A local resonance superstructure wing for a tiltrotor aircraft and a design method thereof

Abstract

The present invention provides a localized resonant metastructure wing for a tiltrotor aircraft and a design method thereof. The localized resonant metastructure wing comprises a skin and multiple localized oscillators periodically arranged on the inner surface of the skin. The present invention employs a space-filling fractal structure to construct a multi-stage nested resonant unit. The localized oscillators are composed of two sets of disc spring assemblies and two sets of resonant masses. These units generate two low- and medium-frequency band gaps within the confined space within the wing, enabling vibration suppression at multiple frequencies for the tiltrotor aircraft. This solves the space requirement for multi-frequency vibration suppression and meets the compactness requirements of aviation structures.

Description

Technical Field

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

[0002] Tilt-rotor aircraft, hybrid aircraft combining the vertical takeoff and landing capabilities of helicopters with the high-speed cruising characteristics of fixed-wing aircraft, have important applications in military transport, civilian commuting, and other fields. Their operating principle is to switch flight modes using a tilting rotor nacelle: during vertical takeoff and landing, the tilt-rotor provides lift; during cruising, the tilt-rotor converts to propulsion, with the wings providing lift. However, this unique design presents significant vibration control challenges. The broadband vibrations generated by the tilt-rotor are transmitted to the fuselage through the hub, nacelle mechanism, tilt shaft, and wings, causing structural fatigue, reduced occupant comfort, and degraded equipment accuracy.

[0003] Research has found that existing vibration suppression technologies have significant limitations for the broadband vibrations generated by the rotor nacelles of tiltrotor aircraft. For example, dynamic vibration absorbers are primarily designed for a single frequency band and cannot cover the multi-order harmonics of low- and mid-frequency rotor vibrations, making it difficult to meet broadband suppression requirements. Active control technologies rely on real-time control of sensors and actuators. While this can expand the frequency range, it significantly increases system mass and energy consumption, conflicting with the need for lightweight aircraft design. Furthermore, reliability is reduced under extreme temperatures and electromagnetic interference conditions.

[0004] The recently emerging elastic metamaterials (EMMs) utilize periodic unit-cell structures and localized resonance to suppress vibration propagation within specific frequency bands (band gaps), offering a new approach to multi-band vibration control. However, a single oscillator can only generate a single primary band gap. To cover multiple harmonics, multiple layers of oscillators must be stacked, resulting in a significant increase in internal wing space utilization and failing to meet the compactness requirements of aviation structures. Furthermore, tiltrotor vibration energy is primarily concentrated in the low- to mid-frequency range (<500 Hz). Achieving this low-frequency band gap requires a significant increase in oscillator mass in existing EMMs, which conflicts with the wing's lightweight and high-load requirements. Furthermore, the limited internal wing space makes it difficult to deploy large oscillators. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the problem to be solved by the present invention is that the existing vibration suppression technology has the limitations of insufficient broadband suppression capability, large space occupancy, and inability to achieve lightweight design, and cannot meet the needs of tilt-rotor aircraft to achieve multi-band collaborative suppression within the limited wing space.

[0006] To solve the above problems, the present invention provides a local resonance metastructure wing for a tiltrotor aircraft in a first aspect, comprising a skin and a plurality of local oscillators, wherein the plurality of local oscillators are periodically arranged on the inner surface of the skin;

[0007] The local oscillator comprises:

[0008] an outer frame assembly connected to the skin;

[0009] a first resonant mass assembly, nested within the outer frame assembly;

[0010] a second resonant mass, nested within the first resonant mass assembly;

[0011] a first disc spring assembly connecting the outer frame assembly and the first resonant mass assembly;

[0012] A second disc spring assembly connects the second resonant mass and the first resonant mass assembly.

[0013] The present invention adopts a space-filling fractal structure to construct a multi-level nested resonant unit. The local oscillator is composed of two groups of disc spring assemblies and two groups of resonant mass blocks. Two medium and low frequency band gaps can be generated in the limited space inside the wing, realizing vibration suppression of multiple frequencies of the tiltrotor aircraft, solving the space occupation problem of multi-frequency vibration suppression, and meeting the compactness requirements of aviation structure.

