a single layer;

[0018] Furthermore, the height of the inner ring convex shell and the radial height of the outer ring convex shell are both 0.5 to 0.8 times the thickness of the elastic ring. Both the inflection point of the inner ring convex shell and the inflection point of the outer ring convex shell are provided with transition fillets, and the radius R of the transition fillets is 0.4 to 0.8 times the radial height of the convex shell.

[0019] Furthermore, both the inner cavity filler and the outer cavity filler are resin-based short-cut carbon fiber clusters or resin-based short-cut glass fiber clusters, and the interior of both the inner cavity filler and the outer cavity filler are disordered structures.

[0020] The beneficial effects of this application compared to the prior art are:

[0021] 1. This application provides an anisotropic stiffness adjustable carbon fiber composite elastic ring. Through targeted design of fiber angles in each region of the ring, the non-load-bearing area has high circumferential stiffness to resist centrifugal expansion, and the load-bearing area has low radial stiffness to provide the required elastic support. This achieves a circumferential variable stiffness distribution in the same ring body, which can adapt to the stringent requirements of aero-engine elastic supports for differentiated stiffness.

[0022] 2. The anisotropic stiffness adjustable carbon fiber composite elastic ring provided in this application has a design with equal wall thickness for the load-bearing convex shell and non-load-bearing area of ​​the inner and outer ring structures, which avoids stiffness abrupt changes and stress concentration caused by abrupt changes in thickness, and can be adapted to the requirements of aero-engine rotor dynamics for a smooth transition of stiffness.

[0023] 3. The anisotropic stiffness adjustable carbon fiber composite elastic ring provided in this application designs the load-bearing area as an integral solid structure composed of a continuously laid fiber shell and a disordered short-cut fiber filler, completely eliminating the internal lattice or cavity, fundamentally eliminating the weak link of interface fatigue, and meeting the design requirements of long life and high reliability of aero-engines.

[0024] 4. The anisotropic stiffness adjustable carbon fiber composite elastic ring provided in this application can independently adjust the radial and circumferential stiffness of the load-bearing and non-load-bearing areas within a large range by flexibly adjusting the layup parameters of each part, which has a large degree of design freedom and strong adaptability. Attached Figure Description

[0025] Figure 1 This is a three-dimensional schematic diagram of an anisotropic stiffness adjustable carbon fiber composite elastic ring as described in this application.

[0026] Figure 2 This is a schematic diagram of the layup of the base layer ring in an anisotropic stiffness adjustable carbon fiber composite elastic ring as described in this application.

[0027] Figure 3 This is a schematic diagram of the plying of the convex shell portion of the inner (outer) ring structure of the anisotropic stiffness adjustable carbon fiber composite elastic ring described in this application.

[0028] Figure 4 This is a schematic diagram of the layup of the non-load-bearing region of the inner (outer) ring structure of an anisotropic stiffness adjustable carbon fiber composite elastic ring as described in this application.

[0029] Figure 5 This is a schematic diagram of the stepped overlap of the transition zone of the inner (outer) ring structure of an anisotropic stiffness adjustable carbon fiber composite elastic ring as described in this application.

[0030] The structure consists of: 1 inner ring convex shell, 2 inner cavity filler, 3 foundation ply ring, 4 outer ring convex shell, 5 outer cavity filler, 6 inner ring structure non-load-bearing area, 7 outer ring structure non-load-bearing area, and 8 transition area. Detailed Implementation

[0031] Specific implementation method one: Combining Figures 1 to 5 This embodiment describes an anisotropic stiffness-adjustable carbon fiber composite elastic ring, which includes a base ply ring 3. An inner ring structure is fixed to the inner circumference of the base ply ring 3, and an outer ring structure is fixed to the outer circumference of the base ply ring 3. The inner ring structure includes multiple inner ring structure load-bearing areas and multiple inner ring structure non-load-bearing areas 6, which are alternately arranged in the circumferential direction. The outer ring structure includes multiple outer ring structure load-bearing areas and multiple outer ring structure non-load-bearing areas 7, which are alternately arranged in the circumferential direction. A transition area 8 is provided at the junction of the inner ring structure load-bearing areas and the inner ring structure non-load-bearing areas 6, and at the junction of the outer ring structure load-bearing areas and the outer ring structure non-load-bearing areas 7.

