Self-adaptive camouflage and self-repairing bionic 4D printing anti-icing aircraft shell
By using biomimetic 4D printing technology combined with multi-layered polymer structures, the adaptive camouflage, self-repair, and anti-icing functions of the aircraft shell are achieved. This solves the problems of insufficient structural toughness, responsiveness, and environmental adaptability of traditional aircraft shells, and improves the safety and operational efficiency of the aircraft.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-17
- Publication Date
- 2026-03-17
AI Technical Summary
Traditional aircraft shells struggle to balance structural toughness and lightweight design under harsh operating conditions, lack proactive response capabilities, have insufficient environmental adaptability, incur high damage repair costs, and cannot achieve dynamic color changes or de-icing.
It adopts a shell-like mother-of-pearl structure design and combines various polymers to construct a multi-layer composite structure. It utilizes temperature-sensitive PLA and conductive PLA layers to achieve adaptive camouflage, self-repair and anti-icing functions. It achieves dynamic color change, damage repair and de-icing by controlling the conductive network through electrically excited contacts to generate Joule heat.
Improving mechanical properties without increasing thickness enables dynamic color change, self-healing of damage, and active de-icing, while reducing energy consumption and enhancing structural integrity and safety.
Smart Images
Figure CN121671925A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aircraft shell design technology, specifically relating to a biomimetic 4D-printed anti-icing aircraft shell with adaptive camouflage and self-healing properties. Background Technology
[0002] In recent years, the development of aircraft technology has rapidly expanded from the traditional aerospace field to many other areas such as logistics and distribution, emergency rescue, environmental monitoring, and national defense security. Against this backdrop, the aircraft shell, as a core component ensuring flight safety and performance, directly affects the overall reliability, functionality, and service life. With the continuous expansion of application scenarios, the requirements for aircraft shells have surpassed traditional basic functions such as load-bearing and protection, gradually developing towards intelligence and multi-functionality.
[0003] Currently, traditional aircraft shell design and manufacturing face the following challenges: First, under harsh operating conditions, it is difficult to simultaneously meet the requirements of structural toughness, impact resistance, and lightweighting. The shell is prone to cracking and rapid propagation when subjected to localized impacts, potentially leading to catastrophic damage. Second, there is a lack of proactive response capabilities; when the aircraft needs to actively change its exterior color, dynamic color changes cannot be implemented as required. Third, environmental adaptability is insufficient; in extreme environments such as rain and snow, most traditional aircraft require additional de-icing equipment, increasing overall complexity, weight, and energy consumption. Fourth, damage repair costs are high; traditional damage repair processes are cumbersome and costly, reducing the operational efficiency and life-cycle economics of the aircraft.
[0004] 4D printing is a smart manufacturing technology that introduces the time dimension into 3D printing. Its products can dynamically evolve in shape, performance, or function over time under preset external stimuli. Bionics, on the other hand, imitates the behavior of organisms in nature or multi-scale, multi-level configurations to achieve efficient utilization and optimization of materials. 4D printing technology, incorporating bionic principles, can not only replicate the dynamic response characteristics of biological systems but also create biomimetic structures with autonomous response and programmable deformation capabilities, fundamentally driving the technological leap from static pre-setting to dynamic evolution in manufacturing.
[0005] In summary, there is an urgent need in this field for a biomimetic 4D-printed aircraft shell with adaptive camouflage, self-repair, and anti-icing capabilities. Summary of the Invention
[0006] To address the problems existing in the aforementioned technical fields, a biomimetic 4D-printed anti-icing aircraft shell with adaptive camouflage and self-healing is provided. It uses mother-of-pearl as a biomimetic prototype and combines various polymers to achieve a multifunctional integrated design.
[0007] The technical solution of the present invention is as follows:
[0008] An adaptive camouflage and self-healing biomimetic 4D-printed anti-icing aircraft shell, based on the biomimetic mother-of-pearl shell, features a multi-layered composite structure with alternating hard and soft phases, consisting of, from the outside to the inside: thermochromic PLA outer layer 101, conductive PLA outer layer 102, hard phase outer layer I, soft phase intermediate layer, hard phase inner layer II, conductive PLA inner layer 106, and thermochromic PLA inner layer 107.
