A surface wetting dynamically adjustable trans-medium aircraft variant nose cone

Abstract

The present application relates to a kind of surface wetting dynamic adjustable cross-media aircraft variant head cone, belong to cross-media aircraft field.It includes variant skeleton and flexible skin.Heating, variant skeleton can drive flexible skin to produce deformation, after normal temperature, flexible skin keeps the state after deformation, to change the curvature distribution and cross section characteristics of head cone configuration.Flexible skin surface covers wetting intelligent response coating.Wetting intelligent response coating can change into superhydrophilic state after surface wetting after ultraviolet irradiation, and can restore to superhydrophobic state after heating.According to specific water entry condition, adjust the configuration and surface wetting layout of cross-media aircraft head, utilize the influence of configuration and surface wetting on water cavity evolution, change the hydrodynamic and hydrodynamic moment received by aircraft during water entry, as needed, reduce impact load and improve attitude and trajectory stability, achieve the purpose of compatible multiple launch platform, guarantee water entry efficiency and safety.

Description

Technical Field

[0001] This invention belongs to the field of cross-medium aircraft technology and relates to a cross-medium aircraft variant nose cone with dynamically adjustable surface wettability. Background Technology

[0002] A cross-medium aircraft is a new concept aircraft capable of amphibious cruising and repeatedly crossing the air-water interface. It combines the advantages of high speed and maneuverability in the air with long underwater endurance and strong stealth. It can carry weapons and equipment to perform reconnaissance, early warning and penetration strike missions, as well as carry sensing equipment to carry out scientific exploration or disaster relief work, and has broad prospects for military and civilian applications.

[0003] Water entry is the most critical phase in a cross-medium spacecraft mission profile. When deployed via airdrop, the high-speed entry of the spacecraft into the water generates enormous impact loads, posing a risk of damage and failure to its structure and equipment. When launched from a ship's side, the tilted entry of the spacecraft into the water generates asymmetric water cavitation and strong hydrodynamic moments, which may cause significant deviations in its attitude and trajectory, leading to instability. Modern advanced cross-medium spacecraft require compatibility with multiple launch platforms, making it crucial to implement load reduction and motion stabilization measures as needed for specific water entry conditions.

[0004] Existing technologies primarily reduce water entry impact loads by adding various buffer components. However, a single-layout buffer component cannot meet the load reduction requirements under all water entry conditions. At the same time, the buffer component disrupts the hydrodynamic shape of the aircraft, which may lead to a deterioration in ballistic stability under certain water entry conditions.

[0005] Existing technologies primarily improve water entry trajectory stability by adding a tail shroud. However, after an aircraft hits water, cavitation bubbles are generated around the fuselage, causing the tail to remain exposed to the air and thus failing to generate sufficient stabilizing torque, resulting in poor water entry trajectory stabilization. Summary of the Invention

[0006] Therefore, this invention, in order to overcome or at least mitigate the deficiencies of the prior art, is of great significance for solving the technical challenges faced in the design of cross-medium aircraft. The technical problem to be solved by the dynamically adjustable surface wettability variant nose cone of this invention is: based on the load reduction and motion stabilization requirements determined by specific water entry conditions, adjusting the nose configuration and surface wettability layout of the cross-medium aircraft, utilizing the influence of configuration and surface wettability on the evolution of cavitation during water entry, changing the hydrodynamic forces and hydrodynamic torque experienced by the aircraft during water entry, reducing impact loads as needed, and improving attitude and ballistic stability, thereby achieving compatibility with multiple launch platforms and ensuring water entry efficiency and safety.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] This invention discloses a dynamically adjustable surface wettability trans-medium aircraft variant nose cone, comprising a variant skeleton and a flexible skin. The flexible skin covers the outside of the variant skeleton and is used to maintain the hydrodynamic shape and watertightness of the entire nose cone; the variant skeleton supports the flexible skin and bears the hydrodynamic load transmitted by the flexible skin; under heating conditions, the variant skeleton can drive the flexible skin to deform, and after returning to normal temperature, the flexible skin retains the deformed state, thereby changing the curvature distribution and cross-sectional characteristics of the nose cone configuration, thereby controlling the hydrodynamic forces and hydrodynamic moments experienced by the aircraft during water entry.

[0009] The variant skeleton further includes a top cover, ring ribs, longitudinal ribs, movable semi-ring ribs, connecting rod longitudinal ribs, and telescopic longitudinal ribs. The top cover and ring ribs are placed along the central axis of the entire nose cone and are connected and fixed as a whole by the longitudinal ribs in sequence. The movable semi-ring ribs are hinged to the longitudinal ribs in two groups and connected to the ring ribs through the telescopic longitudinal ribs and to the top cover through the connecting rod longitudinal ribs. Driven by the telescopic movement of the telescopic longitudinal ribs, the movable semi-ring ribs can rotate and drive the connecting rod longitudinal ribs to move, respectively driving the upper and lower halves of the flexible skin to deform, changing the curvature distribution and cross-sectional characteristics of the configuration between the top cover and the ring ribs, thereby changing the configuration of the transmedium aircraft nose and thus controlling the hydrodynamic force and hydrodynamic torque experienced by the aircraft during water entry.

[0010] The flexible skin further includes a substrate and alloy wires. The alloy wires are embedded inside the substrate, serving two purposes: firstly, to enhance the substrate's toughness and tear resistance, and secondly, to provide electrical heating before the substrate is induced to deform. After heating, the substrate's stiffness decreases, and it deforms by being driven by the movable semi-circular ribs. Once the temperature drops to room temperature, it can restore its original stiffness and withstand water impact loads.

