Flying bird anti-collision device with foamed aluminum sandwich energy absorption structure

Abstract

The invention relates to the technical field of aerospace structure safety, and discloses a flying bird anti-collision device with a foamed aluminum sandwich energy-absorbing structure, the flying bird anti-collision device comprises an assembly frame and an outer frame as the device, the corners of the outer side of the assembly frame are provided with assembly cylinders, and the assembly frame is assembled in the head of an aircraft through the assembly cylinders; the front panel is arranged on the inner side of the assembly frame and is used for bearing a first collision impact; the buffering assembly is arranged on the inner side of the assembling frame and used for buffering the first impact; the sandwich board is arranged on the inner side of the assembly frame and used for bearing the buffered impact; and the rear panel is arranged on the inner side of the assembly frame and is used for bearing the impact which is buffered twice. Through ordered hierarchical arrangement of the front panel, the buffer assembly, the foamed aluminum sandwich panel and the rear panel, a synergistic energy absorption system and a multi-structure synergistic gradient protection mechanism are constructed, impact is decomposed into a plurality of controllable energy dissipation stages, and efficient management and dissipation of impact energy are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aerospace structure safety, in particular to a flying bird anti-collision device with a foam aluminum sandwich energy-absorbing structure. BACKGROUND

[0002] During the flight process, especially during the take-off and landing stages, aircrafts often face the risk of high-speed collision with flying birds and other foreign objects. Such collisions can pose a serious threat to critical parts of the aircraft, such as the nose radar cover, engines, and wing leading edges, resulting in structural damage or even catastrophic accidents. Most of the time, the collisions occur at the nose of the aircraft, so it is necessary to integrate efficient impact-resistant structures at the nose of the aircraft to ensure flight safety.

[0003] Currently, the mainstream anti-bird collision design for aircrafts usually uses high-strength metal materials, fiber-reinforced composite materials, or sandwich structures containing energy-absorbing core layers. For example, some solutions use the plastic deformation of metal materials such as aluminum alloys to absorb energy, while other solutions use materials such as foam aluminum as the sandwich layer to dissipate kinetic energy through the crushing process under impact. However, these existing technologies have inherent limitations in their protection mechanisms. They mainly rely on irreversible damage processes such as plastic deformation, fracture, or crushing of the materials themselves to absorb energy. This protection method results in permanent damage to the structural integrity of the device after it has been subjected to an effective impact, and the device cannot recover its original performance.

[0004] This irreversible damage mode directly leads to high maintenance costs and long aircraft downtime. After each collision event, a complex damage assessment of the protective structure is required, and often large-scale repairs or even complete replacement are necessary, which not only has high economic costs but also seriously affects the aircraft's service rate. In addition, the mechanical properties of traditional protective materials are fixed, and their protective response is passive, unable to adaptively adjust according to the strength of the impact energy, and under extreme impact, the brittle fracture or fragmentation of the material produces secondary debris, posing a new threat to the precision equipment that needs to be protected behind. Therefore, the present application provides a flying bird anti-collision device with a foam aluminum sandwich energy-absorbing structure to solve the problems existing in the prior art. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a flying bird anti-collision device with a foam aluminum sandwich energy-absorbing structure, which solves the problems raised in the background art.

[0006] To achieve the above purpose, the present application realizes the following technical scheme: a flying bird anti-collision device with a foam aluminum sandwich energy-absorbing structure, comprising: An assembly frame is provided as an external frame of the device, and assembly cylinders are arranged at the external corners of the assembly frame, and the assembly frame is assembled in the interior of the head of the airplane through the assembly cylinders; A front panel is arranged in the interior of the assembly frame and used for bearing the first impact; A buffer assembly is arranged in the interior of the assembly frame and used for buffering the first impact; A sandwich panel is arranged in the interior of the assembly frame and used for bearing the buffered impact; A rear panel is arranged in the interior of the assembly frame and used for bearing the impact after being buffered twice; The front panel, the buffer assembly, the sandwich panel and the rear panel are arranged in the interior of the assembly frame in sequence from front to back.