[0009] The thermochromic PLA outer layer 101, hard phase outer layer I, hard phase inner layer II, and thermochromic PLA inner layer 107 are made of hard polymers;
[0010] The conductive PLA outer layer 102, the soft phase middle layer, and the conductive PLA inner layer 106 are made of soft polymer, and the hard phase and soft phase are alternately arranged to hinder crack propagation.
[0011] The thermochromic PLA outer layer 101, conductive PLA outer layer 102, conductive PLA inner layer 106, and thermochromic PLA inner layer 107 are all made of shape memory polymer and have shape memory effect.
[0012] The outer conductive PLA layer 102 and the inner conductive PLA layer 106 respectively constitute an outer and an inner conductive network. When energized, the conductive network generates Joule heating, which can be used to achieve one or more of the following functions:
[0013] a: The temperature-changing PLA outer layer 101 in the multi-layer composite structure is transmitted to make its temperature reach the temperature-changing threshold to achieve dynamic color change and realize the adaptive camouflage of the aircraft.
[0014] b: Activate the shape memory effect of the shape memory polymer in the multilayer composite structure to achieve stimulated self-repair of damage and microcracks;
[0015] c: Raise the temperature of the multi-layer composite structure above the freezing point to achieve active and continuous electric heating for de-icing.
[0016] The outer layer 101 of the thermochromic PLA is thicker than the inner layer 107 of the thermochromic PLA, and the outer layer 102 of the conductive PLA is thicker than the inner layer 106 of the conductive PLA.
[0017] The inner and outer temperature-sensitive PLA layers can be controlled synchronously to ensure uniform stress and deformation, and structural stability.
[0018] The inner and outer conductive networks can be controlled independently by partitions, and multiple independent electrically excited contacts that can be applied voltage are provided, which can selectively apply electrical excitation to specific areas of the aircraft shell;
[0019] The outermost temperature-sensitive PLA outer layer 101 is a fully enclosed layer without any openings. The electrically excited contacts on the conductive PLA outer layer 102 penetrate inward and are electrically connected to the internal electrical control components. The electrically excited contacts can be electrically connected to the conductive PLA inner layer 106.
[0020] The resistance of the electrically excited conductive network is R, its mass is m, the specific heat capacity of the conductive PLA material is c, the applied DC voltage is U, the energizing time is t, and the damage angle of the damaged area is θ. d The angle after electrical excitation repair is θ r The initial temperature of the aircraft's outer shell is T0, and the temperature after power is applied is T1;
[0021] Then, during the energizing time t, the energy gained by the aircraft shell is:
[0022] ;
[0023] During the energizing time t, the temperature rise of the aircraft's outer shell is:
[0024] ;
[0025] The recovery rate of self-damage repair is:
[0026] ;
[0027] The recovery rate of self-damage repair is:
[0028] ;
[0029] The hard outer layer I and hard inner layer II can be PC layers, and the soft intermediate layer can be a TPU 85A layer. The thickness of the soft intermediate layer is less than the thickness of the hard outer layer I and the hard inner layer II.
[0030] When the aircraft needs to be camouflaged, a first electrical excitation is applied to the inner and outer conductive networks to cause the outer layer 101 of the thermochromic PLA to change color.
[0031] When damage to the outer shell is detected, a second electrical excitation is applied to the inner and outer conductive networks where the damaged area is located, and the damage is repaired by activating the shape memory effect of the shape memory polymer near the damaged area.
[0032] When icing conditions begin or are expected to begin, a third electrical excitation is applied to the inner and outer conductive networks to maintain the surface temperature of the aircraft shell above the freezing point.
[0033] A method for designing and fabricating an adaptive camouflage and self-healing biomimetic 4D-printed anti-icing aircraft shell, characterized by: employing the aforementioned adaptive camouflage and self-healing biomimetic 4D-printed anti-icing aircraft shell, the specific steps of which are as follows:
[0034] Step 1: Material selection and preparation for the aircraft shell
[0035] The thermochromic PLA layer is prepared by mixing thermochromic microcapsules with shape memory PLA particles at a weight ratio of 3% to 5%.
[0036] The conductive PLA layer is prepared by mixing carbon nanotubes with shape memory PLA particles at a weight ratio of 3% to 4%.
[0037] The two materials mentioned above can be prepared by drying, ball milling, and twin-screw extrusion. The PC layer is made of PC particles, and the TPU 85A layer is made of polyurethane elastomer 85A particles.