[0014] Furthermore, the first and second disc spring assemblies are in a flattened state. By utilizing the low stiffness of the disc springs in this flattened state, the natural frequency of the local oscillator is significantly reduced while maintaining the resonant mass. This achieves mid- and low-frequency bandgap suppression while avoiding conflicts with wing lightweighting requirements.

[0015] Furthermore, the local oscillator has a double-layer symmetrical structure. The outer frame assembly includes two symmetrically arranged and fixedly connected outer frames. The first resonant mass 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 of which is respectively connected to one of the outer frames and one of the first resonant mass blocks. The second disc spring assembly includes two symmetrically arranged second disc springs, each of which is respectively connected to one of the first resonant mass blocks and one of the second resonant mass blocks. The local oscillator adopts a symmetrical structure, so that the pair of disc springs in each disc spring assembly are simultaneously flattened, maintaining force balance.

[0016] Furthermore, the two outer frames of the outer frame assembly are connected by a method selected from the group consisting of bolting, gluing, riveting, and welding. The two first resonating mass blocks of the first resonating mass block assembly are connected by a method selected from the group consisting of bolting, gluing, riveting, and welding. Multiple options are available for connecting the outer frame assembly and the first resonating mass block assembly, ensuring flexibility in the assembly process while allowing for selection of appropriate connection strength based on different operating conditions.

[0017] Furthermore, the inner wall of the outer frame is provided with a first step surface arranged circumferentially, and the outer wall of the first resonant mass block is provided with a second step surface arranged circumferentially, the first step surface is in opposite directions to the second step surface, 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.

[0018] Furthermore, the inner wall of the first resonant mass block is provided with a circumferentially arranged third step surface, and the outer wall of the second resonant mass block is provided with a circumferentially arranged fourth step surface, the third step surface is in opposite directions to the fourth step surface, 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.

[0019] The outer frame and the resonant mass block are provided with a circumferential step surface structure to play a limiting role, thereby avoiding the band gap frequency deviation caused by the assembly error of the disc spring assembly, thereby achieving vibration suppression of the target frequency.

[0020] A second aspect of the present invention provides a method for designing a local resonant metastructure wing of the tiltrotor aircraft, comprising the following steps:

[0021] S1. Calculate the Nth-order vibration frequency of the tiltrotor aircraft transmitted to the fuselage structure. The expression is:

[0022] f N =NpΩ;

[0023] Where, f N is the Nth-order vibration frequency, N is the harmonic order, p is the number of blades of the tiltrotor, and Ω is the rotation frequency of the tiltrotor;

[0024] S2. Construct the characteristic model of the local oscillator, which is expressed as:

[0025] ;

[0026] Where M is the mass of the first resonant mass assembly, m is the mass of the second resonant mass, 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;

[0027] S3. Using the Nth-order vibration frequency calculated in step S1 as the natural frequency of the local oscillator in step S2, inputting it into the characteristic model of the local oscillator, obtaining the constraint formula of the local oscillator, and designing the parameters of the local oscillator to satisfy the constraint formula.

[0028] The present invention establishes a design model based on the vibration frequency characteristics of the tiltrotor aircraft. By substituting the measured vibration frequency into the characteristic equation for parameter inversion, it is possible to achieve precise matching of the local oscillator's natural frequency and the rotor harmonics, thereby improving the pertinence and effectiveness of vibration suppression.

[0029] Furthermore, the specific process of step S3 includes the following steps:

[0030] S31, 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;

[0031] S32. Using the first-order vibration frequency as the natural frequency of the local oscillator in step S2 and inputting it into the characteristic model of the local oscillator to obtain a first constraint formula of the local oscillator; using the second-order vibration frequency as the natural frequency of the local oscillator in step S2 and inputting it into the characteristic model of the local oscillator to obtain a second constraint formula of the local oscillator;

[0032] S33. Design parameters of the local oscillator to satisfy the first constraint formula and the second constraint formula at the same time.