[0011] Preferably, the ring ribs include a first ring rib, a second ring rib, a third ring rib, and a fourth ring rib; the longitudinal ribs include a left longitudinal rib, a right longitudinal rib, an upper longitudinal rib, and a lower longitudinal rib; the movable semi-ring ribs include an upper movable semi-ring rib and a lower movable semi-ring rib; the telescopic longitudinal ribs include an upper telescopic longitudinal rib and a lower telescopic longitudinal rib; and the connecting rod longitudinal ribs include an upper connecting rod longitudinal rib and a lower connecting rod longitudinal rib. The top cover, the first ring rib, the second ring rib, the third ring rib, and the fourth ring rib are placed along the central axis of the entire head cone and are connected and fixed as a whole by the left and right longitudinal ribs. The first ring rib, the second ring rib, the third ring rib, and the fourth ring rib are further connected from the upper and lower sides by the upper and lower longitudinal ribs, respectively. The upper movable semi-ring rib is located between the top cover and the first ring rib and is hinged to the left and right longitudinal ribs. The lower movable semi-ring rib is located between the top cover and the first ring rib and is hinged to the left and right longitudinal ribs, with the hinge point being the same as that of the upper movable semi-ring rib. The upper telescopic longitudinal rib is hinged at both ends to the upper movable semi-ring rib and the first ring rib, respectively. The lower telescopic longitudinal rib is hinged at both ends to the lower movable semi-ring rib and the first ring rib, respectively. A sliding groove is formed on the inner surface of the top cover. One end of the upper connecting rod longitudinal rib is hinged to the upper movable semi-ring rib, and the pin at the other end engages with the sliding groove of the top cover to achieve sliding within the groove. One end of the lower connecting rod longitudinal rib is hinged to the lower movable semi-ring rib, and the pin at the other end engages with the sliding groove of the top cover to achieve sliding within the groove. Driven by the telescopic movement of the upper and lower telescopic longitudinal ribs, the upper and lower movable semi-ring ribs can rotate respectively, driving the upper and lower connecting rod longitudinal ribs to move. The movement of the upper telescopic longitudinal rib, upper movable semi-ring rib, upper connecting rod longitudinal rib, lower telescopic longitudinal rib, lower movable semi-ring rib, and lower connecting rod longitudinal rib can respectively change the shape of the upper and lower flexible skin of the variant skeleton, thereby changing the curvature distribution and cross-sectional characteristics of the configuration between the top cover and the first ring rib, thus changing the configuration of the transmedium aircraft head, thereby regulating the hydrodynamic force and hydrodynamic torque experienced by the aircraft during water entry.

[0012] Preferably, the substrate is a shape memory polymer, and the alloy wire is a superelastic serpentine alloy wire. The alloy wire is embedded in the substrate in two layers, with the alloy wires in each layer arranged at equal intervals and in the same direction, and the arrangement directions of the two layers of alloy wires are perpendicular to each other.

[0013] The present invention discloses a variant nose cone for a trans-medium aircraft with dynamically adjustable surface wettability. The method for adjusting the nose configuration of the aircraft according to specific water entry conditions, thereby regulating the hydrodynamic forces and hydrodynamic torque experienced by the aircraft during water entry, is as follows:

[0014] During airdrop deployment, the rotation angle of the movable semi-ring rib is determined according to the following formula to minimize the water impact load and the structural load:

[0015]

[0016] In the formula, δu The angle at which the upper movable semi-circular rib rotates forward. δ l The angle at which the lower movable semi-circular rib rotates forward;

[0017] When launching from the ship's side, the rotation angle of the movable semi-ring rib is determined according to the following formula to minimize the hydrodynamic impulse, the aircraft attitude, and the trajectory deflection:

[0018]

[0019] In the formula, δ u The angle at which the upper movable semi-circular rib rotates forward. δ l The angle at which the lower movable semi-circular rib rotates forward. δ max This represents the maximum rotational stroke of the movable semi-circular rib.

[0020] Furthermore, the flexible skin surface is covered with a wettability-responsive smart coating. Before the launch and deployment of the transmedium vehicle, an ultraviolet irradiation device is placed in front of the nose cone of the vehicle variant. The surface wettability of the wettability-responsive smart coating can be transformed into a superhydrophilic state after ultraviolet irradiation, and can be restored to a superhydrophobic state after heating, so that the surface wettability of the upper and lower halves of the flexible skin can be independently changed under the stimulation of ultraviolet light and temperature.

[0021] Preferably, the wettability smart response coating is a titanium dioxide particle coating grafted with perfluorodecyltriethoxysilane.

[0022] Beneficial effects:

[0023] 1. The present invention discloses a variant nose cone for a cross-medium aircraft with dynamically adjustable surface wettability. By utilizing the influence of configuration and surface wettability on the evolution of cavitation during water entry, the hydrodynamic force and hydrodynamic torque experienced by the aircraft during water entry are changed, the impact load is reduced as needed, and the attitude and trajectory stability are improved, so as to achieve compatibility with multiple launch platforms and ensure water entry efficiency and safety.

[0024] 2. The present invention discloses a variant nose cone for a transmedium vehicle with dynamically adjustable surface wettability. Based on the load reduction and motion stabilization requirements determined by specific water entry conditions, the nose configuration and surface wettability layout of the transmedium vehicle are adjusted. Without adding additional devices, it can reduce impact load and improve attitude and ballistic stability. Compared with traditional water entry load reduction and motion stabilization methods, it is simpler, more applicable, and more reliable.

