A partitioned multi-configuration composite fairing and a design method thereof

Abstract

The application belongs to the technical field of composite material casing structure design of an aero-engine, and particularly discloses a partitioned multi-configuration composite material casing and a design method thereof. The casing body is a thin-walled rotary body structure, and includes an inner stiffness maintaining layer, an intermediate lightweight stiffness coordinating layer and an outer containment energy absorption layer which are sequentially arranged along the radial direction from inside to outside. The inner stiffness maintaining layer adopts a two-dimensional woven structure, the intermediate lightweight stiffness coordinating layer adopts a variable stiffness laminated structure with spatially varying fiber laying angles, and the outer containment energy absorption layer adopts a three-dimensional woven structure. The casing of the application forms a continuously transferred load bearing and energy dissipation path from inside to outside by configuring composite material layers with different organizational structures and mechanical properties in the radial direction of the casing. The casing of the application is beneficial to taking into account the profile stability, lightweight, impact resistance and damage tolerance, and improves the problem that a single material or a single structure form is difficult to meet the multi-performance collaborative demand.

Description

Technical Field

[0001] This invention belongs to the technical field of composite material casing structure design for aero-engines, specifically relating to a partitioned multi-configuration composite material casing and its design method. Background Technology

[0002] Thin-walled rotating components such as the fan casing, compressor casing, and bypass casing of aero-engines are crucial for ensuring the engine's containment and structural integrity. With the development of resin-based composite material technology, composite material casings, with their advantages of high specific strength, strong design flexibility, and significant weight reduction, have been gradually applied to aero-engine casing structures.

[0003] During service, aero-engine casings must simultaneously withstand multiple dynamic loads, including vibration loads, aerodynamic loads, inertial loads, and localized impact loads, and may also face complex conditions such as blade fracture impacts, blade tip rubbing, and foreign object impacts. Therefore, composite material casings not only need to meet overall strength and stiffness requirements, but also need to consider various performance requirements such as internal wall surface stability, load transfer efficiency, interlaminar safety, impact resistance, damage tolerance, and lightweight structure. How to achieve a coordinated match between these performance characteristics while controlling structural quality is a crucial technical problem that needs to be solved in the design of composite material casings.

[0004] Existing composite material casings typically employ one of three main load-bearing structures: laminated, two-dimensional braided, or three-dimensional woven. Laminated structures offer flexibility in layup design, adjustable in-plane mechanical properties, and relatively mature molding processes; however, their thickness-direction reinforcement is relatively limited, making them prone to interlaminar stress concentration and delamination damage under impact loads. Two-dimensional braided structures possess good in-plane integrity and multi-directional load-bearing capacity, but their thickness-direction fiber reinforcement remains limited, making it difficult to adequately suppress the propagation of interlaminar damage. Three-dimensional woven structures, by incorporating thickness-direction reinforcing yarns, can improve the structure's resistance to delamination, impact resistance, and damage tolerance; however, when used as the main structure across the entire thickness range of the casing, they may present challenges such as limited fiber configuration design, reduced in-plane stiffness utilization efficiency, increased structural mass, and complex manufacturing processes.

[0005] Since different composite material structures have their own advantages and disadvantages in terms of stiffness maintenance, load transfer, impact energy absorption and damage suppression, it is difficult to meet the comprehensive performance requirements of inner wall surface stability, lightweight load bearing, impact energy absorption and interlaminar damage control within the radial thickness range of the casing by using a single material configuration or a single reinforcement structure. Summary of the Invention

[0006] The purpose of this invention is to solve the problem that composite material casings are difficult to simultaneously achieve internal wall surface stability, load coordination and transfer, interlayer safety and impact energy absorption under the constraint of lightweighting. A partitioned multi-configuration composite material casing and its design method are proposed.

[0007] The technical solution of this invention is as follows: This invention provides a partitioned, multi-configuration composite material casing, including a casing body. The casing body is a thin-walled rotating composite material structure. The casing body has a functionally layered heterogeneous structure, including an inner stiffness-retaining layer, a middle lightweight stiffness-coordinating layer, and an outer energy-absorbing layer that are radially stacked and interconnected from the inside to the outside. The inner stiffness retention layer adopts a two-dimensional triaxial braided structure to maintain the stability of the inner wall surface of the casing body and to diffuse the load input from the inside. The intermediate lightweight stiffness coordination layer adopts a variable angle laminate structure, which is used to transfer and redistribute loads between the inner stiffness retention layer and the outer energy absorption layer. The outer enclosing energy-absorbing layer adopts a three-dimensional woven reinforcement structure to withstand the impact load transmitted from the inner side to the outer side of the casing body and absorb the impact energy.

[0008] Preferably, the two-dimensional triaxial knitting structure includes axial yarns, positive off-axis yarns, and negative off-axis yarns. The axial yarns are arranged along the axial direction of the casing body, and the positive and negative off-axis yarns are arranged at 0° / ±θ° relative to the axial direction of the casing body, thereby forming a multi-directional load-bearing system of 0° / ±θ°, where θ is 30° to 75°.

[0009] Preferably, the variable angle laminate structure includes at least two sets of layers with different fiber layup angles, wherein the fiber layup angles are selected from at least two of 0°, ±45°, 90° and ±60°; At least one of the following factors in the variable angle laminate structure—ply angle, ply ratio, fiber angle difference between adjacent layers, or ply thickness percentage—varies along the axial direction of the casing body and / or the lamination direction of the intermediate lightweight stiffness coordinating layer.

[0010] Preferably, the angle difference between adjacent fiber groups in the variable angle laminate structure varies in a piecewise gradient along the stacking direction of the intermediate lightweight stiffness coordination layer; the piecewise gradient variation is set according to a linear gradient, exponential gradient, power function gradient or S-shaped gradient.

[0011] Preferably, the three-dimensional woven reinforcement structure is one or more of the following: a three-dimensional orthogonal woven structure, a three-dimensional angular interlocking woven structure, a shallow cross-bending three-dimensional woven structure, a multi-layer splicing woven structure, a through-joining woven structure, and a three-dimensional fabric structure containing Z-direction reinforcing yarns. When the three-dimensional woven reinforcement structure includes two or more structures, the different structures are arranged in sections along the axial direction of the casing body and / or the stacking direction of the outer energy-absorbing layer.

[0012] Preferably, an interface transition layer is provided between the inner stiffness retention layer and the middle lightweight stiffness coordination layer, and between the middle lightweight stiffness coordination layer and the outer enclosing energy absorption layer. The interface transition layer is composed of one or more of the following: a short fiber reinforcement layer, a thermoplastic elastomer intermediate layer, a resin toughening layer, a particle reinforcement layer, and a damping film layer.

[0013] Preferably, the inner stiffness retention layer is provided with a wear-resistant and impact-resistant surface layer on the side facing the inner cavity of the casing body.

[0014] Preferably, the casing body is provided with multiple functional areas along the axial direction, including an end mounting area, a main body area, a blade containment area, a blade tip corresponding area, and an inlet / outlet transition area, with different load-bearing thicknesses in different functional areas.