[0033] With the goal of suppressing the first two harmonic vibrations transmitted to the fuselage structure, the parameters are designed by substituting them into the characteristic equations respectively, so that the local oscillator can generate two specified band gaps at the same time, thereby achieving vibration suppression of two frequencies of the tiltrotor aircraft.

[0034] Furthermore, the design method further comprises the following steps:

[0035] S4. Obtain the masses of the first resonant mass block assembly and the second resonant mass block, input them into the first constraint formula and the second constraint formula, and calculate the stiffness of the first disc spring assembly and the second disc spring assembly in a flattened state.

[0036] The vibration suppression performance is strongly correlated with the mass of the local oscillator. The mass of the resonant mass block is designed based on the additional mass that the wing structure can accept, and the stiffness of the disc spring in the flattened state is then determined.

[0037] Furthermore, the design method further comprises the following steps:

[0038] S5. Construct a stiffness model of the disc spring in the flattened state, and its expression is:

[0039] KB=\frac {E} {(1-{\mu}^{2}){({D}_{0} / 2)}^{2}C}\left [ {{t}^{3}-\frac {{h}^{2}} {2}t} \right ] ;

[0040] Where 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, and 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 ;

[0041] 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.

[0042] The spring size and material are designed according to the stiffness model of the disc spring. The designed local oscillator has two natural frequencies, which can achieve vibration suppression of multiple frequencies of the tiltrotor aircraft.

[0043] In summary, the present invention has the following beneficial effects compared to the prior art:

[0044] (1) The present invention adopts a space-filling fractal structure to construct a multi-level nested resonant unit (including two sets of disc springs and a resonant mass block), and uses a periodic arrangement to form a metamaterial band gap, thereby achieving the coordinated suppression of multi-order harmonic vibrations in a limited space, effectively solving the space occupation problem of multi-frequency vibration suppression in tiltrotor aircraft and meeting the compactness requirements of aviation structures.

[0045] (2) The present invention utilizes the low stiffness characteristics of the disc spring in the flattened state to significantly reduce the natural frequency of the local oscillator while maintaining the resonant mass unchanged, thereby achieving a balance between the suppression of the mid- and low-frequency band gap and the lightweight design of the wing, and providing a lightweight solution for vibration suppression of the tiltrotor aircraft.

[0046] (3) The design method of the present invention is based on the modeling of the rotor vibration frequency characteristics. The local oscillator parameters are calculated through the characteristic equation. Combined with the low stiffness design of the disc spring, it achieves precise matching of the natural frequency and harmonics, and realizes multiple medium and low frequency band gaps within the limited wing space, thus solving the problem of suppressing medium and low frequency multi-harmonics. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 An assembly diagram of the tiltrotor, hub, nacelle mechanism, tilt shaft, and wing of the tiltrotor aircraft in an embodiment;

[0048] Figure 2Schematic diagram of the arrangement of local oscillators in the wing of the embodiment;

[0049] Figure 3 is a structural diagram of a local oscillator in an embodiment;

[0050] Figure 4 is a cross-sectional view of a local oscillator in an embodiment;

[0051] Figure 5 is a cross-sectional view of an unassembled local vibrator in an embodiment;

[0052] Figure 6 Schematic diagram of the equivalent structure of the local oscillator in the embodiment;

[0053] Figure 7 Schematic diagram of the dimensions of the disc spring in the embodiment;

[0054] Description of reference numerals:

[0055] 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-fixing 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 DESCRIPTION

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0057] 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 invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0058] It should be noted that similar numbers and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0059] Combine Figure 1As shown, the tiltrotor aircraft includes a fuselage, wings 2, tiltrotors 3, hubs 4, nacelles 5, tilt shafts 6 and other components. The broadband vibration generated by the tiltrotors 3 will be transmitted to the fuselage through the hubs 4, nacelles 5, tilt shafts 6 and wings 2, thereby causing structural fatigue, occupant discomfort, and reduced equipment accuracy. Figure 2 As shown, this embodiment discloses a local resonant meta-structure wing, in which a plurality of local oscillators 1 are periodically arranged on the inner surface of the skin 21 of the wing 2, and the band gap of the local oscillators 1 is used to suppress the vibration generated by the tilt-rotor 3.