[0025] 3. This invention discloses a dynamically adjustable surface wettability nose cone for a trans-medium aircraft, wherein the flexible skin surface is covered with a smart wettability-responsive coating. Before the trans-medium aircraft is launched and deployed, an ultraviolet irradiation device is placed in front of the nose cone. The surface wettability of the smart wettability-responsive coating can be transformed into a superhydrophilic state after ultraviolet irradiation, and can be restored to a superhydrophobic state after heating. This allows the surface wettability of the upper and lower halves of the flexible skin to change independently under the excitation of ultraviolet light and temperature, thereby enabling adjustment of the nose configuration and surface wettability layout of the trans-medium aircraft.

[0026] 4. This invention discloses a dynamically adjustable surface wettability trans-medium aircraft variant nose cone, in which alloy wires are embedded within a substrate. This serves two purposes: firstly, to enhance the substrate's toughness and tear resistance; and secondly, to provide electrical heating before inducing substrate deformation. After heating, the substrate's stiffness decreases, and it deforms through the movement of the semi-circular ribs. Once the temperature drops to room temperature, it recovers its original stiffness and can withstand water impact loads. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the nose cone of a transmedium aircraft variant with dynamically adjustable surface wettability.

[0028] Figure 2 This is a schematic diagram of the structure of a cross-medium aircraft variant nose cone variant skeleton with dynamically adjustable surface wettability.

[0029] Figure 3 This is another schematic diagram of the configuration of a cross-medium aircraft variant's nose cone variant skeleton with dynamically adjustable surface wettability.

[0030] Figure 4 A schematic diagram of one configuration of a cross-medium aircraft variant head cone variant skeleton with dynamically adjustable surface wettability.

[0031] Figure 5 This is a schematic diagram of another configuration of the nose cone variant skeleton of a transmedia aircraft variant with dynamically adjustable surface wettability.

[0032] Figure 6 This is a schematic diagram of the structure of a flexible nose cone skin for a transmedium aircraft variant with dynamically adjustable surface wettability.

[0033] Figure 7 This is a schematic diagram of one configuration of a nose cone variant of a transmedium aircraft with dynamically adjustable surface wettability.

[0034] Figure 8 This is a schematic diagram of the installation of a nose cone for a transmedium aircraft variant with dynamically adjustable surface wettability.

[0035] Figure 9Schematic diagram of a supporting device for a variable nose cone of a trans-medium aircraft with dynamically adjustable surface wettability.

[0036] Figure 10 Schematic diagram of the usage scenario of a variable nose cone of a trans-medium aircraft with dynamically adjustable surface wettability.

[0037] Figure 11 Schematic diagram of another usage scenario of a variable nose cone of a trans-medium aircraft with dynamically adjustable surface wettability.

[0038] Among them, 1 - variable skeleton, 101 - top cover, 102 - first ring rib, 103 - second ring rib, 104 - third ring rib, 105 - fourth ring rib, 106 - left longitudinal rib, 107 - right longitudinal rib, 108 - upper longitudinal rib, 109 - lower longitudinal rib, 110 - upper movable semi-ring rib, 111 - lower movable semi-ring rib, 112 - upper telescopic longitudinal rib, 113 - lower telescopic longitudinal rib, 114 - upper connecting rod longitudinal rib, 115 - lower connecting rod longitudinal rib, 2 - flexible skin, 201 - base, 202 - alloy wire, 3 - ultraviolet irradiation device, 4 - upper half of the nose cone, 5 - lower half of the nose cone. Specific implementation mode

[0039] To make the purpose, technical solution and advantages of the implementation of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0040] In the accompanying drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0041] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the protection scope of the present invention.

[0042] Embodiment 1

[0043] As Figure 1As shown in the figure, this embodiment discloses a dynamically adjustable surface wettability trans-medium aircraft variant nose cone, comprising a variant skeleton 1 and a flexible skin 2. The flexible skin 2 covers the outside of the variant skeleton 1 and is used to maintain the hydrodynamic shape and watertightness of the entire nose cone; the variant skeleton 1 is used to support the flexible skin 2 and bear the hydrodynamic load transmitted by the flexible skin 2; under heating conditions, the variant skeleton 1 can drive the flexible skin 2 to deform, and after returning to normal temperature, the flexible skin 2 can maintain the deformed state, thereby changing the curvature distribution and cross-sectional characteristics of the nose cone configuration, thereby controlling the hydrodynamic force and hydrodynamic torque experienced by the aircraft during water entry.