[0032] In this embodiment, the base ply ring 3 is a base ply ring continuously laid within a 360° circumference. The base ply ring 3 adopts a symmetrical ply, and the ply sequence is [90°]. m / (0° / +45° / -45°) n ]s, where s represents symmetry, m and n are both positive integers, and n is an integer ≥3, and the layup of the basic ply ring is such that the number of layups with fiber orientation ±45° accounts for 60%~65% of the total number of layers in the basic ply ring, the number of 0° layups accounts for 25%~35%, and the number of 90° layups accounts for 5%~10%. The symmetrical layup arrangement can avoid warping deformation during the curing process, ensure the roundness and dimensional accuracy of the ring structure, and at the same time, the symmetrical design also prevents the elastic ring from generating additional bending moment under load, effectively improving the stability of rotor dynamics. Among them, the number of layups with fiber orientation ±45° accounts for the largest proportion in the basic ply ring 3, and its purpose is to transfer shear bearing capacity. The elastic ring needs to withstand torque, centrifugal force and radial load in rotating machinery. Layups with fiber orientation ±45° can effectively transfer shear stress, avoid interlayer delamination or in-plane shear failure, and also enhance the adaptability of the structure to circumferential loads, especially under high speed conditions. To resist diameter expansion deformation, the 0° fiber direction layup is located on both sides of the ±45° fiber direction layup. Its purpose is to provide the necessary axial stiffness and prevent excessive deformation. The 90° fiber direction layup is located on the outermost side and has the smallest proportion. This is to avoid excessive radial stiffness of the ring structure and to ensure that the elastic ring has sufficient flexibility in the radial direction to provide the required elastic support. The number of 0° fiber direction layup and ±45° fiber direction layup groups is greater than or equal to 3 groups. Its purpose is to ensure that the fibers in each direction are evenly distributed in the thickness direction, avoid local stiffness concentration, and ensure that the base layup ring 3 has good comprehensive mechanical properties.

[0033] In this embodiment, multiple inner ring structural bearing areas and multiple outer ring structural bearing areas are staggered, and the distance between each inner ring structural bearing area and the two adjacent outer ring structural bearing areas is equal. The central angles corresponding to the inner and outer ring structural bearing areas are both 8°~12°. Each inner ring structural bearing area includes a radially protruding inner ring shell 1 and an inner cavity filler 2. The inner ring shell 1 is fixed to the inner circumferential side of the base ply ring 3 and forms an inner filling gap with the base ply ring 3. The inner cavity filler 2 fills the inner filling gap. The outer ring structural bearing area includes a... The outer ring protrusion 4 and the outer cavity filler 5 protrude radially outward. The outer ring protrusion 4 is fixed to the outer periphery of the base ply ring 3 and forms an outer filling gap with the base ply ring 3. The outer cavity filler 5 fills the outer filling gap. The wall thickness of the inner ring protrusion 1 is equal to the wall thickness of the non-load-bearing area 6 of the inner ring structure everywhere, and the wall thickness of the outer ring protrusion 4 is equal to the wall thickness of the non-load-bearing area 7 of the outer ring structure everywhere. Both the inner ring protrusion 1 and the outer ring protrusion 4 are made of carbon fiber reinforced resin matrix composite material through layer-by-layer layup and integral curing. The inner ring protrusion 1 and the outer ring protrusion 4 also adopt symmetrical layup, and the layup sequence is [90°]. e / (+45° / -45°) f ]s, where e and f are both positive integers. In the ply of the inner ring convex shell 1 and the outer ring convex shell 4, the number of ply with a fiber direction of 90° accounts for 50% to 80% of the total number of ply in this local area. The proportion of ply with a fiber direction of 90° is the largest in the inner ring convex shell 1 and the outer ring convex shell 4. The purpose is to reduce the radial compressive stiffness of the load-bearing areas of the inner ring structure and the outer ring structure, so as to achieve the function of elastic support. Between the two ply groups with a fiber direction of 90°, a ply group with a fiber direction of ±45° is set with a smaller number of ply groups. The purpose is to transfer shear stress and avoid interlayer delamination or in-plane shear failure during radial compression or bending deformation. The inner cavity filler 2 and the outer cavity filler 5 form an integrated solid structure with the corresponding convex shell structure. The inner cavity filler 2 and the outer cavity filler 5 have the same structural composition, both being resin-based short-cut carbon fiber clusters or resin-based short-cut glass fiber clusters or a combination of both, wherein the resin content is 33%~38% by mass. The interior of the inner cavity filler 2 and the interior of the outer cavity filler 5 are both disordered structures. The design of the inner cavity filler 2 and the outer cavity filler 5 completely eliminates the lattice and cavity inside the ring body, fundamentally eliminating the risk of interface fatigue. The disordered structure ensures that the filler will not produce significant stiffness enhancement in a certain direction like continuous fiber layup, thus not interfering with the low radial stiffness characteristics set by the convex shell in the load-bearing area. At the same time, the disordered structure can also provide uniform support and compressive strength in all directions, avoiding local stress concentration.

