Local resonance super-structure wing of tilt rotorcraft and design method of local resonance super-structure wing

Abstract

The invention provides a local resonance super-structure wing of a tilt rotorcraft and a design method of the local resonance super-structure wing, the local resonance super-structure wing comprises a skin and a plurality of local oscillators, and the plurality of local oscillators are periodically arranged on the inner surface of the skin. The multi-stage nested resonance unit is constructed by adopting a space filling full structure, two groups of belleville spring assemblies and two groups of resonance mass blocks form a local oscillator, two low and medium frequency band gaps can be generated in a limited space in a wing, multi-frequency vibration suppression of the tilt rotorcraft is realized, the problem of space occupation of multi-frequency vibration suppression is solved, and the multi-frequency vibration suppression efficiency of the tilt rotorcraft is improved. And the compact requirement of an aviation structure is met.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and in particular, to a locally resonant metamaterial wing of a tiltrotor aircraft and a design method thereof. Background Art

[0002] As a composite aircraft that combines the vertical takeoff and landing capabilities of a helicopter and the high-speed cruise characteristics of a fixed-wing aircraft, a tiltrotor aircraft has important application values in the fields of military transportation, civilian commuting, etc. Its working principle is to realize the flight mode switching through a tiltable rotor nacelle: during vertical takeoff and landing, the tiltrotor provides lift, and during cruise, the tiltrotor is converted into a propeller, and the wing bears the lift. However, this unique design brings significant vibration control problems - the broadband vibration generated by the tiltrotor will be transmitted to the fuselage through the hub, nacelle mechanism, tilt axis, and wing, causing problems such as structural fatigue, reduced occupant comfort, and deterioration of equipment accuracy.

[0003] Research has found that for the broadband vibration generated by the rotor nacelle of a tiltrotor aircraft, the existing vibration suppression technologies have obvious limitations. For example, a dynamic vibration absorber is mainly designed for a single frequency band and cannot cover the mid-low frequency multi-order harmonics of rotor vibration, making it difficult to meet the broadband suppression requirements. The active control technology relies on sensors and actuators for real-time regulation. Although the frequency range can be expanded, the system mass and energy consumption increase significantly, which conflicts with the lightweight design requirements of the aircraft, and the reliability decreases under working conditions such as extreme temperatures and electromagnetic interference.

[0004] In recent years, the emerging elastic metamaterials (EMM) suppress the vibration propagation in a specific frequency band (bandgap) by designing a periodic unit cell structure and using the local resonance mechanism, providing a new idea for multi-band vibration control. However, a single oscillator can only generate a single main bandgap. If multiple harmonics need to be covered, multiple levels of stacked oscillators are required, resulting in a sharp increase in the internal space occupancy rate of the wing and unable to meet the compactness requirements of the aviation structure; in addition, the vibration energy of the tiltrotor is mainly concentrated in the mid-low frequency band (<500 Hz). To achieve a low-frequency bandgap with the existing EMM, the oscillator mass needs to be significantly increased, which conflicts with the lightweight and high-load requirements of the wing, and it is difficult to deploy large-size oscillators due to the limitation of the internal space of the wing. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the problem to be solved by the present invention is that the existing vibration suppression technologies have limitations in broadband suppression ability, large space occupancy, and inability to achieve lightweight design, and cannot meet the requirements of the tiltrotor aircraft for multi-band collaborative suppression in a limited wing space.

[0006] To solve the above problems, a locally resonant metamaterial wing for a tiltrotor aircraft is provided in the first aspect of the present invention, including a skin and a plurality of local oscillators, and the plurality of local oscillators are periodically arranged on the inner surface of the skin; The local oscillator includes: An outer frame assembly, which is connected to the skin; A first resonant mass block assembly, which is nested inside the outer frame assembly; A second resonant mass block, which is nested inside the first resonant mass block assembly; A first disc spring assembly, which connects the outer frame assembly and the first resonant mass block assembly; A second disc spring assembly, which connects the second resonant mass block and the first resonant mass block assembly.

[0007] The present invention uses a space-filling fractal structure to construct a multi-level nested resonant unit. The local oscillator is composed of two sets of disc spring assemblies and two sets of resonant mass blocks, which can generate two mid-low frequency bandgaps in the limited space inside the wing, realize the vibration suppression of multiple frequencies of the tiltrotor aircraft, solve the problem of space occupation for multi-frequency vibration suppression, and meet the requirements of aviation structure compactness.

