Composite sandwich structure with electromagnetic damage tolerance and preparation method thereof

Abstract

The invention discloses a composite material sandwich structure with electromagnetic damage tolerance and a preparation method thereof, and the preparation method comprises the steps: preparing a 3D printing wire material containing a dielectric absorbent, a 3D printing wire material containing a first magnetic absorbent and a 3D printing wire material containing a second magnetic absorbent, designing a conduction-dissipation type skeleton unit, and building a 3D printing unit model. The model is composed of a conduction-dissipation type framework unit, a first magnetic loss layer, a second magnetic loss layer and a third magnetic loss layer, the first magnetic loss layer, the second magnetic loss layer and the third magnetic loss layer are distributed outside the framework unit from top to bottom, a sandwich structure core layer is obtained through 3D printing, an upper panel, the sandwich structure core layer and a lower panel are cemented and cured, and the composite sandwich structure is obtained. According to the composite material sandwich structure, the excellent electromagnetic wave absorption performance is achieved for the first time when the structural damage ratio is smaller than 40% in the wide frequency band of 2-18 GHz, and the composite material sandwich structure is of great importance for improving the maintainability of a low detectable aircraft and the survivability of the low detectable aircraft in a complex electromagnetic environment.

Description

Technical Field

[0001] The present invention belongs to the field of aviation equipment design and manufacturing, and specifically relates to a composite material sandwich structure with electromagnetic damage tolerance and a preparation method thereof. Background Art

[0002] Absorbing composite sandwich structures are widely used in low-observable aircraft skins, and have excellent load-bearing and stealth characteristics to ensure the survivability of aircraft in complex electromagnetic environments. Under actual service conditions, low-speed or high-speed impact damage caused by bird strikes, lightning strikes, stratospheric ice particle impacts, and impacts of objects such as stones during aircraft landing leads to three typical damage modes in absorbing composite sandwich structures: panel damage, core material damage, and penetrating damage. Near the damaged area, radar waves will produce complex reflection and scattering behaviors, which are easily identified by radar, reducing the survivability of detectable aircraft in complex electromagnetic environments. Therefore, it is crucial to propose a scalable preparation method for composite sandwich structures with both excellent electromagnetic wave absorption performance and electromagnetic damage tolerance to improve the maintainability of aircraft and their survivability in complex electromagnetic environments.

[0003] In response to the above-mentioned practical problems of collaborative design of wave absorption performance and electromagnetic damage tolerance, in a publicly published academic paper, Xing Suli's research group at the National University of Defense Technology proposed a gradient absorption-penetration-absorption stacking design strategy for the laminated structure of wave-absorbing composite materials, which achieved effective absorption of electromagnetic wave energy when the perforation damage ratio is less than 20% in the 6-18GHz frequency band (Compos Commun 2024;46:101838). The research group proposed a multi-resonance peak distributed construction design strategy for wave-absorbing honeycomb sandwich structures, which achieved effective absorption of electromagnetic wave energy when the perforation damage ratio is less than 18% in the 4-18GHz frequency band (Compos Struct 2023;325:117581). The current problems are: 1) The current design concepts or design schemes are based on engineering experience, a large number of simulations or speculations, which limit the design space of electromagnetic damage tolerance and lack a scalable structural design concept to guide industrial production; 2) At the research object level, only two widely used mature structures, laminated structures and honeycomb structures, are considered. The regulatory effect of structural unit design on electromagnetic response cannot be fully exerted, and it is difficult to achieve the best match between absorption performance and damage tolerance; 3) At the level of achieving performance indicators, excellent broadband (2-18GHz) electromagnetic damage tolerance (damage ratio <40% and electromagnetic wave absorption performance can be effectively maintained) has not been achieved. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a broadband, structural damage-resistant composite sandwich structure with electromagnetic damage tolerance and a preparation method thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0006] A method for preparing a composite sandwich structure with electromagnetic damage tolerance comprises the following steps: S1. Prepare 3D printing filaments: mix, granulate and draw a dielectric absorbent filler with a first resin to obtain a 3D printing filament containing a dielectric absorbent, so that the electromagnetic resonance of the 3D printing filament containing a dielectric absorbent covers a frequency band of 4 GHz to 8 GHz; mix, granulate and draw a first magnetic absorbent filler with a second resin to obtain a 3D printing filament containing a first magnetic absorbent, so that the electromagnetic resonance of the 3D printing filament containing the first magnetic absorbent covers a frequency band of 8 GHz to 18 GHz; mix, granulate and draw a second magnetic absorbent filler with a third resin to obtain a 3D printing filament containing a second magnetic absorbent, so that the electromagnetic resonance of the 3D printing filament containing the second magnetic absorbent covers a frequency band of 2 GHz to 4 GHz; S2. Design of conductive-dissipative skeleton unit: Design of conductive-dissipative skeleton unit by the following formula (I): (I) in, l The value of is 8mm~15mm, and the value of c is 0.35~0.7; l Represents the projection size of the skeleton unit in the x, y, and z directions, and is also the thickness of the core layer. c The duty cycle of the skeleton unit is determined and controlled between 20% and 40%.