[0044] In this embodiment, the variant skeleton 1 further includes a top cover 101, ring ribs, longitudinal ribs, movable semi-ring ribs, connecting rod longitudinal ribs, and telescopic longitudinal ribs, such as... Figure 2 and Figure 3 As shown. The ring ribs include a first ring rib 102, a second ring rib 103, a third ring rib 104, and a fourth ring rib 105. The longitudinal ribs include a left longitudinal rib 106, a right longitudinal rib 107, an upper longitudinal rib 108, and a lower longitudinal rib 109. The movable semi-ring ribs include an upper movable semi-ring rib 110 and a lower movable semi-ring rib 111. The telescopic longitudinal ribs include an upper telescopic longitudinal rib 112 and a lower telescopic longitudinal rib 113. The connecting rod longitudinal ribs include an upper connecting rod longitudinal rib 114 and a lower connecting rod longitudinal rib 115. The top cover 101, first annular rib 102, second annular rib 103, third annular rib 104, and fourth annular rib 105 are placed along the central axis of the entire head cone and connected and fixed as a whole by the left longitudinal rib 106 and right longitudinal rib 107. The first annular rib 102, second annular rib 103, third annular rib 104, and fourth annular rib 105 are further connected sequentially from the upper and lower sides by the upper longitudinal rib 108 and lower longitudinal rib 109, respectively. The upper movable semi-annular rib 110 is located between the top cover 101 and the first annular rib 102 and is hinged to the left longitudinal rib 106 and right longitudinal rib 107. The lower movable semi-annular rib 111 is located between the top cover 101 and the first annular rib 102 and is hinged to the left longitudinal rib 106 and right longitudinal rib 107, with the hinge point being the same as that of the upper movable semi-annular rib 110. The two ends of the upper telescopic longitudinal rib 112 are hinged to the upper movable semi-annular rib 110 and the first annular rib 102, respectively. The lower telescopic longitudinal rib 113 is hinged at both ends to the lower movable semi-ring rib 111 and the first ring rib 102, respectively. A sliding groove is formed on the inner surface of the top cover 101, see [reference needed]. Figure 4 and Figure 5One end of the upper connecting rod longitudinal rib 114 is hinged to the upper movable semi-ring rib 110, and the pin at the other end engages with the sliding groove of the top cover 101 to achieve sliding within the groove. One end of the lower connecting rod longitudinal rib 115 is hinged to the lower movable semi-ring rib 111, and the pin at the other end engages with the sliding groove of the top cover 101 to achieve sliding within the groove. Driven by the telescopic movement of the upper telescopic longitudinal rib 112 and the lower telescopic longitudinal rib 113, the upper movable semi-ring rib 110 and the lower movable semi-ring rib 111 can rotate respectively, with the axis of rotation being the line connecting the hinge points of the upper movable semi-ring rib 110 and the left longitudinal rib 106 and the right longitudinal rib 107. The rotational movement of the upper movable semi-ring rib 110 and the lower movable semi-ring rib 111 can respectively drive the movement of the upper connecting rod longitudinal rib 114 and the lower connecting rod longitudinal rib 115. The movement of the upper telescopic longitudinal rib 112, upper movable semi-ring rib 110, upper connecting rod longitudinal rib 114, and lower telescopic longitudinal rib 113, lower movable semi-ring rib 111, and lower connecting rod longitudinal rib 115 can respectively change the shape of the upper and lower flexible skins of the variant skeleton 1, thereby driving the upper and lower halves of the flexible skin 2 to deform, changing the curvature distribution and cross-sectional characteristics of the configuration between the top cover 101 and the first ring rib 102, thereby changing the configuration of the transmedium aircraft's nose, and thus regulating the hydrodynamic force and hydrodynamic torque experienced by the aircraft during water entry, such as... Figure 6 As shown in the figure, the upper movable semi-ring rib 110 is at a rotation angle of 0°, with an angle of 75° to the central axis, while the lower movable semi-ring rib 111 is at its maximum rotation angle, with an angle of 115° to the central axis. The maximum rotational stroke of the movable semi-ring rib is shown in the figure. δ max It is 40°.

[0045] In this embodiment, the flexible skin 2 further includes a substrate 201 and an alloy wire 202, such as Figure 7 As shown. The substrate 201 is a shape memory polymer, and the alloy wire 202 is a superelastic serpentine alloy wire. The substrate 201 experiences a decrease in stiffness upon heating, allowing it to deform under the influence of movable semi-circular ribs. After cooling to room temperature, it regains its original stiffness and can withstand water impact loads. The variable stiffness of the substrate 201 allows the flexible skin 2 to balance deformation and load-bearing capacity requirements. The alloy wire 202 is embedded in the substrate 201 in two layers, with the alloy wires 202 in each layer arranged at equal intervals and in the same direction, and the arrangement directions of the two layers of alloy wires 202 perpendicular to each other. The alloy wire 202 serves two purposes: firstly, to enhance the toughness and tear resistance of the substrate 201, and secondly, to provide electrical heating before deformation of the substrate 201.

[0046] In this embodiment, the operating method of the dynamically adjustable surface wettability transmedium aircraft variant nose cone is as follows.

[0047] The aforementioned dynamically adjustable surface wettability trans-medium vehicle variant nose cone is mounted on the head of the trans-medium vehicle, such as... Figure 8 As shown.

[0048] After the transmedium vehicle is transported and loaded onto a specific launch platform, the configuration of the nose cone of the aforementioned dynamically adjustable transmedium vehicle is determined based on the specific launch method, launch parameters, and requirements for water entry unloading and motion stabilization. Specifically, the angle at which the movable semi-ring rib should rotate is:

[0049] Step 1: See Figure 10 During airdrop deployment, the cross-medium vehicle enters the water at high speed with an attitude angle of 60° to 90°. The high entry velocity generates a significant impact load, necessitating load reduction upon entry. However, the angle of inclination of the fuselage relative to the plumb line during entry is relatively small, resulting in a smaller asymmetric hydrodynamic moment and eliminating the need for motion stabilization. Under these conditions, the described cross-medium vehicle variant head cone with dynamically adjustable surface wettability should adopt a configuration with a smooth transition between the top cover 101 and the ring rib, and with the upper half 4 and lower half 5 being symmetrical. This symmetrical configuration improves the cavitation symmetry during entry, thereby reducing the hydrodynamic moment that causes attitude deflection and instability. The smooth transition configuration avoids abrupt changes in cross-sectional area, further reducing the impact load. Therefore, the rotation angle of the movable semi-ring rib is determined according to the following formula to minimize the impact load and structural load.

