Lightweight anti-chattering gradient honeycomb composite aileron structure

Abstract

The present application relates to the technical field of aircraft structure design, and specifically discloses a lightweight anti-chattering gradient honeycomb composite aileron structure, which comprises an aileron body, the aileron body is a gradient honeycomb sandwich composite structure, and the overall configuration is adapted to a wing trailing edge mounting slot; a honeycomb core layer is arranged inside the aileron body and is composed of a plurality of honeycomb units arranged in an array, is divided into a leading edge torsion-resistant area, an intermediate transition area and a trailing edge flexible area along the chord direction, and presents continuous gradient changes in cell angle and density; a leading edge beam is fixed to the leading edge of the aileron body and is used for force bearing and counterweighting; a rotating shaft seat is installed at the two spanwise ends of the leading edge beam and is used for installing a rotating shaft to hinge the aileron body with a wing; an embedded force transmission type rudder seat is fixed to the lower surface of the aileron body and is used for connecting a rudder driving mechanism; and a tuning damping unit is embedded in the honeycomb core layer, so that the problem that a traditional aircraft aileron is difficult to balance between lightweight, anti-chattering and high reliability is solved.

Description

Technical Field

[0001] This invention relates to the field of aircraft structural design technology, and in particular to a lightweight anti-flutter gradient honeycomb composite aileron structure. Background Technology

[0002] During flight, the control surfaces of unmanned aerial vehicles (UAVs), such as ailerons, are prone to flutter. This is an aeroelastic instability phenomenon, characterized by the coupling of airflow and structural elastic deformation, resulting in a rapid divergence of vibration amplitude. In severe cases, it can lead to structural fracture or control failure within a very short time. Therefore, flutter prevention is one of the core requirements in aileron structure design.

[0003] To improve the flutter critical velocity, traditional methods mainly focus on the following aspects: First, by adding independent counterweights at the leading edge, the aileron's center of mass is moved forward to before the hinge axis to achieve mass overbalancing and suppress flutter tendencies caused by inertial coupling; second, damping material layers are pasted onto the outer surface or locally of the skin, relying on the shear hysteresis effect of viscoelastic materials to dissipate vibration energy. However, these measures have significant shortcomings: independent counterweights and their connectors significantly increase the structural weight and number of parts, which is extremely detrimental to lightweighting; surface damping layers occupy external aerodynamic space, and their energy dissipation efficiency is limited by the pasting area and deformation mode, and they are easily subject to environmental erosion or detachment. On the other hand, the bending and torsional stiffness distribution of conventional uniform honeycomb sandwich structures is relatively fixed, making it difficult to achieve effective separation of bending and torsional mode frequencies, and modal coupling flutter is still prone to occur at increased flight speeds. At the same time, the connection areas of existing structures (such as pivot seats and servo seats) often have problems such as concentrated load transfer, large local stress, and direct vibration transmission paths, which adversely affect the overall flutter resistance reliability and structural lifespan. Summary of the Invention

[0004] The purpose of this invention is to propose a lightweight anti-flutter gradient honeycomb composite aileron structure to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A lightweight anti-flutter gradient honeycomb composite aileron structure includes an aileron body, wherein the aileron body is a gradient honeycomb sandwich composite structure and the overall configuration is adapted to the wing trailing edge mounting groove. The honeycomb core layer is disposed inside the aileron body and is composed of several honeycomb units arranged in a chord direction, divided into a leading edge anti-torsion zone, an intermediate transition zone and a trailing edge flexible zone, showing a continuous gradient change in the lattice tilt angle and density. The leading edge beam is fixed to the leading edge of the aileron body and is used for load-bearing and counterweight. A pivot seat, installed at both ends of the leading edge beam in the spanwise direction, is used to install a pivot so that the aileron body is hinged to the wing; An embedded force-transmitting servo mount is fixed to the lower surface of the aileron body and is used to connect the servo drive mechanism. A tuned damping unit is embedded inside the honeycomb core layer to assist in vibration suppression.

[0006] Preferably, the aileron body includes an upper skin and a lower skin; Both the upper and lower skins are made of carbon fiber prepreg through multi-directional symmetrical layup, wherein the oblique layup is used to bear shear load, the spanwise layup is used to bear spanwise bending load, and the tangential layup is used to bear tangential bending load. The number of layers in the leading edge region of the upper and lower skins is greater than that in the trailing edge region, and the thickness is smoothly reduced to match the stiffness gradient of the core layer. Damping membranes are partially embedded between the intermediate layers of the pivot periphery and the front bearing area of ​​the upper and lower skin.