[0015] Preferably, the load-bearing thickness of the casing body in each functional area is composed of the thickness of the inner stiffness retention layer, the middle lightweight stiffness coordination layer, and the outer energy-absorbing layer. The load-bearing thickness of the casing body in the blade containment area is greater than that in the main body shell area; the load-bearing thickness of the casing body in the main body shell area is less than that in the end mounting area. The blade containment area has a different thickness or thickness ratio than at least one of the inner stiffness retention layer, the intermediate lightweight stiffness coordination layer, and the outer containment energy absorption layer in the main body area.

[0016] This invention provides a design method for a partitioned multi-configuration composite material casing, applicable to the partitioned multi-configuration composite material casing described in any of the above embodiments, the method comprising: Step 1: Establish the geometric model and finite element model of the composite material casing, divide the casing body into axial functional areas, and define the macroscopic equivalent material performance parameters of the two-dimensional triaxial braided structure, the three-dimensional woven reinforcement structure, and the variable angle laminated structure. Step 2: Based on the service conditions of the composite material casing, determine the inner wall radial deformation limit, impact energy absorption requirements, interlayer safety requirements, and structural mass constraints; Step 3: Define the functional layer parameters for each functional layer and the interface transition layer parameters between different functional layers, and use the interface transition layer parameters and the functional layer parameters as design variables; The interface transition layer parameters include: interface transition layer type, interface stiffness parameters, interface damping parameters, and interlayer connection method. The functional layer parameters include: the weaving angle of the two-dimensional triaxial braided structure, the layup angle, layup ratio and angle gradient of the variable angle laminated structure, the structural type of the three-dimensional woven reinforcement structure, the load-bearing thickness of the main body of the casing and the thickness ratio of each functional layer. Step 4: Perform dynamic and impact response analysis on different functional layered heterogeneous schemes to obtain the radial deformation of the inner wall of the composite material casing, impact absorption energy, interlaminar stress or interlaminar failure index, and structural quality. Step 5: With the optimization objectives of reducing the structural mass and radial deformation of the inner wall of the composite material casing and increasing the impact absorption energy, and with the constraint that the interlaminar stress or the interlaminar failure index does not exceed a set threshold, multi-objective optimization is performed on the design variables. Step 6: Obtain the optimized solution that satisfies the constraints, and output the interface transition layer parameters and the functional layer parameters.

[0017] The beneficial effects of this invention are: 1. The partitioned multi-configuration composite material casing of the present invention, based on the different load characteristics and functional requirements of the inner, middle, and outer regions of the casing wall, sequentially arranges an inner stiffness-maintaining layer, a middle lightweight stiffness-coordinating layer, and an outer containment energy-absorbing layer. The inner stiffness-maintaining layer is mainly used to control the shape of the inner wall of the casing and diffuse the initial disturbance load; the middle lightweight stiffness-coordinating layer is used to adjust the stiffness transition and load redistribution; and the outer containment energy-absorbing layer is used to undertake impact protection, anti-delamination, and anti-penetration functions. Through the combination of a two-dimensional triaxial braided structure, a variable-angle laminated structure, and a three-dimensional woven reinforcement structure, the load is gradually diffused and transferred from the inside to the outside of the casing wall. The middle lightweight stiffness-coordinating layer can mitigate the stiffness difference between the inner stiffness-maintaining layer and the outer containment energy-absorbing layer. Together, the three form a continuous load-bearing and energy-dissipating path of "inner stable diffusion - middle coordinated transfer - outer energy-absorbing protection," enabling the casing to simultaneously take into account surface stability, lightweight, impact resistance, and damage tolerance, avoiding the problem that a single material configuration cannot meet multiple performance requirements.

[0018] 2. The design method for partitioned multi-configuration composite material casings of the present invention uses layer proportions, axial partitioning, two-dimensional and three-dimensional main load-bearing directions, laminate layup angles, three-dimensional woven reinforcement forms, and interface transition parameters as design variables to adjust the overall stiffness distribution, mass distribution, and damping energy dissipation capacity of the casing. This is beneficial for optimizing the key modal frequency distribution, increasing the interval between key modes and the main excitation frequency, and reducing the resonance peak response caused by blade passage frequency, aerodynamic pressure fluctuations, vibration transmitted from mounting edges, and local impact loads, thereby improving the operational stability of the casing under multi-source excitation environments. It is applicable to the design of composite material structures for aero-engine fan casings, compressor casings, bypass casings, and other thin-walled rotating bodies, exhibiting good engineering adaptability. Attached Figure Description

[0019] Figure 1 The diagram shown is a schematic of a partitioned multi-configuration composite material casing; Figure 2 The diagram shows the gradient variation of the interlayer angle difference in the intermediate lightweight stiffness coordination layer. Figure 3 An example diagram showing the load-bearing thickness of the main body of the multi-configuration composite material casing in different functional zones; Figure 4 The figure shows the equivalent stiffness and axial and circumferential tensile and compressive strength parameters of each functional layer of a partitioned multi-configuration composite material casing. Figure 5 The diagram shows a design method for a partitioned multi-configuration composite material casing. Detailed Implementation

[0020] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the drawings are merely exemplary and are intended to illustrate the principles and spirit of the invention, and are not intended to limit the scope of the invention.

[0021] In a first aspect, embodiments of the present invention provide a partitioned, multi-configuration composite material casing. See also... Figure 1 , Figure 1 The diagram shown is a schematic of a partitioned, multi-configuration composite material casing. Figure 1 As shown, the partitioned multi-configuration composite material casing of this embodiment includes a casing body, which is a thin-walled rotating composite material structure. The casing body has a functionally layered heterogeneous structure, including an inner stiffness-retaining layer, a middle lightweight stiffness-coordinating layer, and an outer energy-absorbing layer that are stacked and interconnected sequentially from the inside to the outside along the radial direction of the casing body.

[0022] In this embodiment, the inner stiffness retention layer adopts a two-dimensional triaxial braided structure to maintain the stability of the inner wall surface of the casing body and to diffuse the load input from the inside.

[0023] Specifically, the two-dimensional triaxial braided structure includes axial yarns, positive offset yarns, and negative offset yarns. The axial yarns are arranged along the axial direction of the casing body, and the positive and negative offset yarns are arranged at 0° / ±θ° relative to the axial direction of the casing body, thereby forming a multi-directional load-bearing system of 0° / ±θ°, where θ is 30° to 75°.

[0024] It should be noted that when the inner stiffness retention layer is mainly used to limit the radial deformation of the inner wall of the casing, the principal stiffness direction of the two-dimensional triaxial braided structure is preferably arranged along the circumferential or near-circumferential direction of the casing. When the inner stiffness retention layer is mainly used to improve the axial load-bearing capacity or torsional resistance of the casing, the principal stiffness direction of the two-dimensional triaxial braided structure can be arranged along the axial, circumferential, or helical direction of the casing.

[0025] In this embodiment, a two-dimensional triaxial braided stiffness-maintaining layer is provided inside the casing. Utilizing a multi-directional load-bearing network composed of axial yarns and positive and negative off-axis yarns, the in-plane stiffness, torsional resistance, and shear load-bearing capacity of the inner region are improved. When the casing is subjected to blade tip rubbing, aerodynamic pressure fluctuations, local indentation, or vibration disturbances, this functional layer can limit local deformation of the inner wall, reduce deformation concentration, and diffuse local loads circumferentially and axially. Compared with simply using laminated plates to control inner wall deformation, the yarn continuity and multi-directional load-bearing capacity of the two-dimensional triaxial braided structure are more conducive to maintaining the stability of the inner wall surface, providing a more stable deformation boundary for the load-bearing and energy dissipation of subsequent layers.

