Self-adaptive energy-absorbing conformal head cap of air-water cross-medium aircraft

Abstract

The invention relates to a self-adaptive energy-absorbing conformal head cap of an air-water cross-medium aircraft, which is mainly applied to aircrafts capable of switching motion between two media of air and water. The head cap comprises a top cover, a skin combination, an energy absorption mechanism, a shape preserving mechanism and a modular adaptive interface, wherein the skin combination comprises an outer-layer skin and an inner-layer skin; the energy absorption mechanism is arranged in the inner-layer skin; the conformal structure is arranged between the inner-layer skin and the outer-layer skin; the modular adaptive interface comprises a base and a switching section, the base is connected with one end of the inner-layer skin, and the switching section is connected with the aircraft body; and the top cover is connected with the other end of the inner-layer skin. Stable hydrodynamic performance and low underwater resistance can be provided under different water entry speeds and angles, head appearance damage caused in the deformation process of a traditional energy absorption structure is effectively avoided, and the key technical problems in design of the air-water cross-medium aircraft are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft structure design, and particularly relates to an adaptive energy-absorbing and shape-preserving head cap for an air-water trans-medium aircraft. This head cap is mainly applied to aircraft that can convert their motion between air and water media. By effectively absorbing axial energy and maintaining the overall external contour during the water entry process, it reduces the peak overload borne by the aircraft and ensures its hydrodynamic characteristics in water. Background Art

[0002] Driven by application requirements such as marine exploration, environmental monitoring, military reconnaissance, and emergency rescue in recent years, air-water trans-medium aircraft are rapidly emerging as a multi-functional and comprehensive flight platform. Such aircraft can not only perform flight missions in the atmospheric environment in the manner of drones or conventional aircraft but also play the functions of autonomous underwater vehicles (AUVs) or remotely operated vehicles (ROVs) after entering the water. Compared with traditional aircraft that are only applicable to air or water media, air-water trans-medium aircraft face more stringent requirements in terms of structural design and performance indicators, and must simultaneously take into account the hydrodynamic and structural mechanical characteristics in these two completely different media of air and water.

[0003] When such an aircraft transforms from high-speed flight in the air to the water entry condition, the density of water and the impact resistance it generates are much higher than those of air, resulting in the front end of the aircraft bearing sudden and intense impact loads and a certain degree of radial loads. Without effective buffering and energy absorption, front-end components such as the nose, head cap, or fairing are extremely prone to severe deformation or rupture under this high-intensity impact, and internal precision instruments will also face the risk of failure. At the same time, the overly rapid deceleration process may also bring excessive vibration or stress concentration to the aircraft body connection parts, attitude control systems, and key sensors, thereby weakening the stability and controllability of underwater navigation.

[0004] The conventional solution strategy is to add energy-absorbing components or cover energy-absorbing materials at the head of the aircraft, and convert and dissipate part of the water entry kinetic energy through elastic or plastic deformation to reduce the peak overload borne by the aircraft. However, these energy-absorbing methods often significantly change the head shape during the deformation process, especially the radial expansion or depression that occurs under oblique water entry conditions. Since underwater navigation requires a streamlined geometric appearance to ensure predictable hydrodynamic characteristics, the deformation of the head shape is likely to cause abnormal flow field distribution, deviation of the fluid separation point or pressure center position, thus seriously affecting the attitude control and maneuverability of the aircraft underwater and reducing the accuracy and efficiency of tasks such as detection, salvage, and reconnaissance.

[0005] Therefore, how to achieve effective energy absorption when entering the water while maintaining the integrity and stability of the head shape has become a key problem that needs to be solved in the design of the head cap of air-water cross-medium aircraft. To this end, some improvement schemes try to adopt a multi-layer or segmented structure to concentrate the energy absorption deformation at a specific axial position, thereby reducing the distortion in the radial or circumferential direction; another public scheme sets a sliding or foldable mechanism between the head shell and the inner load-bearing frame, so that the head cap can produce controllable compression along the axial direction under high impact loads, avoiding excessive circumferential deformation. However, these technical paths often face problems such as complex structure, high assembly process requirements, and inconvenient maintenance and replacement. In addition, the reliability and repeatability of some designs under extreme conditions of high-speed water entry still need to be further verified. Summary of the invention

[0006] The present invention aims to solve the key problems such as the strong impact load suffered by the air-water medium-spanning aircraft at the moment of entering the water and the damage to the hydrodynamic shape caused by energy absorption deformation, and proposes an adaptive energy-absorbing conformal head cap for the air-water medium-spanning aircraft. The present invention can effectively reduce the peak overload borne by the aircraft during the water entry stage and maintain the integrity and stability of its head shape, thereby ensuring that the aircraft has better maneuverability and attitude control capabilities in the underwater environment.