[0007] S3. Prepare the core layer of the sandwich structure: prepare a multi-bin 3D printing device, add the 3D printing filament containing the dielectric absorbent, the 3D printing filament containing the first magnetic absorbent, the 3D printing filament containing the second magnetic absorbent, and the 3D printing filament containing the first magnetic absorbent into different silos respectively, and establish a 3D printing unit model. The 3D printing unit model is composed of the conductive-dissipative skeleton unit and the first magnetic loss layer, the second magnetic loss layer, and the third magnetic loss layer distributed from top to bottom outside the conductive-dissipative skeleton unit, and uses three-dimensional modeling. The software arrays the 3D printing unit models to form a sandwich structure core layer model for 3D printing, wherein the conductive-dissipative skeleton unit corresponds to the bin of the 3D printing filament containing the dielectric absorbent, the first magnetic loss layer corresponds to one of the bins of the 3D printing filament containing the first magnetic absorbent, the second magnetic loss layer corresponds to the bin of the 3D printing filament containing the second magnetic absorbent, and the third magnetic loss layer corresponds to another bin of the 3D printing filament containing the first magnetic absorbent. After the 3D printing is completed, the sandwich structure core layer is obtained; S4. Prepare a composite sandwich structure: use a resin-based composite plate containing glass fiber as an upper panel, and a resin-based composite plate containing a second magnetic absorber as a lower panel, the electromagnetic resonance of the resin-based composite plate containing the second magnetic absorber covers a frequency band of 2 GHz to 4 GHz, and glue and cure the upper panel, the sandwich structure core layer, and the lower panel to obtain a composite sandwich structure with electromagnetic damage tolerance.

[0008] In the above-mentioned method for preparing a composite sandwich structure with electromagnetic damage tolerance, preferably, in step S1, the mass of the dielectric absorbent filler is 7% to 20% of the total mass of the dielectric absorbent filler and the first resin, the mass of the first magnetic absorbent filler is 30% to 45% of the total mass of the first magnetic absorbent filler and the second resin, and the mass of the second magnetic absorbent filler is 50% to 60% of the total mass of the second magnetic absorbent filler and the third resin.

[0009] In the above-mentioned method for preparing a composite sandwich structure with electromagnetic damage tolerance, preferably, in step S3, the thickness of the first magnetic loss layer is 3mm to 5mm, the thickness of the second magnetic loss layer is 2mm to 4mm, and the thickness of the third magnetic loss layer is 2mm to 3mm.

