Lightweight helical structure integrating load-bearing and thermal protection and laser additive manufacturing method

Abstract

This invention discloses a lightweight helical structure integrating load-bearing and thermal protection, and a laser additive manufacturing method thereof. The lightweight helical structure comprises several bidirectional helical structures; each bidirectional helical structure consists of first and second spatial helical units. The first spatial helical unit extends along a first direction in three-dimensional space, and the second spatial helical unit extends along a second direction in three-dimensional space, with the first and second directions perpendicular to each other. The first spatial helical units are linearly arrayed in the second and third directions, and the second spatial helical units are linearly arrayed in the first and third directions, with the helical rods between adjacent array units connected at spatial intersection nodes to form a three-dimensional network structure; wherein the third direction is perpendicular to both the first and second directions. Therefore, the lightweight helical structure of this invention simultaneously meets the requirements of load-bearing, energy absorption, and thermal protection, and can be integrally formed through laser additive manufacturing.

Description

Technical Field

[0001] This invention relates to a lightweight spiral structure integrating load-bearing and thermal protection and a laser additive manufacturing method, belonging to the technical field of bionics and material structure integration. Background Technology

[0002] Aerodynamic rudders, as key aerodynamic surfaces that generate control torque through deflection, are widely used in various aerospace vehicles, and their performance directly determines the maneuverability, stability, and mission reliability of the aircraft. However, as aircraft move towards hypersonic speeds, aerodynamic rudders face the core challenge of extreme thermo-mechanical coupling, not only having to withstand enormous aerodynamic loads but also coping with extreme high-temperature environments. The superposition of huge loads and high temperatures severely reduces the structural load-bearing efficiency.

[0003] Currently, lightweight lattice structures have attracted attention due to their excellent specific strength and designability, and are considered a potential way to achieve both thermal protection and load-bearing capacity. However, most lattice structures have a single function and cannot meet the requirements of load-bearing capacity and thermal protection at the same time. Some existing solutions adopt a composite strategy of "metal skeleton + functional material filling", such as filling with aerogel to achieve thermal insulation, but there are the following shortcomings: (1) the manufacturing process is complicated and requires two-step or multi-step forming; (2) the reliability of the interface bonding between the filling material and the skeleton is difficult to guarantee; (3) the overall structural weight increases, weakening the advantages of lightweight.

[0004] With the advancement of aerospace technology and materials science, the thermal protection technology of air rudders has continued to develop. The application of advanced manufacturing technologies such as laser additive manufacturing, as well as the design and optimization of biomimetic structures, have provided more possibilities for the design and optimization of air rudder thermal protection structures.

[0005] Existing biomimetic helical structures are mostly limited to two-dimensional layups or single-directional stacking, failing to achieve collaborative design and integrated molding of multi-directional helical rods in three-dimensional space. For example, some existing technologies apply helical structures to composite material layups (fiber direction rotation), but are essentially two-dimensional laminate designs; some existing technologies use simple stacking of helical rods in the same direction, but lack spatial interconnection, making it difficult to form a stable three-dimensional network structure.

[0006] Therefore, there is an urgent need for a lightweight spiral structure that can simultaneously meet the requirements of load-bearing, energy absorption, and thermal protection, and can be integrally formed. Summary of the Invention

[0007] The purpose of this invention is to provide a lightweight spiral structure integrating load-bearing and thermal protection and a laser additive manufacturing method, so as to simultaneously meet the requirements of load-bearing, energy absorption and thermal protection, and to achieve integrated forming.

[0008] To achieve the above-mentioned technical objectives, the present invention will adopt the following technical solution:

[0009] A lightweight spiral structure integrating load-bearing and thermal protection includes several bidirectional spiral structures; each bidirectional spiral structure is composed of two spatial spiral units.

[0010] The two spatial spiral units are referred to as the first spatial spiral unit and the second spatial spiral unit. The first spatial spiral unit extends along a first direction in three-dimensional space, and the second spatial spiral unit extends along a second direction in three-dimensional space. The first direction and the second direction are perpendicular to each other. The starting ends of the first spatial spiral unit and the starting ends of the second spatial spiral unit are fixedly connected.

[0011] Each spatial spiral unit includes four spiral rods, corresponding to the first to fourth spiral rods; in the same spatial spiral unit, each spiral rod extends in a spiral curve, and the projection of the starting end of each spiral rod in its extension direction onto a plane perpendicular to that extension direction forms a polygon; the second and third spiral rods are replicas of the first spiral rod formed by rotating it 180° along its extension direction; the fourth spiral rod is a replica of the first spiral rod translated along the second and third directions; in the same spatial spiral unit, the first to fourth spiral rods are fixedly connected to each other at spatial intersection nodes;

[0012] The first spatial spiral unit is linearly arrayed in the second direction and the third direction, and the second spatial spiral unit is linearly arrayed in the first direction and the third direction. The spiral rods between adjacent array units are connected to each other at spatial intersection nodes to form a three-dimensional network structure. The third direction is perpendicular to the first direction and the second direction, respectively.

