A hybrid continuous fiber 3D printed double-diagonal reinforced biomimetic lattice composite structure and a preparation method thereof

Abstract

The application belongs to the technical field of composite materials, and particularly relates to a hybrid continuous fiber 3D printed double-diagonal reinforced bionic lattice composite structure, a tough phase outer frame constraint structure, and a high-strength bearing core structure. The tough phase outer frame constraint structure is a simple cubic lattice configuration and is made of continuous glass fiber reinforced polyamide composite material. The high-strength bearing core structure is a double-diagonal line topology configuration of a deep-sea glass sponge and is made of continuous carbon fiber reinforced polyamide composite material. The application adopts a differentiated material layout strategy of "high toughness of outer frame and high strength of core body", prepares the outer frame constraint structure by using CGF / PA high-toughness composite material, effectively disperses external impact load, delays initial cracking of the structure, reduces the initial peak force of compression, and inhibits local stress concentration and micro-defect expansion on the basis of excellent fracture toughness and deformation adaptation characteristics.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure and its preparation method. Background Technology

[0002] With the increasing demand for lightweight, high-strength, and functionally integrated structural components in aerospace, new energy vehicles, and high-end equipment manufacturing, continuous fiber reinforced thermoplastic composites are gradually becoming core alternative materials to traditional metal structural components due to their advantages such as high specific strength, high specific modulus, corrosion resistance, strong designability, and recyclability. Among them, continuous carbon fiber reinforced polyamide (CCF / PA) and continuous glass fiber reinforced polyamide (CGF / PA) composites possess excellent mechanical properties, thermal stability, and processing adaptability, and are widely used in research and application in the field of continuous fiber 3D printing.

[0003] Continuous fiber 3D printing technology, also known as continuous fiber reinforced fused deposition modeling, enables the integrated manufacturing of complex topological structures without molds and with controllable layer-by-layer processing. This overcomes the limitations of traditional autoclave, molding, and winding processes in fabricating complex hollow lattices and biomimetic irregular structures. Current technology can already achieve composite printing of single continuous fibers (carbon fiber or glass fiber) with thermoplastic matrices, and has seen initial applications in drone structural components, lightweight load-bearing supports, and cushioning and protective components.

[0004] However, existing continuous fiber 3D printed composite structures still have many technical shortcomings: First, existing structures mostly use a single type of fiber for reinforcement, making it difficult to achieve synergistic optimization of high strength and high toughness in the same component. Continuous carbon fiber has excellent load-bearing strength and modulus, but its toughness is poor, its impact deformation resistance is limited, and it is prone to brittle fracture. Glass fiber has excellent toughness and good impact resistance, but its load-bearing strength and stiffness are relatively insufficient. Single fiber materials cannot simultaneously meet the dual requirements of high load-bearing capacity and efficient energy absorption. Second, existing continuous fiber 3D printed structures mostly adopt regular configurations such as traditional honeycomb, square grid, and simple cubic lattice, which have problems such as obvious stress concentration, weak buckling resistance, low energy absorption efficiency, and susceptibility to local collapse, and cannot fully utilize the anisotropic reinforcement effect of continuous fibers. Third, the deep-sea glass sponge skeleton, with its unique topological structure reinforced by double diagonals, exhibits high stiffness, high stability, excellent buckling resistance and energy absorption characteristics, making it a model of biomimetic design for efficient mechanical structures. However, this type of biomimetic configuration has not yet been combined with continuous fiber 3D printing technology and dual-material differentiated reinforcement strategies, and related structural design and integrated fabrication technology are still lacking.