[0007] Preferably, the specific configuration of each partition of the honeycomb core layer is as follows: The leading edge anti-torsion zone is located on the front side of the rotating shaft, and the pore axis of the honeycomb unit is approximately perpendicular to the chord plane, adopting a pore configuration with small side length and high wall thickness. The cellular cells in the intermediate transition zone gradually tilt towards the rear edge along the chord direction, with smooth changes in side length and wall thickness, and a gradual decrease in density. The cell tilt angle of the honeycomb unit in the trailing edge flexible region is further increased, and a low-density cell with large side length and low wall thickness is adopted. A gradient zone with several rows of holes is set at the boundary of each zone to ensure the continuity of stiffness variation.

[0008] Preferably, viscoelastic damping columns are embedded in the torsional zone at the leading edge of the honeycomb core layer and in specific honeycomb cells around the pivot. The damping column is bonded to the inner surfaces of the upper and lower skins respectively at its upper and lower ends, and is laterally attached to the hole wall. It generates shear hysteresis as the cell deforms to dissipate vibration energy.

[0009] Preferably, the leading edge beam is arranged along the span of the aileron and adopts an I-beam configuration with high-density core material, including an upper flange, a lower flange, a web and a counterweight core segment; The counterweight core segment is embedded in the front edge of the I-beam and is made of high-density alloy. Its outer fiber layup is integrated with the upper flange, lower flange and web. The web is provided with irregularly shaped weight-reducing holes arranged along the spanwise direction, and the hole diameter is adaptively designed according to the bending moment distribution law. The leading edge beam extends beyond the end face of the aileron body at both ends in the spanwise direction, and connecting holes are provided on the upper and lower flanges of the extended section.

[0010] Preferably, the tuned damping unit comprises several groups of small units, which are discretely distributed along the spanwise direction at the aileron midchord position on the rear side of the pivot. Each unit consists of a high-density mass block and a viscoelastic damping layer covering it. It is embedded in the reserved holes of the honeycomb core layer and bonded to the surrounding honeycomb wall through filler adhesive, so as to exert the inertial anti-resonance effect and viscoelastic energy dissipation function.

[0011] Preferably, the rotating shaft seat includes a stepped embedded base and a shaft hole seat; The two ends of the honeycomb core layer are processed with stepped mounting cavities, which are adapted to the embedded base. Each step surface is bonded to the honeycomb end face and the inner surface of the skin of the corresponding partition. The shaft hole seat has a built-in damping bushing.

[0012] Preferably, the upper part of the embedded force transmission servo mount is provided with an embedded boss; The lower skin has a preset hole, the embedded boss is embedded in the preset hole and directly bolted to the lower flange of the front edge beam, and the seat flange surface is attached to the outer surface of the skin for auxiliary fixation.

[0013] Preferably, it includes the following steps: S1: Gradient honeycomb core layer prefabrication and damping functionalization: The honeycomb core layer is processed to form a chordal variable tilt angle and density dual gradient configuration, and damping columns are inserted into the predetermined cell. S2: Leading edge beam forming: Precision casting of counterweight core segment, laying carbon fiber prepreg on special tooling to form uncured beam blank, and sending it into autoclave for independent curing to obtain leading edge beam; S3: Pre-embedded tuned damping unit: Drill blind holes in the honeycomb core layer, insert the tuned damping unit and fill the gap with foam; Pre-machine the two ends of the honeycomb core layer to generate mounting cavities, install the rotating shaft seat and rigidly connect it with the front edge beam; S4: Modular assembly and co-curing: The lower skin, structural adhesive film, pre-embedded damping unit and damping column honeycomb core layer, front edge beam and upper skin are laid sequentially from bottom to top on the assembly tooling, and after sealing, they are sent into the autoclave for co-curing. S5: End-end precision machining and component assembly: Install embedded force transmission servo mounts, and perform non-destructive testing and shape trimming on the aileron as a whole.

[0014] Preferably, in step S2, the surface of the counterweight core segment made of high-density alloy is sandblasted and cleaned to enhance the bonding force; In step S4, the bonding tension and alignment accuracy are controlled during the assembly process to ensure that the upper end face of the embedded damping column is in close contact with the upper damping film and the inner surface of the skin. In step S3, after connecting the embedded base to the front edge beam with high-strength bolts, high-toughness structural adhesive is injected into the joints between the base's various step surfaces and the honeycomb core layer and skin.