[0026] In this embodiment, the intermediate lightweight stiffness coordination layer adopts a variable angle laminate structure to transfer and redistribute the load between the inner stiffness retention layer and the outer containment energy absorption layer.

[0027] In this embodiment, the variable angle laminate structure can diffuse the local loads, bending loads and shear loads transmitted by the inner stiffness retention layer to the outside, thereby reducing the structural mass while meeting the overall stiffness and dynamic performance requirements of the casing, and reducing the stiffness abrupt change between the inner and outer functional layers.

[0028] Optionally, the variable angle laminate structure includes at least two sets of layers with different fiber layup angles, wherein the fiber layup angles are selected from at least two of 0°, ±45°, 90°, and ±60°. In this embodiment, at least one of the layup angle, layup ratio, fiber angle difference between adjacent layers, or layup thickness ratio of the variable angle laminate structure varies along the axial direction of the casing body and / or the lamination direction of the intermediate lightweight stiffness coordination layer.

[0029] It is understandable that the fiber laying angle changes between different layers or different layers in a variable angle laminated structure, while curved laying or continuous variable angle fiber trajectories are used within a single layer.

[0030] In this embodiment, the variable angle laminate structure adjusts the stiffness transition characteristics, load diffusion capacity, and mass distribution between the inner stiffness retention layer and the outer energy absorption layer by changing the ply angle, ply ratio, fiber angle difference between adjacent layers, or ply thickness ratio.

[0031] Optionally, the fiber angle difference between adjacent layers in the variable-angle laminate structure varies in a piecewise gradient along the stacking direction of the intermediate lightweight stiffness coordinating layer; wherein the piecewise gradient variation is set according to a linear gradient, exponential gradient, power function gradient, or S-shaped gradient. See also Figure 2 , Figure 2 The diagram shows the gradient variation of the interlayer angle difference in the intermediate lightweight stiffness coordination layer. (a) is a linear variation diagram; (b) is a piecewise function variation diagram; (c) is an S-curve variation diagram; and (d) is a power function variation diagram.

[0032] It is understandable that by setting an interlayer angle gradient field inside the intermediate lightweight stiffness coordination layer, the stiffness abrupt change between the inner stiffness retention layer and the outer containment energy absorption layer can be reduced, the interlayer shear stress concentration can be reduced, and the dynamic response of the casing can be improved.

[0033] For example, with the axial coordinate of the casing as z and the circumferential coordinate as φ, the ply angle in the variable angle laminate structure can be expressed as θ(z,φ), where θ(z,φ) can vary along the axial, circumferential, or both directions of the casing to adjust the in-plane stiffness distribution and load diffusion capability of the intermediate lightweight stiffness coordination layer.

[0034] For example, the ply angle θ(z,φ) can take one of the following forms: Linear variation form: θ(z) = θ0 + a·z / H, where θ0 is the initial ply angle, a is the angle variation coefficient, and H is the casing height; Nonlinear variation form: θ(z) = θ0 + a·sin(πz / H), where a is the angle amplitude adjustment coefficient; The circumferential periodic variation form is: θ(φ) = θ0 + b·sin(mφ), where b is the amplitude of the circumferential angle variation and m is the circumferential wave number.

[0035] By varying the ply angles as described above, the intermediate lightweight stiffness coordination layer can achieve an adjustable in-plane stiffness distribution in the axial or circumferential direction of the casing, thereby improving the load diffusion and stiffness coordination effect between the inner stiffness retention layer and the outer energy absorption layer.

[0036] For example, the intermediate lightweight stiffness coordination layer is divided into N layer groups along the thickness direction, and each layer group includes at least one composite material layup. Let the layup angle of the i-th layer group be θ. i The fiber angle difference between adjacent layers is: Δθi =|θ i+1 θ i | where i = 1, 2, ..., N 1.

[0037] Fiber angle difference Δθ between adjacent layers i The thickness of the intermediate lightweight stiffness coordination layer can vary continuously or piecewise to form an interlayer angular gradient field. The interlayer angular gradient field can gradually increase, gradually decrease, or vary piecewise along the layer group number i from the first layer group to the last layer group.

[0038] For example, the interlayer angle difference Δθ i One of the following variations may be adopted: Linear change: ,in The coefficient is linear growth. Power function changes: ,in To minimize the inter-story angle difference, For the maximum inter-story angle difference, This represents the number of layers in the thickness direction. The exponent of the power function; Piecewise function changes: ,in For segmentation positions, and These are the angular variation coefficients for different thickness ranges. This refers to the inter-story angle difference at the segment location; S-shaped curve variation: ,in This is the curve steepness coefficient. This is the inflection point.

[0039] By using the above-mentioned interlayer angle gradient design, excessive abrupt changes in fiber angles between adjacent layups or adjacent layers within the intermediate lightweight stiffness coordination layer can be avoided, resulting in a smoother stiffness transition in the thickness direction of the intermediate lightweight stiffness coordination layer. This reduces the concentration of interlayer shear stress between the inner stiffness retention layer and the outer energy-absorbing layer, and improves the dynamic response of the casing.

[0040] In this embodiment, a lightweight stiffness coordination layer with a variable-angle laminate structure is set in the middle region of the casing, which can improve the lightweight load-bearing and stiffness coordination capabilities of the middle layer. The laminate structure has the characteristics of high layup efficiency, high specific stiffness and specific strength, and easy adjustment of the layup angle, enabling it to provide the necessary axial, circumferential, and shear load-bearing capabilities at a relatively low mass cost. By adjusting the layup angle, layup ratio, angle difference between adjacent layers, and layer group ratio, the equivalent stiffness, bending-torsional coupling characteristics, and load transfer mode of the middle region can be controlled, allowing it to play a connecting, transitioning, and coordinating role between the inner two-dimensional triaxial braided layer and the outer three-dimensional woven layer. This avoids abrupt stiffness changes between different structures and reduces the potential increase in mass and manufacturing complexity that might result from using a three-dimensional woven structure throughout the entire region.

[0041] In this embodiment, the outer energy-absorbing layer adopts a three-dimensional woven reinforcement structure to withstand the impact load transmitted from the inner side of the casing body to the outer side and absorb the impact energy.

[0042] In this embodiment, the impact load includes the residual impact energy transferred to the outside from blade shedding, fragment impact, blade tip rubbing, or localized indentation loads inside the casing via the inner stiffness retention layer and the intermediate lightweight stiffness coordination layer. The three-dimensional woven reinforcement structure absorbs impact energy through controlled deformation, fiber stretching, yarn slippage, matrix cracking, interfacial friction, or controlled delamination, thereby improving the damage control capability and overall safety of the casing's back side.

[0043] Optionally, the three-dimensional woven reinforcement structure can be one or more of the following: a three-dimensional orthogonal woven structure, a three-dimensional interlocking woven structure, a shallowly interlaced three-dimensional woven structure, a multi-layered spliced ​​woven structure, a through-joined woven structure, and a three-dimensional fabric structure containing Z-direction reinforcing yarns. When the three-dimensional woven reinforcement structure includes two or more structures, the different structures are arranged in sections along the axial direction of the casing body and / or the stacking direction of the outer side containing the energy-absorbing layer.