[0005] Furthermore, current research on multi-material 3D printing largely focuses on short-fiber hybrid doping or discontinuous fiber composite systems. The technology for topologically deploying heterogeneous materials at the continuous fiber level is still immature, especially lacking an integrated fabrication scheme for a glass sponge-inspired biomimetic lattice structure using CCF / PA to fabricate a double-diagonal load-bearing core and CGF / PA to fabricate an outer frame constraint structure. Therefore, how to leverage continuous fiber 3D printing technology, combining the high strength of CCF / PA with the high toughness of CGF / PA, and drawing inspiration from the double-diagonal topology of deep-sea glass sponges for structural innovation, to achieve a comprehensive improvement in structural strength, toughness, and lightweight has become a key technical problem urgently needing to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure and its preparation method. By using a coupling strategy of biomimetic topology design and heterogeneous materials, this invention solves the technical problem that existing single continuous fiber and simple topological lattice structures cannot simultaneously achieve high strength load-bearing capacity, high toughness energy absorption and buckling stability, and realizes multi-dimensional mechanical property synergistic optimization of lightweight structures.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure, comprising: A tough phase outer frame constraint structure, wherein the tough phase outer frame constraint structure is a simple cubic lattice configuration and is made of continuous glass fiber reinforced polyamide (CGF / PA) composite material; The high-strength load-bearing core structure is a double-diagonal topological configuration that mimics deep-sea glass sponge and is made of continuous carbon fiber reinforced polyamide (CCF / PA) composite material. The tough outer frame constraint structure and the high-strength load-bearing core structure are interlocked and superimposed in a repeating array. They are integrated by multi-material continuous fiber 3D printing to form a heterogeneous fusion biomimetic lattice composite structure.

[0008] As a hybrid continuous fiber 3D printing double diagonal reinforced biomimetic lattice composite structure of the present invention, preferably, the simple cubic lattice configuration is composed of several cubic units with the same shape and size, the length and width of a single cubic unit are both 15mm, and the unit wall thickness is 1mm; multiple cubic units are arranged in a two-dimensional plane in a single row of four, for a total of four columns to form a two-dimensional lattice array.

[0009] As a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure of the present invention, preferably, the two-dimensional lattice array extends and is formed along a direction perpendicular to the array plane to form a three-dimensional lattice structure with an overall height of 20mm.

[0010] As a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure of the present invention, preferably, the double diagonal topology is composed of multiple sets of offset cross rib units, each set of cross rib units is symmetrically embedded in the internal cavity of the tough outer frame constraint structure, and the two ends of the ribs are integrally connected to the inner wall of the outer frame.

[0011] As a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure of the present invention, preferably, the tough outer frame constraint structure of CGF / PA material is the main force transmission constraint skeleton of the overall biomimetic lattice composite structure, which is used to uniformly distribute external loads, transmit stress step by step, reduce the initial peak force of the structure, constrain the initial deformation of the structure and ensure the integrity of the overall molding.

[0012] As a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure of the present invention, preferably, the high-strength load-bearing core structure of CCF / PA material is the core load-bearing unit of the overall biomimetic lattice composite structure, which is used to suppress internal shear slip and shear band expansion under external load, and improve the buckling stability and continuous load-bearing capacity of the composite lattice structure under high stress.

[0013] As a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure of the present invention, preferably, the tough outer frame constraint structure and the high-strength load-bearing core structure form an interface in situ during the 3D printing process, without subsequent splicing and assembly processes, and the interface between the two is a seamless integrated connection structure.

[0014] As a method for preparing a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to the present invention, the method includes the following steps: S1. Structural Modeling: Construct a biomimetic lattice 3D model containing a simple cubic outer frame and a double diagonal core, and define the printing layer thickness; S2. Path planning: Independent continuous fiber 3D printing paths are planned for the CGF / PA outer frame structure and the CCF / PA core structure, and the same printing layer includes the outer frame contour path and the core rib path. S3. Integrated printing: Using a dual-material continuous fiber fused deposition modeling (FDM) equipment, the core structure and the outer frame structure are formed sequentially within the same printed layer. The two are bonded together in situ within the layer, and after being stacked layer by layer, an integrated biomimetic lattice composite structure is obtained.

[0015] As a method for preparing a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to the present invention, preferably, the equipment in S3 is equipped with two independent continuous fiber conveying and printing nozzles, which respectively convey CGF / PA continuous fiber composite filaments and CCF / PA continuous fiber composite filaments, and the two sets of nozzles alternately complete the printing operation of the same layer according to a preset path.