[0010] The above-mentioned method for preparing a composite sandwich structure with electromagnetic damage tolerance, preferably, in step S1, the dielectric absorbent filler includes one or more of chopped carbon fiber, carbon nanotube, graphene and carbon black, the average length of the chopped carbon fiber is 0.5mm-1.5mm, the outer diameter of the carbon nanotube is 40nm-60nm, the particle size of the graphene is 40nm-60nm, and the particle size of the carbon black is 40nm-60nm; the first resin includes one or more of polyamide resin, polylactic acid resin and polyethylene terephthalate; the first magnetic The absorbent filler includes one or more of carbonyl iron, ferrite, iron-cobalt alloy and iron-nickel alloy, the particle size of the first magnetic absorbent filler is 10μm~50μm, and the second resin includes one or more of polyamide resin, polylactic acid resin and polyethylene terephthalate; the second magnetic absorbent filler includes one or more of carbonyl iron, ferrite, iron-cobalt alloy and iron-nickel alloy, the particle size of the second magnetic absorbent filler is 10μm~50μm, and the third resin includes one or more of polyamide resin, polylactic acid resin and polyethylene terephthalate.

[0011] In the above-mentioned method for preparing a composite sandwich structure with electromagnetic damage tolerance, preferably, in step S4, in the resin-based composite material plate containing glass fiber, the volume fraction of the glass fiber is 35% to 45%, and the resin includes one or more of epoxy resin, polyamide resin, polylactic acid resin and polyethylene terephthalate; in the resin-based composite material plate containing the second magnetic absorber, the mass fraction of the second magnetic absorber is 50% to 60%, and the resin includes one or more of polyamide resin, polylactic acid resin and polyethylene terephthalate.

[0012] In the above-mentioned method for preparing a composite sandwich structure with electromagnetic damage tolerance, preferably, in step S4, the thickness of the upper panel is 1 mm to 1.5 mm, and the thickness of the lower panel is 1 mm to 2 mm.

[0013] In the above-mentioned method for preparing a composite sandwich structure with electromagnetic damage tolerance, preferably, in step S4, the bonding is implemented using epoxy resin E51 film, the curing temperature is 80°C to 120°C, the pressure during the curing process is controlled at 0.1MPa to 0.15MPa, and the curing time is 1h to 2h.

[0014] As a general technical concept, the present invention also provides a composite material sandwich structure with electromagnetic damage tolerance obtained by the preparation method of the composite material sandwich structure with electromagnetic damage tolerance.

[0015] In the present invention, the conductive-dissipative skeleton unit refers to a type of skeleton structure with a continuous conductive air cavity in the structural unit. The skeleton unit is composed of a waveguide air cavity penetrating in six directions and a skeleton dielectric dissipative layer (dielectric dissipative layer + magnetic dissipative layer). The conductive air cavity plays a role in manipulating the propagation path of electromagnetic waves, and the absorber in the skeleton unit loses electromagnetic wave energy.

[0016] Compared with the prior art, the advantages of the present invention are: Compared with the electromagnetic damage tolerance design concept for traditional structures, this invention focuses on the novel and unique control characteristics of the periodic structural unit (i.e., 3D printed unit model) design on the electromagnetic response behavior and its effect on improving the electromagnetic damage tolerance, and then proposes a "conduction-dissipation" structural unit design scheme to effectively "manipulate" the transmission behavior of electromagnetic waves, and for the first time achieves excellent electromagnetic wave absorption performance when the structural damage ratio is less than 40% in the 2-18GHz wide frequency band. This research is crucial to improving the maintainability of low-observable aircraft and their survivability in complex electromagnetic environments.

[0017] The present invention selects three absorbing materials that can generate electromagnetic resonance in different frequency bands, and arranges them in a refined space to achieve broadband effective absorption in the 2-18 GHz frequency band with a reflectivity of less than -10dB.

[0018] The present invention constructs a magnetic loss layer with different filler contents on the periphery of the dielectric lossy skeleton to form a rich magnetic / dielectric heterogeneous interface, and further uses the conductive dissipative skeleton unit to manipulate the transmission of electromagnetic waves along the magnetic / dielectric heterogeneous interface, so that the electromagnetic wave absorption performance under different damage modes can still be effectively maintained when the damage ratio reaches 40%.