[0044] For example, the splicing yarn, through yarn, or Z-direction reinforcing yarn can be made of carbon fiber bundles, aramid fiber bundles, glass fiber bundles, or hybrid fiber bundles thereof, preferably T700 carbon fiber bundles the same as the main reinforcing fiber. The monofilament diameter of the Z-direction reinforcing yarn is 5-8 μm, preferably 6-7 μm; the fiber bundle is 1K-6K, preferably 1K or 3K; the equivalent yarn diameter of the Z-direction reinforcing yarn is 0.10-0.50 mm, preferably 0.18-0.30 mm. The splicing yarn or Z-direction reinforcing yarn is arranged at intervals along the axial and circumferential directions of the casing, with an axial spacing of 1.5-5.0 mm and a circumferential spacing of 1.5-5.0 mm, preferably 2.0-3.5 mm; the corresponding splice density is 4-30 points / cm. 2 Preferably 6-16 per cm 2 The Z-axis reinforcing yarn accounts for 1%-8% of the volume fraction of the outer energy-absorbing layer fibers, preferably 2%-5%.

[0045] It is understandable that when the inner side of the casing is subjected to blade shedding, fragment impact, blade tip rubbing, or localized indentation load, the outer energy-absorbing layer can absorb the remaining impact energy transmitted to the outer side of the casing, thereby improving the overall impact damage resistance and penetration resistance of the casing.

[0046] In this embodiment, the composite materials used for the inner stiffness retention layer, the middle lightweight stiffness coordination layer, and the outer energy absorption layer can be carbon fiber reinforced epoxy resin matrix composites, glass fiber reinforced resin matrix composites, aramid fiber reinforced resin matrix composites, or other fiber reinforced resin matrix composites.

[0047] In this embodiment, the casing body is divided into several functional areas along the axial direction. In an optional embodiment, the casing body is provided with multiple functional areas along the axial direction, including an end mounting area, a main body area, a blade containment area, a blade tip corresponding area, and an inlet / outlet transition area, wherein the blade tip corresponding area is a sub-region of the blade containment area. The casing body has different load-bearing thicknesses in different functional areas.

[0048] Specifically, within each functional area, the load-bearing thickness of the casing body is composed of the thicknesses of the inner stiffness-maintaining layer, the intermediate lightweight stiffness-coordinating layer, and the outer energy-absorbing enclosure layer. The load-bearing thickness of the casing body in the blade enclosure area is greater than that in the main body shell area. The load-bearing thickness of the casing body in the main body shell area is less than that in the end-mounting area. At least one of the inner stiffness-maintaining layer, the intermediate lightweight stiffness-coordinating layer, and the outer energy-absorbing enclosure layer differs in thickness or thickness percentage between the blade enclosure area and the main body shell area. Please refer to [link / reference]. Figure 3 , Figure 3 The diagram shows an example of the load-bearing thickness of the casing body in different functional zones of the partitioned multi-configuration composite casing.

[0049] In this embodiment, based on the load-bearing thickness of the casing body, the sum of the thicknesses of the inner stiffness-maintaining layer, the intermediate lightweight stiffness-coordinating layer, and the outer energy-absorbing layer is 100%. Optionally, the thickness of the inner stiffness-maintaining layer accounts for 15% to 45% of the load-bearing thickness of the casing body, the thickness of the intermediate lightweight stiffness-coordinating layer accounts for 20% to 55% of the load-bearing thickness of the casing body, and the thickness of the outer energy-absorbing layer accounts for 15% to 45% of the load-bearing thickness of the casing body.

[0050] It should be noted that the thickness ratio of each functional layer is determined based on the radial deformation limit of the inner wall of different functional areas, the impact energy absorption requirements of the outer side, the out-of-plane shear stress, and the structural mass constraints. Adjacent functional areas can achieve a continuous gradual transition or a segmented stepped transition through an axial thickness transition zone.

[0051] In this embodiment, for the blade containment area or end mounting area, the load-bearing thickness of the casing body can be increased to improve local impact resistance, connection stiffness, or interlayer safety. For the main casing area, the load-bearing thickness of the casing body can be reduced to decrease structural mass. For the inlet and outlet transition area, a gradual thickness or segmented thickness transition can be adopted to reduce abrupt changes in local stiffness and stress concentration.

[0052] Understandably, the thickness ratio of each functional layer within each functional area can also be designed to meet the requirements of dynamic response control, inner wall radial deformation control, impact protection, and lightweighting for each functional area.

[0053] For example, in the blade tip region, the thickness ratio of the inner stiffness retention layer can be increased or the principal stiffness direction of the two-dimensional triaxial braided structure can be adjusted to reduce the radial deformation of the inner wall of the casing; in areas with high external impact risk, the thickness ratio of the outer energy-absorbing layer can be increased to enhance the outer impact energy absorption capacity; in the end mounting area, the interface transition layer or local toughening layer can be enhanced to reduce the interlayer stress concentration caused by connection constraints.

[0054] In this embodiment, the main load-bearing dimensions of different axial functional areas of the casing, as well as the thickness ratios of the inner stiffness-maintaining layer, the intermediate lightweight stiffness-coordinating layer, and the outer containment energy-absorbing layer, are used as design variables. For locations with high load-bearing or protection requirements, such as the blade containment area, external impact-sensitive area, and mounting edge connection area, the thickness ratio of the outer containment energy-absorbing layer or the inner stiffness-maintaining layer can be appropriately increased. For the main casing area, the thickness ratio of the intermediate lightweight stiffness-coordinating layer can be increased to meet the requirements of weight reduction and stiffness matching. This allows for localized reinforcement in areas requiring protection, avoiding unnecessary overall thickening in ordinary load-bearing areas, thereby improving the problem of significant weight increases associated with traditional equal-wall-thickness reinforcement schemes.

[0055] In an optional embodiment, an interface transition layer is provided between the inner stiffness retention layer and the intermediate lightweight stiffness coordination layer, and between the intermediate lightweight stiffness coordination layer and the outer enclosing energy absorption layer.

[0056] Optionally, the interface transition layer is composed of one or more of the following: a short fiber reinforcement layer, a thermoplastic elastomer interlayer, a resin toughening layer, a particle reinforcement layer, and a damping film layer. This interface transition layer serves to reduce interlaminar shear stress concentration between adjacent functional layers and improve vibration energy dissipation.

[0057] Optionally, the elastic modulus, loss factor, damping coefficient, or fracture toughness of the interface transition layer may vary continuously or segmentally along the thickness direction, axial direction, or circumferential direction of the casing, in order to reduce abrupt changes in stiffness between adjacent functional layers and stress concentration between layers, and to improve the vibration energy dissipation capacity.

[0058] For example, the thickness of the interface transition layer is 0.02-0.30 mm, preferably 0.05-0.15 mm, and the thickness of the interface transition layer can be 0.5%-5% of the total thickness of the adjacent functional layers, preferably 1%-3%. The equivalent elastic modulus of the interface transition layer is located between the equivalent elastic moduli of the two adjacent functional layers, and changes continuously or segmentally along the casing wall from the inside to the outside, axially or circumferentially; its loss factor is 0.02-0.20, preferably 0.05-0.12; the equivalent damping ratio is 2%-8%, preferably 3%-6%; the type I fracture toughness is 0.3-1.5 kJ / m², the type II fracture toughness is 0.8-3.0 kJ / m², and preferably not less than 1.2 times that of the adjacent resin matrix interface.