[0034] In this embodiment, both the inner ring structure non-load-bearing region 6 and the outer ring structure non-load-bearing region 7 are constructed by layering and integrally curing carbon fiber reinforced resin matrix composite material. Furthermore, both the inner ring structure non-load-bearing region 6 and the outer ring structure non-load-bearing region 7 employ symmetrical layering, with the layering sequence being [0°]. p / (+45° / -45°) q ]s, where p and q are both positive integers. In the layups of the inner ring structure non-load-bearing region 6 and the outer ring structure non-load-bearing region 7, the number of layups with a fiber direction of 0° accounts for 60%~80% of the total number of local layers in this region. The inner ring structure non-load-bearing region 6 and the outer ring structure non-load-bearing region 7 contrast with the inner ring convex shell 1 and the outer ring convex shell 4. The number of layups with a fiber direction of 0° in the non-load-bearing region accounts for 60%~80% of the total number of local layers in this region, which makes the non-load-bearing region have extremely high tensile and compressive stiffness in the circumferential direction. When rotating machinery is working, the elastic ring tends to expand outward under the action of centrifugal force. The high circumferential stiffness can effectively resist centrifugal expansion deformation, ensure the circumferential positioning accuracy of the elastic ring and adjacent components, and avoid fit failure due to expansion.

[0035] In this embodiment, the circumferential range of the transition zone 8 is 5°~15°. The ends of each layer in the non-load-bearing area of ​​the transition zone 8 are processed into a slope shape, and the slopes at the ends of adjacent ply groups are staggered circumferentially, forming overlapping steps. The non-load-bearing area in the transition zone 8 is erected on the load-bearing area within the transition zone 8 via these overlapping steps. The circumferential stagger distance between the slopes at the ends of adjacent ply groups in the non-load-bearing area of ​​the transition zone 8 is 15%~30% of the circumferential arc length of the transition zone, and not less than 20 times the single-layer cured thickness. The ply groups in the non-load-bearing area of ​​the transition zone 8 are obtained by stacking multiple ply layers, such as... Figure 4 and Figure 5 As shown, the non-load-bearing zone comprises three ply groups: two ply groups with fiber orientations of 0° and one ply group with fiber orientations of ±45°. The circumferential offset of the end ramps of adjacent ply groups is equal to the overall offset of the upper ply group relative to the lower ply group. This circumferential offset is 15% to 30% of the circumferential arc length of the transition zone. This is to ensure that each step has sufficient circumferential contact length to fully transfer the load without slippage or local debonding. The single-layer cured thickness is typically 0.1 to 0.2 mm, and 20 times that is 2 to 4 mm. This lower limit requirement ensures that the circumferential overlap length of each step is much greater than the layer thickness. According to the mechanics of composite laminates, the overlap length is proportional to the interlaminar shear strength. Sufficiently long overlaps can prevent interlayer delamination in the transition zone, especially in areas with high interlayer shear stress under alternating radial loads. The transition zone 8 achieves gradual changes in fiber angle and smooth transition of stiffness through the slope and stepped overlap at the ends of the layers, effectively alleviating stress abrupt changes between different stiffness regions and improving the operational stability of the rotor system.