[0015] The beneficial effects of this invention are as follows: By designing the honeycomb core layer into a leading-edge torsional zone, an intermediate transition zone, and a trailing-edge flexible zone with continuously varying chordal lattice angle and density, this invention achieves differentiated configurations of structural bending and torsional stiffness. The high shear modulus of the leading-edge torsional zone effectively improves torsional stiffness, while the trailing-edge flexible zone reduces chordal bending stiffness, significantly increasing the frequency interval between the first-order bending mode and the first-order torsional mode, thus fundamentally disrupting the modal coupling conditions for flutter. Simultaneously, the continuous gradient change in stiffness avoids localized stress concentration. By embedding tuned damping units inside the honeycomb core layer, it is equivalent to integrating a micro-tuned mass damper inside the structure. When the flight speed approaches the flutter critical speed and excites bending-torsional coupled vibrations at a specific frequency, the internal mass block moves in opposite phase, efficiently dissipating vibration energy through the shear deformation of the viscoelastic damping layer, specifically widening the stable flight boundary, increasing the flutter critical speed, and without occupying any external space; The pivot bearing uses a multi-stage stepped base that mates with the stepped mounting cavity of the honeycomb core layer, which distributes the concentrated load at the beam end in stages to the surrounding honeycomb and skin, significantly reducing stress concentration. The damping bushing built into the pivot bearing ensures the flexibility of the hinge rotation and absorbs and blocks the transmission of high-frequency vibrations to the wing, suppressing aileron-wing coupled flutter. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of the skin in an embodiment of the present invention; Figure 3 This is a schematic diagram of the honeycomb core layer structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the leading edge beam structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the tuned damping unit structure according to an embodiment of the present invention; Figure 6 This is a schematic diagram showing the position of the damping column in an embodiment of the present invention; Figure 7 This is a schematic diagram of the servo mount position according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the rotating shaft seat structure according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the preset hole position in an embodiment of the present invention.

[0017] In the diagram: 1. Aileron body; 11. Upper skin; 12. Lower skin; 13. Preset hole; 2. Honeycomb core layer; 21. Honeycomb unit; 22. Damping column; 23. Leading edge anti-torsion zone; 24. Intermediate transition zone; 25. Trailing edge flexible zone; 26. Mounting cavity; 3. Leading edge beam; 31. Upper flange; 32. Lower flange; 33. Web; 34. Counterweight core segment; 35. Irregular weight reduction hole; 36. Connecting hole; 4. Tuned damping unit; 41. Mass block; 42. Viscoelastic damping layer; 5. Rotary bearing seat; 51. Embedded base; 52. Shaft hole seat; 6. Servo mount; 61. Embedded boss. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] Please see Figure 1-9 The embodiments of the present invention provide a technical solution: a lightweight anti-flutter gradient honeycomb composite aileron structure, suitable for high-speed aircraft, including an aileron body 1, wherein the aileron body 1 is a gradient honeycomb sandwich composite structure, and the overall configuration is adapted to the wing trailing edge mounting groove. The aileron body 1 has a honeycomb core layer 2 inside. A leading edge beam 3 is fixed to the leading edge of the aileron body 1. The leading edge beam 3 is used to support the aileron body 1 and provide counterweight. A tuned damping unit 4 is embedded inside the honeycomb core layer 2. A pivot seat 5 is installed at both ends of the leading edge beam 3 in the spanwise direction. The pivot seat 5 is used to install a pivot so that the aileron body 1 is hinged to the wing. An embedded force transmission servo mount 6 is fixed to the lower surface of the aileron body 1.

[0020] This structure employs a dual-gradient distributed honeycomb core layer 2 to achieve differentiated control of bending and torsional stiffness, combined with the synergistic vibration suppression mechanism of the tuned damping unit 4, thereby improving the flutter critical velocity of the structure without significantly increasing structural complexity and weight.

[0021] The aileron body 1 includes an upper skin 11 and a lower skin 12, both of which are made of carbon fiber prepreg through multi-directional symmetrical layup. In the layup design, the diagonal layup is used to bear shear loads, the spanwise layup is used to bear spanwise bending loads, and the chordwise layup is used to bear chordwise bending loads.

[0022] The upper skin 11 and the lower skin 12 have a large number of layers and a large thickness in the leading edge area, which matches the leading edge beam 3 and strengthens the torsional resistance of the structure. The number of layers in the upper skin 11 and the lower skin 12 decreases gradually along the trailing edge direction of the chord, and the thickness decreases smoothly to match the stiffness gradient of the core layer, so as to avoid abrupt changes in stiffness and reduce the structural weight of the non-load-bearing area at the trailing edge.

[0023] The rotational axis periphery and leading edge bearing area of ​​the upper skin 11 and lower skin 12 are high strain regions, and a damping film is partially embedded between the intermediate layers; the damping film and the damping column 22 are aligned and can be integrally formed during the co-curing process without additional processing steps, which is used to enhance the overall damping characteristics of the structure.

[0024] The honeycomb core layer 2 is disposed between the upper skin 11 and the lower skin 12, and is composed of a number of honeycomb units 21 arranged together. It is divided into a leading edge anti-torsion zone 23, a middle transition zone 24 and a trailing edge flexible zone 25 along the chord direction, showing a continuous gradient change in the pore tilt angle and density.