[0050]

[0051] Step Two: See Figure 11 During shipboard launch, the transmedium vehicle enters the water at a low speed with an attitude angle of 30° to 60°. The impact load upon entry is relatively small, and there is no need for load reduction upon entry. However, the fuselage tilts at a large angle relative to the plumb line during entry, and cavitation typically occurs on the upper side of the vehicle while it does not usually occur on the lower side. Therefore, the cavitation upon entry exhibits significant asymmetry, resulting in a large asymmetric hydrodynamic moment during entry and necessitating motion stabilization. Under these conditions, the upper half 4 of the nose cone of the aforementioned dynamically adjustable transmedium vehicle variant should have a smooth transition between the top cover 101 and the ring rib, while the lower half 5 should have a non-smooth transition between the top cover 101 and the ring rib. The upper part (4) with its smooth transition configuration induces the free liquid surface to adhere to the aircraft surface, reducing water entry cavitation on the upper side of the aircraft. Conversely, the lower part (5) with its non-smooth transition configuration induces the free liquid surface to separate from the aircraft surface, increasing water entry cavitation on the lower side of the aircraft. This improves the symmetry of the water entry cavitation and reduces the hydrodynamic moment that causes attitude deflection and instability. Figure 11 As shown. Therefore, the rotation angle of the movable semi-ring rib is determined according to the following formula to achieve the minimum hydrodynamic impulse moment, and the minimum attitude and trajectory deflection of the aircraft.

[0052]

[0053] After determining the rotation angles of the upper movable semi-ring rib 110 and the lower movable semi-ring rib 111, the alloy wire 202 embedded in the flexible skin 2 is energized and heated. As the temperature of the flexible skin 2 increases, its stiffness decreases. The telescopic longitudinal rib pushes the movable semi-ring rib to rotate and drives the connecting rod longitudinal rib to move, thereby driving the upper and lower halves of the flexible skin 2 to deform respectively. After the upper movable semi-ring rib 110 and the lower movable semi-ring rib 111 rotate to the predetermined angle and drive the flexible skin 2 to deform into the predetermined configuration, the telescopic longitudinal rib, the movable semi-ring rib, and the connecting rod longitudinal rib maintain support for the flexible skin 2. The energization of the alloy wire 202 embedded in the flexible skin 2 is stopped. After the temperature of the flexible skin 2 drops to room temperature, it restores its original stiffness and has the ability to withstand water impact loads. At this point, the configuration of the modified nose cone of the transmedium aircraft with dynamically adjustable surface wettability has been adjusted according to the specific launch method, launch parameters, and requirements for water entry load reduction and motion stabilization. The transmedium aircraft enters the launch standby state.

[0054] When launching and deploying cross-medium aircraft, the aircraft can utilize the influence of its nose configuration on the evolution of water cavitation during water entry to change the hydrodynamic forces and hydrodynamic torque it experiences during water entry, thereby reducing impact loads and improving attitude and trajectory stability as needed, achieving the goal of being compatible with multiple launch platforms and ensuring water entry efficiency and safety.

[0055] Example 2

[0056] The configuration of this embodiment is consistent with that described in the invention, including a variant skeleton 1 and a flexible skin 2, such as... Figure 1 As shown. The flexible skin 2 covers the outside of the variant frame 1 and is used to maintain the hydrodynamic shape and watertightness of the entire nose cone; the variant frame 1 is used to support the flexible skin 2 and bear the hydrodynamic load transmitted by the flexible skin 2; under heating conditions, the variant frame 1 can drive the flexible skin 2 to deform, and after returning to normal temperature, the flexible skin 2 can maintain the deformed state, thereby changing the curvature distribution and cross-sectional characteristics of the nose cone configuration, thereby controlling the hydrodynamic force and hydrodynamic moment experienced by the aircraft during water entry.