[0060] Combine Figures 3 to 5 As shown, the local oscillator 1 adopts a multi-stage nested structure design, including an outer frame assembly, a first resonant mass assembly, a second resonant mass 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 assembly is nested within the outer frame assembly, the first disc spring assembly connects the outer frame assembly and the first resonant mass assembly, the second resonant mass 13 is nested within the first resonant mass assembly, and the second disc spring assembly connects the second resonant mass 13 and the first resonant mass assembly. The local oscillator 1, consisting of two sets of disc spring assemblies and two sets of resonant masses, can generate two low- and medium-frequency band gaps, achieving vibration suppression at multiple frequencies in the tiltrotor aircraft.

[0061] More specifically, the local oscillator 1 adopts a double-layer symmetrical structure. The outer frame assembly includes two symmetrically arranged and fixedly connected outer frames 11, each with the same structure, dimensions, and mass. The first resonant mass assembly includes two symmetrically arranged and fixedly connected first resonant mass blocks 12, each with the same structure, dimensions, and mass. The first disc spring assembly includes two symmetrically arranged first disc springs 14, each with the same structure, dimensions, and material. The second disc spring assembly includes two symmetrically arranged second disc springs 15, each with the same structure, dimensions, and material. Each first disc spring 14 is connected to an outer frame 11 and a first resonant mass block 12, respectively. Each second disc spring 15 is connected to the upper and lower sides of a first resonant mass block 12 and a second resonant mass block 13, respectively. The symmetrical structure of the local oscillator 1 ensures that each pair of disc springs in each disc spring assembly is simultaneously subjected to the same force, maintaining force balance.

[0062] In some preferred embodiments, each first disc spring 14 and each second disc spring 15 is in a flattened state. Disc springs have nonlinear stiffness characteristics, and their stiffness in the flattened state is very low. This can significantly reduce the natural frequency of the local oscillator 1 while maintaining the resonant mass, thereby achieving low-frequency bandgap performance.

[0063] In some preferred embodiments, the local oscillator 1 includes a limiting structure for defining the installation position of the disc springs. Specifically, the inner wall of the outer frame 11 includes a groove structure, forming a circumferentially arranged first step surface 101; the outer wall of the first resonant mass block 12 includes a convex ring structure, forming a circumferentially arranged second step surface 102, with the first step surface 101 and the second step surface 102 oriented in opposite directions; the inner wall of the first resonant mass block 12 includes a groove structure, forming a circumferentially arranged third step surface 103; and the outer wall of the second resonant mass block 13 includes a convex ring structure, forming a circumferentially arranged fourth step surface 104, with the third step surface 103 and the fourth step surface 104 oriented in opposite directions. During assembly of the disc spring assembly, the outer edge of the first disc spring 14 abuts the first step surface 101, and the inner edge abuts the second step surface 102; the outer edge of the second disc spring 15 abuts the third step surface 103, and the inner edge abuts the fourth step surface 104, thereby reducing assembly errors of the disc spring assembly.

[0064] 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 fixing bolts 16, and the two first resonating masses 12 of the first resonating mass assembly are also connected by fixing bolts 16. After assembly, the first disc springs 14 and the second disc springs 15 are in a flattened state. In some other embodiments, the outer frame assembly and the first resonating mass assembly can also be assembled using methods such as gluing, riveting, and welding to achieve appropriate connection strength depending on different operating conditions.

[0065] The local oscillator 1 provided in the above embodiment adopts a space-filling fractal structure to construct a multi-level nested resonant unit, and uses a periodic arrangement to form a metamaterial band gap, so as to simultaneously achieve the coordinated suppression of multi-order harmonic vibrations in a limited space, which can effectively solve the space occupation problem of multi-frequency vibration suppression of the tilt-rotor aircraft; and utilizes the low stiffness characteristics 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, thereby achieving the suppression of medium and low frequency band gaps while avoiding conflict with the lightweight requirements of the wing 2.