[0059] In this embodiment, an interface transition layer is used to further adjust the shear stiffness, damping characteristics, and fracture toughness between adjacent structures. This reduces interface shear stress concentration, suppresses rapid propagation of delamination damage, and improves the damage tolerance of the composite casing under impact, vibration, and complex loads.

[0060] Optionally, the interface transition layer can be further configured as an interface stiffness-damping synergistic gradient layer. The interface stiffness-damping synergistic gradient layer is used to adjust the interlaminar shear stiffness, interlaminar stress transfer characteristics, and vibration energy dissipation characteristics between adjacent functional layers. The interface stiffness-damping synergistic gradient layer can be one or more combinations of short fiber reinforced layers, thermoplastic elastomer interlayers, resin toughening layers, particle reinforced layers, locally cured modified layers, or damping film layers. The elastic modulus, loss factor, damping coefficient, or fracture toughness of the interface stiffness-damping synergistic gradient layer can vary continuously or segmentally along the casing thickness direction, axially, or circumferentially to reduce abrupt stiffness changes and interlaminar stress concentration between adjacent functional layers and improve vibration energy dissipation capacity.

[0061] In an optional embodiment, an abrasive and anti-collision surface layer is provided on the inner side of the inner stiffness retention layer of the casing body. The abrasive and anti-collision surface layer is used to generate controlled wear during blade tip rubbing and protect the inner stiffness retention layer.

[0062] Alternatively, the abrasion-resistant surface layer may be made of abrasion-resistant resin-based composite material, abrasion-resistant coating, honeycomb abrasion-resistant material, or other controllable abrasion-resistant material.

[0063] For example, the thickness of the wear-resistant and impact-resistant surface layer is 0.1-1.0 mm, preferably 0.2-0.5 mm.

[0064] Furthermore, the structure of the partitioned multi-configuration composite material casing of this embodiment will be illustrated by specific examples.

[0065] Specifically, the partitioned multi-configuration composite material casing is a cylindrical thin-walled casing structure, with a mid-surface radius Rm = 300 mm, an axial length L = 400 mm, and a main body load-bearing thickness t = 3.0 mm. The casing is arranged radially from the inside to the outside as follows: an inner stiffness-maintaining layer, a middle lightweight stiffness-coordinating layer, and an outer energy-absorbing layer. The inner stiffness-maintaining layer has a thickness t1 = 0.90 mm, the middle lightweight stiffness-coordinating layer has a thickness t2 = 1.35 mm, and the outer energy-absorbing layer has a thickness t3 = 0.75 mm, satisfying t = t1 + t2 + t3. The thicknesses of the three layers account for 30%, 45%, and 25%, respectively.

[0066] In this embodiment, the intermediate lightweight stiffness coordination layer adopts a variable-angle laminate structure, and its equivalent mechanical properties are determined by a preset layup pattern. For example, the preset layup pattern is [0° / 60° / 60° / 60° / 60° / 0°] 2S The 0° direction corresponds to the casing axial direction, and the ±60° direction is the off-axis direction relative to the casing axial direction. This layup method enables the laminated plate structure to form a relatively balanced equivalent in-plane stiffness between the axial and circumferential directions. The ±60° off-axis layup improves the equivalent in-plane shear stiffness and load diffusion capacity, allowing the intermediate lightweight stiffness coordination layer to play a role in stiffness coordination and load transition between the inner two-dimensional triaxial woven structure and the outer three-dimensional orthogonal woven structure.

[0067] In this embodiment, each functional layer adopts a T700 carbon fiber / E862 epoxy resin matrix composite material system. The equivalent stiffness and axial and circumferential tensile and compressive strength parameters of the three functional layers are as follows: Figure 4 As shown, Figure 4 The figure shows the equivalent stiffness and axial and circumferential tensile and compressive strength parameters of each functional layer of a partitioned multi-configuration composite material casing. Here, E11 is the axial equivalent elastic modulus of the casing, E22 is the circumferential equivalent elastic modulus of the casing, E33 is the thickness equivalent elastic modulus, and G12 is the axial-circumferential in-plane shear modulus.

[0068] As shown in the figure, the axial and circumferential equivalent stiffnesses of the two-dimensional triaxial braided structure are 49.57 GPa and 48.14 GPa, respectively, which are close to those of the laminated plate structure. Meanwhile, its axial tensile strength and circumferential tensile strength reach 978.0 MPa and 573.0 MPa, respectively, significantly higher than those of the laminated plate structure. Therefore, arranging the two-dimensional triaxial braided structure near the inner wall of the casing can improve the in-plane tensile load-bearing capacity of the inner region while maintaining high in-plane stiffness. This helps to limit radial deformation of the inner wall of the casing, maintain the stability of the inner wall surface, and improve the in-plane diffusion capacity of the inner region against blade tip rubbing, internal pressure fluctuations, or local loads.

[0069] The laminate structure exhibits an axial and circumferential equivalent stiffness of 48.95 GPa, demonstrating relatively balanced in-plane stiffness. Furthermore, the axial, circumferential, and in-plane shear stiffness can be adjusted by varying the layup angle and ratio. Although its axial and circumferential tensile strengths are lower than those of two-dimensional triaxial braided structures and three-dimensional orthogonal woven structures, its structural form is simple, its layup efficiency is high, and its thickness and angle are easily adjustable. Therefore, placing the laminate structure in the intermediate lightweight stiffness-coordinating layer can create a continuous load-bearing path with relatively low structural complexity and weight cost. This path coordinates the stiffness difference between the inner two-dimensional triaxial braided layer and the outer three-dimensional orthogonal woven layer, reducing abrupt stiffness changes and localized stress concentrations.

[0070] The axial and circumferential equivalent stiffness of the three-dimensional orthogonal woven structure are 63.28 GPa and 71.78 GPa, respectively, both higher than those of the laminated plate structure and the two-dimensional triaxial woven structure. Its axial tensile, axial compressive, circumferential tensile, and circumferential compressive strengths are 1272.0 MPa, 672.0 MPa, 1461.0 MPa, and 760.0 MPa, respectively, the highest among the three structures. Therefore, arranging the three-dimensional orthogonal woven structure on the outside of the casing can improve the axial and circumferential load-bearing margins of the outer region under external impact, local indentation, fragment impact, or loads transferred from the inside to the outside, giving the outer region a higher containment and protection capacity.

[0071] Based on the aforementioned differences in material properties, this embodiment employs a functional layering approach: an inner two-dimensional triaxial braided structure, a middle laminated plate structure, and an outer three-dimensional orthogonal woven structure. This allows the inner layer to maintain stiffness and diffuse in-plane loads, the middle layer to provide lightweight load-bearing capacity and stiffness coordination, and the outer layer to provide high-strength load-bearing capacity and external protection. This layering approach is not a simple superposition of the three materials, but rather, based on the differences in axial / circumferential stiffness and tensile / compressive strength among the three structures, they are arranged in the most suitable positions to fulfill their functions. This achieves a synergistic improvement in the stability of the casing's inner wall surface, overall stiffness coordination, and external load-bearing and protective capabilities.