[0019] The composite sandwich structure with electromagnetic damage tolerance of the present invention utilizes 3D printed conductive-dissipative structural units to achieve fine-grained control of the electromagnetic wave transmission path, thereby effectively manipulating the transmission behavior of the electromagnetic wave. The complex curved surface structure is more conducive to increasing the transmission path of the electromagnetic wave and producing a stronger loss effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of a composite sandwich structure with electromagnetic damage tolerance in Example 1 of the present invention.

[0021] Figure 2 3D view and cross-sectional view of the array unit including the upper panel and the lower panel in Example 1 of the present invention.

[0022] Figure 3 Graph (a) of the reflectivity of the composite sandwich structure with electromagnetic damage tolerance in Example 1 of the present invention when it is undamaged and graph (b) of the reflectivity of different damage types when the structural damage accounts for 40%.

[0023] Figure 4 The conductive-dissipative structure design concept of the array unit in Example 1 of the present invention (a) and the manipulation effect of the conductive-dissipative structure on electromagnetic waves (b) are shown.

[0024] Legend: 1. Sandwich structure core layer; 2. Upper panel; 3. Lower panel; 4. Conductive-dissipative skeleton unit; 5. First magnetic loss layer; 6. Second magnetic loss layer; 7. Third magnetic loss layer; 8. Air cavity. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available, wherein the multi-bin 3D printing device uses iBridger i341, and the 3D modeling software uses Catia or Abaqus, but is not limited thereto.

[0026] Example 1 A method for preparing a composite sandwich structure with electromagnetic damage tolerance of the present invention comprises the following steps: S1. Preparation of 3D printing filaments: mixing, granulating and drawing a dielectric absorbent filler with a first resin to obtain a 3D printing filament containing a dielectric absorbent, so that the electromagnetic resonance of the 3D printing filament containing a dielectric absorbent covers a frequency band of 4 GHz to 8 GHz; mixing, granulating and drawing a first magnetic absorbent filler with a second resin to obtain a 3D printing filament containing a first magnetic absorbent, so that the electromagnetic resonance of the 3D printing filament containing the first magnetic absorbent covers a frequency band of 8 GHz to 18 GHz; mixing, granulating and drawing a second magnetic absorbent filler with a third resin to obtain a 3D printing filament containing a second magnetic absorbent, so that the electromagnetic resonance of the 3D printing filament containing the second magnetic absorbent covers a frequency band of 2 GHz to 4 GHz. z band; wherein, the dielectric absorbent filler is chopped carbon fiber, the average length of the chopped carbon fiber is 1.2mm, the first resin is polyamide resin (nylon), the mass of the dielectric absorbent filler is 10% of the total mass of the dielectric absorbent filler and the first resin, the first magnetic absorbent filler is carbonyl iron, the particle size of carbonyl iron is 40μm, the second resin is polyamide resin, the mass of the first magnetic absorbent filler accounts for 40% of the total mass of the first magnetic absorbent filler and the second resin, the second magnetic absorbent filler is carbonyl iron, the particle size of carbonyl iron is 40μm, the third resin is polyamide resin, and the mass of the second magnetic absorbent filler accounts for 60% of the total mass of the second magnetic absorbent filler and the third resin. In this embodiment, the diameters of the three 3D printing filaments are all 1.75mm, but are not limited to this.

[0027] S2. Design of conductive-dissipative skeleton unit 4: Design of conductive-dissipative skeleton unit 4 is performed by the following formula (I). (I) in, l The value of is 10mm, the value of c is 0.52, and the volume proportion of the skeleton is 30%.