[0038] Step 2: Establishing a 3D model of the aircraft's outer shell
[0039] Three-dimensional modeling software was used to design the layer thickness and precisely combine the multi-layer composite structure; generative shape design was used to create the curved surface contour.
[0040] Step 3: Slicing and printing the 3D model of the aircraft's outer shell
[0041] Export the completed 3D model to the STL standard format for slicing; adjust printing parameters such as infill density and printing speed; generate Gcode instruction files to drive the printing equipment.
[0042] Step 4: Printing and molding the aircraft shell
[0043] Using multi-material FDM printing technology, four polymer materials are fed into the printer's printhead through four independent feeding channels; the printing process proceeds sequentially according to a preset program to achieve the construction of a multi-layer composite structure.
[0044] This invention provides a biomimetic 4D-printed anti-icing aircraft shell with adaptive camouflage and self-healing capabilities, belonging to the field of aircraft shell design technology. Using mother-of-pearl as a biomimetic prototype, it features a multi-layered composite structure alternating between hard and soft phases. From the outside in, it consists of: a thermochromic PLA outer layer, a conductive PLA outer layer, a hard outer layer I, a soft intermediate layer, a hard inner layer II, a conductive PLA inner layer, and a thermochromic PLA inner layer. The conductive PLA outer and inner layers respectively form outer and inner conductive networks. When energized, these networks generate Joule heat, enabling one or more of the following functions: transferring heat to the thermochromic PLA outer layer in the multi-layered composite structure, raising its temperature to a temperature threshold for dynamic color change, thus achieving adaptive camouflage for the aircraft; activating the shape memory effect of the shape memory polymer in the multi-layered composite structure, achieving self-repair of damage and microcracks; and raising the temperature of the multi-layered composite structure above the freezing point, achieving active and continuous electrothermal de-icing.
[0045] The beneficial effects of this invention compared to the prior art are as follows:
[0046] 1. By designing biomimetic structures and using a variety of polymers, biomimetic structures can improve their mechanical properties without increasing their thickness.
[0047] 2. By using thermochromic material as the outermost layer of a multilayer composite structure, and the adjacent layer being a conductive network made of conductive PLA polymer; by utilizing the Joule heating effect and material properties, the color-changing threshold of the material is reached under specific electrical excitation, thus achieving active response-dynamic color change.
[0048] 3. By introducing shape memory polymers into a multilayer structure, the adjacent conductive network generates a Joule thermal activation shape memory effect under electrical excitation, thereby repairing microcracks caused by collision damage or flight, effectively improving the structural integrity and safety of the aircraft.
[0049] 4. By introducing a double-layer conductive network into the multi-layer composite structure, ice formation on the outer shell can be prevented by electrical excitation when icing conditions begin or are expected to begin.
[0050] 5. By designing multiple electrically excited contacts on the aircraft shell, the conductive network of the inner layer can be controlled in sections, effectively reducing energy consumption. Attached Figure Description
[0051] Figure 1 This is a schematic diagram of the overall structure and installation position of a biomimetic 4D-printed anti-icing aircraft shell with adaptive camouflage and self-healing according to the present invention.
[0052] Figure 2 This is a schematic diagram of the biomimetic multi-layered three-dimensional structure of a biomimetic 4D-printed anti-icing aircraft shell with adaptive camouflage and self-repairing according to the present invention.
[0053] Figure 3 This is a schematic diagram of the three-dimensional structure of the electrically excited contact of a biomimetic 4D-printed anti-icing aircraft shell with adaptive camouflage and self-healing properties, according to the present invention.
[0054] Figure 4 This is a schematic diagram of the three-dimensional cross-sectional structure of the outer shell of a biomimetic 4D-printed anti-icing aircraft shell with adaptive camouflage and self-healing properties according to the present invention.
[0055] Figure 5 This is a schematic diagram of the electrical excitation contact installation distribution of a biomimetic 4D-printed anti-icing aircraft shell with adaptive camouflage and self-healing according to the present invention.