[0025] The leading edge anti-torsion zone 23 is located on the front side of the rotating shaft. The axial direction of the cellular unit 21 is approximately perpendicular to the chord plane. It adopts a cellular configuration with small side length and high wall thickness, which has a high in-plane shear modulus and bears the main torsional load of the structure.

[0026] The cellular cells 21 in the intermediate transition zone 24 gradually tilt towards the rear edge along the chord direction, and the side length and wall thickness change smoothly accordingly, and the density gradually decreases, so as to achieve a smooth transition from torsional stiffness to bending stiffness.

[0027] The cell angle of the honeycomb unit 21 in the trailing edge flexible region 25 is further increased. A low-density cell with a large side length and low wall thickness is adopted to retain appropriate spanwise bending flexibility, which is conducive to optimizing the chordal load distribution and alleviating the stress concentration at the trailing edge.

[0028] A gradient zone with several rows of holes is set at the boundary of each zone to ensure the continuity of stiffness changes and avoid stress concentration.

[0029] The honeycomb core layer 2 can be made of aramid paper impregnated and cured with resin; for high-speed and high-temperature conditions, metal foil honeycomb material can also be used to ensure stiffness stability under operating conditions. Viscoelastic damping columns 22 are embedded in specific honeycomb units 21 around the leading edge anti-torsion zone 23 and the pivot shaft; the upper and lower ends of the damping columns 22 are bonded to the inner surface of the skin, and laterally attached to the hole walls. When the aileron vibrates, the damping columns 22 generate shear hysteresis as the cell deforms, dissipating vibration energy, resulting in higher space utilization and damping efficiency compared to surface-applied damping layers. The upper skin 11, lower skin 12, and honeycomb core layer 2 are bonded together with adhesive film and co-cured in an autoclave; the end face of the honeycomb unit 21 is attached to the inner surfaces of the upper skin 11 and lower skin 12, and the adhesive layer mainly bears the shear load, which helps reduce peel stress. The embedded damping columns 22 are also cured synchronously with the adhesive layer, forming an integrated damping and load-bearing interface.

[0030] The leading edge beam 3 is set along the span of the aileron and adopts an I-beam structure with high-density core material. Its outer side is covered with a composite material layer, which integrates load-bearing and counterweight functions, eliminating the need for independent counterweights and their connecting parts.

[0031] The leading edge beam 3 includes an upper flange 31, a lower flange 32, a web 33, and a counterweight core segment 34. The web 33 is approximately perpendicular to the chord plane, and the upper flange 31 and lower flange 32 are respectively attached to the inner surfaces of the upper skin 11 and lower skin 12. The counterweight core segment 34 is embedded in the leading edge of the I-beam, and its outer fiber layup is integrated with the upper flange 31, lower flange 32, and web 33, and is formed in the same curing cycle. The web 33 has irregularly shaped weight-reducing holes 35 arranged along the spanwise direction. The hole diameter is adaptively designed according to the bending moment distribution law, and the hole edges are rounded and locally thickened to balance structural strength and lightweight requirements. The two ends of the leading edge beam 3 extend beyond the end face of the aileron body 1 in the spanwise direction. The upper flange 31 and lower flange 32 of the extended section have connecting holes 36 for fixed connection with the pivot seat 5.

[0032] The counterweight core segment 34 is continuously integrated into the front edge beam 3 along the spanwise direction, located on the front side of the pivot chord, and is made of high-density alloy. This segment is both a load-bearing component of the beam and the main source of counterweight mass, avoiding additional adhesives and fasteners and improving the stability of mass distribution.

[0033] The tuned damping unit 4 comprises several groups of small units, discretely distributed along the spanwise direction at the aileron midchord position behind the pivot. Each unit consists of a high-density mass block 41 and a viscoelastic damping layer 42 covering it, pre-embedded in the reserved holes of the honeycomb core layer 2, and bonded to the surrounding honeycomb wall surface with filler adhesive. During vibration, the tuned damping unit can simultaneously exert an inertial anti-resonance effect and a viscoelastic energy dissipation effect, equivalent to integrating a miniature tuned mass damper within the structure, achieving a combination of frequency modulation and energy dissipation functions.

[0034] When in use, the mass and distribution of the counterweight core segment 34 are first determined based on the balance requirements, so that the center of mass of the aileron is located at an appropriate position in front of the pivot, to prevent the aileron from turning more and more under the action of airflow, which could lead to structural breakage or control failure.

[0035] Secondly, under the given counterweight conditions, the parameters and position of the rear damping unit and the rotational inertia of the aileron are adjusted accordingly to increase the frequency interval of the bending and torsional modes and avoid modal coupling.