[0036] In this embodiment, the carbon fiber reinforced resin matrix composite material used for layup in the basic layup ring 3, inner ring structure and outer ring structure has a fiber volume content of 60%~65% and a resin volume content of 35%~40% after curing.

[0037] Specific Implementation Method Two: Combining Figures 1 to 5 This embodiment further defines the inner ring convex shell 1 and the outer ring convex shell 4 in specific embodiment one. The radial height of the inner ring convex shell 1 and the radial height of the outer ring convex shell 4 are both 0.5 to 0.8 times the thickness of the elastic ring. Both the inflection point of the inner ring convex shell 1 and the inflection point of the outer ring convex shell 4 are provided with transition fillets. The radius R of the transition fillet is 0.4 to 0.8 times the radial height of the convex shell. Other components and connection methods are the same as in specific embodiment one.

[0038] In this embodiment, the greater the height of the convex shell, the lower the radial stiffness of the load-bearing area, and the more significant the elastic support effect. However, excessive height will lead to an increase in the overall radial dimension and may cause instability. A convex shell with a height in the range of 0.5 to 0.8 times the thickness of the elastic ring has moderate radial flexibility, which can provide the required amount of elastic deformation while avoiding excessive softening and instability. The transition fillet at the inflection point of the convex shell is to enable continuous conformal laying between the load-bearing and non-load-bearing areas, avoiding stress concentration caused by sharp corners. At the same time, the fillet design avoids sharp inner and outer corners, which is beneficial to the conformability of the prepreg layup at the corners and reduces defects such as bridging and wrinkles.

[0039] Example:

[0040] Example 1: This example provides an anisotropic stiffness adjustable carbon fiber composite elastic ring, which is a ring structure formed by layer-by-layer layup and integral curing of carbon fiber reinforced resin matrix composite material. The outer diameter of the base layup ring is 200 mm, and the total wall thickness is 10.0 mm. The ring structure includes a base layup ring 3, an inner ring structure, and an outer ring structure. The base layup ring 3 is a base layup ring uniformly laid within a 360° range around the circumference, adopting a symmetrical layup design, with a layup sequence of [90° / (0° / +45° / -45°)5]s (i.e., n=5), a single layer curing thickness of 0.125 mm, a total of 32 layers, and a total thickness of 4.0 mm, accounting for 40% of the total wall thickness; among which, the ±45° layup accounts for 62.5%, the 0° layup accounts for 31.25%, and the 90° layup accounts for 6.25%, ensuring good comprehensive mechanical properties of the matrix;

[0041] The inner ring structure is located on the inner circumference of the foundation ply ring 3, and the outer ring structure is located on the outer circumference of the foundation ply ring 3. Both the inner and outer ring structures are alternately divided into eight load-bearing zones and eight non-load-bearing zones along the circumference. The central angle of each load-bearing zone is 10°. A transition zone (inner (outer) ring structure transition zone) with a circumferential span of 10° is provided at the boundary between the load-bearing and non-load-bearing zones. The total wall thickness of the ring structure is equal everywhere in both the load-bearing and non-load-bearing zones.

[0042] The carbon fiber layup methods for the inner ring structure and the outer ring structure are exactly the same. The following describes the inner ring structure as an example in detail. The layup method and structure of the outer ring structure are the same as those of the inner ring structure. The only difference is that the bosses of the outer ring structure protrude outward along the radial direction.

[0043] In the non-load-bearing zone 6 of the inner ring structure, a local reinforcement layer is laid on the inner surface of the foundation ply ring 3 (near the inner ring side), and the ply sequence is [0° 10 The fiber has 24 layers (+45° / -45°), a thickness of 3.0 mm, and accounts for 30% of the total wall thickness. The 0° fiber accounts for 83.3%, giving the area extremely high circumferential tensile stiffness and effectively resisting centrifugal expansion under high-speed rotation.