[0057] In this embodiment, the variant skeleton 1 further includes a top cover 101, ring ribs, longitudinal ribs, movable semi-ring ribs, connecting rod longitudinal ribs, and telescopic longitudinal ribs, such as... Figure 2 and Figure 3As shown. The ring ribs include a first ring rib 102, a second ring rib 103, a third ring rib 104, and a fourth ring rib 105. The longitudinal ribs include a left longitudinal rib 106, a right longitudinal rib 107, an upper longitudinal rib 108, and a lower longitudinal rib 109. The movable semi-ring ribs include an upper movable semi-ring rib 110 and a lower movable semi-ring rib 111. The telescopic longitudinal ribs include an upper telescopic longitudinal rib 112 and a lower telescopic longitudinal rib 113. The connecting rod longitudinal ribs include an upper connecting rod longitudinal rib 114 and a lower connecting rod longitudinal rib 115. The top cover 101, first annular rib 102, second annular rib 103, third annular rib 104, and fourth annular rib 105 are placed along the central axis of the entire head cone and connected and fixed as a whole by the left longitudinal rib 106 and right longitudinal rib 107. The first annular rib 102, second annular rib 103, third annular rib 104, and fourth annular rib 105 are further connected sequentially from the upper and lower sides by the upper longitudinal rib 108 and lower longitudinal rib 109, respectively. The upper movable semi-annular rib 110 is located between the top cover 101 and the first annular rib 102 and is hinged to the left longitudinal rib 106 and right longitudinal rib 107. The lower movable semi-annular rib 111 is located between the top cover 101 and the first annular rib 102 and is hinged to the left longitudinal rib 106 and right longitudinal rib 107, with the hinge point being the same as that of the upper movable semi-annular rib 110. The two ends of the upper telescopic longitudinal rib 112 are hinged to the upper movable semi-annular rib 110 and the first annular rib 102, respectively. The lower telescopic longitudinal rib 113 is hinged at both ends to the lower movable semi-ring rib 111 and the first ring rib 102, respectively. A sliding groove is formed on the inner surface of the top cover 101, see [reference needed]. Figure 4 and Figure 5 One end of the upper connecting rod longitudinal rib 114 is hinged to the upper movable semi-ring rib 110, and the pin at the other end engages with the sliding groove of the top cover 101 to achieve sliding within the groove. One end of the lower connecting rod longitudinal rib 115 is hinged to the lower movable semi-ring rib 111, and the pin at the other end engages with the sliding groove of the top cover 101 to achieve sliding within the groove. Driven by the telescopic movement of the upper telescopic longitudinal rib 112 and the lower telescopic longitudinal rib 113, the upper movable semi-ring rib 110 and the lower movable semi-ring rib 111 can rotate respectively, with the axis of rotation being the line connecting the hinge points of the upper movable semi-ring rib 110 and the left longitudinal rib 106 and the right longitudinal rib 107. The rotational movement of the upper movable semi-ring rib 110 and the lower movable semi-ring rib 111 can respectively drive the movement of the upper connecting rod longitudinal rib 114 and the lower connecting rod longitudinal rib 115. The movement of the upper telescopic longitudinal rib 112, upper movable semi-ring rib 110, upper connecting rod longitudinal rib 114, and lower telescopic longitudinal rib 113, lower movable semi-ring rib 111, and lower connecting rod longitudinal rib 115 can respectively change the shape of the upper and lower flexible skins of the variant skeleton 1, thereby driving the upper and lower halves of the flexible skin 2 to deform, changing the curvature distribution and cross-sectional characteristics of the configuration between the top cover 101 and the first ring rib 102, thereby changing the configuration of the transmedium aircraft's nose, and thus regulating the hydrodynamic force and hydrodynamic torque experienced by the aircraft during water entry, such as... Figure 6As shown in the figure, the upper movable semi-ring rib 110 is at a rotation angle of 0°, with an angle of 75° to the central axis, while the lower movable semi-ring rib 111 is at its maximum rotation angle, with an angle of 115° to the central axis. The maximum rotational stroke of the movable semi-ring rib is shown in the figure. δ max It is 40°.

[0058] In this embodiment, the flexible skin 2 further includes a substrate 201 and an alloy wire 202, such as Figure 7 As shown. The substrate 201 is a shape memory polymer, and the alloy wire 202 is a superelastic serpentine alloy wire. The substrate 201 reduces stiffness after heating and can be deformed by the movable semi-ring ribs. After the temperature drops to room temperature, it can restore its original stiffness and be used to withstand water impact loads. The variable stiffness of the substrate 201 allows the flexible skin 2 to meet both deformation and load-bearing requirements. The alloy wire 202 is embedded in the substrate 201 in two layers, with the alloy wires 202 in each layer arranged at equal intervals and in the same direction. The arrangement directions of the two layers of alloy wires 202 are perpendicular to each other. The alloy wire 202 serves to enhance the toughness and tear resistance of the substrate 201 and to heat the substrate 201 before deformation. The surface of the flexible skin 2 is covered with a wettability-intelligent responsive coating. Its surface wettability can be transformed into a superhydrophilic state under ultraviolet irradiation and can be restored to a superhydrophobic state after heating, realizing that the surface wettability of the upper and lower halves of the flexible skin 2 can be changed independently under the stimulation of ultraviolet light and temperature. The wettability-responsive coating covering the surface of the flexible skin 2 is a titanium dioxide particle coating grafted with perfluorodecyltriethoxysilane.

[0059] In this embodiment, the operating method of the dynamically adjustable surface wettability transmedium aircraft variant nose cone is as follows.

[0060] The aforementioned dynamically adjustable surface wettability trans-medium vehicle variant nose cone is mounted on the head of the trans-medium vehicle, such as... Figure 8 As shown. When the transmedium vehicle is stored in the bomb bay, an ultraviolet irradiation device 3 is placed in front of the variant's nose cone, as shown. Figure 9 As shown. During the pre-launch preparation of the transmedium vehicle, the ultraviolet irradiation device 3 can irradiate the surfaces of the upper half 4 and the lower half 5 of the variant nose cone as needed, and after the transmedium vehicle is launched from the cabin, the ultraviolet irradiation device 3 can detach and separate from the transmedium vehicle.

[0061] After the transmedium vehicle is transported and loaded onto a specific launch platform, the configuration and surface wettability layout of the nose cone of the aforementioned dynamically adjustable transmedium vehicle variant are determined based on the specific launch method, launch parameters, and requirements for water entry unloading and motion stabilization. Specifically, this includes the rotation angle of the movable semi-ring rib and the surface wettability of the upper half 4 and lower half 5 of the nose cone.

[0062] Step 1: See Figure 10 During airdrop deployment, the cross-medium vehicle enters the water at high speed with an attitude angle of 60° to 90°. The high entry velocity generates a significant impact load, necessitating load reduction upon entry. However, the angle of inclination of the fuselage relative to the vertical direction during entry is relatively small, resulting in a smaller asymmetric hydrodynamic moment and eliminating the need for motion stabilization. Under these conditions, the described cross-medium vehicle variant nose cone with dynamically adjustable surface wettability should adopt a configuration with a smooth transition between the top cover 101 and the ring rib, and with the upper half 4 and lower half 5 being symmetrical. Furthermore, both the upper half 4 and lower half 5 should have a superhydrophobic surface wettability layout. The symmetrical configuration and surface wettability layout improve the symmetry of the entry cavitation, thereby reducing the hydrodynamic moment that causes attitude deflection and instability. The smooth transition configuration avoids abrupt changes in cross-sectional area, thus reducing the entry impact load. The superhydrophobic surface wettability layout increases the entry cavitation, further reducing the entry impact load. Therefore, both the upper half 4 and the lower half 5 of the head cone should have superhydrophobic surface wettability. Based on this, the rotation angle of the movable semi-ring rib is determined according to the following formula to achieve the minimum water impact load and the lowest structural load.