[0028] S3, prepare sandwich structure core layer 1: prepare multi-bin 3D printing equipment, in this embodiment, there are specifically 4 bins, add 3D printing filaments containing dielectric absorbent, 3D printing filaments containing first magnetic absorbent, 3D printing filaments containing second magnetic absorbent, and 3D printing filaments containing first magnetic absorbent into the 4 bins respectively, and establish a 3D printing unit model (i.e., array unit), which is composed of the conductive-dissipative skeleton unit 4 designed as above and the first magnetic loss layer 5, the second magnetic loss layer 6, and the third magnetic loss layer 7 distributed from top to bottom on the periphery of the conductive-dissipative skeleton unit 4, as shown in FIG. Figure 2 As shown in the diagram ( Figure 2In the schematic diagram, there is an upper panel 2 and a lower panel 3, a conductive-dissipative skeleton unit 4 is provided with a connected air cavity 8, a first magnetic loss layer 5 is 3.7 mm thick, a second magnetic loss layer 6 is 2.7 mm thick, and a third magnetic loss layer 7 is 2.4 mm thick. In this embodiment, the three sides of the 3D printed unit model are surrounded by a cubic structure (the length and width are both 10 mm). The 3D printed unit model is arrayed using a 3D modeling software. In this embodiment, the 3D printed unit models are arranged in an array to obtain a sandwich structure core layer model. The length × width × thickness of the sandwich structure core layer model is 3 00mm×300mm×10mm, and then 3D printing is performed, the printer nozzle diameter is 0.3mm, the printer nozzle moving speed is 90mm / s, the conductive-dissipative skeleton unit 4 corresponds to the silo of the 3D printing filament containing the dielectric absorbent, the first magnetic loss layer 5 corresponds to one of the silos of the 3D printing filament containing the first magnetic absorbent, the second magnetic loss layer 6 corresponds to the silo of the 3D printing filament containing the second magnetic absorbent, and the third magnetic loss layer 7 corresponds to another silo of the 3D printing filament containing the first magnetic absorbent. After 3D printing is completed, the sandwich structure core layer 1 is obtained.

[0029] S4. Prepare a composite sandwich structure: use a resin-based composite material plate containing glass fiber as the upper panel 2, and a resin-based composite material plate containing a second magnetic absorber as the lower panel. The electromagnetic resonance of the resin-based composite material plate containing the second magnetic absorber covers the frequency band of 2GHz to 4GHz. The upper panel 2, the sandwich structure core layer 1, and the lower panel 3 are sequentially bonded using epoxy resin E51 film. The adhesive is cured at 90°C for 1.5h. During the curing process, the pressure is controlled at 0.1MPa to obtain a composite sandwich structure with electromagnetic damage tolerance. The structure is shown in the figure. Figure 1 As shown. The volume fraction of glass fiber in the upper panel 2 is 40%, the resin in the upper panel 2 is epoxy resin, the thickness of the upper panel 2 is 1 mm, and the upper panel 2 (resin-based composite material plate containing glass fiber) can be prepared by a vacuum bag-autoclave curing process; the mass fraction of the second magnetic absorbent in the lower panel 3 is 60%, the resin in the lower panel 3 is polyamide resin, and the thickness of the lower panel 3 is 1.6 mm.

[0030] In this embodiment, the dielectric absorbent filler can also be selected from one or more of carbon nanotubes, graphene and carbon black, the outer diameter of the carbon nanotubes is 40nm~60nm, the particle size of the graphene is 40nm~60nm, and the particle size of the carbon black is 40nm~60nm. The first magnetic absorbent filler can also be selected from one or more of ferrite, iron-cobalt alloy and iron-nickel alloy. The second magnetic absorbent filler can also be selected from one or more of ferrite, iron-cobalt alloy and iron-nickel alloy. The first resin, the second resin and the third resin can also be selected from polylactic acid resin, polyethylene terephthalate, etc.

[0031] Wave absorption performance and electromagnetic damage tolerance verification: The composite sandwich structure with electromagnetic damage tolerance prepared in this embodiment is subjected to an electromagnetic reflectivity test in the 2-18GHz frequency band according to GJB-2038A to verify the electromagnetic wave absorption performance. Subsequently, a square damage unit with a size of 30mm×30mm is defined according to the actual structural damage size (such as lightning strike), and different structural damage modes (panel damage, core material damage, perforation damage) and damage proportions are processed in the damage unit using the water cutting method for reflectivity testing. The wave absorption performance of the undamaged composite sandwich structure and the damaged composite sandwich structure is compared to verify the electromagnetic damage tolerance.