[0007] Preferably, the external side of the front panel is embedded in the interior of the assembly frame, the front panel is made of aluminum alloy material, and a part of impact kinetic energy is absorbed through local plastic deformation, petal-shaped tearing or crushing process, and the concentrated impact load is dispersed to the buffer assembly.

[0008] Preferably, the buffer assembly comprises a plurality of hexagonal plates, the left and right sides of the hexagonal plate are fixedly connected with connecting blocks, and the hexagonal plates are symmetrically arranged with the hexagonal plate as the center, the top and the bottom of the hexagonal plate are rotatably connected with connecting columns, the connecting columns pass through the connecting blocks on different sides of another two adjacent hexagonal plates at the same time, and the three hexagonal plates are combined, and the external sides of two hexagonal plates are hingedly connected with the interior of the assembly frame.

[0009] Preferably, the middle interlayer of the sandwich panel is made of foamed aluminum, and the foamed aluminum is dynamically compacted under high-speed impact, and is used for absorbing the impact force of the collision.

[0010] Preferably, the rear panel is made of composite material, and the energy generated by high-speed impact is converted into heat energy at the bearing point of the rear panel, and is used for absorbing the last kinetic energy of the impact.

[0011] Preferably, four clamping grooves are arranged on the external side of the assembly frame, two embedded plates are fixedly connected to the external side of the front panel, at least two mounting holes are arranged in the interior of the embedded plate, the external side of the embedded plate is clamped in the interior of the clamping groove, and the embedded plate and the assembly frame are connected through the mounting holes by the stud.

[0012] Preferably, the other side of the assembly frame is fixedly connected with a ring-shaped limiting plate, one side of the ring-shaped limiting plate is attached to the external side of the rear panel, and the rear panel is packaged.

[0013] A panel preparation process of a flying bird anti-collision device with a foamed aluminum sandwich energy absorption structure, the rear panel is made of the following raw materials by weight parts: Polyvinyl alcohol: 10-18 parts; Sodium alginate: 2-4 parts; Nano-silica: 3-7 parts; Poly (N-isopropyl acrylamide): 1-3 parts; Glycerol: 2-5 parts; Borax: 3-6% of the weight of polyvinyl alcohol; Calcium chloride: 5-15% of the weight of sodium alginate; Deionized water: 100 parts.

[0014] Preferably, the alcoholysis degree of the polyvinyl alcohol is 98.0-99.8 mol%, and the average polymerization degree is 1700-2000; The primary particle size of the nano-silica is 15-40 nm, and the specific surface area is 180-260 m 2 / g; The weight average molecular weight of the poly (N-isopropyl acrylamide) is 25,000-45,000 g / mol, and the eutectic dissolution temperature of its aqueous solution is 35-45℃.

[0015] Preferably, the following steps are included: Step 1, preparation of shear thickening suspension: mix glycerol, nano-silica and deionized water, and form a uniform suspension by ultrasonic treatment; Step 2, preparation of multifunctional composite precursor solution: add poly (N-isopropyl acrylamide), polyvinyl alcohol and sodium alginate to the suspension obtained in step 1, heat and stir at 90-95℃ for 3-5 hours to obtain a composite precursor solution; Step 3, primary physical crosslinking and molding: pour the solution obtained in step 2 into a mold, add 3-6% of the mass of polyvinyl alcohol borax aqueous solution and stir, and stand for 1-2 hours to form a gel; Step 4, secondary ionic crosslinking and strengthening: soak the gel obtained in step 3 in a 3%-8% (w / v) calcium chloride aqueous solution for 3-7 hours; Step 5, dehydration shaping and product preparation: control the dehydration of the gel obtained in step 4 at 38-48℃ and relative humidity of 55%-75% for 24-48 hours until the final water content reaches 25-45wt%, to obtain a backplane.