[0008] Furthermore, the first disc spring assembly and the second disc spring assembly are in a flattened state. Utilizing the low stiffness characteristics of the disc spring in the flattened state, the natural frequency of the local oscillator is significantly reduced under the condition of keeping the resonant mass unchanged, realizing the suppression of the mid-low frequency bandgap while avoiding conflict with the lightweight requirement of the wing.

[0009] Furthermore, the local oscillator is a double-layer symmetric structure. The outer frame assembly includes two symmetrically arranged and fixedly connected outer frames. The first resonant mass block assembly includes two symmetrically arranged and fixedly connected first resonant mass blocks. The first disc spring assembly includes two symmetrically arranged first disc springs. Each first disc spring connects one outer frame and one first resonant mass block respectively. The second disc spring assembly includes two symmetrically arranged second disc springs. Each second disc spring connects both sides of one first resonant mass block and the second resonant mass block respectively. The local oscillator adopts a symmetric structure, so that a pair of disc springs in each disc spring assembly are simultaneously in a flattened state, maintaining force balance.

[0010] Furthermore, the connection method of the two outer frames of the outer frame assembly is selected from one of bolt connection, adhesive bonding, riveting, and welding. The connection method of the two first resonant mass blocks of the first resonant mass block assembly is selected from one of bolt connection, adhesive bonding, riveting, and welding. There are multiple optional connection methods for the outer frame assembly and the first resonant mass block assembly, which not only ensure the flexibility of the assembly process but also can select the appropriate connection strength according to different working conditions.

[0011] Further, a circumferentially arranged first step surface is provided on the inner wall of the outer frame, and a circumferentially arranged second step surface is provided on the outer wall of the first resonant mass block. The directions of the first step surface and the second step surface are opposite. The outer edge of the first disc spring abuts against the first step surface, and the inner edge of the first disc spring abuts against the second step surface.

[0012] Further, a circumferentially arranged third step surface is provided on the inner wall of the first resonant mass block, and a circumferentially arranged fourth step surface is provided on the outer wall of the second resonant mass block. The directions of the third step surface and the fourth step surface are opposite. The outer edge of the second disc spring abuts against the third step surface, and the inner edge of the second disc spring abuts against the fourth step surface.

[0013] The circumferential step surface structures provided on the outer frame and the resonant mass block play a limiting role, avoiding the bandgap frequency shift caused by the assembly error of the disc spring assembly, thereby realizing the vibration suppression of the target frequency. The second aspect of the present invention provides a design method for the locally resonant metamaterial wing of the above tilt-rotor aircraft, including the following steps: S1. Calculate the Nth-order vibration frequency transmitted from the tilt-rotor of the tilt-rotor aircraft to the fuselage structure, and its expression is: f N = NpΩ; In the formula, f N is the Nth-order vibration frequency, N is the harmonic order, p is the number of blades of the tilt-rotor aircraft, and Ω is the rotational frequency of the tilt-rotor; S2. Construct the characteristic model of the local oscillator, and its expression is: ; In the formula, M is the mass of the first resonant mass block assembly, m is the mass of the second resonant mass block, K is the stiffness of the first disc spring assembly in the flattened state, k is the stiffness of the second disc spring assembly in the flattened state, and ω is the natural frequency of the local oscillator; S3. Take the Nth-order vibration frequency calculated in step S1 as the natural frequency of the local oscillator in step S2, input it into the characteristic model of the local oscillator, obtain the constraint formula of the local oscillator, and design the parameters of the local oscillator to satisfy the constraint formula.

[0014] Based on the vibration frequency characteristics of the tilt-rotor aircraft, the present invention establishes a design model. By substituting the measured vibration frequency into the characteristic equation for parameter back-calculation, the accurate matching of the natural frequency of the local oscillator and the rotor harmonics can be realized, improving the pertinence and effectiveness of vibration suppression.