[0072] Secondly, embodiments of the present invention provide a design method for a partitioned multi-configuration composite material casing, applicable to the partitioned multi-configuration composite material casing provided in the first aspect. Please refer to... Figure 5 , Figure 5 The diagram shown illustrates the design method for a partitioned, multi-configuration composite material casing. Figure 5 As shown, the method includes: Step 1: Establish the geometric model and finite element model of the composite material casing, divide the casing body into axial functional zones, and define the macroscopic equivalent material performance parameters of the two-dimensional triaxial braided structure, the three-dimensional woven reinforcement structure, and the variable angle laminated structure.

[0073] In this embodiment, the finite element model can be established using shell elements, continuous shell elements, or solid elements. When using the macroscopic equivalent modeling method, the two-dimensional triaxial braided structure, the variable angle laminated structure, and the three-dimensional woven reinforcement structure can be equivalently represented as anisotropic or orthotropic materials, and the functional layers in the thickness direction can be assigned corresponding material parameters and material directions.

[0074] Step 2: Determine the inner wall radial deformation limit, impact energy absorption requirements, interlayer safety requirements, and structural mass constraints based on the service conditions of the casing.

[0075] In this embodiment, the design requirements for the inner stiffness retention layer include radial deformation control of the casing inner wall, surface stability, in-plane load diffusion, torsional resistance, and in-plane shear bearing capacity. The design requirements for the intermediate lightweight stiffness coordination layer include continuous bearing capacity, stiffness coordination, mass control, and load diffusion.

[0076] Step 3: Define the functional layer parameters for each functional layer and the interface transition layer parameters between different functional layers, and use the interface transition layer parameters and functional layer parameters as design variables.

[0077] In this embodiment, the interface transition layer parameters include: interface transition layer type, interface stiffness parameters, interface damping parameters, and interlayer connection method; the functional layer parameters include: material configuration, main body load-bearing thickness of the casing, and thickness ratio of each functional layer.

[0078] Specifically, the inner stiffness-maintaining layer adopts a two-dimensional triaxial braided structure, the middle lightweight stiffness-coordinating layer adopts a variable-angle laminated structure, and the outer energy-absorbing layer adopts a three-dimensional woven reinforcement structure. Based on the radial displacement limit of the casing inner wall, torsional stiffness, modal frequency, resonant peak response, outer impact energy absorption requirements, out-of-plane shear stress, and structural mass constraints, the thickness proportion and material orientation of each functional layer are determined. For locations where there is abrupt stiffness changes or interlayer stress concentration risk between adjacent functional layers, interface transition layers, interface toughening layers, or damping layers are set, and the interface stiffness parameters, damping parameters, and interlayer connection methods are determined.

[0079] Optionally, the material performance parameters of each functional layer can be obtained through tensile, compression, shear, impact, and dynamic mechanical tests on a single-layer plate, or through homogenization calculations using representative volume elements to obtain macroscopically equivalent material performance parameters. These material performance parameters include density, elastic modulus, shear modulus, Poisson's ratio, strength parameters, damping parameters, and impact energy absorption parameters.

[0080] Step 4: Perform dynamic and impact response analysis on different functional layered heterogeneous schemes to obtain the radial deformation of the inner wall of the composite material casing, impact absorption energy, interlaminar stress or interlaminar failure index, and structural quality.

[0081] In this embodiment, the dynamic and impact response analysis includes modal analysis, harmonic response analysis, or transient response analysis. The dynamic performance evaluation results include: the natural frequency, mode shape, peak resonance response, radial displacement of the inner wall of the casing, out-of-plane shear stress, external impact energy absorption, external damage range, and penetration resistance.

[0082] Specifically, after establishing the finite element model, modal analysis, harmonic response analysis, or transient response analysis are performed on functional layering schemes with different thicknesses. Modal analysis is used to obtain the natural frequencies, mode shapes, and mode participation characteristics of the casing. Harmonic response analysis is used to obtain the resonant peak response of the casing under the action of blade frequency excitation, vibration transmitted from the mounting edge, or aerodynamic pressure fluctuations. Transient response analysis is used to obtain the radial displacement, stress response, out-of-plane shear stress, outer damage range, and impact energy absorption response of the casing under external impact loads, foreign object impact loads, local mechanical impact loads, blade tip rubbing loads, local radial indentation loads, or debris impact loads. Boundary conditions can be selected according to the actual installation method of the casing and the analysis conditions. Boundary conditions include one or more of the following: two-end fixed support, single-end fixed support, mounting edge constraint, periodic constraint, elastic support constraint, or equivalent connection stiffness constraint. The excitations for harmonic response analysis and transient response analysis can include one or more of the following: external impact load, foreign object impact load, local mechanical impact load, internal distributed pressure load, blade passing frequency excitation, blade tip rubbing excitation, local radial indentation load, circumferential friction load, debris impact load, and vibration excitation transmitted from the mounting edge.

[0083] Step 5: With the optimization objectives of reducing the structural mass and radial deformation of the inner wall of the composite material casing and increasing the impact absorption energy, and with the constraint that the interlaminar stress or interlaminar failure index does not exceed the set threshold, multi-objective optimization of the design variables is carried out.

[0084] Optionally, when optimizing design variables, interlaminar failure constraints, strength constraints, stiffness constraints, deformation constraints, mass constraints, and manufacturing process constraints can also be introduced. Interlaminar failure constraints include one or more of the following: maximum interlaminar shear stress constraints, interlaminar peeling constraints, interface damage initiation constraints, or delamination propagation constraints based on energy release rate. Manufacturing process constraints include one or more of the following constraints during two-dimensional triaxial weaving, three-dimensional weaving, automated yarn placement, automated tape placement, resin transfer molding, autoclave curing, or co-curing processes: minimum fiber turning radius, maximum fiber angle change rate, minimum functional layer thickness, maximum gap between adjacent tapes, maximum overlap width, splice yarn spacing, and functional layer continuity constraints.

[0085] Step 6: Obtain the optimized solution that satisfies the constraints, and output the interface transition layer parameters and the functional layer parameters.

[0086] Optionally, optimization can be performed using response surface methodology, genetic algorithm, particle swarm optimization, surrogate model optimization algorithm, or multi-objective optimization algorithm. During each round of optimization, the finite element model of the casing is updated based on the current design variables, and modal analysis, harmonic response analysis, or transient response analysis is performed again to calculate each optimization objective and constraint condition until the optimization result meets the convergence condition.

[0087] Exemplarily, the construction of the multi-objective optimization model and the optimization process of the design in this embodiment are described. Specifically, a multi-objective optimization model is constructed with the objectives of casing dynamic performance, outer containment energy absorption capacity, interlayer safety, and lightweighting. The main load-bearing dimensions of different axial functional areas of the casing, the proportion of the inner stiffness retention layer, the proportion of the middle lightweight stiffness coordination layer, the proportion of the outer containment energy absorption layer, the two-dimensional triaxial braided main stiffness direction, the laminate layup angle, the three-dimensional woven reinforcement form, and the interface transition layer parameters are used as design variables. The design variables can be expressed as: ; in, Design the set of variables; For the first The main load-bearing dimensions of each axial functional zone; To maintain the inner stiffness of the layer ratio; The proportion of the intermediate lightweight stiffness coordination layer; The proportion of the outer containment energy-absorbing layer; The principal stiffness direction of the two-dimensional triaxial braided structure; For variable angle laminates, the layup angle or a combination of layup angles is used. For three-dimensional woven reinforcement structure type or splicing yarn parameters; These are parameters for the interface transition layer.