[0016] The present application provides a flying bird anti-collision device with a foam aluminum sandwich energy absorption structure. It has the following advantages: 1. The application builds a synergistic energy absorption system through the orderly hierarchical arrangement of the front panel, the buffer assembly, the foam aluminum sandwich panel and the rear panel. The initial concentrated high-speed impact load is converted into non-concentrated load with larger action area and lower peak stress through the plastic deformation of the front panel and the mechanical dispersion of the buffer assembly, then acts on the foam aluminum sandwich panel, further prolongs the action time and absorbs the main energy, and finally transfers to the residual energy of the rear panel. The gradient protection mechanism of multiple structures cooperates to decompose the impact into multiple controllable energy dissipation stages, realizing efficient management and dissipation of impact energy.

[0017] 2. The foam aluminum sandwich panel in the device plays a key role in impact energy absorption and load regulation. The large number of uniformly distributed cell structures inside the panel collapse layer by layer under high-speed impact. This process is carried out under a relatively stable platform stress, converting a large amount of impact kinetic energy into plastic deformation energy of the panel itself. The dynamic compaction process greatly prolongs the action time of the impact pulse, significantly reduces the peak load transferred to the rear panel, provides favorable conditions for intelligent response of the rear panel, and effectively prevents instantaneous failure of the entire structure due to overload.

[0018] 3. The application provides the final protection for the entire anti-collision device by using the response rear panel. The rear panel integrates the shear thickening, impact thermal phase change and dynamic network energy dissipation triple synergistic mechanisms, which can adaptively and instantaneously increase the stiffness and efficiently absorb energy according to the residual impact strength transferred, ensuring the penetration resistance under extreme working conditions. The dynamic reversible chemical bonds give the material the characteristics of damage self-repairing, making the device have the potential of functional recovery after non-penetrating impact, improving the damage tolerance and maintainability of the structure. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a perspective view of the application; Figure 2 is a structural schematic view of the assembly frame of the application; Figure 3 is a structural schematic view of the buffer assembly of the application; Figure 4 is Figure 3 is an enlarged view of position A in FIG. 6; Figure 5 is a structural schematic view of the ring-shaped limiting plate of the application; Figure 6 is a structural schematic view of the assembly cylinder of the application; Figure 7 is a preparation process flow chart of the rear panel of the application.

[0020] Wherein, 1, assembly frame; 2, front panel; 3, buffer assembly; 301, hexagonal plate; 302, connecting block; 303, connecting column; 4, sandwich panel; 5, rear panel; 6, annular limiting plate; 7, assembly cylinder; 8, clamping groove; 9, embedded plate; 10, mounting hole. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0022] Please refer to the accompanying drawings of the present application Figure 1 - the accompanying drawings of the present application Figure 7The embodiment of the present application provides a flying bird anti-collision device with a foam aluminum sandwich energy absorption structure, which comprises: an assembly frame 1 serving as an external frame of the device, assembly cylinders 7 are arranged at the outer corners of the assembly frame 1, and the assembly frame 1 is assembled in the interior of the head of an airplane through the assembly cylinders 7; a front panel 2 arranged on the inner side of the assembly frame 1 and used for bearing a first impact; a buffer assembly 3 arranged on the inner side of the assembly frame 1 and used for buffering the first impact; a sandwich panel 4 arranged on the inner side of the assembly frame 1 and used for bearing the buffered impact; and a rear panel 5 arranged on the inner side of the assembly frame 1 and used for bearing the impact after being buffered twice; the front panel 2, the buffer assembly 3, the sandwich panel 4 and the rear panel 5 are arranged in sequence from front to back on the inner side of the assembly frame 1, the outer side of the front panel 2 is embedded in the inner side of the assembly frame 1, the front panel 2 is made of aluminum alloy material, a part of impact kinetic energy is absorbed through a local plastic deformation, petal-shaped tearing or crushing process, and the concentrated impact load is dispersed onto the buffer assembly 3, the buffer assembly 3 comprises a plurality of hexagonal plates 301, the left side and the right side of each hexagonal plate 301 are fixedly connected with a connecting block 302 and are symmetrically arranged with the hexagonal plate 301 as the center, a connecting column 303 is rotatably connected to the top and the bottom of the hexagonal plate 301, the connecting column 303 simultaneously penetrates through the connecting blocks 302 on different sides of another two adjacent hexagonal plates 301, and the three hexagonal plates 301 are combined, the outer sides of the two hexagonal plates 301 are hingedly connected to the inner side of the assembly frame 1, the middle layer of the sandwich panel 4 is made of foam aluminum, the foam aluminum is dynamically compacted under high-speed impact, and is used for absorbing the impact force of the collision, the rear panel 5 is made of a composite material, energy generated by high-speed impact is converted into heat energy at the bearing point of the rear panel 5, and the heat energy is used for absorbing the last kinetic energy of the impact, four clamping grooves 8 are formed in the outer side of the assembly frame 1, two embedded plates 9 are fixedly connected to the outer side of the front panel 2, at least two mounting holes 10 are formed in the inner side of the embedded plate 9, the outer side of the embedded plate 9 is clamped in the inner side of the clamping groove 8, the embedded plate 9 and the assembly frame 1 are connected through the threaded studs penetrating through the mounting holes 10, and the other side of the assembly frame 1 is fixedly connected with a ring-shaped limiting plate 6, one side of the ring-shaped limiting plate 6 is attached to the outer side of the rear panel 5, and the ring-shaped limiting plate 6 is used for packaging the rear panel 5.