[0015] Further, the specific process of step S3 includes the following steps: When the harmonic order N is 1, the first-order vibration frequency is calculated according to the expression in step S1; when the harmonic order N is 2, the second-order vibration frequency is calculated according to the expression in step S1. S32. Use the first-order vibration frequency as the natural frequency of the local oscillator in step S2 and input it into the characteristic model of the local oscillator to obtain the first constraint equation of the local oscillator; use the second-order vibration frequency as the natural frequency of the local oscillator in step S2 and input it into the characteristic model of the local oscillator to obtain the second constraint equation of the local oscillator. S33. Design the parameters of the local oscillator to satisfy both the first constraint equation and the second constraint equation simultaneously.

[0016] With the goal of suppressing the first two-order harmonic vibrations transmitted to the fuselage structure, by substituting into the characteristic equation for parameter design respectively, the local oscillator generates two specified bandgaps simultaneously, realizing the vibration suppression of two frequencies of the tiltrotor aircraft.

[0017] Furthermore, the design method further includes the following steps: S4. Obtain the masses of the first resonant mass block assembly and the second resonant mass, input them into the first constraint equation and the second constraint equation, and calculate the stiffness of the first disc spring assembly and the second disc spring assembly in the flattened state.

[0018] The vibration suppression performance is strongly related to the mass of the local oscillator. Design the mass of the resonant mass block based on the additional mass acceptable to the wing structure, and then confirm the stiffness of the disc spring in the flattened state accordingly.

[0019] Furthermore, the design method further includes the following steps: S5. Construct a stiffness model for the disc spring in the flattened state, and its expression is: KB=\frac {E} {(1-{\mu}^{2}){({D}_{0} / 2)}^{2}C}\left [ {{t}^{3}-\frac {{h}^{2}} {2}t} \right ] ; In the formula, KB is the stiffness of the disc spring when flattened, E is the elastic modulus of the disc spring, μ is the Poisson's ratio of the disc spring, D0 is the outer diameter of the disc spring, D i is the inner diameter of the disc spring, t is the thickness of the disc spring, h is the free height of the disc spring minus the thickness, and the constant C is ; S6. Input the calculation result of step S4 into the stiffness model of the disc spring in the flattened state in step S5, and design the materials and dimensions of the first disc spring assembly and the second disc spring assembly.

[0020] Design the spring size and material according to the stiffness model of the disc spring. The designed local oscillator has two natural frequencies, which can achieve the vibration suppression of multiple frequencies of the tilt-rotor aircraft.

[0021] In summary, the present invention has the following beneficial effects compared with the prior art: (1) The present invention uses a space-filling fractal structure to construct a multi-stage nested resonant unit (including two groups of disc springs and resonant mass blocks), and uses periodic arrangement to form a metamaterial bandgap, synchronously realizing the collaborative suppression of multi-order harmonic vibrations in a limited space, effectively solving the problem of space occupation for multi-frequency vibration suppression of tilt-rotor aircraft, and meeting the requirements of aviation structure compactness.

[0022] (2) The present invention utilizes the low stiffness characteristic of the disc spring in the flattened state, significantly reducing the natural frequency of the local oscillator under the condition of keeping the resonant mass unchanged, achieving a balance between mid-low frequency bandgap suppression and wing lightweight design, and providing a lightweight solution for the vibration suppression of tilt-rotor aircraft.

[0023] (3) The design method of the present invention is based on the modeling of the rotor vibration frequency characteristics, calculates the parameters of the local oscillator through the characteristic equation, and combines the low stiffness design of the disc spring to achieve the precise matching of the natural frequency and harmonics, realizing multiple mid-low frequency bandgaps in the limited wing space and solving the problem of mid-low frequency multi-harmonic suppression. Description of the Drawings

[0024] Figure 1 It is an assembly drawing of the tilt-rotor, hub, nacelle mechanism, tilt axis and wing of the tilt-rotor aircraft in the embodiment; Figure 2 It is a layout structure diagram of the local oscillator in the wing in the embodiment; Figure 3 It is a structure diagram of the local oscillator in the embodiment; Figure 4 It is a cross-sectional view of the local oscillator in the embodiment; Figure 5 It is a cross-sectional view of the local oscillator in the unassembled state in the embodiment; Figure 6 It is an equivalent structure schematic diagram of the local oscillator in the embodiment; Figure 7 It is a size schematic diagram of the disc spring in the embodiment; Description of the Reference Numerals: 1 - Local oscillator, 11 - Outer frame, 12 - First resonant mass block, 13 - Second resonant mass block, 14 - First disc spring, 15 - Second disc spring, 16 - Fixed bolt, 101 - First step surface, 102 - Second step surface, 103 - Third step surface, 104 - Fourth step surface, 2 - Wing, 21 - Skin, 3 - Tilt-rotor, 4 - Hub, 5 - Nacelle mechanism, 6 - Tilt axis. Detailed implementation manners