[0056] In the attached diagram
[0057] 101. Temperature-sensitive PLA outer layer; 102. Conductive PLA outer layer; 103. PC outer layer; 104. TPU 85A layer; 105. PC inner layer; 106. Conductive PLA inner layer; 107. Temperature-sensitive PLA inner layer; 108. Electrically excited contact I; 109. Electrically excited contact II; 110. Electrically excited contact III; 111. Electrically excited contact IV; 112. Electrically excited contact V; 113. Electrically excited contact VI; 114. Electrically excited contact VII. Detailed Implementation
[0058] To make the technical solution, objectives and advantages of the present invention clearer, the implementation process of the present invention will be clearly and completely described below in conjunction with specific embodiments.
[0059] Example 1: An adaptive camouflage and self-healing biomimetic 4D-printed anti-icing aircraft shell
[0060] Please see Figure 1-5 An adaptive camouflage and self-healing biomimetic 4D-printed anti-icing aircraft shell, based on mother-of-pearl (with alternating hard and soft phases), has a multi-layered composite structure with seven layers, from the outside to the inside: thermochromic PLA outer layer 101, conductive PLA outer layer 102, PC outer layer 103, TPU 85A layer 104, PC inner layer 105, conductive PLA inner layer 106, and thermochromic PLA inner layer 107.
[0061] The thermochromic PLA outer layer 101, PC outer layer 103, PC inner layer 105, and thermochromic PLA inner layer 107 are made of rigid polymers, simulating a "hard phase" as a load-bearing unit to provide strength and stiffness.
[0062] The conductive PLA outer layer 102, TPU 85A layer 104, and conductive PLA inner layer 106 are made of soft polymers to simulate the energy dissipation of cracks by deflecting them in a "soft phase". The alternation of hard and soft phases causes cracks in the hard phase to stop when they encounter the soft phase, thus avoiding stress concentration and fracture of the structure.
[0063] The thermochromic PLA outer layer 101, conductive PLA outer layer 102, conductive PLA inner layer 106, and thermochromic PLA inner layer 107 are all made of shape memory polymers and have a shape memory effect. When the temperature reaches the glass transition temperature, they automatically recover their initial shape from a temporary deformed state and are used for self-repair of the structure in this invention.
[0064] The outer conductive PLA layer 102 and the inner conductive PLA layer 106 respectively constitute their respective conductive networks. When energized, the conductive networks generate Joule heating, which can be used to achieve one or more of the following functions:
[0065] a: The temperature-changing PLA outer layer 101 in the multi-layer composite structure is transmitted to make its temperature reach the temperature-changing threshold to achieve dynamic color change and realize the adaptive camouflage of the aircraft.
[0066] b: Activate the shape memory effect of the shape memory polymer in the multilayer composite structure to achieve stimulated self-repair of damage and microcracks;
[0067] c: Raise the temperature of the multi-layer composite structure above freezing point to achieve active and continuous electric heating de-icing (conductive network - uniform planar heater).
[0068] In this embodiment, the thickness of each of the seven-layer composite structure from the outside to the inside is: 0.6 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.3 mm, 0.2 mm, and 0.4 mm, with a total thickness of 2.4 mm. That is, the thickness of the outer layer 101 of the thermochromic PLA is greater than that of the inner layer 107 of the thermochromic PLA, and the thickness of the outer layer 102 of the conductive PLA is greater than that of the inner layer 106 of the conductive PLA.
[0069] The design employs temperature-sensitive PLA layers both inside and out (synchronous control): firstly, it fixes the inner layer structure, enhancing the integrity and stability of the overall structure; secondly, it utilizes the internal and external clamping repair mechanism to ensure the uniformity of self-repair. Under specific electrical excitation, the inner and outer shape memory polymer layers work together to provide deformation recovery force, effectively avoiding uneven deformation or stress concentration that may result from unilateral repair.
[0070] The inner and outer conductive networks can be controlled independently by partitions, and multiple independent electrically excited contacts that can be applied with voltage can be set up to selectively apply electrical excitation to specific areas of the aircraft shell, thereby achieving local camouflage, local damage repair and local anti-icing;
[0071] See appendix Figure 3 The outermost thermo-sensitive PLA outer layer 101 is a fully enclosed layer without openings (to ensure aerodynamics). The electrically excited contacts I 108 and II on the conductive PLA outer layer 102 pass inward through the PC outer layer 103, TPU 85A layer 104, PC inner layer 105, conductive PLA inner layer 106 and thermo-sensitive PLA inner layer 107 and are electrically connected to the internal electrical control components. The electrically excited contacts are also connected to the conductive PLA inner layer 106 when they pass from the outside to the inside. That is, the inner and outer conductive networks share electrical contacts.