[0023] Specifically, the assembly frame 1 is installed in the interior of the aircraft head through the assembly cylinder 7 on the outside, when colliding with a bird, the impact force will first act on the front panel 2, the front panel 2 is made of high-strength and high-toughness aluminum alloy, which resists the initial penetration of the bird body by using its strength and toughness, and absorbs part of the impact kinetic energy through the process of local plastic deformation, petal-shaped tearing or crushing, and at the same time, the concentrated impact load is dispersed to the buffer assembly 3, a plurality of hexagonal plates 301 are combined into a larger area flexible panel structure through the connecting block 302 and the connecting column 303, which can disperse and buffer the impact force transmitted from the front panel 2, and then transmit to the sandwich panel 4, the dispersed load is transmitted to the foam aluminum core layer, a large number of cell structures in the foam aluminum dynamically compact under high-speed impact, and the cell structures sequentially buckle, yield and collapse layer by layer, this process continues at a relatively stable stress level, and the huge kinetic energy of the bird body is converted into the dissipation energy of the plastic deformation of the foam aluminum, which greatly prolongs the action time of the impact load and significantly reduces the peak load transmitted to the rear panel 5, finally, the high-speed impact wave of the bird body attenuated by the foam aluminum is transmitted to the rear panel 5, the extremely high strain rate triggers the shear thickening effect instantaneously, the dispersed nano-SiO2 particles in the matrix rapidly gather to form a rigid "particle cluster", so that the modulus and stiffness of the material increase by several orders of magnitude in the impact moment, and the flexible plate material is instantaneously changed into a hard shield, effectively resisting the initial penetration of the impact force, the energy generated by high-speed impact is rapidly converted into heat energy at the impact point, causing the local temperature to rise sharply, when the temperature exceeds the preset LCST value, the polymers such as poly (N-isopropyl acrylamide) dissolved in the matrix will undergo instantaneous phase change from the hydrophilic state of dissolving in water to the hydrophobic solid phase of dehydration shrinkage, the phase change process is a strong endothermic process, which absorbs a large amount of impact kinetic energy in the form of heat energy, at the same time, the precipitated solid polymer particles play the role of in-situ reinforcing filler, further improving the local stiffness of the impact point, the residual energy that penetrates the first two defenses will act on the polyvinyl alcohol-boric acid hydrogen bond network and sodium alginate-Ca 2+ The dynamic and reversible chemical bonds can absorb energy by breaking, effectively preventing the material from macroscopic fracture, and after impact, the broken chemical bonds can spontaneously recombine under the action of molecular thermal motion, so that the microcracks generated in the material can be healed, thereby realizing the self-repairing of the structure and avoiding the damage to the aircraft interior caused by the breakage of the rear panel 5.