[0007] The core idea of ​​the present invention is to use an axial guide rail array to connect the energy absorption mechanism and the hydrodynamic head cap, thereby ensuring that the axial energy absorption of the head cap during the water entry process is carried out smoothly, and limiting the radial deformation of the head cap, so that the main deformation of the head cap during the water entry process is concentrated in the axial direction, and the radial direction remains relatively stable. In order to achieve the above technical objectives, the technical solution adopted by the present invention is: an air-water cross-medium aircraft adaptive energy absorption conformal head cap, the head cap includes a top cover, a skin combination, an energy absorption mechanism, a conformal mechanism and a modular adapter interface, wherein: the skin combination includes an outer skin and an inner skin; the energy absorption mechanism is arranged in the inner skin; the conformal structure is arranged between the inner skin and the outer skin; the modular adapter interface includes a base and a transition section, the base is connected to one end of the inner skin, and the transition section is connected to the aircraft body; the top cover is connected to the other end of the inner skin.

[0008] As a preferred technical solution: the outer skin is a hydrodynamic skin with a streamlined profile, which is used to maintain good fluid dynamics properties of the aircraft when sailing underwater.

[0009] As a preferred technical solution: the energy absorbing mechanism comprises energy absorbing units arranged along the axial direction; the energy absorbing units are hierarchical energy absorbing structures; the energy absorbing units are filled inside the inner skin.

[0010] As a preferred technical solution: the conformal mechanism comprises a guide rail assembly arranged in an annular array along the outer circumference of the inner skin; The guide rail assemblies are circumferentially distributed and have multiple guide rail units; slideways that cooperate with the guide rail units are provided on the inner wall of the outer skin; the sliding direction of the guide rails is parallel to the axial direction of the aircraft, ensuring that the head cap mainly deforms in the axial direction under the action of impact loads, and the radial deformation is effectively restricted.

[0011] As a preferred technical solution: the outer skin is an integral structure made of a composite material with corrosion resistance or a corrosion-resistant metal material.

[0012] As a preferred technical solution: the shape of the top cover is one of a flat head type, a cone type, a hemispherical type, and an arc cone type.

[0013] As a preferred technical solution: the modular adaptor interface can quickly replace each functional module according to the requirements of the aircraft, and the overall energy absorption capacity of the modular-designed head cap and the hydrodynamic top cover structure can be flexibly adjusted to adapt to different aircraft models, water entry speeds, and mission scenarios.

[0014] As a preferred technical solution: the assembly height of the inner energy absorption mechanism and the number of circumferential array guide rails can both be adjusted according to the load reduction and shape retention requirements of the aircraft to ensure the stability and energy absorption effect of the head cap during high-speed water entry.

[0015] An air-water transmedia aircraft includes the head cap described above.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Reduce peak overload: The inner energy absorption mechanism consumes most of the energy at the moment of water entry impact, significantly reducing the peak acceleration transmitted to the airframe and internal electronic devices, and enhancing the impact survival ability of the aircraft. 2. Maintain the integrity of the shape: With the cooperation of the circumferential array guide rails and the hydrodynamic head cap, the present invention can concentrate most of the deformation in the axial direction, reducing unnecessary expansion or depression of the head cap in the radial direction, thereby maintaining the optimal hydrodynamic shape. 3. Improve underwater maneuverability: The overall shape of the head cap remains streamlined after water entry, improving the controllability of the aircraft's attitude and direction, adapting to multi-condition marine environments, and achieving more efficient cruising and maneuvering capabilities. 4. High adaptability and maintainability: Through the modular adaptor interface, not only can corresponding adjustments or modifications be made for different aircraft models, water entry speeds, and water entry postures, but also the disassembly, replacement, and upgrade of components are facilitated. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the head cap structure with different hydrodynamic shapes; Figure 2 It is a schematic diagram of the energy absorption units stacked axially inside the head cap; Figure 3 Schematic diagram of the circumferential guide rail array used in the present invention; Figure 4 Schematic diagram of the modular design of the head cap used in the present invention; Figure 5 An embodiment of the head cap structure design used in the present invention; Figure 6 Top view of the guide rail array in the embodiment of the present invention.