[0072] In some embodiments, the inner and outer conductive networks may each be provided with their own electrical contacts.
[0073] See appendix Figure 5Only a portion of the electrically excited contacts are shown. Applying voltage simultaneously to electrically excited contacts III 110 and IV 111 can apply electrical excitation to the corner of the aircraft shell between the two contacts; while applying voltage simultaneously to electrically excited contacts VI 113 and VII 114 can apply electrical excitation to the front half of the aircraft shell; in addition, electrically excited contact IV 111 can be paired with electrically excited contacts III 110 and V 112 respectively, thereby stimulating different areas of the conductive network.
[0074] Therefore, when the aircraft needs to be camouflaged, a first electrical excitation is applied to the inner and outer conductive networks to cause the outer layer 101 of the thermochromic PLA to change color.
[0075] When damage to the outer shell is detected, a second electrical excitation is applied to the inner and outer conductive networks where the damaged area is located, and the damage is repaired by activating the shape memory effect of the shape memory polymer near the damaged area.
[0076] When icing conditions begin or are expected to begin, a third electrical excitation is applied to the inner and outer conductive networks to maintain the surface temperature of the aircraft shell above the freezing point.
[0077] Let's take the conductive network in a certain area as an example:
[0078] The conductive network in the inner layer of this region has a resistance of R, a mass of m, a specific heat capacity of c for the conductive PLA material, an applied DC voltage of U, an energizing time of t, and a damage angle of θ in the damaged area. d The angle after electrical excitation repair is θ r The initial temperature of the aircraft's outer shell is T0, and the temperature after power is applied is T1;
[0079] Then, during the energizing time t, the energy gained by the aircraft shell is:
[0080] ;
[0081] During the energizing time t, the temperature rise of the aircraft's outer shell is:
[0082] ;
[0083] The recovery rate of self-damage repair is:
[0084] ;
[0085] The recovery rate of self-damage repair is:
[0086] ;
[0087] In this embodiment, the PC (polycarbonate) used has excellent impact toughness and extremely high dimensional stability, balancing high strength and high hardness; the TPU 85A (thermoplastic polyurethane elastomer 85A) used has high flexibility, high resilience, good mechanical strength, excellent tear resistance and fatigue resistance.
[0088] The specific steps for designing and manufacturing the aircraft's outer shell are as follows:
[0089] Step 1: Material selection and preparation for the aircraft shell
[0090] The thermochromic PLA layer is prepared by mixing thermochromic microcapsules into shape memory PLA particles at a weight ratio of 3% to 5%.
[0091] The conductive PLA layer is prepared by mixing carbon nanotubes into shape memory PLA particles at a weight ratio of 3% to 4%.
[0092] After drying the above material particles to ensure quality stability, the material particles are placed in a ball mill in proportion for thorough mixing to ensure uniform dispersion of each component. Finally, a twin-screw extruder is used to prepare thermochromic PLA material and conductive PLA material.
[0093] In addition, the PC layer is made of PC polycarbonate particles, and the TPU 85A layer is made of polyurethane elastomer 85A particles.
[0094] Step 2: Establishing a 3D model of the aircraft's outer shell
[0095] Using CATIA 3D modeling software, the generative shape design module and the part design module were used in combination; the layer thickness was designed and precisely combined for the multi-layer composite structure; the curved surface contour was drawn in the generative shape design module, and then the 3D model was built in the part design module. Finally, the model details were optimized to complete the model building.
[0096] Step 3: Slicing and printing the 3D model of the aircraft's outer shell
[0097] After the 3D model is built, it is exported to the STL standard format for slicing. Key printing parameters such as infill density, selection of printing materials, and printing speed are adjusted according to the design. Finally, the slicing software generates Gcode instruction files to drive the printing equipment.
[0098] Step 4: Printing and molding the aircraft shell
[0099] Using multi-material FDM printing technology, four kinds of polymers are fed into the printer nozzle through four independent feeding channels; the printing process proceeds sequentially according to a preset program, and the seven-layer composite structure is built layer by layer from the inside out through precise material switching and deposition.