[0024] The panel preparation process of the bird collision-resistant device with the foam aluminum sandwich energy-absorbing structure provided by the embodiment of the application comprises the following raw materials: Polyvinyl alcohol: alcoholysis degree 98.0-99.8 mol%; average polymerization degree 1700-2000, corresponding to a weight average molecular weight range of 75,000-90,000 g / mol, as the main network skeleton, providing the basic mechanical strength and toughness, and a large number of hydroxyl groups (-OH) on the molecular chain are the reaction sites for forming a dynamic reversible hydrogen bond network with borax, giving the material preliminary self-repairing ability and viscoelasticity; Sodium alginate: food grade or pharmaceutical grade, 1% (w / v) aqueous solution viscosity at 20°C is 150-250 mPa-s, guluronic acid (G) unit content > 65%, as a precursor of ionic crosslinking network, the carboxyl groups (-COO -） Can coordinate chelation with divalent cations (such as Ca 2+ ), forming a stronger and more stable dynamic ionic bond network, significantly improving the macroscopic strength and modulus of the material; Nanosilica: prepared by gas phase method, primary particle size 15-40 nm; specific surface area 180-260 m 2 / g; surface properties are hydrophilic, and after surface silanol group treatment, as a shear thickening functional phase, under high strain rate (i.e. high speed impact), its particles will quickly form "particle clusters" due to the failure of fluid dynamic lubrication, resulting in a sharp increase in system viscosity or modulus, thus instantaneously hardening to resist impact; Poly (N-isopropyl acrylamide): weight average molecular weight 25,000-45,000 g / mol, the low consolute solution temperature (LCST) of its aqueous solution ranges from 35 to 45°C, as an impact heat-induced phase change energy absorption phase, dissolves in water at room temperature, when impact causes local temperature to exceed its LCST, a rapid phase transition from hydrophilic groups to hydrophobic globules occurs, which is a strong endothermic process that can absorb and dissipate part of the impact energy; Borax (sodium tetraborate tetrahydrate, Na2B4O7-10H2O): analytical pure, as a physical crosslinking agent for polyvinyl alcohol; Anhydrous calcium chloride (CaCl 2）： Analytical pure, as an ionic crosslinking agent for sodium alginate; Glycerol (glycerol): analytical pure, as a plasticizer and humectant, to improve the flexibility of the material and lower its glass transition temperature; Deionized water: resistivity > 18 MΩ-cm, as a solvent for all reaction and dispersion processes.

[0025] The preparation of the back panel 5 comprises the following steps: Preparation of shear-thickened suspension: 3.5g glycerol and 100g deionized water were placed in a 250mL beaker and magnetically stirred for 10 minutes. While stirring continuously, 5g nano silica powder was slowly added. The mixture was then transferred to a high-power ultrasonic processor cooled by an ice-water bath and subjected to intermittent ultrasonic treatment, working for 3 seconds and pausing for 2 seconds, for a total ultrasonic time of 60 minutes, until a uniform and stable semi-transparent colloidal suspension was formed. Preparation of multifunctional composite precursor solution: The above suspension was transferred to a 500mL three-necked flask, a mechanical stirrer and a reflux condenser were connected, and the flask was heated to 92°C in an oil bath. After the temperature stabilized, 2g of poly(N-isopropylacrylamide), 12g of sodium alginate and 3g of sodium alginate powder were added slowly in sequence. The mixture was stirred at this temperature for 4 hours until all polymer components were completely dissolved and the solution was clear, viscous and homogeneous. Heating was stopped and the solution was allowed to cool naturally to room temperature with stirring. Initial physical crosslinking and molding: The cooled precursor solution was poured into a pre-cleaned polytetrafluoroethylene flat mold. A 4% (w / v) borax aqueous solution was prepared. Using a syringe pump, 12 mL of borax aqueous solution, corresponding to 4% of the mass of polyvinyl alcohol, was slowly added dropwise to the solution in the mold at a flow rate of 0.5 mL / min. After the addition was completed, the mixture was slowly stirred in the mold for 8 minutes, and then allowed to stand for 1.5 hours to allow the gel to fully form. Secondary ionic crosslinking and reinforcement: Prepare a 5% (w / v) calcium chloride aqueous solution, and slowly immerse the mold with the initial gel in the above calcium chloride aqueous solution to ensure complete coverage. Static soaking at room temperature for 5 hours. After soaking, remove the mold and gently rinse the gel surface with deionized water. Dehydration and shaping and finished product preparation: The gel plate was carefully removed from the mold and placed on the Teflon grid. It was then placed in a constant temperature and humidity chamber with a temperature of 45°C and a relative humidity of 65%. Under these conditions, controlled dehydration was carried out for 36 hours. After dehydration, the final water content was measured to ensure that it reached 35wt%±2wt%, which is the solid composite material back panel sample 5.