[0063]

[0064] Step Two: See Figure 11During shipboard launch, the transmedium vehicle enters the water at a low speed with an attitude angle of 30° to 60°. The impact load upon entry is relatively small, and there is no need for load reduction upon entry. However, the fuselage tilts at a large angle relative to the plumb line during entry, and cavitation typically occurs on the upper side of the vehicle while it does not usually occur on the lower side. Therefore, the cavitation upon entry exhibits significant asymmetry, resulting in a large asymmetric hydrodynamic moment during entry and necessitating motion stabilization. Under these conditions, the upper half 4 of the nose cone of the aforementioned transmedium vehicle variant with dynamically adjustable surface wettability should adopt a configuration with a smooth transition between the top cover 101 and the ring rib and a superhydrophilic surface wettability layout, while the lower half 5 should adopt a configuration with a non-smooth transition between the top cover 101 and the ring rib and a superhydrophobic surface wettability layout. The smooth transition configuration and superhydrophilic surface wettability of the upper part (4) induce the free liquid surface to adhere to the aircraft surface, reducing water entry cavitation on the upper side of the aircraft. Conversely, the non-smooth transition configuration and superhydrophobic surface wettability of the lower part (5) induce the free liquid surface to separate from the aircraft surface, increasing water entry cavitation on the lower side of the aircraft. This improves the symmetry of the water entry cavitation and reduces the hydrodynamic torque that causes attitude deflection and instability. Figure 11 As shown. Therefore, the upper half 4 and lower half 5 of the nose cone should adopt superhydrophilic and superhydrophobic surface wettability, respectively. Based on this, the rotation angle of the movable semi-ring rib is determined according to the following formula to achieve the minimum hydrodynamic impulse moment and the minimum attitude and trajectory deflection of the aircraft.

[0065]

[0066] After determining the rotation angles of the upper movable semi-ring rib 110 and the lower movable semi-ring rib 111, as well as the surface wettability of the upper half 4 and the lower half 5 of the head cone, the alloy wire 202 embedded in the flexible skin 2 is energized and heated. As the temperature of the flexible skin 2 increases, its stiffness decreases. The telescopic longitudinal ribs push the movable semi-ring ribs to rotate, driving the connecting rod longitudinal ribs to move, thus deforming the upper and lower halves of the flexible skin 2 respectively. Once the upper movable semi-ring rib 110 and the lower movable semi-ring rib 111 have rotated to the predetermined angle and driven the flexible skin 2 to deform into the predetermined configuration, the telescopic longitudinal ribs, the movable semi-ring ribs, and the connecting rod longitudinal ribs maintain support for the flexible skin 2. The energization of the alloy wire 202 embedded in the flexible skin 2 is stopped. After the temperature of the flexible skin 2 drops to room temperature, it recovers its original stiffness and is capable of withstanding water impact loads. Since the flexible skin 2 has undergone one heating process, the surface wettability of its upper and lower halves has changed to a superhydrophobic state. At this time, the ultraviolet irradiation device 3 irradiates the outer surfaces of the upper and lower halves of the flexible skin 2 with ultraviolet light as needed, thereby further transforming the surface wettability of the upper and lower halves of the flexible skin 2 to a predetermined state. Thus, the configuration and surface wettability of the nose cone of the dynamically adjustable cross-medium aircraft have been adjusted according to the specific launch method, launch parameters, and requirements for water entry load reduction and motion stabilization, and the cross-medium aircraft enters the launch standby state.

[0067] When launching and deploying a cross-medium aircraft, the ultraviolet irradiation device 3 automatically detaches and separates from the aircraft after it exits the cabin. When entering the water, the aircraft can utilize the influence of its nose configuration and surface wettability on the evolution of water cavitation to change the hydrodynamic force and hydrodynamic torque it experiences during water entry, thereby reducing the impact load as needed and improving attitude and trajectory stability. This achieves the goal of being compatible with multiple launch platforms and ensuring water entry efficiency and safety.

[0068] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is used to explain the present invention. It is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A trans-medium aircraft variant nose cone with dynamically adjustable surface wettability, characterized in that: The aircraft's variant nose cone includes a variant skeleton and flexible skin; The flexible skin covers the outside of the variant skeleton to maintain the hydrodynamic shape and watertightness of the entire head cone; The variant skeleton is used to support the flexible skin and withstand the hydrodynamic loads transmitted by the flexible skin; Under heating conditions, the variant skeleton can drive the flexible skin to deform. After returning to normal temperature, the flexible skin retains the deformed state, thereby changing the curvature distribution and cross-sectional characteristics of the nose cone configuration, thereby regulating the hydrodynamic force and hydrodynamic torque experienced by the aircraft during water entry. The variant skeleton includes a top cover, ring ribs, longitudinal ribs, movable semi-ring ribs, connecting rod longitudinal ribs, and telescopic longitudinal ribs; The top cover and the ring ribs are placed along the central axis of the entire head cone, and are connected and fixed together as a whole by the longitudinal ribs in sequence; The movable semi-ring ribs are hinged to the longitudinal ribs in two groups, and are connected to the ring ribs through telescopic longitudinal ribs and to the top cover through connecting rod longitudinal ribs. Driven by the telescopic movement of the telescopic longitudinal rib, the movable semi-ring rib can rotate and drive the connecting rod longitudinal rib to move, thereby driving the upper and lower halves of the flexible skin to deform and changing the curvature distribution and cross-sectional characteristics of the configuration between the top cover and the ring rib.