[0018] In the figure: aircraft body 1, head cap 2, adapter section 3, base 4, energy absorption unit 5, top cover 6, guide rail monomer 7, outer skin 8, inner skin 9, slideway 10. Detailed implementation manners

[0019] The following further describes the present invention with reference to the accompanying drawings and embodiments.

[0020] The present invention discloses an adaptive energy absorption and shape retention head cap for an air-water trans-medium aircraft. The present invention proposes a head cap for an air-water trans-medium aircraft that combines axial energy absorption and shape retention functions, and by making the main deformation of the head cap during water entry concentrated on axial compression, the adverse effects of radial deformation on the hydrodynamic shape of the aircraft are greatly reduced.

[0021] The present invention also discloses such an air-water trans-medium aircraft including the above-mentioned head cap.

[0022] This adaptive energy absorption and shape retention head cap for an air-water trans-medium aircraft includes a top cover 6, a skin combination, an energy absorption mechanism, a shape retention mechanism, and a modular adaptation interface, wherein: the skin combination includes an outer skin 8 and an inner skin 9; the energy absorption mechanism is arranged inside the inner skin 9. The shape retention structure is arranged between the inner skin 9 and the outer skin 8. The modular adaptation interface includes a base 4 and an adapter section 3. One end of the base 4 is threadedly connected to the inner skin 9, and the adapter section 3 is threadedly connected to the aircraft body 1. Threads are provided on the inner wall of the side surface of the top cover 6, and external threads are provided on the outer wall of the end of the inner skin 9, and the two are threadedly connected as a whole.

[0023] 1. Hydrodynamic head shape for enhanced navigation stability As a preferred embodiment, the outer skin 8 is a hydrodynamic skin with a streamlined profile for maintaining good hydrodynamic characteristics of the aircraft during underwater navigation.

[0024] The present invention provides a hydrodynamic head shape with a streamlined profile on the outer layer of the head cap. The shape of the top cover is one of a flat head shape, a conical shape, a hemispherical shape, and a conical arc shape, which is used to maintain good hydrodynamic characteristics during underwater navigation. The shape of the head can be optimized according to the requirements of the resistance, lift, and flow field distribution of the aircraft underwater. Generally, materials with good smoothness and corrosion resistance (such as composite materials or corrosion-resistant metals) are used. According to the speed range and navigation depth requirements of the aircraft, the head is optimized in terms of its curved surface to ensure the lowest possible drag coefficient and a reasonable pressure distribution. During water entry collision and underwater navigation, the head cap also plays a role in protecting the internal structure, preventing rubbing, and reducing the influence of vortex shedding.

[0025] In the hydrodynamic head cap, the shape of the head cap can be flexibly adjusted according to different water entry conditions to minimize the underwater navigation resistance and ensure the stable water entry attitude of the aircraft. The head cap can also play a certain role in protection and drag reduction when the aircraft enters the water or flies in the air. Figure 1 As shown, it is the head cap structure with different hydrodynamic shapes.

[0026] 2. Inner energy absorption mechanism The energy absorption mechanism includes energy absorption units arranged along the axial direction. Preferably, the energy absorption units are hierarchical energy absorption structures, such as honeycomb structures, bird's nest-like structures, etc. The energy absorption units are enveloped into a cylinder and filled inside the inner skin 9. Preferably, concave positioning grooves are respectively provided on the inner walls of the base 4 and the top cover 6, and the two ends of the energy absorption units are placed in the positioning grooves to achieve positioning and improve stability.

[0027] An axially compressible energy absorption mechanism is provided in the head cap. This mechanism can consume part of the kinetic energy through elastic or plastic deformation when the aircraft enters the water at high speed and is subjected to instantaneous impact loads, so as to reduce the peak overload transmitted to the airframe. The specific design of the energy absorption mechanism can be selected in combination with the material characteristics and the load reduction requirements of the aircraft. When designing, the geometric and mechanical parameters of the energy absorption structure are optimized for different speeds or water entry angles to form a stable energy absorption channel within a specific load range.