[0066] Another embodiment of the present invention provides a method for designing a local resonant metastructure wing for a tiltrotor aircraft, comprising the following steps:

[0067] S1. Calculate the Nth-order vibration frequency of the tiltrotor 3 of the tiltrotor aircraft transmitted to the fuselage structure. The expression is:

[0068] f N =NpΩ;

[0069] Where, f N is the Nth-order vibration frequency, N is the harmonic order, p is the number of blades of the tiltrotor, and Ω is the rotation frequency of the tiltrotor 3;

[0070] For example, the rated speed of the tiltrotor is 1800 RPM (Ω = 30 Hz), the number of blades is 3, and the goal is to suppress the first two 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.

[0071] S2. Construct the characteristic model of the local oscillator, and its equivalent structure is as follows Figure 6 As shown, its expression is:

[0072] ;

[0073] Where M is the mass of the first resonant mass assembly, m is the mass of the second resonant mass, 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.

[0074] S3, the Nth order vibration frequency f calculated in step S1 N The natural frequency ω of the local oscillator is input into the characteristic model of the local oscillator to obtain the constraint formula of the local oscillator, and the parameters of the local oscillator are designed to meet the constraint formula.

[0075] In a specific implementation, the harmonic order N is set to 1, and the first-order vibration frequency is calculated according to the expression of step S1; the harmonic order N is set to 2, and the second-order vibration frequency is calculated according to the expression of step S1.

[0076] 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 formula 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 formula of the local oscillator: .

[0077] The parameters of the local oscillator are designed to satisfy both the first and second constraints. Specifically, after designing the mass M of the first resonant mass assembly and the mass m of the second resonant mass, the stiffness K of the first disc spring assembly in a flattened state and the stiffness k of the second disc spring assembly in a flattened state can be calculated based on the first and second constraints. After designing the stiffness K of the first disc spring assembly in a flattened state and the stiffness k of the second disc spring assembly in a flattened state, the mass M of the first resonant mass assembly and the mass m of the second resonant mass can be calculated based on the first and second constraints.

[0078] For example, the first two 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 local oscillator characteristic model, the complete first constraint formula and second constraint formula can be obtained, that is, 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 are in a certain constraint relationship.

[0079] S4. Based on the additional mass that the wing structure can accept, design the masses of the first resonant mass block assembly and the second resonant mass block, input them into the first constraint formula and the second constraint formula, and calculate the stiffness of the first disc spring assembly and the second disc spring assembly in the flattened state.

[0080] The mass M of the first resonant mass block assembly and the mass m of the second resonant mass block are input into the first constraint formula and the second constraint formula to obtain a set of equations, and 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.

[0081] S5. Construct a stiffness model of the disc spring in a flattened state. The dimensional parameters of the disc spring are as follows: Figure 7 As shown, its expression is:

[0082] KB=\frac {E} {(1-{\mu}^{2}){({D}_{0} / 2)}^{2}C}\left [ {{t}^{3}-\frac {{h}^{2}} {2}t} \right ] ;

[0083] Where 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, and 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 .

[0084] According to the stiffness model of the disc spring in the flattened state, by designing the material and size of the disc spring, the disc spring can exhibit low stiffness characteristics in the flattened state, thereby reducing the natural frequency of the local oscillator while keeping the resonant mass unchanged, achieving mid- and low-frequency band gap suppression while avoiding conflicts with the lightweight requirements of the wing.

[0085] 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.

[0086] The above design method determines the specific parameters of the local oscillator. Combined with the low-stiffness design of the disc spring, this method achieves precise matching of the natural frequency and harmonics. Periodically placing the assembled local oscillators on the inner wall of the skin 21 creates multiple low- and medium-frequency band gaps within the limited wing space, solving the challenge of suppressing multiple low- and medium-frequency harmonics while meeting the compactness requirements of aviation structures.