[0036] Finally, based on the dominant flutter frequency, the mechanical properties of the viscoelastic damping layer 42 are matched to enable it to play a highly efficient energy dissipation role in the target frequency band.

[0037] The pivot bearing 5 is installed on the extended section of the leading edge beam 3 for hinge connection with the wing; it includes a stepped embedded base 51 and a shaft hole seat 52, wherein the embedded base 51 is designed with multi-step design. The two ends of the honeycomb core layer 2 are machined with stepped mounting cavities 26, which are adapted to the embedded base 51.

[0038] After assembly, each step surface is bonded to the honeycomb end face and inner surface of the skin of the corresponding partition. Through the design of the gradient contact surface, the concentrated load at the beam end is gradually and evenly distributed to the surrounding honeycomb core layer 2 and skin, reducing the risk of stress concentration.

[0039] The shaft hole seat 52 has a built-in damping bushing, which can ensure the flexibility of hinge rotation and provide a certain amount of damping to suppress vibration transmission.

[0040] The embedded force-transmitting servo mount 6 is fixed to the lower surface of the aileron body 1 and is used to connect the servo drive mechanism. Its upper part is provided with an embedded boss 61, which is embedded into a pre-set hole 13 in the lower skin 12 and directly bolted to the lower flange 32 of the leading edge beam 3. The flange surface of the mount is fitted to the outer surface of the skin for auxiliary fixation. This design establishes a direct force transmission path from the servo to the leading edge beam 3, avoiding direct impact of control loads on the honeycomb core layer 2, and improving force transmission efficiency and structural reliability. Example 1: In this example, the above-mentioned lightweight anti-flutter gradient honeycomb composite aileron structure is fabricated using a co-curing integral molding technology, specifically in the following steps:

[0041] S1: Gradient honeycomb core layer prefabrication and damping functionalization: Aramid paper honeycomb blanks are processed using CNC precision machining equipment. Based on the dual gradient design scheme of chordal variable tilt angle and density, the excess material at the transition of the partition is precisely removed using a CNC milling machine. Custom tooling is used to perform secondary stretching and shaping of the cells in the intermediate transition zone 24 and the trailing edge flexible zone 25, ensuring continuous changes in cell tilt angle and wall thickness to form a stepless gradient configuration. Damping pillars 22 are inserted into predetermined cells in the anti-torsion zone at the leading edge of the core layer and around the rotation axis. Pre-fixation is achieved using the micro-adhesion of the damping pillars 22 themselves or through a small amount of adhesive film, ensuring that the axial direction of the damping pillars 22 is consistent with the inner normal direction of the skin, preventing displacement during subsequent laying processes.

[0042] S2: Forming the Leading Edge Beam 3. First, a high-density alloy counterweight core segment 34 is precision cast according to the counterweight requirements, and its surface is sandblasted and cleaned to enhance its bonding strength with the composite material interface. Then, carbon fiber prepregs of the web 33, upper flange 31, and lower flange 32 are sequentially laid on a special tooling. The pretreated counterweight core segment 34 is positioned in a pre-set cavity on the leading edge side of the beam, and the outer fiber prepreg is laid to form an uncured beam blank of "alloy core + composite coating layer". The beam blank is sent to an autoclave for independent curing. The heating rate and pressure point are controlled to ensure that the deformation of the alloy core and the composite coating layer is coordinated during the curing process, avoiding micro-cracks at the interface due to the difference in thermal expansion coefficients, thus obtaining the leading edge beam 3.

[0043] S3: The tuned damping unit 4 is pre-embedded with blind holes at the mid-chord position of the honeycomb core layer 2, based on the coordinates determined by the aileron dynamics optimization model. The pre-fabricated tuned damping unit 4 is placed into the blind holes, and the annular gap between the unit and the hole wall is filled with low-density foam. The foam is pre-cured at room temperature, and its expansion pressure is used to eliminate the voids. At the same time, the viscoelastic damping layer 42 is tightly pressed between the honeycomb hole wall and the mass block 41 to form a stable friction-adhesion composite interface.

[0044] The two ends of the honeycomb core layer 2 are precision machined to form the mounting cavity 26. First, the embedded base 51 of the rotating shaft seat 5 is inserted into the mounting cavity 26 and rigidly connected to the front edge beam 3 through high-strength bolts and connecting holes 36. Then, high-toughness structural adhesive is injected into the joints between the base step surfaces and the honeycomb core layer and skin, and the micro gaps are filled by capillary action to achieve the combined force transmission of mechanical connection and adhesive bonding.