[0028] The energy absorption mechanism is located between the head cap and the aircraft body and is mainly composed of a number of energy absorption units. The energy absorption units are stacked and arranged along the axis of the aircraft, as Figure 2 shown. When the head cap is subjected to instantaneous impact loads during the high-speed water entry of the aircraft, these energy absorption units will successively undergo elastic-plastic collapse or buckling along the axis, absorbing most of the kinetic energy, thereby significantly reducing the overload impact transmitted to the aircraft body.

[0029] 3. Circumferential array guide rail design The conformal mechanism includes a guide rail combination arranged in a circumferential array along the outer circumference of the inner skin; the guide rail combination has a plurality of guide rail monomers 7 and is distributed circumferentially. On the inner wall of the outer skin 8, a slideway 10 is provided that cooperates with the guide rail monomer 7.

[0030] The sliding direction of the guide rail is parallel to the axial direction of the aircraft, ensuring that the head cap mainly deforms in the axial direction under the action of impact load, and the radial deformation is effectively restricted. To achieve the goal of "axial energy absorption and radial shape retention", the present invention adopts a circumferentially distributed guide rail and slideway combination as a sliding support component between the energy absorption mechanism and the head cap skin. The guide rail design has the following characteristics: Multi-point constraint: Several guide rails are distributed along the circumference of the head cap and are connected to the inner and outer layers in a sliding or rolling manner, ensuring uniform force on the head cap during the compression process and avoiding local warping or excessive torsion.

[0031] Directional sliding: The longitudinal direction of the guide rail is parallel to the axial direction of the aircraft, enabling the head cap to mainly contract in the axial direction when impacted, while the radial direction is effectively restricted, thus minimizing the shape distortion to the greatest extent.

[0032] Detachability: According to actual maintenance requirements, the guide rail can be designed modularly, facilitating quick replacement after damage or wear, and improving the reliability and maintainability of the overall structure.

[0033] The circumferential guide rail array is between the head cap skin and the energy absorption mechanism, and multiple guide rails are arranged at equal intervals along the circumferential direction. The longitudinal axis of each guide rail is parallel to the axis of the aircraft, and is connected to the inner surface of the skin and the energy absorption mechanism through a slider or a rolling component, as Figure 3 shown. When the head cap is compressed under the action of impact load, all the guide rails can ensure that the head cap mainly produces controllable sliding and displacement in the axial direction, and the radial deformation is effectively restricted. This design enables the head cap to maintain a hydrodynamic shape close to the original while achieving energy absorption.

[0034] 4. Modular adaptation interface The modular adaptation interface includes a base 4 and an adapter section 3. The base 4 is threadedly connected to one end of the inner skin 9, and the adapter section 3 is threadedly connected to the aircraft body 1. Preferably, an inner concave hole with an inner wall thread is provided at the end of the aircraft body, and an external thread matching the inner concave hole is provided on the adapter section 3, and the two are threadedly connected as a whole. The modular adaptation interface can quickly replace each functional module according to the requirements of the aircraft, and the overall energy absorption capacity and hydrodynamic top cover structure of the modularly designed head cap can be flexibly adjusted to adapt to different aircraft models, entry speeds and mission scenarios.

[0035] In the present invention, modular interface designs are adopted for both the connection part between the head cap and the aircraft body and among various functional modules inside the head cap, so as to meet the requirements of quick replacement and flexible combination for different models or different mission needs. Standardized sizes and fixing methods are configured at the connection flange or support of the head cap and the main aircraft body, reducing the use of customized structures. The energy absorption mechanism, hydrodynamic top cover, rail combination, etc. can be assembled layer by layer or section by section according to requirements, and can be replaced with components of different strengths or shapes, being compatible with various aircraft sizes and water entry speed conditions.

[0036] The assembly height of the inner energy absorption mechanism and the number of circumferential array rails can both be adjusted according to the load reduction and shape retention requirements of the aircraft, so as to ensure the stability and energy absorption effect of the head cap during the high-speed water entry process. Based on the modular design concept, the aircraft can, in the later stage, locally replace or expand the performance of the head cap according to mission changes or performance upgrade requirements, greatly reducing the maintenance cost and the difficulty of later modification.