[0013] Preferably, the helical rod is a single helical rod or a double helical rod; when the helical rod is a double helical rod, it is formed by connecting two helical rods with different directions of rotation in parallel.

[0014] Preferably, the bidirectional helical structure includes an X-axis helical structure and a Y-axis helical structure, which are connected as one unit at the origin O of the spatial rectangular coordinate system O-XYZ.

[0015] The first, second, and third directions are the X, Y, and Z axes of the spatial rectangular coordinate system O-XYZ, respectively.

[0016] The X-axis spiral structure is the first spatial spiral unit, arranged along the X-axis of the spatial rectangular coordinate system O-XYZ; the Y-axis spiral structure is the second spatial spiral unit, arranged along the Y-axis of the spatial rectangular coordinate system O-XYZ.

[0017] Preferably, the X-direction helical structure includes four helical rods extending along the positive X-axis in the length direction, namely: X1, X2, X3, and X4 helical rods; in the X-direction helical structure, the X2 and X3 helical rods are arranged with the starting rotation angles of the X1 helical rod offset by 180° in the X direction, and the starting rotation angle of the X4 helical rod is the same as that of the X1 helical rod;

[0018] The Y-axis helical structure includes four helical rods, each extending along the positive Y-axis, namely: Y1, Y2, Y3, and Y4 helical rods. In the Y-axis helical structure, the Y2 and Y3 helical rods are arranged with the initial rotation angles of the Y1 helical rod offset by 180° in the Y direction, and the initial rotation angle of the Y4 helical rod is the same as that of the Y1 helical rod.

[0019] Preferably, in the spatial rectangular coordinate system O-XYZ, the starting point of both the X1 and X2 screw rods is the origin O, and the ending point is point O. Furthermore, the X2 helical rods are arranged in the Y direction of the X1 helical rod and are interconnected with the X1 helical rod; the X3 helical rods are arranged in the Z direction of the X1 helical rod and are interconnected with the X1 helical rod, with the starting point of the X3 helical rod being... The destination is The X4 helical rods are arranged on the line connecting the X2 helical rod in the Z direction and the X3 helical rod in the Y direction, and are interconnected with the X2 and X3 helical rods respectively. The starting point of the X4 helical rod is... The destination is ;

[0020] In the spatial rectangular coordinate system O-XYZ, the starting points of both the Y1 and Y2 helical rods are located at the origin O, and the ending points are located at... Furthermore, the Y2 helical rods are arranged in the X direction of the Y1 helical rod and are interconnected with the Y1 helical rod; the Y3 helical rods are arranged in the Z direction of the Y1 helical rod and are interconnected with the Y1 helical rod, with the starting point of the Y3 helical rod located at... The finish line is located at The Y4 helical rods are arranged on the line connecting the Y2 helical rod in the Z direction and the Y3 helical rod in the X direction, and are interconnected with the Y2 and Y3 helical rods respectively. The starting point of the Y4 helical rod is located at... The destination is d is the mean diameter of the screw rod.

[0021] Preferably, in the bidirectional helical structure, when the screw is a single helical rod, each helical rod included in the X-direction helical structure is a left-handed helix, and each helical rod included in the Y-direction helical structure is a right-handed helix.

[0022] Preferably, the screw has a mean diameter of 2mm, a pitch of 6mm, and a period of 4.

[0023] Preferably, the helical rod is a rod structure with a circular cross-section and a diameter of 0.6 mm.

[0024] Another technical objective of this invention is to provide a laser additive manufacturing method for a lightweight helical structure integrating load-bearing and thermal protection, comprising the following steps:

[0025] Step S1: Establish a three-dimensional model of the integrated load-bearing and thermal protection lightweight spiral structure;

[0026] Step S2: Slice the three-dimensional model into layers to obtain cross-sectional contour data;

[0027] Step S3: Import the cross-sectional contour data into the laser additive manufacturing equipment, and use laser powder bed melting technology to melt nickel-based superalloy HX powder layer by layer to integrally form the load-bearing and thermal protection integrated lightweight spiral structure; the process parameters of the laser powder bed melting process are: laser energy density 190J / mm². 3 Up to 205J / mm 3 Laser power 160W-200W, scanning speed 550mm / s-650mm / s.

[0028] Preferably, the laser powder bed melting process employs a unidirectional remelting scanning strategy with an interlayer rotation angle of 67°.

[0029] Based on the above-mentioned technical objectives, the present invention has the following advantages compared with the prior art:

[0030] 1. The lightweight spiral structure integrating load-bearing and thermal protection proposed in this invention, through a simple geometric design (specifically, through the spatial arrangement of multi-directional spiral rods and a 180° offset in the initial rotation angle), forms rigid nodes between the spiral rods to provide strong constraints. During the LPBF forming process, weld points are formed. The rigid nodes formed by the offset allow the structure to work collaboratively as a whole under pressure, resulting in stronger resistance to deformation. The rigid nodes also avoid stress concentration points common in traditional structures, delaying the occurrence of local failures. At the same time, the failure mode under compression changes from layer-by-layer collapse to a more controllable node failure process, improving energy absorption performance.