[0100] The specific application methods and scenarios of the multi-functional integration of the aircraft shell are as follows:
[0101] Adaptive camouflage application method: When it is necessary to change the appearance of the aircraft, a first electrical excitation is applied to the inner and outer conductive networks of the target area. The generated Joule heat will be efficiently transferred to the outermost layer of the multilayer composite structure, so that the temperature of the outer layer thermochromic material reaches the color change threshold, thereby actively and quickly adjusting the appearance of the aircraft.
[0102] Adaptive camouflage applications include: military reconnaissance, where aircraft can change their fuselage color in real time according to the external environment to achieve dynamic camouflage and reduce the probability of being observed; and safety indication, where the aircraft can change its shell color during flight to indicate its current status (e.g., green for idle flight, yellow for mission execution, red for emergency), making it easier for ground personnel to identify and record.
[0103] Self-healing application method: After detecting damage to the outer shell, a second electrical excitation is applied to the inner and outer conductive networks where the damaged area is located; the shape memory effect of the shape memory polymer near the damaged area is activated by Joule heating, driving the material to undergo a phase change to restore the initial shape and promote the closure of internal microcracks, thereby realizing the self-healing of the aircraft outer shell;
[0104] Self-healing application scenarios: such as collision damage repair, after a minor collision, the system can repair dents and cracks on the surface through electrical excitation, maintaining aerodynamic shape and structural strength; such as microcrack repair, aircraft are subjected to aerodynamic loads and vibrations during flight, and the outer shell is prone to internal microcracks that are difficult to be detected by the naked eye. The self-healing system can repair microcrack damage before an accident occurs.
[0105] De-icing system application method: When icing conditions begin or are expected to begin, the surface of critical components can be actively and continuously heated by applying a third electrical excitation to the internal and external conductive networks of critical parts; the Joule heating effect is used to keep the temperature above the freezing point, preventing the formation of ice layers, thereby ensuring the normal operation of critical components under harsh conditions and maintaining the aerodynamic design of the shell.
[0106] Examples of de-icing system application scenarios: such as flying in extreme environments, when an aircraft is flying in known icing weather conditions, the anti-icing system can be activated in advance based on the concept of predictive protection; such as high-altitude photography, electrothermal de-icing of the camera part, i.e. the critical part, can effectively prevent ice and snow from covering the camera.
[0107] In summary, this invention provides a biomimetic 4D-printed integrated aircraft shell with adaptive camouflage, self-repair, and anti-icing functions. Based on the high design freedom and complex structure molding capabilities of additive manufacturing technology, the aircraft shell achieves integrated molding of various polymers. Compared to traditional aircraft shells, this invention aims to promote the intelligence and multifunctionality of aircraft shells, providing an innovative solution to the challenges faced by the aircraft industry.
Claims
1. An adaptive camouflage and self-repairing biomimetic 4D printed anti-icing aircraft shell, characterized in that: taking the imitation shell pearl as the biomimetic prototype, a multi-layer composite structure with alternating hard and soft phases is set, from outside to inside in turn: temperature-variable PLA outer layer (101), conductive PLA outer layer (102), hard phase outer layer I, soft phase middle layer, hard phase inner layer II, conductive PLA inner layer (106) and temperature-variable PLA inner layer (107); the temperature-variable PLA outer layer (101), hard phase outer layer I, hard phase inner layer II and temperature-variable PLA inner layer (107) are made of hard polymer; the conductive PLA outer layer (102), soft phase middle layer and conductive PLA inner layer (106) are made of soft polymer, and the alternating hard and soft phases hinder crack propagation; the temperature-variable PLA outer layer (101), conductive PLA outer layer (102), conductive PLA inner layer (106) and temperature-variable PLA inner layer (107) are all made of shape memory polymer and have shape memory effect.
2. The adaptive camouflage and self-repairing biomimetic 4D printed anti-icing aircraft shell according to claim 1, characterized in that: the conductive PLA outer layer (102) and conductive PLA inner layer (106) respectively constitute outer and inner conductive networks, and the conductive networks generate Joule heat when powered on to achieve a, b and / or c functions; a is to transfer to the temperature-variable PLA outer layer (101) in the composite structure to make its temperature reach the temperature-variable threshold to achieve dynamic color change and realize adaptive camouflage of the aircraft; b is to activate the shape memory effect of the shape memory polymer in the composite structure to realize excitation self-repair of damage and micro-cracks; c is to make the temperature of the composite structure itself rise above the freezing point to realize active and continuous electric heating deicing.