[0016] As a method for preparing a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to the present invention, preferably, the layer thickness in the printing process of S3 is set to 0.2-0.5 mm, the printing temperature is 240-280℃, the printing platform temperature is 60-100℃, and the fiber filling rate is parametrically adjusted within the range of 30%-60% according to the load-bearing requirements.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention employs a differentiated material layout strategy of "high-toughness outer frame and high-strength core." The outer frame constraint structure is prepared using CGF / PA high-toughness composite material, leveraging its excellent fracture toughness and deformation adaptability to effectively disperse external impact loads, delay initial cracking, reduce initial peak compressive force, and suppress local stress concentration and micro-defect propagation. The internal double-diagonal load-bearing core is prepared using CCF / PA high-strength, high-modulus composite material, utilizing the ultra-high specific modulus, high specific strength, and excellent buckling resistance of carbon fiber to construct an efficient three-dimensional force transmission path. The complementary properties of these two components overcome the limitations of homogeneous performance and prominent mechanical shortcomings of single continuous fiber composite materials, simultaneously achieving the dual functions of high-toughness buffering and high-strength load-bearing in the same component.

[0018] This invention draws inspiration from the double-diagonal reinforced topological features of deep-sea glass sponges, embedding them as the core load-bearing element within a simple cubic frame. Through the mechanical gain effect of the biomimetic topological structure, it effectively restricts structural shear slip and constrains the spread of shear bands, avoiding the defects of traditional simple lattice structures prone to local instability and collapse. This significantly improves the stability and anti-collapse performance of the lattice structure under high strain conditions. Simultaneously, the simple cubic frame, as a continuous constraint skeleton, ensures the overall integrity of the structure's forming and the uniformity of deformation, forming a synergistic "constraint-load-bearing" mechanism with the biomimetic core, achieving stable and controllable structural deformation throughout the entire process.

[0019] This invention achieves integrated molding of heterogeneous structures through multi-material continuous fiber 3D printing technology, eliminating the need for molds and subsequent splicing and assembly processes. The outer frame and core form an interface bond in situ during the printing process, effectively avoiding problems such as interface defects, performance dispersion, and poor assembly accuracy caused by traditional splicing and assembly. It maximizes the integrity of the composite lattice structure, the interface bonding strength, and the stability of mechanical properties, while realizing high-precision, customizable, and efficient fabrication of complex biomimetic heterogeneous structures.

[0020] Compared to traditional 3D-printed lattice composite materials with single continuous fibers and simple topological configurations, this invention achieves simultaneous improvements in structural load-bearing strength, buckling stability, buffer energy absorption characteristics, and deformation uniformity while strictly maintaining the advantages of lightweight structure. It effectively solves the technical problems of excessively high peak stress, severe deformation instability, low energy absorption efficiency, and easy local collapse in traditional lattice structures. It takes into account the comprehensive performance of low initial peak force, high plateau stress, large deformation stable load-bearing capacity, and high specific energy absorption, and can be widely adapted to the application needs of lightweight load-bearing, buffer protection, and impact-resistant structural components in aerospace, new energy vehicles, intelligent equipment and other fields. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of a bi-diagonally reinforced biomimetic lattice composite structure 3D printed with hybrid continuous fibers.

[0022] Figure 2 This is a front view of a bi-diagonally reinforced biomimetic lattice composite structure 3D printed with hybrid continuous fibers.

[0023] Figure 3 The front view of the toughened outer frame constraint structure of the hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure.

[0024] Figure 4 A front view of the high-strength load-bearing core structure of a hybrid continuous fiber 3D-printed double diagonally reinforced biomimetic lattice composite structure.

[0025] Figure 5 This is a physical image of a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure.

[0026] Figure 6 A schematic diagram of the fabrication process for a hybrid continuous fiber 3D printed double diagonally reinforced biomimetic lattice composite structure.

[0027] In the figure: 1. Tough outer frame constraint structure; 2. High-strength load-bearing core structure. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1 This embodiment provides a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure, such as... Figure 1 - Figure 4 As shown, it includes a tough outer frame constraint structure 1 and a high-strength load-bearing core structure 2, which are integrally formed by continuous fiber 3D printing to form a heterogeneous fusion biomimetic lattice composite structure.