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0028] Combined with Figure 1 As shown, the tiltrotor aircraft includes components such as a fuselage, a wing 2, a tiltrotor 3, a hub 4, a nacelle mechanism 5, a tilt axis 6, etc. The broadband vibration generated by the tiltrotor 3 will be transmitted to the fuselage through the hub 4, the nacelle mechanism 5, the tilt axis 6, and the wing 2, thereby causing problems such as structural fatigue, discomfort of crew members, and decline in equipment accuracy. Combined with Figure 2 As shown, this embodiment discloses a locally resonant metamaterial wing. A plurality of local resonators 1 are periodically arranged on the inner surface of the skin 21 of the wing 2, and the vibration generated by the tiltrotor 3 is suppressed by the bandgap of the local resonators 1.

[0029] Combined with Figures 3 to 5 As shown, the local resonator 1 adopts a multi-stage nested structure design, including an outer frame assembly, a first resonant mass block assembly, a second resonant mass block 13, a first disc spring assembly, and a second disc spring assembly. The outer frame assembly is connected to the skin 21, the first resonant mass block assembly is nested inside the outer frame assembly, the first disc spring assembly connects the outer frame assembly and the first resonant mass block assembly, the second resonant mass block 13 is nested inside the first resonant mass block assembly, and the second disc spring assembly connects the second resonant mass block 13 and the first resonant mass block assembly. This local resonator 1 is composed of two groups of disc spring assemblies and two groups of resonant mass blocks, and can generate two mid-low frequency bandgaps to achieve vibration suppression of the tiltrotor aircraft at multiple frequencies.

[0030] More specifically, the local oscillator 1 adopts an upper and lower double-layer symmetric structure. The outer frame assembly includes two symmetrically arranged and fixedly connected outer frames 11, and the structures, dimensions, and masses of the two outer frames 11 are the same. The first resonant mass block assembly includes two symmetrically arranged and fixedly connected first resonant mass blocks 12, and the structures, dimensions, and masses of the two first resonant mass blocks 12 are the same. The first disc spring assembly includes two symmetrically arranged first disc springs 14, and the structures, dimensions, and materials of the two first disc springs 14 are the same. The second disc spring assembly includes two symmetrically arranged second disc springs 15, and the structures, dimensions, and materials of the two second disc springs 15 are the same. Each first disc spring 14 is respectively connected to an outer frame 11 and a first resonant mass block 12, and each second disc spring 15 is respectively connected to the upper and lower sides of a first resonant mass block 12 and a second resonant mass block 13. The local oscillator 1 adopts a symmetric structure, so that a pair of disc springs in each disc spring assembly are simultaneously in the same stress state, maintaining force balance.

[0031] In some preferred embodiments, each of the first disc springs 14 and each of the second disc springs 15 are in a flattened state. The disc spring has a non-linear stiffness characteristic, and its stiffness in the flattened state is very low. Thus, the natural frequency of the local oscillator 1 can be significantly reduced under the condition of keeping the resonant mass unchanged, obtaining low-frequency bandgap performance.

[0032] In some preferred embodiments, the local oscillator 1 has a limiting structure for limiting the installation position of the disc spring. Specifically, the inner wall of the outer frame 11 has a groove structure, forming a circumferentially arranged first step surface 101; the outer wall of the first resonant mass block 12 has a convex ring structure, forming a circumferentially arranged second step surface 102, and the directions of the first step surface 101 and the second step surface 102 are opposite; the inner wall of the first resonant mass block 12 has a groove structure, forming a circumferentially arranged third step surface 103, and the outer wall of the second resonant mass block 13 has a convex ring structure, forming a circumferentially arranged fourth step surface 104, and the directions of the third step surface 103 and the fourth step surface 104 are opposite. When the disc spring assembly is assembled, the outer edge of the first disc spring 14 abuts against the first step surface 101, and the inner edge abuts against the second step surface 102; the outer edge of the second disc spring 15 abuts against the third step surface 103, and the inner edge abuts against the fourth step surface 104, thereby reducing the assembly error of the disc spring assembly.