[0032] Depend on Figure 3 It can be seen that when the damage ratio is less than 40%, the electromagnetic wave absorption performance can be effectively maintained, which proves the effectiveness of the electromagnetic damage tolerance design concept of the present invention. Figure 3 The measured reflectivity-frequency variation curve of the undamaged sandwich structure in (a) and the simulation curve have basically the same variation trend. Figure 3 In (b), when the damage ratio is 40%, the electromagnetic wave absorption performance under different damage modes can be effectively maintained, wherein the reflectivity-frequency curve is <-10dB in the 3-18 GHz frequency band, and the electromagnetic wave absorption performance can be effectively maintained when the damage ratio is <40% in the 2-18 GHz frequency band, indicating that the composite sandwich structure with electromagnetic damage tolerance of the present invention has excellent electromagnetic damage tolerance.

[0033] Figure 4 The design concept of designing the array unit into a conductive-dissipative structure in this embodiment is demonstrated. Figure 4 As shown in (a) (with the lower panel), the air cavity 8 (i.e., the waveguide air cavity) connected in the conductive-dissipative skeleton unit 4 forms a waveguide channel, which makes the incident electromagnetic wave reflect and scatter along the direction of multiple open cavities, which is also Figure 4 The current density in (b) proves that the current flows along the surface of the cavity structure to form a loop cavity, thereby achieving precise control of the electromagnetic response. At the same time, the dielectric dissipative layer and the magnetic dissipative layer fully absorb the reflected and scattered electromagnetic wave energy, achieving the optimal synergy of excellent electromagnetic wave absorption performance and electromagnetic damage tolerance.

[0034] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a composite sandwich structure with electromagnetic damage tolerance, characterized in that: The following steps are involved: S1. Prepare 3D printing filaments: mix, granulate and draw a dielectric absorbent filler with a first resin to obtain a 3D printing filament containing a dielectric absorbent, so that the electromagnetic resonance of the 3D printing filament containing a dielectric absorbent covers a frequency band of 4 GHz to 8 GHz; mix, granulate and draw a first magnetic absorbent filler with a second resin to obtain a 3D printing filament containing a first magnetic absorbent, so that the electromagnetic resonance of the 3D printing filament containing the first magnetic absorbent covers a frequency band of 8 GHz to 18 GHz; mix, granulate and draw a second magnetic absorbent filler with a third resin to obtain a 3D printing filament containing a second magnetic absorbent, so that the electromagnetic resonance of the 3D printing filament containing the second magnetic absorbent covers a frequency band of 2 GHz to 4 GHz; S2. Designing a conductive-dissipative skeleton unit (4): Designing a conductive-dissipative skeleton unit (4) by the following formula (I): （Ⅰ） in, l The value of is 8mm~15mm, and the value of c is 0.35~0.7; S3, preparing the core layer of the sandwich structure (1): preparing a multi-bin 3D printing device, adding the 3D printing filament containing the dielectric absorbent, the 3D printing filament containing the first magnetic absorbent, the 3D printing filament containing the second magnetic absorbent, and the 3D printing filament containing the first magnetic absorbent into different bins respectively, and establishing a 3D printing unit model, wherein the 3D printing unit model is composed of the conductive-dissipative skeleton unit (4) and the first magnetic loss layer (5), the second magnetic loss layer (6), and the third magnetic loss layer (7) distributed from top to bottom outside the conductive-dissipative skeleton unit (4), using a three-dimensional The modeling software arrays the 3D printing unit models to form a sandwich structure core layer model for 3D printing, wherein the conductive-dissipative skeleton unit (4) corresponds to the bin of the 3D printing filament containing the dielectric absorbent, the first magnetic loss layer (5) corresponds to one of the bins of the 3D printing filament containing the first magnetic absorbent, the second magnetic loss layer (6) corresponds to the bin of the 3D printing filament containing the second magnetic absorbent, and the third magnetic loss layer (7) corresponds to another bin of the 3D printing filament containing the first magnetic absorbent. After the 3D printing is completed, the sandwich structure core layer (1) is obtained; S4. Prepare a composite sandwich structure: use a glass fiber-containing resin-based composite plate as an upper panel (2), and use a second magnetic absorber-containing resin-based composite plate as a lower panel (3), wherein the electromagnetic resonance of the second magnetic absorber-containing resin-based composite plate covers a frequency band of 2 GHz to 4 GHz, and bond and cure the upper panel (2), the sandwich structure core layer (1), and the lower panel (3) to obtain a composite sandwich structure with electromagnetic damage tolerance.