[0030] Specifically, the tough outer frame constraint structure 1 is a simple cubic lattice configuration made of continuous glass fiber reinforced polyamide (CGF / PA) composite material. In this embodiment, the simple cubic lattice configuration consists of 16 cubic units with identical shape and size. The length and width of each cubic unit are 15mm, and the unit wall thickness is 1mm. The 16 cubic units are arranged in a single row of four, forming a 4×4 two-dimensional lattice array in a two-dimensional plane. This two-dimensional lattice array extends along a direction perpendicular to the array plane to form a three-dimensional lattice structure with an overall height of 20mm.

[0031] The CGF / PA tough outer frame constraint structure 1 is the main force-transmitting constraint skeleton of the overall biomimetic lattice composite structure. When the structure is under load, it can achieve uniform distribution and step-by-step transmission of load, effectively reduce the initial peak force of the structure, constrain the initial deformation of the whole structure, and at the same time ensure the overall integrity of the structure and deformation stability. With the excellent toughness of glass fiber, it can alleviate impact load and delay the propagation of microcracks.

[0032] The high-strength load-bearing core structure 2 is a double-diagonal topological configuration mimicking deep-sea glass sponge, made of continuous carbon fiber reinforced polyamide (CCF / PA) composite material. In this embodiment, the double-diagonal topological configuration consists of multiple sets of offset intersecting rib units. Each set of intersecting rib units is arranged symmetrically and regularly fitted into each internal cavity of the tough outer frame constraint structure 1. The two ends of the ribs are integrally connected to the inner wall of the outer frame, forming a continuous, uniformly stressed three-dimensional force transmission grid system.

[0033] The high-strength load-bearing core structure 2 made of CCF / PA material is the core load-bearing unit of the overall biomimetic lattice composite structure. Relying on the unique topological mechanical advantages of deep-sea glass sponge, it can construct multi-directional and efficient force transmission paths under external loads, effectively constrain structural shear slip, suppress the continuous expansion of shear bands, avoid the defects of traditional lattice structures that are prone to local instability and collapse, achieve continuous and stable load bearing under high stress and high strain conditions, and significantly improve the overall load-bearing strength and buckling resistance of the structure.

[0034] In this embodiment, the tough outer frame constraint structure 1 and the high-strength load-bearing core structure 2 form an interface in situ during the 3D printing process, without any subsequent splicing and assembly process. The interface between the two is a seamless integrated structure, which effectively avoids the stress concentration and performance degradation problems caused by the assembly interface.

[0035] Example 2 This embodiment provides a method for preparing the above-mentioned hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure, which specifically includes the following steps: S1. Structural Modeling: Based on the load-bearing and lightweight requirements of the target working condition, a biomimetic lattice 3D model containing a simple cubic outer frame and a double diagonal core is constructed using 3D modeling software. Combined with the process parameters of the continuous fiber 3D printing equipment, the 3D model is sliced ​​to divide the printing layer thickness. In this embodiment, the layer thickness is set to 0.3mm.

[0036] S2. Path Planning: Independent continuous fiber 3D printing paths are planned for the CGF / PA outer frame structure and the CCF / PA core structure respectively. The outer frame structure adopts the contour and infill path mode, while the core rib adopts the continuous fiber laying path along the rib direction to ensure that the fiber direction is consistent with the force direction. The same printing layer contains both the outer frame path and the core path, and the docking positions of the two material structures are precisely matched to ensure the interface bonding quality.

[0037] S3, Integrated Printing: Employs a continuous fiber fused deposition modeling (CFDM) system equipped with dual printheads, loading CGF / PA continuous fiber composite filaments and CCF / PA continuous fiber composite filaments respectively. The two printheads correspond to two independent fiber delivery systems. Printing process parameters are set as follows: nozzle temperature 260℃, printing platform temperature 80℃, printing speed 30mm / s, and fiber volume fill rate 45%. After the printing program is started, the equipment completes the printing job layer by layer according to the preset path. Within the same printing layer, two sets of print heads work alternately, first printing the CCF / PA core rib structure, and then printing the CGF / PA outer frame constraint structure. The two materials are bonded in situ at the interface in a molten state. After the layer-by-layer printing is completed, the integrated double diagonal reinforced bionic lattice composite structure is obtained after natural cooling.