[0026] Experimental test: Simulating actual bird strike conditions, the composite rear panel was evaluated for its ability to absorb and dissipate high-speed impact energy and its protective effect on the rear structure when used as an aircraft baffle component, and its damage tolerance was verified.

[0027] Experimental equipment and samples: Test system: Horizontal air cannon firing system, equipped with projectile velocity measuring device and high-speed camera; Target support: A rigid fixing device used to securely install multi-layer composite targets and ensure that impact loads can be effectively transferred; Data acquisition: impact force sensor and displacement sensor, connected to high-speed data acquisition system; Projectile: cylindrical gelatin projectile, density 0.98-1.02 g / cm 3 , diameter 30 mm, length 50 mm, mass 35-45 g, used to simulate a bird body; Test target assembly: Front panel 2: 2 mm thick 7075-T6 aluminum alloy plate, size 200 mm x 200 mm; Sandwich panel 4: closed-cell aluminum foam plate, thickness 30 mm, porosity 80%, density 0.27 g / cm 3 , size 200 mm x 200 mm; Rear panel 5: composite rear panel 5 prepared in Example 1, size 200 mm x 200 mm, thickness 5 mm; Assembly method: the front panel 2, sandwich panel 4 and rear panel 5 are combined into a whole target assembly by epoxy resin adhesive, the edge of the target assembly is fixed on a rigid support by bolts, the force sensor is installed at the center position behind the target assembly, and the displacement sensor is installed at the center of the back of the rear panel.

[0028] Experimental procedure: Target assembly and installation: according to the order of front panel 2-sandwich panel 4-rear panel 5, the three-layer structure is combined into one body using epoxy resin adhesive, and cured at room temperature for 24 hours, the cured composite target assembly is firmly installed on the gas gun target support, ensuring that the center of the target plate is aligned with the launch axis of the gas gun; Sensor arrangement and connection: the impact force sensor and displacement sensor are installed at the center of the back of the rear panel, and the connection with the high-speed data acquisition system is ensured to be normal, and the system calibration is completed; Projectile preparation and loading: weigh the gelatin projectile, confirm that it is within the specified range, and load the projectile into the gas gun launch chamber; Impact parameter setting: adjust the gas pressure of the gas gun, set the initial launch speed of the projectile, and use the laser grating velocity measurement system to accurately measure the actual impact speed of the projectile before it leaves the chamber, three groups of impact speeds are set in this experiment, which are 100 m / s, 150 m / s and 200 m / s; Impact test execution: start the gas gun system and launch the projectile to hit the center area of the front panel 2 of the target assembly; Data acquisition: high-speed camera records the entire dynamic process of the projectile hitting the target plate, including projectile fragmentation, target plate deformation and energy absorption, high-speed data acquisition system records the instantaneous data of the force sensor and displacement sensor during the impact process, including the peak impact force transmitted to the rear, the impact load action time and the maximum deformation of the back of the rear panel 5; Damage evaluation: after each impact test, the target assembly was removed, and the macroscopic damage of the back panel 5 was recorded in detail by visual observation and high-precision caliper measurement, including whether there were perforations, whether cracks appeared, crack length, pit depth, and whether material fragments fell off; Repeatability verification: for each impact speed condition, at least three effective experiments were repeated to ensure the reliability of the data.