3. The adaptive camouflage and self-repairing biomimetic 4D printed anti-icing aircraft shell according to claim 1 or 2, characterized in that: the thickness of the temperature-variable PLA outer layer (101) is greater than that of the temperature-variable PLA inner layer (107), and the thickness of the conductive PLA outer layer (102) is greater than that of the conductive PLA inner layer (106); the inner and outer temperature-variable PLA layers are synchronously controlled to ensure uniform stress and deformation and stable structure.
4. The adaptive camouflage and self-repairing biomimetic 4D printed anti-icing aircraft shell according to claim 3, characterized in that: the inner and outer conductive networks are independently controlled in zones, a plurality of electric excitation contacts for independently applying voltage are provided, and selective electric excitation can be applied to specific areas of the aircraft shell; the outermost temperature-variable PLA outer layer (101) is a fully enclosed layer without openings, the electric excitation contacts on the conductive PLA outer layer (102) are inwardly penetrated and electrically connected with the internal electric control components, and the electric excitation contacts are electrically connected with the conductive PLA inner layer (106) when passing through the conductive PLA inner layer (106).
5. The adaptive camouflage and self-repairing biomimetic 4D printed anti-icing aircraft shell according to claim 4, characterized in that: The resistance of the electrically conductive network applied with the electric excitation is R, the mass is m, the specific heat capacity of the conductive PLA material is c, the applied direct current voltage is U, the electrification time is t, the damage angle of the damaged area is θ d , the angle after the electric excitation repair is θ r , the initial temperature of the aircraft shell is T0, and the temperature after electrification is T1; then in the power-on time t, the energy obtained by the aircraft shell is: ； in the power-on time t, the temperature raised by the aircraft shell is: ； the recovery rate of self-damage repair is: ； The recovery rate from damage repair is: 。 6. The self-adapting and self-repairing bionic 4D printed anti-icing aircraft shell according to claim 5, characterized in that: The hard outer layer I and the hard inner layer II are PC layers, the soft middle layer is a TPU 85A layer, and the thickness of the soft middle layer is less than the thickness of the hard outer layer I and the hard inner layer II.
7. The self-adapting and self-repairing bionic 4D printed anti-icing aircraft shell according to claim 6, characterized in that: When the aircraft needs to be camouflaged, a first electric excitation is applied to the inner and outer conductive networks to change the color of the temperature-variable PLA outer layer (101); When damage to the shell is detected, a second electric excitation is applied to the inner and outer conductive networks in the damaged area to repair the damage by activating the shape memory effect of the shape memory polymer near the damaged area; When icing conditions begin or are expected to begin, a third electric excitation is applied to the inner and outer conductive networks to maintain the surface temperature of the aircraft shell above the freezing point.
8. A method for designing and manufacturing a self-adapting and self-healing biomimetic 4D printed anti-icing aircraft skin, characterized in that: The specific steps of using the self-adapting and self-repairing bionic 4D printed anti-icing aircraft shell according to claim 6 are as follows: Step one: selection and preparation of aircraft shell materials The preparation material of the temperature-variable PLA layer: heat-induced color-changing microcapsules are mixed with shape memory PLA particles at a weight ratio of 3% to 5%; The preparation material of the conductive PLA layer: carbon nanotubes are mixed with shape memory PLA particles at a weight ratio of 3% to 4%; The above two materials are prepared by drying treatment, ball mill mixing, and double-screw extruder, PC particles are selected for the PC layer, and polyurethane elastomer 85A particles are selected for the TPU 85A layer; Step two: establishment of a three-dimensional model of the aircraft shell Using three-dimensional modeling software, the layer thickness of the multi-layer composite structure is designed and accurately combined, and the surface profile of the generative shape design is created. Step three: slicing processing of the three-dimensional model of the aircraft shell The completed three-dimensional model is exported in stl standard format for slicing processing; the printing parameters such as filling density and printing speed are adjusted; Generate Gcode instruction files to drive the operation of the printing equipment; Step four: printing and forming of the aircraft shell Using multi-material FDM printing technology, the four types of high molecular polymers are sent into the printing nozzle of the printer through four independent feeding channels. The printing process is carried out in sequence according to the preset program to realize the construction of the multi-layer composite structure.