2. The method for preparing a composite sandwich structure with electromagnetic damage tolerance according to claim 1, characterized in that: In step S1, the mass of the dielectric absorbent filler is 7% to 20% of the total mass of the dielectric absorbent filler and the first resin, the mass of the first magnetic absorbent filler is 30% to 45% of the total mass of the first magnetic absorbent filler and the second resin, and the mass of the second magnetic absorbent filler is 50% to 60% of the total mass of the second magnetic absorbent filler and the third resin.

3. The method for preparing a composite sandwich structure with electromagnetic damage tolerance according to claim 1, characterized in that: In step S3, the thickness of the first magnetic loss layer (5) is 3 mm to 5 mm, the thickness of the second magnetic loss layer (6) is 2 mm to 4 mm, and the thickness of the third magnetic loss layer (7) is 2 mm to 3 mm.

4. The method for preparing a composite sandwich structure with electromagnetic damage tolerance according to any one of claims 1 to 3, characterized in that: In step S1, the dielectric absorbent filler includes one or more of chopped carbon fiber, carbon nanotube, graphene and carbon black, the average length of the chopped carbon fiber is 0.5mm-1.5mm, the outer diameter of the carbon nanotube is 40nm-60nm, the particle size of the graphene is 40nm-60nm, and the particle size of the carbon black is 40nm-60nm; the first resin includes one or more of polyamide resin, polylactic acid resin and polyethylene terephthalate; the first magnetic absorbent filler includes carbonyl iron, ferrite, One or more of iron-cobalt alloy and iron-nickel alloy, the particle size of the first magnetic absorbent filler is 10μm~50μm, and the second resin includes one or more of polyamide resin, polylactic acid resin and polyethylene terephthalate; the second magnetic absorbent filler includes one or more of carbonyl iron, ferrite, iron-cobalt alloy and iron-nickel alloy, the particle size of the second magnetic absorbent filler is 10μm~50μm, and the third resin includes one or more of polyamide resin, polylactic acid resin and polyethylene terephthalate.

5. The method for preparing a composite sandwich structure with electromagnetic damage tolerance according to any one of claims 1 to 3, characterized in that: In step S4, in the resin-based composite material plate containing glass fiber, the volume fraction of the glass fiber is 35% to 45%, and the resin includes one or more of epoxy resin, polyamide resin, polylactic acid resin and polyethylene terephthalate; in the resin-based composite material plate containing the second magnetic absorber, the mass fraction of the second magnetic absorber is 50% to 60%, and the resin includes one or more of polyamide resin, polylactic acid resin and polyethylene terephthalate.

6. The method for preparing a composite sandwich structure with electromagnetic damage tolerance according to any one of claims 1 to 3, characterized in that: In step S4, the thickness of the upper panel (2) is 1 mm to 1.5 mm, and the thickness of the lower panel (3) is 1 mm to 2 mm.

7. The method for preparing a composite sandwich structure with electromagnetic damage tolerance according to any one of claims 1 to 3, characterized in that: In step S4, the bonding is implemented by using epoxy resin E51 film, the curing temperature is 80° C. to 120° C., the pressure during the curing process is controlled at 0.1 MPa to 0.15 MPa, and the curing time is 1 h to 2 h.

8. A composite material sandwich structure with electromagnetic damage tolerance obtained by the method for preparing a composite material sandwich structure with electromagnetic damage tolerance according to any one of claims 1 to 7.

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