2. The surface wettability dynamically adjustable transmedium aircraft variant nose cone according to claim 1, characterized in that: The flexible skin includes a substrate and alloy wires; The alloy wire is embedded inside the substrate, which serves two purposes: firstly, to enhance the substrate's toughness and tear resistance, and secondly, to heat the substrate before it is induced to deform. The substrate's stiffness decreases after heating, and it deforms by being driven by the movable semi-circular ribs. After the temperature drops to room temperature, it recovers its original stiffness and can withstand the impact load of water immersion.

3. The surface wettability dynamically adjustable transmedium aircraft variant nose cone according to claim 1, characterized in that: The ring ribs include a first ring rib, a second ring rib, a third ring rib, and a fourth ring rib; The longitudinal ribs include a left longitudinal rib, a right longitudinal rib, an upper longitudinal rib, and a lower longitudinal rib; The movable semi-ring rib includes an upper movable semi-ring rib and a lower movable semi-ring rib; The telescopic longitudinal rib includes an upper telescopic longitudinal rib and a lower telescopic longitudinal rib; The connecting rod longitudinal rib includes an upper connecting rod longitudinal rib and a lower connecting rod longitudinal rib; The top cover, first ring rib, second ring rib, third ring rib and fourth ring rib are placed along the central axis of the entire head cone, and are connected and fixed as a whole by the left longitudinal rib and the right longitudinal rib; The first ring rib, the second ring rib, the third ring rib and the fourth ring rib are further connected from the upper side and the lower side by the upper longitudinal rib and the lower longitudinal rib, respectively; The upper movable semi-ring rib is located between the top cover and the first ring rib, and is hinged to the left longitudinal rib and the right longitudinal rib; The lower movable semi-ring rib is located between the top cover and the first ring rib, and is hinged to the left longitudinal rib and the right longitudinal rib, with the hinge point being the same as that of the upper movable semi-ring rib. The two ends of the upper telescopic longitudinal rib are respectively hinged to the upper movable semi-circular rib and the first circular rib; The two ends of the lower telescopic longitudinal rib are respectively hinged to the lower movable semi-circular rib and the first circular rib; The inner surface of the top cover has a sliding groove; One end of the upper connecting rod longitudinal rib is hinged to the upper movable semi-ring rib, and the pin at the other end is engaged with the sliding groove of the top cover to achieve sliding within the sliding groove; One end of the lower connecting rod longitudinal rib is hinged to the lower movable semi-ring rib, and the pin at the other end is engaged with the sliding groove of the top cover to achieve sliding within the sliding groove; Driven by the telescopic movements of the upper and lower telescopic longitudinal ribs, the upper and lower movable semi-ring ribs can rotate respectively, thereby driving the upper and lower connecting rod longitudinal ribs to move. The movement of the upper telescopic longitudinal rib, upper movable semi-ring rib, upper connecting rod longitudinal rib, lower telescopic longitudinal rib, lower movable semi-ring rib, and lower connecting rod longitudinal rib changes the shape of the upper and lower flexible skin of the variant skeleton, thereby changing the curvature distribution and cross-sectional characteristics of the configuration between the top cover and the first ring rib, thus changing the configuration of the transmedium aircraft head, thereby regulating the hydrodynamic force and hydrodynamic torque experienced by the aircraft during water entry.

4. The surface wettability dynamically adjustable transmedium aircraft variant nose cone according to claim 2, characterized in that: The substrate is a shape memory polymer; The alloy wire is a super-elastic serpentine alloy wire; The alloy wires are embedded in the substrate in two layers. The alloy wires in each layer are arranged at equal intervals in the same direction, and the arrangement directions of the two layers of alloy wires are perpendicular to each other.

5. The surface wettability dynamically adjustable transmedium aircraft variant nose cone according to claim 3, characterized in that: The method for adjusting the configuration of the aircraft's nose based on specific water entry conditions, thereby controlling the hydrodynamic forces and torques experienced by the aircraft during water entry, is as follows: During airdrop deployment, the rotation angle of the movable semi-ring rib is determined according to the following formula to minimize the water impact load and the structural load: In the formula, δ u The angle at which the upper movable semi-circular rib rotates forward. δ l The angle at which the lower movable semi-circular rib rotates forward; When launching from the ship's side, the rotation angle of the movable semi-ring rib is determined according to the following formula to minimize the hydrodynamic impulse, the aircraft attitude, and the trajectory deflection: In the formula, δ u The angle at which the upper movable semi-circular rib rotates forward. δ l The angle at which the lower movable semi-circular rib rotates forward. δ max This represents the maximum rotational stroke of the movable semi-circular rib.

6. The surface wettability dynamically adjustable transmedium aircraft variant nose cone according to claim 1, characterized in that: The flexible skin surface is covered with a wettability-responsive smart coating. Before the launch and deployment of the cross-medium aircraft, an ultraviolet irradiation device is placed in front of the nose cone of the aircraft variant. The surface wettability of the intelligent response coating changes to a superhydrophilic state after being irradiated with ultraviolet light, and then returns to a superhydrophobic state after being heated, so that the surface wettability of the upper and lower halves of the flexible skin can be changed independently under the excitation of ultraviolet light and temperature.

7. The nose cone of a transmedium vehicle with dynamically adjustable surface wettability according to claim 6, characterized in that: The wettability smart response coating is a titanium dioxide particle coating grafted with perfluorodecyltriethoxysilane.

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