[0044] In the load-bearing area of ​​the inner ring structure, a local reinforcing layer is laid on the inner surface of the base ply ring 3, and continuously laid together with the base ply ring 3 along with the mold surface, forming a radially protruding boss in the middle of the load-bearing area, namely the inner ring structure boss 1. The ply sequence of this local reinforcing layer is [90° 10 The annular body, consisting of 24 layers (+45° / -45°), is 3.0 mm thick, accounting for 30% of the total wall thickness. 90° fibers comprise 83.3% of the structure, significantly reducing the radial compressive stiffness in the load-bearing area and achieving elastic support. The total wall thickness of the annular body is 10.0 mm in both the load-bearing and non-load-bearing areas, remaining constant throughout.

[0045] The inner ring structure boss 1 has a radial height of 6 mm, is located in the circumferential center of the load-bearing area, has a central angle of 10°, and a transition fillet with a radius of R=4 mm at its root. All layers of the base ply ring 3 and the 3.0 mm local reinforcement layer of the load-bearing area forming the boss shell are continuously laid conformally on the boss sidewalls and at the transition fillets, forming a 10.0 mm thick fiber shell. Before curing, a filler made of chopped carbon fibers and epoxy resin, i.e., the inner cavity filler 2, is filled into the cavity enclosed by this fiber shell. The chopped carbon fibers are 5-15 mm in length, randomly oriented, and fully impregnated with the resin. After curing, the filler exhibits an isotropic disordered structure, solidifying with the fiber shell into an integrated solid structure. It has no internal lattice or cavities, serving only to uniformly transfer and distribute external loads, thus avoiding the risk of interfacial fatigue.

[0046] The inner (outer) ring structure transition zone 8 is located between the circumferential boundary of the load-bearing zone and the non-load-bearing zone, with a span of 10°. The fiber angle of the local reinforcement layer in the transition zone gradually transitions from 90° to 0°, and the ends of each ply group are processed into a slope shape. The slopes at the ends of adjacent ply groups are staggered by 3 mm in the circumferential direction, forming a strong stepped overlap, which ensures the structural integrity and a smooth transition of stiffness.

[0047] The outer ring structure is laid up with reference to the inner ring structure, the difference being that the local reinforcement layer of the outer ring structure is laid on the outer surface of the base ply ring 3, and its load-bearing area forms a radially outward protrusion (outer ring structure protrusion 4). The inner cavity of the protrusion is filled with the outer ring structure protrusion cavity filler 5. The non-load-bearing area is the outer ring structure non-load-bearing area 7, and the transition area is the inner (outer) ring structure transition area 8. The ply sequence, number of layers, thickness, and protrusion size of the outer ring structure are the same as those of the inner ring structure.

[0048] This embodiment uses T800 grade carbon fiber reinforced and toughened epoxy resin prepreg, with a resin content of 35% by mass. The prepreg is cured in an autoclave at 180°C and 0.6 MPa, resulting in a composite material with a fiber volume content of 62% and a resin volume content of 38%. This material exhibits both high load-bearing capacity and excellent fatigue resistance, making it particularly suitable for elastic supports for high-pressure rotors in aero-engines.

[0049] Example 2: This embodiment is basically the same as the structure and layup principle of Specific Embodiment 1. The difference lies in the boss size, filler type and transition zone parameters, in order to adapt to medium load and reduce cost scenarios.

[0050] The outer diameter of the base ply ring remains 200 mm. The ply sequence, total number of layers, and total wall thickness of the base ply ring and local reinforcing layers are the same as in Implementation Method 1. The radial height of the inner ring structure boss 1 and the outer ring structure boss 4 are both adjusted to 7 mm to further reduce radial stiffness; the transition radius at the root of the boss is increased to R=5 mm to further alleviate stress concentration. The filler is made of resin-based chopped glass fiber bundles with a length of 8~20 mm, which are mixed with epoxy resin and filled into the inner cavity of the fiber shell. After curing, the glass fiber filler also exhibits a disordered structure, which can effectively transfer loads and significantly reduce costs compared to carbon fiber fillers. The circumferential span of the transition zone 8 of the inner (outer) ring structure is selected as 12°, and the end slopes of adjacent ply groups are staggered by 4 mm circumferentially to make the stiffness transition more gradual. The prepreg resin content is increased to 38%, and the fiber volume content after curing is 60%. This elastic ring is suitable for cost-sensitive and lower radial stiffness requirements in the elastic support unit of the aero-engine accessory casing.