[0045] S4: Modular Assembly and Co-curing. On precision assembly fixtures, modular assembly is performed from bottom to top: First, the lower skin 12 prepreg is laid, and a localized damping membrane is applied to its inner surface corresponding to the high-strain area; then, a structural membrane is laid on the lower skin 12, followed by the honeycomb core layer 2 with pre-embedded damping units 4 and damping columns 22; then, an integrated leading-edge beam 3 is placed at the corresponding position above the core layer, ensuring precise alignment between the beam's web 33 and the leading-edge end face of the core layer; finally, the upper skin 11 prepreg and internal structural membrane are laid, completing the encapsulation. During assembly, the laying tension and alignment accuracy are strictly controlled to ensure close contact between the upper end face of the embedded damping column 22 and the upper damping membrane and the inner surface of the skin. After the entire component is encapsulated, it is sent to an autoclave and subjected to a curing process that includes heating, heat preservation, pressurization and cooling stages. This process allows the skin, film, honeycomb core layer 2 and leading edge beam 3 to be co-cured as a whole in one thermal cycle, forming a sandwich structure with intrinsic damping characteristics.

[0046] S5: After the end-finish machining and component assembly are co-cured, the aileron seat 5 is assembled first: the embedded base 51 of the aileron seat 5 is inserted into the mounting cavity 26 at the end of the honeycomb core layer 2, and rigidly connected to the leading edge beam 3 by high-strength bolts passing through the connecting hole 36; then, high-toughness structural adhesive is injected into the joints between the base's stepped surfaces and the honeycomb core layer and skin, using capillary action to fill the micro-gaps, achieving a composite force transmission of mechanical connection and adhesive bonding. The embedded force-transmitting servo seat 6 is installed: the embedded boss 61 of the servo seat 6 is placed into the preset hole 13, and fixed to the lower flange 32 of the integrated leading edge beam 3 by bolts penetrating the lower skin 12, and sealed with adhesive on the flange surface. Finally, the aileron is subjected to non-destructive testing and shape trimming to complete the manufacturing process.

[0047] Example 2: This example illustrates the working process of the aileron structure prepared in Example 1 in suppressing bending-torsional flutter. This structure utilizes the honeycomb core layer 2 to achieve differentiated stiffness in different regions, and, in conjunction with mass distribution adjustment and various damping energy dissipation measures, jointly prevents the occurrence and aggravation of flutter from multiple levels.

[0048] First, the stiffness distribution is altered by the gradient configuration of the honeycomb core layer 2. The leading-edge torsional zone 23 employs a densely perforated structure perpendicular to the airfoil surface, exhibiting a high in-plane shear modulus and significantly enhancing the torsional stiffness of the aileron around the chordal axis, thereby increasing the natural frequency of the first-order torsional vibration. Simultaneously, the leading-edge beam 3 bears the main spanwise bending, maintaining the characteristics of the first-order bending vibration. In this way, the frequency difference between bending and torsional vibrations is significantly widened, making it less likely for them to couple and resonate, thus fundamentally disrupting the frequency conditions for flutter formation. Furthermore, the trailing-edge flexible zone 25 allows for slight deformation of the trailing edge under airflow, making aerodynamic load changes more gradual and reducing sudden excitation forces.

[0049] Secondly, dynamic and static stability is improved through mass distribution. The counterweight core segment 34 is placed entirely in front of the pivot axis along the spanwise direction, so that the overall center of gravity of the aileron falls in front of the hinge axis (i.e., overbalanced design). Under airflow, this arrangement can generate a restoring moment, effectively suppressing the divergence tendency caused by the rearward center of gravity and reducing the inertial coupling between the aileron and the wing. Several tuned damping units 4 are embedded in the center chord position behind the pivot axis. By fine-tuning the mass and placement of these units, the rotational inertia of the aileron about the hinge axis can be precisely adjusted, changing the mass distribution of the system and further offsetting the nodal positions of the bending and torsional vibration modes, thus enhancing the independence of the two modes.

[0050] Secondly, various damping measures are used to dissipate vibration energy at different scales. The damping membrane embedded between the skin layers and the damping pillars 22 in the honeycomb cells constitute the first line of defense. In the high-frequency micro-vibrations caused by general airflow disturbances, the damping pillars 22 undergo shear deformation along with the honeycomb cell walls, utilizing the viscoelastic hysteresis effect of the material to convert the initial vibration energy into heat and dissipate it, thus avoiding amplitude accumulation.

[0051] The tuned damping unit 4 serves as the second line of defense. When the flight speed approaches the flutter critical speed and induces bending-torsional coupled vibrations at a specific frequency, the natural frequencies of these units are close to the dominant flutter frequency. The internal mass block 41 will move in the opposite direction relative to the main structure, causing the viscoelastic damping layer 42 surrounding it to undergo shear deformation. It uses inertial force to offset part of the external aerodynamic force and converts the vibrational kinetic energy into heat energy through internal friction, providing efficient energy dissipation near the flutter critical point and widening the speed boundary for stable flight.