[0033] In this embodiment, the local oscillator 1 is assembled using fixing bolts 16. The two outer frames 11 of the outer frame assembly are connected by the fixing bolts 16, and the two first resonant mass blocks 12 of the first resonant mass block assembly are also connected by the fixing bolts 16. After assembly, the first disc spring 14 and the second disc spring 15 are in a flattened state. In some other embodiments, the outer frame assembly and the first resonant mass block assembly can also adopt assembly methods such as bonding, riveting, and welding to achieve appropriate connection strength according to different working conditions.

[0034] The local oscillator 1 provided in the above embodiment uses a space-filling fractal structure to construct a multi-level nested resonant unit, forms a metamaterial bandgap by periodic arrangement, and can effectively solve the problem of space occupation for multi-frequency vibration suppression of a tilt-rotor aircraft by synchronously suppressing multi-order harmonic vibrations in a limited space; and uses the low stiffness characteristic of the disc spring in the flattened state to significantly reduce the natural frequency of the local oscillator 1 while keeping the resonant mass unchanged, achieving low-frequency bandgap suppression while avoiding conflicts with the lightweight requirements of the wing 2.

[0035] Another embodiment of the present invention provides a design method for a local resonance meta-wing of a tilt-rotor aircraft, including the following steps: S1. Calculate the Nth-order vibration frequency transmitted from the tilt rotor 3 of the tilt-rotor aircraft to the fuselage structure, and its expression is: f N = NpΩ; In the formula, f N is the Nth-order vibration frequency, N is the harmonic order, p is the number of blades of the tilt-rotor aircraft, and Ω is the rotational frequency of the tilt rotor 3;

[0036] For example, when the rated rotational speed of the tilt rotor is 1800 RPM (Ω = 30 Hz), the number of blades of the tilt-rotor aircraft is 3, and the goal is to suppress the first two-order harmonic vibrations transmitted to the fuselage structure, that is, the harmonic order N is selected as 1 and 2, and the calculated vibration frequencies are 90 Hz and 180 Hz.

[0037] S2. Construct the characteristic model of the local oscillator, and its equivalent structure is as Figure 6 shown, and its expression is: ; In the formula, M is the mass of the first resonant mass block assembly, m is the mass of the second resonant mass block, K is the stiffness of the first disc spring assembly in the flattened state, k is the stiffness of the second disc spring assembly in the flattened state, and ω is the natural frequency of the local oscillator.

[0038] S3. Substitute the Nth-order vibration frequency f calculated in step S1 NThe natural frequency ω of the local oscillator is input into the characteristic model of the local oscillator to obtain the constraint equation of the local oscillator, and the parameters of the local oscillator are designed to satisfy the constraint equation.

[0039] In a specific implementation, the harmonic order N is taken as 1, and the first-order vibration frequency is calculated according to the expression in step S1; the harmonic order N is taken as 2, and the second-order vibration frequency is calculated according to the expression in step S1.

[0040] The first-order vibration frequency is used as the natural frequency of the local oscillator in step S2 and input into the characteristic model of the local oscillator to obtain the first constraint equation of the local oscillator: ; The second-order vibration frequency is used as the natural frequency of the local oscillator in step S2 and input into the characteristic model of the local oscillator to obtain the second constraint equation of the local oscillator: .

[0041] Design the parameters of the local oscillator to satisfy both the first constraint equation and the second constraint equation. Specifically, after designing the mass M of the first resonant mass block assembly and the mass m of the second resonant mass block, the stiffness K of the first disc spring assembly in the flattened state and the stiffness k of the second disc spring assembly in the flattened state can be obtained according to the first constraint equation and the second constraint equation. After designing the stiffness K of the first disc spring assembly in the flattened state and the stiffness k of the second disc spring assembly in the flattened state, the mass M of the first resonant mass block assembly and the mass m of the second resonant mass block can be obtained according to the first constraint equation and the second constraint equation.