[0037] The modular adaptation interface design enables the connection part between the head cap and the aircraft body and various functional modules inside the head cap to adopt standardized interface forms. Therefore, the head cap can be disassembled into a top cover, an energy absorption mechanism, an inner skin, an outer skin, rails, a base, etc., as Figure 4 shown. Through this modular design, the energy absorption capacity or the head shape structure of the head cap can be quickly replaced or upgraded without changing the main structure. It is also possible to adjust the shape of the energy absorption unit and the top cover according to different water entry speeds or target mission scenarios, realizing the structure-function matching between the head cap and the aircraft, thereby improving the flexibility of use and reducing the maintenance cost. Embodiment

[0038] In this example, a flat head type top cover is taken as an example for the description of the embodiment. Refer to Figures 5-6 , in this embodiment, the outer diameter of the top cover is Φ1 = 100 mm, the top cover and the inner skin are connected by threads, the inner skin is a hollow cylindrical structure with an inner diameter of Φ2 = 60 mm, the assembly height of the inner skin rails is h1 = 60 mm, and the assembly height of the inner skin energy absorption mechanism is H1 = 100 mm. The outer skin and the base are connected by threads, the outer diameter of the outer skin is Φ3 = 100 mm, the assembly height of the outer skin rails is h2 = 60 mm, and the assembly height of the outer skin energy absorption mechanism is H2 = 100 mm. The total height of the energy absorption structure inside the head cap is H = 160 mm. The number of circumferential array rails is 10.

[0039] The above is only a design of a load reduction head cap structure for the aircraft to perform air-water cross-medium, and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An adaptive energy-absorbing and shape-preserving headgear for an air-water cross-medium aircraft, characterized in that, The head cap includes a top cover, a skin assembly, an energy absorption mechanism, a shape retention mechanism, and a modular adaptation interface, where: The skin assembly includes an outer skin and an inner skin; the energy absorption mechanism is disposed inside the inner skin; The shape retention structure is disposed between the inner skin and the outer skin; The modular adaptation interface includes a base and a transition section. The base is connected to one end of the inner skin, and the transition section is connected to the aircraft body; the top cover is connected to the other end of the inner skin.

2. The air-water trans-medium aircraft adaptive energy-absorbing and shape-preserving headgear according to claim 1, characterized in that The outer skin is a hydrodynamic skin with a streamlined profile for maintaining good hydrodynamic characteristics of the aircraft during underwater navigation.

3. The adaptive energy-absorbing and shape-preserving headgear for the air-water trans-medium aircraft according to claim 1, wherein The energy absorption mechanism includes energy absorption units arranged along the axial direction; The energy absorption unit is a hierarchical energy absorption structure; The energy absorption units are filled inside the inner skin.

4. The adaptive energy-absorbing and shape-preserving headgear for the air-water cross-medium aircraft according to claim 1, wherein The shape retention mechanism includes a guide rail assembly arranged in a circumferential array along the outer circumference of the inner skin; The guide rail assembly is distributed circumferentially and has a plurality of guide rail monomers; sliding grooves matching the guide rail monomers are provided on the inner wall of the outer skin; The sliding direction of the guide rail is parallel to the axis of the aircraft, ensuring that the head cap deforms mainly in the axial direction under the action of impact load, and the radial deformation is effectively restricted.

5. The air-water trans-medium aircraft adaptive energy-absorbing and shape-preserving headgear according to claim 1, characterized in that, The outer skin is an integral structure made of a composite material with corrosion resistance or a corrosion-resistant metal material.

6. The air-water trans-medium aircraft adaptive energy-absorbing and shape-preserving headgear according to claim 1, characterized in that, The shape of the top cover is one of a flat head type, a cone type, a hemisphere type, and an arc cone type.

7. The adaptive energy-absorbing and shape-preserving headgear of the air-water cross-medium aircraft according to claim 6, characterized in that, The modular adaptation interface can quickly replace each functional module according to the requirements of the aircraft, and the overall energy absorption capacity and the hydrodynamic top cover structure of the modular-designed head cap can be flexibly adjusted to adapt to different aircraft models, entry speeds, and mission scenarios.

8. The adaptive energy-absorbing and shape-preserving headgear for the air-water trans-medium aircraft according to claim 6, wherein, The assembly height of the inner energy absorption mechanism and the number of circumferential arrayed guide rails can both be adjusted according to the load reduction and shape retention requirements of the aircraft to ensure the stability and energy absorption effect of the head cap during high-speed water entry.

9. An air-water trans-medium aircraft comprising the head cap according to any one of claims 1-8.

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