[0029] Experimental data: Table 1. Simulation bird impact protection performance test results

[0030] The simulation bird impact protection performance test results show that the composite back panel 5 prepared by the application exhibits excellent impact resistance and energy dissipation capability in the multi-layer structure. At a relatively low impact speed of 100 m / s, the back panel only shows slight surface indentation, no macroscopic cracks or structural damage are detected, and the peak force transmitted remains at a low level, benefiting from the fact that the aluminum foam core layer has absorbed most of the initial impact energy, and the viscoelasticity of the back panel 5 and the dynamic key fracture and recombination mechanism further dissipate the residual energy; As the impact speed increases to 150 m / s, the pit depth and the transmitted peak force of the back panel 5 both increase, but in most cases, no penetrating cracks appear, indicating that at a higher strain rate, the shear thickening effect inside the material is activated, instantaneously increasing the local stiffness, effectively resisting further penetration, and the millimeter-level surface cracks that appear locally can theoretically be healed through the material's self-repairing ability, ensuring the functionality of the structure after non-limiting impact; When the impact speed reaches 200 m / s, the back panel 5 forms a deep pit accompanied by multiple radial surface cracks, and no material perforation or fragment shedding occurs in all tests. Under extremely high impact energy, the front panel 2, the buffer assembly 3, and the aluminum foam core layer have completed the main energy absorption task, and the back panel 5 provides instantaneous high stiffness through the shear thickening effect, limiting the penetration of the projectile. At the same time, the local temperature rise induced by the impact triggers the endothermic phase transition of poly(N-isopropylacrylamide), further dissipating a large amount of energy. Finally, the dynamic reversible crosslinking network of the material absorbs a large amount of energy through the fracture and recombination of the keys in the macroscopic deformation, and suppresses catastrophic brittle fracture and perforation, thereby effectively protecting the rear equipment. The transmitted peak force and the maximum back deformation are within a controllable range, proving that the back panel 5 can still maintain its function as the last line of defense under extreme impact, effectively blocking the penetration of the impacting object. Moreover, the device also has a buffer assembly 3 as an intermediate buffer layer that is not included in the experimental test, so the limit bearing of the back panel 5 is better than the experimental results, and therefore the device has excellent bird impact resistance.

Claims

1. A bird collision avoidance device with an aluminum foam sandwich energy-absorbing structure, characterized in that, include: The assembly frame (1) serves as the external frame of the device. Each outer corner of the assembly frame (1) is provided with an assembly tube (7). The assembly frame (1) is assembled into the interior of the aircraft nose through the assembly tube (7). The front panel (2) is located inside the assembly frame (1) and is used to withstand the first impact. The buffer assembly (3) is located inside the assembly frame (1) and is used to buffer the first impact. The sandwich panel (4) is set inside the assembly frame (1) to withstand the impact after buffering; The rear panel (5) is located inside the assembly frame (1) and is used to withstand the impact after being buffered twice. The front panel (2), buffer assembly (3), sandwich panel (4) and rear panel (5) are arranged in sequence from front to back on the inner side of the assembly frame (1).

2. The bird collision prevention device with a foamed aluminum sandwich energy-absorbing structure according to claim 1, characterized in that, The outer side of the front panel (2) is fitted into the inner side of the assembly frame (1). The front panel (2) is made of aluminum alloy. Through local plastic deformation, petal-shaped tearing or breaking process, it absorbs part of the impact kinetic energy and disperses the concentrated impact load to the buffer assembly (3).

3. The bird collision prevention device with a foamed aluminum sandwich energy-absorbing structure according to claim 1, characterized in that, The buffer assembly (3) includes multiple hexagonal plates (301). Connecting blocks (302) are fixedly connected to both the left and right sides of the hexagonal plates (301) and are symmetrically arranged with the hexagonal plates (301) as the center. Connecting columns (303) are rotatably connected to the top and bottom of the hexagonal plates (301). The connecting columns (303) pass through the connecting blocks (302) on different sides of two other adjacent hexagonal plates (301) to combine the three hexagonal plates (301). The outer sides of two hexagonal plates (301) are hinged to the inner side of the assembly frame (1).