[0052] Furthermore, a reasonable load transfer path reduces coupling risks. Aerodynamic loads are mainly transferred from the skin to the honeycomb core layer 2, and then converge on the leading edge beam 3. Since the leading edge beam 3 bears most of the shear force and bending moment, the honeycomb core layer 2 mainly bears in-plane shear, resulting in a clear stress state and avoiding premature local instability. The pivot seat 5 utilizes a multi-step structure to evenly diffuse the concentrated force at the beam end to the surrounding honeycomb and skin. Its varying interface stiffness can also reflect and scatter elastic waves transmitted from the wing. The damping bushing built into the pivot hole seat 52 further absorbs high-frequency vibration energy, blocks the propagation of vibration to the wing, and prevents coupled flutter between the aileron and the wing.

[0053] Example 3: This example is based on the anti-flutter mechanism of Example 2, illustrating the process by which the aileron structure automatically adapts to and suppresses vibration under different flight conditions.

[0054] During the low-speed cruise phase, the structure exhibits high overall stiffness, with minimal deformation of the honeycomb core layer 2 and almost no involvement of the tuned damping unit 4. The structure can maintain stability solely through the basic damping of the material itself, fully meeting the requirements for stiffness and maneuverability during normal flight.

[0055] During high-speed maneuvers or high angle-of-attack flight, the aerodynamic load on the aileron increases significantly. At this time, the stiffness distribution characteristics of the honeycomb core layer 2 begin to emerge: the leading-edge torsional zone 23 continues to maintain high rigidity, ensuring that the control efficiency does not decrease; while the trailing-edge flexible zone 25 allows for moderate elastic deformation, which plays a role in dispersing stress peaks and alleviating local stress concentration, thereby better adapting to high load conditions.

[0056] As the flight speed continues to increase and approaches the flutter critical speed, the tuned damping unit 4 is fully activated. Since its natural frequency is close to the harmful vibration frequency at this time, the unit acts like a built-in vibration absorber, specifically absorbing the vibration energy of the corresponding frequency, thereby delaying the occurrence of flutter and increasing the critical speed.

[0057] Throughout the entire flight range, the structural stiffness distribution, mass distribution, and damping characteristics of the aileron always work together to ensure that the structure maintains a stable vibration damping effect under various operating conditions.

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A lightweight anti-flutter gradient honeycomb composite aileron structure, characterized in that, include: Aileron body (1), wherein the aileron body (1) is a gradient honeycomb sandwich composite structure, and the overall configuration is adapted to the trailing edge mounting slot of the wing; The honeycomb core layer (2) is disposed inside the aileron body (1) and is composed of several honeycomb units (21). It is divided into a leading edge anti-torsion zone (23), an intermediate transition zone (24) and a trailing edge flexible zone (25) along the chord direction, presenting a continuous gradient change in the lattice tilt angle and density. The leading edge beam (3) is fixed to the leading edge of the aileron body (1) and is used for load bearing and counterweight. A pivot seat (5) is installed at both ends of the leading edge beam (3) in the spanwise direction and is used to install a pivot so that the aileron body (1) is hinged to the wing; An embedded force-transmitting servo mount (6) is fixed to the lower surface of the aileron body (1) and is used to connect the servo drive mechanism; The tuned damping unit (4) is embedded inside the honeycomb core layer (2) and is used to suppress vibration in a coordinated manner.

2. The lightweight anti-flutter gradient honeycomb composite aileron structure according to claim 1, characterized in that, The aileron body (1) includes an upper skin (11) and a lower skin (12). The upper skin (11) and the lower skin (12) are both made of carbon fiber prepreg through multi-directional symmetrical layup, wherein the oblique layup is used to bear shear load, the spanwise layup is used to bear spanwise bending load, and the chordwise layup is used to bear chordwise bending load. The number of layers in the leading edge region of the upper skin (11) and the lower skin (12) is greater than that in the trailing edge region, and the thickness is smoothly reduced to match the stiffness gradient of the core layer. Damping membranes are partially embedded between the intermediate layers of the pivot periphery and the front bearing area of ​​the upper skin (11) and the lower skin (12).

3. The lightweight anti-flutter gradient honeycomb composite aileron structure according to claim 2, characterized in that, The specific configuration of each partition of the honeycomb core layer (2) is as follows: The leading edge anti-torsion zone (23) is located on the front side of the rotating shaft. The pore axis of the honeycomb unit (21) is approximately perpendicular to the chord plane, and a pore configuration with small side length and high wall thickness is adopted. The cellular cells (21) of the intermediate transition zone (24) gradually tilt towards the rear edge along the chord direction, with smooth changes in side length and wall thickness, and a gradual decrease in density; The cell tilt angle of the honeycomb unit (21) in the trailing edge flexible region (25) is further increased, and a low-density cell with large side length and low wall thickness is adopted. A gradient zone with several rows of holes is set at the boundary of each zone to ensure the continuity of stiffness variation.