[0088] The comprehensive evaluation function is established as follows: ; in, This is a comprehensive evaluation value; the smaller the value, the better the overall performance. As a kinetic performance evaluation index; As an evaluation index for the external containment and energy absorption capacity; As an indicator for inter-layer safety evaluation; As a lightweight evaluation indicator; These are the weight coefficients for the four categories of indicators mentioned above, and they satisfy the following: ; Optionally, Take 0.30-0.40, Take a value of 0.20-0.30. Take a value of 0.20-0.30. Take a value of 0.10-0.20. For the blade containment zone or impact-sensitive zone, the value can be increased. and For the main tube area, it can be improved. .

[0089] The dynamic performance evaluation index can be expressed as: ; in, To optimize the maximum spectral response amplitude of the scheme within the operating frequency band; This represents the maximum spectral response amplitude of the benchmark scheme under the same operating conditions. The first-order natural frequency of the optimized scheme; The first-order natural frequency of the reference scheme; To optimize the scheme, the minimum frequency interval between the key modal frequencies and the main excitation frequencies is required. The frequency interval corresponding to the reference scheme; For the weighting coefficients within the dynamic evaluation index, and The smaller this index, the lower the spectral response, the higher the natural frequency, and the better the ability to avoid the main excitation frequency.

[0090] The evaluation index for the outer containment energy absorption capacity can be expressed as: ; in, To input energy for impact or rubbing loads; The energy absorbed by the outer energy-absorbing layer and adjacent areas; The maximum deformation of the casing under impact or friction. To allow the maximum deformation; This is a damage evaluation coefficient used to characterize the degree of matrix cracking, fiber breakage, delamination, or penetration damage. To include the weighting coefficients within the energy absorption evaluation indicators, and The smaller this indicator is, the stronger the energy absorption capacity, the smaller the deformation, and the lower the degree of damage.

[0091] Inter-layer safety evaluation indicators can be expressed as: ; in, This represents the maximum shear stress at the interface between adjacent structures. Allowable shear stress at the interface; For the interface normal tensile stress; Allowable normal tensile stress at the interface; Energy release rate for interface crack propagation; This represents the critical fracture energy at the interface. The smaller this value, the lower the interfacial stress level and the lower the risk of delamination.

[0092] The lightweight evaluation index can be expressed as: ; in, To optimize the casing quality of the design; This represents the casing mass of the baseline design. The smaller this value, the more significant the weight reduction.

[0093] The following constraints should also be met during optimization: ; in, , , The first The ratio of the inner stiffness-maintaining layer, the middle lightweight stiffness-coordinating layer, and the outer energy-absorbing layer in each axial functional zone.

[0094] Simultaneously satisfy: ; in, and The first The minimum and maximum values ​​of the main load-bearing dimensions of each axial functional zone.

[0095] The optimization algorithm can employ genetic algorithms, non-dominated sorting genetic algorithms, response surface optimization algorithms, or surrogate model optimization algorithms. It is preferred to use non-dominated sorting genetic algorithms to obtain the Pareto optimal solution set, and then apply the comprehensive evaluation function. Select the solution with better overall performance.

[0096] The convergence criterion can be optimized as follows: ; in, For the first The second iteration or the first The optimal comprehensive evaluation value obtained through optimization; This is the optimal comprehensive evaluation value obtained from the previous iteration or the previous generation of optimization. The convergence threshold is preferably set to 0.01. That is, after several consecutive generations of optimization, the change in the comprehensive evaluation value is less than 1%, and all constraints are satisfied, the optimization is considered to have converged.

[0097] Understandably, in the service environment of an aero-engine, the casing is subjected to both temperature fields and mechanical loads. In one optional embodiment, a thermo-mechanical-vibrational coupled analysis model can be established. Based on the casing's operating temperature field, the elastic modulus, damping coefficient, and interlaminar strength of the two-dimensional triaxial braided structure, three-dimensional woven reinforced structure, variable-angle laminated structure, and interface transition layer can be corrected. Modal analysis, harmonic response analysis, or transient response analysis can then be performed under the combined effects of temperature loads and mechanical excitations. Through thermo-mechanical-vibrational coupled correction, the adaptability of the optimization results to the actual service environment can be improved, avoiding adverse effects of material stiffness degradation, interface performance changes, or thermal stress on the casing's dynamic stability and interlaminar safety.

[0098] After determining the final design parameters based on the optimization results, composite material casing prototypes are manufactured according to the optimized functional layer thickness ratio, two-dimensional triaxial weaving direction, variable angle laminate layup scheme, three-dimensional woven structure form, and interface transition layer parameters. The inner stiffness-retaining layer can be formed using a two-dimensional triaxial woven preform or a two-dimensional triaxial woven layup. The intermediate lightweight stiffness-coordinating layer can be formed using prepreg layup, automatic yarn placement, or automatic tape placement, and a variable angle laminate structure can be formed by changing the layup angle, layup ratio, fiber angle difference between adjacent layers, or layup thickness ratio. The outer energy-absorbing layer can be formed using a three-dimensional woven preform, three-dimensional orthogonal weaving, three-dimensional angle interlocking weaving, shallow cross-bending three-dimensional weaving, or a three-dimensional fabric structure containing Z-direction reinforcing yarns. The functional layers can be integrated using processes such as co-curing, secondary bonding, resin transfer molding, or autoclave curing to form a unified structure.

[0099] In the specific manufacturing process, the curing temperature profile, including the heating section, the holding section, and the cooling section, can be determined based on the thermal properties of the resin system and the interface material. Preferably, the heating rate is controlled within the range of 1℃ / min to 3℃ / min to reduce the risk of interlayer debonding caused by thermal stress during curing. For the interface transition layer, it can be formed by processes such as short fiber spraying, thermoplastic film laying, resin toughening layer coating, particle reinforcement layer laying, or local curing modification.

[0100] After the prototype is manufactured, the composite material casing can be subjected to modal tests, harmonic response tests, impact tests, and rubbing tests. Modal tests can use the hammer impact method or vibrator method to determine the first few natural frequencies, damping ratios, and mode shapes of the casing. Harmonic response tests can use an electromagnetic vibrator, an electro-hydraulic servo dynamic testing machine, or other dynamic loading devices to apply simple harmonic excitation and measure the displacement response, acceleration response, and peak resonance response of the casing near the main excitation frequency. Impact tests can apply external impact loads or localized mechanical impact loads to the outside of the casing to measure the extent of damage on the outside, impact energy absorption, and penetration resistance. Rubbing tests can simulate localized contact or friction loads between the blade tip and the inner wall of the casing to measure the radial deformation of the inner wall and the damage on the inner side.

[0101] In an optional embodiment, the equivalent stiffness, interface stiffness, interface damping, and energy absorption parameters of the two-dimensional triaxial braided structure, variable angle laminated structure, three-dimensional woven reinforced structure, and interface transition layer in the finite element model can be inverted and corrected based on the measured natural frequency, damping ratio, mode shape, resonance peak response, radial displacement response, outer damage morphology, and impact energy absorption results obtained from modal tests, harmonic response tests, rubbing tests, or impact containment tests. Based on the corrected finite element model, the functional layering scheme is re-optimized to form the final design scheme.