4. The bird collision prevention device with a foamed aluminum sandwich energy-absorbing structure according to claim 1, characterized in that, The sandwich panel (4) has an intermediate layer of aluminum foam, which is dynamically compacted under high-speed impact to absorb the impact force of the collision.

5. A bird collision prevention device with a foamed aluminum sandwich energy-absorbing structure according to claim 1, characterized in that, The rear panel (5) is made of composite material. The energy generated by the high-speed impact will be converted into heat energy at the bearing point of the rear panel (5) to absorb the final kinetic energy of the impact.

6. A bird collision prevention device with a foamed aluminum sandwich energy-absorbing structure according to claim 1, characterized in that, The assembly frame (1) has four slots (8) on its outer side. The front panel (2) has two embedded plates (9) fixedly connected to its outer side. The embedded plates (9) have at least two mounting holes (10) through them. The outer side of the embedded plates (9) is engaged with the inner side of the slots (8). The embedded plates (9) and the assembly frame (1) are connected by studs passing through the mounting holes (10).

7. A bird collision prevention device with a foamed aluminum sandwich energy-absorbing structure according to claim 1, characterized in that, An annular limiting plate (6) is fixedly connected to the other side of the assembly frame (1). One side of the annular limiting plate (6) is attached to the outer side of the rear panel (5) to encapsulate the rear panel (5).

8. A panel manufacturing process for a bird impact protection device with a foamed aluminum core energy-absorbing structure, applied to the bird impact protection device with a foamed aluminum core energy-absorbing structure as described in claims 1-7, characterized in that, The rear panel (5) is made of the following raw materials in parts by weight: Polyvinyl alcohol: 10-18 parts; Sodium alginate: 2-4 parts; Nano-silica: 3-7 parts; Poly(N-isopropylacrylamide): 1-3 parts; Glycerin: 2-5 parts; Borax: 3-6% of the weight of polyvinyl alcohol; Calcium chloride: 5-15% of the weight of sodium alginate; Deionized water: 100 parts.

9. The panel manufacturing process of a bird impact protection device with a foamed aluminum sandwich energy-absorbing structure according to claim 8, characterized in that, The polyvinyl alcohol has a degree of alcoholysis of 98.0–99.8 mol% and an average degree of polymerization of 1700–2000. The original particle size of the nano-silica is 15–40 nm, and the specific surface area is 180–260 m². 2 / g; The poly(N-isopropylacrylamide) has a weight-average molecular weight of 25,000 to 45,000 g / mol, and its aqueous solution has a eutectic dissolution temperature of 35 to 45 °C.

10. The panel manufacturing process of a bird impact protection device with a foamed aluminum sandwich energy-absorbing structure according to claim 9, characterized in that, Includes the following steps: Step 1: Preparation of shear-thickening suspension: Glycerol, nano-silica and deionized water are mixed and ultrasonically treated to form a uniform suspension; Step 2: Preparation of multifunctional composite precursor solution: Poly(N-isopropylacrylamide), polyvinyl alcohol and sodium alginate are added to the suspension obtained in step 1, and heated and stirred at 90-95℃ for 3-5 hours to obtain composite precursor solution; Step 3, Initial physical cross-linking and molding: Pour the solution obtained in step 2 into the mold, add 3-6% of the borax aqueous solution by mass of polyvinyl alcohol and stir, let stand for 1-2 hours to form a gel; Step 4, Secondary ionic crosslinking and reinforcement: Immerse the gel obtained in step 3 in a calcium chloride aqueous solution with a concentration of 3% to 8% (w / v) for 3 to 7 hours; Step 5, Dehydration and Finished Product Preparation: The gel obtained in Step 4 is subjected to controlled dehydration at 38-48℃ and 55%-75% relative humidity for 24-48 hours until the final water content reaches 25-45wt%, and the back panel (5) is obtained.

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