[0042] For example, the first two-order vibration frequencies of 90 Hz and 180 Hz calculated in step S1 are designed as the natural frequencies of the local oscillator, that is , substituting into the characteristic model of the local oscillator can obtain the complete first constraint equation and the second constraint equation, that is, there is a certain constraint relationship among the mass M of the first resonant mass block assembly, the mass m of the second resonant mass block, the stiffness K of the first disc spring assembly in the flattened state, and the stiffness k of the second disc spring assembly in the flattened state.

[0043] S4. Design the masses of the first resonant mass block assembly and the second resonant mass block based on the additional mass acceptable by the wing structure, input them into the first constraint equation and the second constraint equation, and calculate the stiffnesses of the first disc spring assembly and the second disc spring assembly in the flattened state.

[0044] The masses M of the obtained first resonant mass block assembly and m of the second resonant mass block are both input into the first constraint equation and the second constraint equation to obtain a system of equations, and then the stiffness K of the first disc spring assembly in the flattened state and the stiffness k of the second disc spring assembly in the flattened state can be calculated.

[0045] S5. Construct the stiffness model of the disc spring in the flattened state. The dimensional parameters of the disc spring are as Figure 7 shown, and its expression is: KB=\frac {E} {(1-{\mu}^{2}){({D}_{0} / 2)}^{2}C}\left [ {{t}^{3}-\frac {{h}^{2}} {2}t} \right ] ; In the formula, KB is the stiffness of the disc spring when flattened, E is the elastic modulus of the disc spring, μ is the Poisson's ratio of the disc spring, D0 is the outer diameter of the disc spring, D i is the inner diameter of the disc spring, t is the thickness of the disc spring, h is the free height of the disc spring minus the thickness, and the constant C is .

[0046] According to the stiffness model of the disc spring in the flattened state, it can be seen that by designing the material and dimensions of the disc spring, the disc spring can exhibit low stiffness characteristics in the flattened state, and then reduce the natural frequency of the local oscillator without changing the resonant mass, achieving the suppression of the mid-low frequency bandgap while avoiding conflicts with the lightweight requirements of the wing.

[0047] S6. Input the calculation result of step S4 into the stiffness model of the disc spring in the flattened state in step S5, and design the materials and dimensions of the first disc spring assembly and the second disc spring assembly.

[0048] Using the above design method, the specific parameters of the local oscillator can be determined. Combining with the low stiffness design of the disc spring, the natural frequency and harmonics can be accurately matched. Periodically arranging the assembled local oscillators on the inner wall of the skin 21 can achieve multiple mid-low frequency bandgaps in the limited wing space, solve the problem of mid-low frequency multi-harmonic suppression, and meet the requirements of the compactness of the aviation structure at the same time.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A locally resonant metamaterial wing of a tiltrotor aircraft, characterized in that, It includes a skin (21) and a plurality of local oscillators (1), and the plurality of local oscillators (1) are periodically arranged on the inner surface of the skin (21); The local oscillator (1) includes: An outer frame assembly, which is connected to the skin (21); A first resonant mass block assembly, which is nested inside the outer frame assembly; A second resonant mass block (13), which is nested inside the first resonant mass block assembly; A first disc spring assembly, which connects the outer frame assembly and the first resonant mass block assembly; A second disc spring assembly, which connects the second resonant mass block (13) and the first resonant mass block assembly.

2. The locally resonant metamaterial wing of a tiltrotor aircraft according to claim 1, wherein The first disc spring assembly and the second disc spring assembly are in a flattened state.

3. The locally resonant metamaterial wing of a tiltrotor aircraft according to claim 2, wherein The local oscillator (1) has a double-layer symmetric structure. The outer frame assembly includes two symmetrically arranged and fixedly connected outer frames (11). The first resonant mass block assembly includes two symmetrically arranged and fixedly connected first resonant mass blocks (12). The first disc spring assembly includes two symmetrically arranged first disc springs (14). Each first disc spring (14) is respectively connected to one outer frame (11) and one first resonant mass block (12). The second disc spring assembly includes two symmetrically arranged second disc springs (15). Each second disc spring (15) is respectively connected to both sides of one first resonant mass block (12) and the second resonant mass block (13).