[0102] The design method of the partitioned multi-configuration composite material casing in this embodiment results in a partitioned multi-configuration composite material casing that, while ensuring structural strength and manufacturing feasibility, enables the inner two-dimensional triaxial braided structure to maintain stiffness, resist torsion, and bear in-plane shear loads; enables the middle variable-angle laminated structure to provide lightweighting, stiffness coordination, and load diffusion; and enables the outer three-dimensional woven reinforcement structure to withstand impact loads transmitted from the inner side of the casing body to the outer side, absorb impact energy, and limit the further expansion of impact damage and interlaminar damage. Through the synergistic optimization of functional layer thickness ratio, variable-angle laminate layup parameters, and interface transition parameters, the dynamic performance of the casing is improved, the resonance peak response is reduced, the out-of-plane shear stress concentration is reduced, and the structural reliability of the composite material casing under multi-source excitation and external impact conditions is improved.

[0103] For details regarding the design method of the partitioned multi-configuration composite material casing and its corresponding beneficial effects, please refer to the relevant content on partitioned multi-configuration composite material casing provided in the first aspect, which will not be repeated here.

[0104] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device comprising said element. Terms such as "connected" or "linked" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect. The orientations or positional relationships indicated by terms such as "upper," "lower," "left," and "right" are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0105] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0106] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A partitioned multi-configuration composite material casing, comprising a casing body, wherein the casing body is a thin-walled rotating composite material structure, characterized in that, The casing body has a functionally layered heterogeneous structure, including an inner stiffness-maintaining layer, a middle lightweight stiffness-coordinating layer, and an outer energy-absorbing layer that are radially stacked and interconnected from the inside out; wherein... The inner stiffness retention layer adopts a two-dimensional triaxial braided structure to maintain the stability of the inner wall surface of the casing body and to diffuse the load input from the inside. The intermediate lightweight stiffness coordination layer adopts a variable angle laminate structure, which is used to transfer and redistribute loads between the inner stiffness retention layer and the outer energy absorption layer. The outer enclosing energy-absorbing layer adopts a three-dimensional woven reinforcement structure to withstand the impact load transmitted from the inner side to the outer side of the casing body and absorb the impact energy.

2. The partitioned multi-configuration composite material casing according to claim 1, characterized in that, The two-dimensional triaxial knitting structure includes axial yarns, positive off-axis yarns, and negative off-axis yarns. The axial yarns are arranged along the axial direction of the casing body, and the positive and negative off-axis yarns are arranged at 0° / ±θ° relative to the axial direction of the casing body, thereby forming a multi-directional load-bearing system of 0° / ±θ°, where θ is 30° to 75°.

3. The partitioned multi-configuration composite material casing according to claim 1, characterized in that, The variable angle laminate structure includes at least two sets of layers with different fiber lay-up angles, wherein the fiber lay-up angles are selected from at least two of 0°, ±45°, 90° and ±60°; At least one of the following factors in the variable angle laminate structure—ply angle, ply ratio, fiber angle difference between adjacent layers, or ply thickness percentage—varies along the axial direction of the casing body and / or the lamination direction of the intermediate lightweight stiffness coordinating layer.

4. The partitioned multi-configuration composite material casing according to claim 3, characterized in that, The angle difference between adjacent fiber groups in the variable angle laminate structure varies in a piecewise gradient along the stacking direction of the intermediate lightweight stiffness coordination layer; the piecewise gradient variation is set according to a linear gradient, exponential gradient, power function gradient or S-shaped gradient.

5. The partitioned multi-configuration composite material casing according to claim 1, characterized in that, The three-dimensional woven reinforcement structure is one or more of the following: three-dimensional orthogonal woven structure, three-dimensional angular interlocking woven structure, shallow cross-bending three-dimensional woven structure, multi-layer splicing woven structure, through-link splicing woven structure, and three-dimensional fabric structure containing Z-direction reinforcing yarn. When the three-dimensional woven reinforcement structure includes two or more structures, the different structures are arranged in sections along the axial direction of the casing body and / or the stacking direction of the outer energy-absorbing layer.

6. The partitioned multi-configuration composite material casing according to claim 1, characterized in that, An interface transition layer is provided between the inner stiffness retention layer and the middle lightweight stiffness coordination layer, and between the middle lightweight stiffness coordination layer and the outer enclosing energy absorption layer. The interface transition layer is composed of one or more of the following: a short fiber reinforcement layer, a thermoplastic elastomer intermediate layer, a resin toughening layer, a particle reinforcement layer, and a damping film layer.

7. The partitioned multi-configuration composite material casing according to claim 1, characterized in that, The inner stiffness retention layer has a wear-resistant and impact-resistant surface layer on the side facing the inner cavity of the casing body.

8. The partitioned multi-configuration composite material casing according to claim 1, characterized in that, The casing body is provided with multiple functional areas along the axial direction, including an end mounting area, a main body area, a blade containment area, a blade tip corresponding area, and an inlet / outlet transition area. The casing body has different load-bearing thicknesses in different functional areas.

9. The partitioned multi-configuration composite material casing according to claim 8, characterized in that, The load-bearing thickness of the casing body in each of the functional areas is composed of the thickness of the inner stiffness retention layer, the middle lightweight stiffness coordination layer, and the outer energy-absorbing layer. The load-bearing thickness of the casing body in the blade containment area is greater than that in the main body barrel area; the load-bearing thickness of the casing body in the main body barrel area is less than that in the end mounting area. The blade containment area has a different thickness or thickness ratio than at least one of the inner stiffness retention layer, the intermediate lightweight stiffness coordination layer, and the outer containment energy absorption layer in the main body area.

10. A design method for a partitioned multi-configuration composite material casing, characterized in that, The method applicable to the partitioned multi-configuration composite material casing according to any one of claims 1-9 includes: Step 1: Establish the geometric model and finite element model of the composite material casing, divide the casing body into axial functional areas, and define the macroscopic equivalent material performance parameters of the two-dimensional triaxial braided structure, the three-dimensional woven reinforcement structure, and the variable angle laminated structure. Step 2: Based on the service conditions of the composite material casing, determine the inner wall radial deformation limit, impact energy absorption requirements, interlayer safety requirements, and structural mass constraints; Step 3: Define the functional layer parameters for each functional layer and the interface transition layer parameters between different functional layers, and use the interface transition layer parameters and the functional layer parameters as design variables; The interface transition layer parameters include: interface transition layer type, interface stiffness parameters, interface damping parameters, and interlayer connection method. The functional layer parameters include: the weaving angle of the two-dimensional triaxial braided structure, the layup angle, layup ratio and angle gradient of the variable angle laminated structure, the structural type of the three-dimensional woven reinforcement structure, the load-bearing thickness of the main body of the casing and the thickness ratio of each functional layer. Step 4: Perform dynamic and impact response analysis on different functional layered heterogeneous schemes to obtain the radial deformation of the inner wall of the composite material casing, impact absorption energy, interlaminar stress or interlaminar failure index, and structural quality. Step 5: With the optimization objectives of reducing the structural mass and radial deformation of the inner wall of the composite material casing and increasing the impact absorption energy, and with the constraint that the interlaminar stress or the interlaminar failure index does not exceed a set threshold, multi-objective optimization is performed on the design variables. Step 6: Obtain the optimized solution that satisfies the constraints, and output the interface transition layer parameters and the functional layer parameters.

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