4. The lightweight anti-flutter gradient honeycomb composite aileron structure according to claim 3, characterized in that, Viscoelastic damping columns (22) are embedded in the anti-torsion zone (23) at the leading edge of the honeycomb core layer (2) and in the specific honeycomb unit (21) around the rotating shaft. The damping column (22) is bonded to the inner surfaces of the upper skin (11) and lower skin (12) at its upper and lower ends, respectively, and is laterally attached to the hole wall. It generates shear hysteresis as the cell deforms to dissipate vibration energy.

5. The lightweight anti-flutter gradient honeycomb composite aileron structure according to claim 1, characterized in that, The leading edge beam (3) is set along the span of the aileron and adopts an I-beam configuration with high-density core material, including an upper flange (31), a lower flange (32), a web (33) and a counterweight core segment (34). The counterweight core segment (34) is embedded in the front edge of the I-beam and is made of high-density alloy. Its outer fiber layup is integrated with the upper flange (31), lower flange (32) and web (33). The web (33) is provided with irregular weight-reducing holes (35) arranged along the span direction, and the hole diameter is adaptively designed according to the bending moment distribution law; The front edge beam (3) extends out of the end face of the aileron body (1) at both ends in the spanwise direction, and connecting holes (36) are provided on the upper flange (31) and lower flange (32) of the extended section.

6. The lightweight anti-flutter gradient honeycomb composite aileron structure according to claim 1, characterized in that, The tuned damping unit (4) comprises several groups of small units, which are discretely distributed along the spanwise at the aileron midchord position behind the pivot. Each unit consists of a high-density mass block (41) and a viscoelastic damping layer (42) covering it. It is embedded in the reserved hole of the honeycomb core layer (2) and bonded to the surrounding honeycomb wall through filling adhesive, so as to exert the inertial anti-resonance effect and viscoelastic energy dissipation effect.

7. The lightweight anti-flutter gradient honeycomb composite aileron structure according to claim 1, characterized in that, The rotating shaft seat (5) includes a stepped embedded base (51) and a shaft hole seat (52). The two ends of the honeycomb core layer (2) are processed with stepped mounting cavities (26), which are adapted to the embedded base (51). Each step surface is bonded to the honeycomb end face and the inner surface of the skin of the corresponding partition. The shaft hole seat (52) has a built-in damping bushing.

8. The lightweight anti-flutter gradient honeycomb composite aileron structure according to claim 1, characterized in that, The upper part of the embedded force transmission servo mount (6) is provided with an embedded boss (61). The lower skin (12) has a preset hole (13), the embedded boss (61) is embedded in the preset hole (13) and is directly bolted to the lower flange (32) of the front edge beam (3), and the seat flange surface is attached to the outer surface of the skin for auxiliary fixation.

9. A method for preparing the lightweight anti-flutter gradient honeycomb composite aileron structure according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Gradient honeycomb core layer prefabrication and damping functionalization: The honeycomb core layer (2) is processed to form a chordal variable tilt angle and density double gradient configuration, and damping columns (22) are inserted into the predetermined cell. S2: Forming of leading edge beam (3): Precision casting of counterweight core segment (34), laying carbon fiber prepreg on special tooling to form uncured beam blank, and sending it into autoclave for independent curing to obtain leading edge beam (3). S3: Pre-embedded tuning damping unit (4): Drill blind holes in the honeycomb core layer (2), insert the tuning damping unit (4) and fill the gap with foam; finely process the two ends of the honeycomb core layer (2) to generate mounting cavities (26), install the rotating shaft seat (5) and rigidly connect it with the front edge beam (3); S4: Modular assembly and co-curing: The lower skin (12), structural adhesive film, pre-embedded damping unit (4) and damping column (22) honeycomb core layer (2), front edge beam (3) and upper skin (11) are laid sequentially from bottom to top on the assembly tooling. After sealing, they are sent to the autoclave for co-curing. S5: End fine machining and component assembly: Install embedded force transmission servo mount (6), and perform non-destructive testing and shape trimming on the aileron as a whole.

10. The preparation method according to claim 9, characterized in that, In step S2, the surface of the counterweight core segment (34) made of high-density alloy is sandblasted and cleaned to enhance the bonding force; In step S4, the bonding tension and alignment accuracy are controlled during the assembly process to ensure that the upper end face of the embedded damping column (22) is in close contact with the upper damping film and the inner surface of the skin. In step S3, after connecting the embedded base (51) to the front edge beam (3) with high-strength bolts, high-toughness structural adhesive is injected into the joints between the base step surfaces and the honeycomb core layer and skin.

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