4. The locally resonant metamaterial wing of the tiltrotor aircraft according to claim 3, characterized in that, The connection method of the two outer frames (11) of the outer frame assembly is selected from one of bolt connection, adhesive bonding, riveting, and welding. The connection method of the two first resonant mass blocks (12) of the first resonant mass block assembly is selected from one of bolt connection, adhesive bonding, riveting, and welding.

5. The locally resonant metamaterial wing of a tiltrotor aircraft according to claim 3, characterized in that, The inner wall of the outer frame (11) is provided with a circumferentially arranged first step surface (101). The outer wall of the first resonant mass block (12) is provided with a circumferentially arranged second step surface (102). The directions of the first step surface (101) and the second step surface (102) are opposite. The outer edge of the first disc spring (14) abuts against the first step surface (101). The inner edge of the first disc spring (14) abuts against the second step surface (102).

6. The locally resonant metamaterial wing of a tiltrotor aircraft according to claim 3, characterized in that The inner wall of the first resonant mass block (12) is provided with a circumferentially arranged third step surface (103). The outer wall of the second resonant mass block (13) is provided with a circumferentially arranged fourth step surface (104). The directions of the third step surface (103) and the fourth step surface (104) are opposite. The outer edge of the second disc spring (15) abuts against the third step surface (103). The inner edge of the second disc spring (15) abuts against the fourth step surface (104).

7. A design method for a locally resonant metamaterial wing of a tilt-rotor aircraft as described in any one of claims 1-6, characterized in that, It includes the following steps: S1. Calculate the Nth-order vibration frequency transmitted from the tilting rotor (3) of the tiltrotor aircraft to the fuselage structure, and its expression is: f N = NpΩ; where f N is the vibration frequency of the Nth order, N is the harmonic order, p is the number of blades of the tiltrotor, and Ω is the rotational frequency of the tiltrotor (3); S2. Construct a characteristic model of the local oscillator, and its expression is: ； Wherein, M is the mass of the first resonant mass block assembly, m is the mass of the second resonant mass block, K is the stiffness of the first disc spring assembly in the flattened state, k is the stiffness of the second disc spring assembly in the flattened state, and ω is the natural frequency of the local oscillator; S3. Use the Nth-order vibration frequency calculated in step S1 as the natural frequency of the local oscillator in step S2, input it into the characteristic model of the local oscillator to obtain the constraint equation of the local oscillator, and design the parameters of the local oscillator to satisfy the constraint equation.

8. The design method of the local resonance metamaterial wing of a tilt-rotor aircraft according to claim 7, characterized in that The specific process of step S3 includes the following steps: S31. When the harmonic order N is 1, calculate the first-order vibration frequency according to the expression in step S1; when the harmonic order N is 2, calculate the second-order vibration frequency according to the expression in step S1. S32. Use the first-order vibration frequency as the natural frequency of the local oscillator in step S2, input it into the characteristic model of the local oscillator to obtain the first constraint equation of the local oscillator; use the second-order vibration frequency as the natural frequency of the local oscillator in step S2, input it into the characteristic model of the local oscillator to obtain the second constraint equation of the local oscillator. S33. Design the parameters of the local oscillator to satisfy both the first constraint equation and the second constraint equation.

9. The design method of the local resonance metamaterial wing of a tiltrotor aircraft according to claim 8, characterized in that It further includes the following steps: S4. Obtain the masses of the first resonant mass block assembly and the second resonant mass block, input them into the first constraint equation and the second constraint equation, and calculate the stiffnesses of the first disc spring assembly and the second disc spring assembly in the flattened state.

10. The design method of the locally resonant metamaterial wing of a tiltrotor aircraft according to claim 9, characterized in that, It further includes the following steps: S5. Construct a stiffness model of the disc spring in the flattened state, and its expression is: ； Wherein, KB is the stiffness when the disc spring is flattened, E is the elastic modulus of the disc spring, μ is the Poisson's ratio of the disc spring, D0 is the outer diameter of the disc spring, D i is the inner diameter of the disc spring, t is the thickness of the disc spring, h is the free height of the disc spring minus the thickness, and the constant C is ; S6. Input the calculation result of step S4 into the stiffness model of the disc spring in the flattened state in step S5, and design the materials and dimensions of the first disc spring assembly and the second disc spring assembly.

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