[0038] The biomimetic lattice composite structure prepared in this embodiment, as verified by quasi-static compression tests, shows that compared with a simple cubic lattice structure of the same volume and mass, the initial peak force is reduced by 32%, the plateau stress is increased by 27%, the specific energy absorption is increased by 41%, and the deformation process is uniform and stable without local brittle collapse, resulting in a significant improvement in comprehensive mechanical properties.

[0039] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure, characterized in that, include: The tough outer frame constraint structure (1) is a simple cubic lattice configuration and is made of continuous glass fiber reinforced polyamide (CGF / PA) composite material; High-strength load-bearing core structure (2), wherein the high-strength load-bearing core structure (2) is a double diagonal topology configuration that imitates deep-sea glass sponge, and is made of continuous carbon fiber reinforced polyamide (CCF / PA) composite material; The tough outer frame constraint structure (1) and the high-strength load-bearing core structure (2) are interlocked and superimposed in a repeating array. They are integrated by multi-material continuous fiber 3D printing to form a heterogeneous fusion biomimetic lattice composite structure.

2. The hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to claim 1, characterized in that: The simple cubic lattice configuration is composed of several cubic units with the same shape and size. The length and width of each cubic unit are 15mm and the wall thickness is 1mm. Multiple cubic units are arranged in a two-dimensional plane in a single row of four, for a total of four columns, to form a two-dimensional lattice array.

3. The hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to claim 1, characterized in that: The two-dimensional dot array extends in a direction perpendicular to the array plane to form a three-dimensional dot array structure with an overall height of 20mm.

4. The hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to claim 1, characterized in that: The double diagonal topology is composed of multiple sets of offset cross rib units. Each set of cross rib units is symmetrically fitted into the internal cavity of the tough outer frame constraint structure (1), and the two ends of the ribs are integrally connected to the inner wall of the outer frame.

5. The hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to claim 1, characterized in that: The tough outer frame constraint structure (1) of the CGF / PA material is the main force-transmitting constraint skeleton of the overall biomimetic lattice composite structure. It is used to uniformly distribute external loads, transmit stress step by step, reduce the initial peak force of the structure, constrain the initial deformation of the structure and ensure the integrity of the overall forming.

6. The hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to claim 5, characterized in that: The high-strength load-bearing core structure (2) made of CCF / PA material is the core load-bearing unit of the overall biomimetic lattice composite structure. It is used to suppress internal shear slip and shear band expansion under external load, and improve the buckling stability and continuous load-bearing capacity of the composite lattice structure under high stress.

7. The hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to claim 3, characterized in that: The tough outer frame constraint structure (1) and the high-strength load-bearing core structure (2) form an interface in situ during the 3D printing process, without subsequent splicing and assembly processes, and the interface between the two is a seamless integrated connection structure.

8. A method for preparing a hybrid continuous fiber 3D printed bi-diagonally reinforced biomimetic lattice composite structure as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Structural Modeling: Construct a biomimetic lattice 3D model containing a simple cubic outer frame and a double diagonal core, and define the printing layer thickness; S2. Path planning: Independent continuous fiber 3D printing paths are planned for the CGF / PA outer frame structure and the CCF / PA core structure, and the same printing layer includes the outer frame contour path and the core rib path. S3. Integrated printing: Using a dual-material continuous fiber fused deposition modeling (FDM) equipment, the core structure and the outer frame structure are formed sequentially within the same printed layer. The two are bonded together in situ within the layer, and after being stacked layer by layer, an integrated biomimetic lattice composite structure is obtained.

9. The method for preparing a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to claim 8, characterized in that: The device in S3 is equipped with two independent sets of continuous fiber conveying and printing nozzles, which respectively convey CGF / PA continuous fiber composite filament and CCF / PA continuous fiber composite filament. The two sets of nozzles alternately complete the printing operation of the same layer according to the preset path.

10. The method for preparing a hybrid continuous fiber 3D printed double diagonal reinforced biomimetic lattice composite structure according to claim 9, characterized in that: In the S3 process, the layer thickness is set to 0.2-0.5mm, the printing temperature is 240-280℃, the printing platform temperature is 60-100℃, and the fiber filling rate is parameterized within the range of 30%-60% according to the load-bearing requirements.

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