[0051] Example 3: This embodiment provides a design scheme with higher radial stiffness and lower contact stress level in the load-bearing area, focusing on optimizing the boss structure, infill and transition area.

[0052] The outer diameter of the base ply ring is 200 mm. The ply scheme for the base ply ring body and the local reinforcement layers of the inner and outer rings is the same as in Implementation Method 1. The radial height of both the inner ring structural boss 1 and the outer ring structural boss 4 is reduced to 5 mm, and the radius of the transition corner at the root of the boss is R=3 mm to reduce the space occupied by the structure, while still ensuring continuous fiber laying at the corner to avoid stress concentration. The filler is a 1:1 volume ratio mixture of chopped carbon fiber and chopped glass fiber, with 5% by weight of core-shell rubber nanoparticles toughened epoxy resin added as the matrix. After the mixed filler is cured in the fiber shell, it forms a disordered distribution structure, which has good load dispersion capability and further improves the impact toughness and damping characteristics of the boss area through the rubber particles. The transition zone span is 5°, and the end slopes of adjacent ply groups are staggered by 2.5 mm in the circumferential direction. This minimizes the circumferential dimension of the transition zone while ensuring a smooth transition, which is beneficial to the overall structural compactness. The prepreg resin content is 33%, and the fiber volume content is 65%. This solution is suitable for high-speed, heavy-duty flexible couplings with high radial stiffness requirements and large impact loads.

[0053] This application has disclosed preferred embodiments above, but it is not intended to limit this application. Any person skilled in the art should be able to make some modifications or alterations to the structure and technical content disclosed above, without departing from the scope of the technical solution of this application, to form equivalent embodiments. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. An anisotropic, adjustable stiffness carbon fiber composite elastic ring, characterized in that: The elastic ring includes a base ply ring (3), with an inner ring structure fixed to the inner circumference of the base ply ring (3) and an outer ring structure fixed to the outer circumference of the base ply ring (3). The inner ring structure includes multiple inner ring structure load-bearing areas and multiple inner ring structure non-load-bearing areas (6), and the multiple inner ring structure load-bearing areas and multiple inner ring structure non-load-bearing areas (6) are arranged alternately along the circumference; The outer ring structure includes multiple outer ring structure load-bearing areas and multiple outer ring structure non-load-bearing areas (7), and the multiple outer ring structure load-bearing areas and multiple outer ring structure non-load-bearing areas (7) are arranged alternately along the circumference; A transition zone (8) is provided at the junction of the load-bearing area of ​​the inner ring structure and the non-load-bearing area of ​​the inner ring structure (6) and at the junction of the load-bearing area of ​​the outer ring structure and the non-load-bearing area of ​​the outer ring structure (7).

2. The anisotropic stiffness-adjustable carbon fiber composite elastic ring according to claim 1, characterized in that: The inner ring structure bearing area includes an inner ring convex shell (1) that protrudes radially inward and an inner cavity filler (2). The inner ring convex shell (1) is fixed to the inner circumferential side of the base ply ring (3) and forms an inner filling gap with the base ply ring (3). The inner cavity filler (2) fills the inner filling gap. The outer ring structure bearing area includes an outer ring convex shell (4) that protrudes radially outward and an outer cavity filler (5). The outer ring convex shell (4) is fixed to the outer periphery of the base ply ring (3) and forms an outer filling gap with the base ply ring (3). The outer cavity filler (5) fills the outer filling gap.