[0087] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A local resonant superstructure wing for a tiltrotor aircraft, characterized in that: It comprises a skin (21) and a plurality of local oscillators (1), wherein the plurality of local oscillators (1) are periodically arranged on the inner surface of the skin (21); The local oscillator (1) comprises: an outer frame assembly connected to the skin (21); a first resonant mass assembly, nested within the outer frame assembly; a second resonant mass block (13) nested within the first resonant mass block assembly; a first disc spring assembly connecting the outer frame assembly and the first resonant mass assembly; a second disc spring assembly connecting the second resonant mass block (13) and the first resonant mass block assembly; The first disc spring assembly and the second disc spring assembly are in a flattened state; The local oscillator (1) has a double-layer symmetrical structure, the outer frame component comprises two symmetrically arranged and fixedly connected outer frames (11), and the first resonant mass block component comprises two symmetrically arranged and fixedly connected first resonant mass blocks (12).

2. The local resonant metastructure wing of a tiltrotor aircraft according to claim 1, characterized in that: The first disc spring assembly comprises two symmetrically arranged first disc springs (14), each of the first disc springs (14) being respectively connected to one of the outer frames (11) and one of the first resonant mass blocks (12); the second disc spring assembly comprises two symmetrically arranged second disc springs (15), each of the second disc springs (15) being respectively connected to two sides of one of the first resonant mass blocks (12) and the second resonant mass block (13).

3. The local resonant metastructure wing of a tiltrotor aircraft according to claim 2, 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 connection, 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 connection, riveting, and welding.

4. The local resonant metastructure wing of a tiltrotor aircraft according to claim 2, characterized in that: The inner wall of the outer frame (11) is provided with a first step surface (101) arranged circumferentially, and the outer wall of the first resonant mass block (12) is provided with a second step surface (102) arranged circumferentially, the first step surface (101) and the second step surface (102) are in opposite directions, the outer edge of the first disc spring (14) abuts against the first step surface (101), and the inner edge of the first disc spring (14) abuts against the second step surface (102).

5. The local resonant metastructure wing of a tiltrotor aircraft according to claim 2, 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 third step surface (103) and the fourth step surface (104) are in opposite directions, the outer edge of the second disc spring (15) abuts against the third step surface (103), and the inner edge of the second disc spring (15) abuts against the fourth step surface (104).

6. A method for designing a local resonant metastructure wing for a tiltrotor aircraft according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Calculate the Nth-order vibration frequency of the tiltrotor (3) of the tiltrotor aircraft transmitted to the fuselage structure. The expression is: f N =NpΩ ; Where, f N is the Nth-order vibration frequency, N is the harmonic order, p is the number of blades of the tiltrotor, and Ω is the rotation frequency of the tiltrotor (3); S2. Construct the characteristic model of the local oscillator, which is expressed as: ； Where M is the mass of the first resonant mass assembly, m is the mass of the second resonant mass, 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. Using the Nth-order vibration frequency calculated in step S1 as the natural frequency of the local oscillator in step S2, inputting it into the characteristic model of the local oscillator, obtaining the constraint formula of the local oscillator, and designing the parameters of the local oscillator to satisfy the constraint formula.

7. The method for designing a local resonant metastructure wing for a tiltrotor aircraft according to claim 6, characterized in that: The specific process of step S3 includes the following steps: S31, 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. Using the first-order vibration frequency as the natural frequency of the local oscillator in step S2 and inputting it into the characteristic model of the local oscillator to obtain a first constraint formula of the local oscillator; using the second-order vibration frequency as the natural frequency of the local oscillator in step S2 and inputting it into the characteristic model of the local oscillator to obtain a second constraint formula of the local oscillator; S33. Design parameters of the local oscillator to satisfy the first constraint formula and the second constraint formula at the same time.

8. The method for designing a local resonant metastructure wing for a tiltrotor aircraft according to claim 7, characterized in that: The following steps are also included: S4. Obtain the masses of the first resonant mass block assembly and the second resonant mass block, input them into the first constraint formula and the second constraint formula, and calculate the stiffness of the first disc spring assembly and the second disc spring assembly in a flattened state.

9. The method for designing a local resonant metastructure wing for a tiltrotor aircraft according to claim 8, characterized in that: The following steps are also included: S5. Construct a stiffness model of the disc spring in the flattened state, and its expression is: ； Where 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, and 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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