3. The anisotropic stiffness-adjustable carbon fiber composite elastic ring according to claim 2, characterized in that: The central angles corresponding to the load-bearing area of ​​the inner ring structure and the load-bearing area of ​​the outer ring structure are both 8°~12°. The wall thickness of the inner ring convex shell (1) is equal to the wall thickness of the non-load-bearing area (6) of the inner ring structure everywhere, and the wall thickness of the outer ring convex shell (4) is equal to the wall thickness of the non-load-bearing area (7) of the outer ring structure everywhere.

4. The anisotropic stiffness-adjustable carbon fiber composite elastic ring according to claim 3, characterized in that: The base ply ring (3) is formed by layering carbon fiber reinforced resin matrix composite material and integrally curing it. The base ply ring (3) adopts symmetrical plying, and the ply sequence is [90° m / (0° / +45° / -45°) n ]s, where m is a positive integer and n is an integer ≥3. In the basic ply ring, the sum of the number of ply with fiber orientation ±45° accounts for 60%~65% of the total number of ply rings, the number of 0° ply accounts for 25%~35% of the total number of ply rings, and the number of 90° ply accounts for 5%~10% of the total number of ply rings.

5. The anisotropic stiffness-adjustable carbon fiber composite elastic ring according to claim 4, characterized in that: Both the inner ring structure non-load-bearing region (6) and the outer ring structure non-load-bearing region (7) are constructed by layering and integrally curing carbon fiber reinforced resin matrix composites. Both the inner ring structure non-load-bearing region (6) and the outer ring structure non-load-bearing region (7) employ symmetrical layups, with a layup sequence of [0°]. p / (+45° / -45°) q ]s, where p and q are both positive integers. In the non-load-bearing area (6) of the inner ring structure and the non-load-bearing area (7) of the outer ring structure, the number of layups with fiber direction of 0° accounts for 60% to 80% of the total number of local layers in this area.

6. The anisotropic stiffness-adjustable carbon fiber composite elastic ring according to claim 5, characterized in that: Both the inner ring convex shell (1) and the outer ring convex shell (4) are made of carbon fiber reinforced resin matrix composite material through layer-by-layer layup and integral curing. Both the inner ring convex shell (1) and the outer ring convex shell (4) adopt symmetrical layup, and the layup sequence is [90°]. e / (+45° / -45°) f ]s, where e and f are both positive integers. In the inner ring convex shell (1) and outer ring convex shell (4) layup, the number of layup with fiber direction of 90° accounts for 50%~80% of the total number of local layers in this area.

7. The anisotropic stiffness-adjustable carbon fiber composite elastic ring according to claim 1, characterized in that: The circumferential range of the transition zone (8) is 5°~15°. The ends of each layer in the non-load-bearing area of ​​the transition zone (8) are processed into a slope shape, and the slopes at the ends of adjacent ply groups are staggered in the circumferential direction to form an overlapping step. The non-load-bearing area in the transition zone (8) is erected on the load-bearing area in the transition zone (8) through the overlapping step.

8. The anisotropic stiffness-adjustable carbon fiber composite elastic ring according to claim 1, characterized in that: In the transition zone (8), the slopes at the ends of adjacent ply groups in the non-load-bearing zone are staggered in the circumferential direction by 15% to 30% of the circumferential arc length of the transition zone, and not less than 20 times the thickness of a single layer of curing.

9. The anisotropic stiffness-adjustable carbon fiber composite elastic ring according to claim 2, characterized in that: The radial height of the inner ring convex shell (1) and the radial height of the outer ring convex shell (4) are both 0.5 to 0.8 times the thickness of the elastic ring. The inflection point of the inner ring convex shell (1) and the inflection point of the outer ring convex shell (4) are provided with transition fillets, and the radius R of the transition fillets is 0.4 to 0.8 times the radial height of the convex shell.

10. The anisotropic stiffness-adjustable carbon fiber composite elastic ring according to claim 2, characterized in that: The inner cavity filler (2) and the outer cavity filler (5) are both resin-based short-cut carbon fiber clusters or resin-based short-cut glass fiber clusters or a combination of the two, and the interior of the inner cavity filler (2) and the interior of the outer cavity filler (5) are both disordered structures.

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