[0031] 2. The lightweight helical structure integrating load-bearing and thermal protection proposed in this invention exhibits excellent anisotropy. By adjusting the helix direction (left-handed / right-handed), number, and array density of the helical rods in different directions, differentiated mechanical and thermal properties of the structure in the X, Y, and Z directions can be achieved. Specifically, the helical structure exhibits excellent thermal protection performance and moderate load-bearing capacity in one direction, and moderate load-bearing capacity and stiffness in another direction, meeting the multifunctional requirements under complex working conditions.

[0032] 3. The screw adopts a small-diameter curved rod (0.6mm diameter), which has obvious advantages in lightweight structure; it is integrally formed by laser powder bed melting technology, eliminating the need for post-processing assembly and significantly reducing manufacturing costs and cycle time.

[0033] 4. The integrated load-bearing and thermal protection lightweight spiral structure proposed in this invention possesses anisotropic properties due to its heterogeneous orientation. By adjusting the spiral direction of the spiral rods and the number of spiral rods per unit volume, the load-bearing capacity, deformation capacity, and energy absorption capacity of the spiral structure can be effectively controlled to meet different needs. Furthermore, the integrated load-bearing and thermal protection lightweight spiral structure has a relatively small self-weight and requires less model data, which can reduce the cost of components during processing and use. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a three-dimensional bidirectional helical structure (specifically a bidirectional single helical structure) in three-dimensional space.

[0035] Figure 2 Based on Figure 1 The diagram shows a three-dimensional structural schematic of a lightweight spiral structure that integrates load-bearing and thermal protection, which is an extension of a bidirectional single spiral structure.

[0036] Figure 3 This is a schematic diagram of a three-dimensional bidirectional helical structure (specifically a bidirectional double helical structure) in three-dimensional space.

[0037] Figure 4 Based on Figure 3 The diagram shows a three-dimensional structural schematic of a lightweight spiral structure that integrates load-bearing and thermal protection, derived from a bidirectional double helix structure.

[0038] Figure 5 Based on Figure 2 A schematic diagram of the lightweight spiral structure integrating load-bearing and thermal protection for simulation performance testing in the first direction;

[0039] Figure 6 Based on Figure 2 A schematic diagram of the lightweight spiral structure integrating load-bearing and thermal protection for simulation performance testing in the second direction;

[0040] Figure 7 This is the strength-elastic modulus diagram of the plateau region of the bidirectional single-helix structure obtained through compression simulation.

[0041] Figure 8 The energy absorption-specific energy absorption diagram of the bidirectional single-helix structure was obtained through compression simulation.

[0042] Figure 9This is a physical diagram of the bidirectional single-helix structure of the present invention printed using an SLM80 device;

[0043] Figure 10 This is the force-displacement curve of the bidirectional single-helix structure obtained through quasi-static compression tests.

[0044] Figure 11 The thermal conductivity of the bidirectional single-helix structure obtained by thermal conductivity testing experiments according to the present invention is as follows. Detailed Implementation

[0045] 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise specifically stated, the relative arrangement, expressions, and values ​​of components and steps set forth in these embodiments do not limit the scope of the present invention. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0046] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used here to describe the spatial positional relationship of a device or feature as shown in the figure with other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figure. For example, if the device in the figure is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations).

[0047] like Figure 1-6As shown, the lightweight spiral structure integrating load-bearing and thermal protection disclosed in this invention is designed by creating spatial spiral units through a biomimetic spiral collagen structure. The spatial spiral units are then arranged in a linear array in two mutually perpendicular directions in three-dimensional space (such as the X-axis and Y-axis), so that adjacent spatial spiral units are interconnected in space to form a three-dimensional network structure, thereby obtaining the lightweight spiral structure.

[0048] Specifically, the integrated lightweight spiral structure for load bearing and thermal protection described in this invention includes several bidirectional spiral structures; each bidirectional spiral structure is composed of two spatial spiral units.

[0049] The two spatial spiral units are referred to as the first spatial spiral unit and the second spatial spiral unit. The first spatial spiral unit extends along a first direction in three-dimensional space, and the second spatial spiral unit extends along a second direction in three-dimensional space. The first direction and the second direction are perpendicular to each other. The starting ends of the first spatial spiral unit and the starting ends of the second spatial spiral unit are fixedly connected.

[0050] Each spatial spiral unit includes four spiral rods, corresponding to the first to fourth spiral rods; in the same spatial spiral unit, each spiral rod extends in a spiral curve, and the projection of the starting end of each spiral rod in its extension direction onto a plane perpendicular to that extension direction forms a polygon; the second and third spiral rods are replicas of the first spiral rod formed by rotating it 180° along its extension direction; the fourth spiral rod is a replica of the first spiral rod translated along the second and third directions; in the same spatial spiral unit, the first to fourth spiral rods are fixedly connected to each other at spatial intersection nodes;

[0051] The first spatial spiral unit is linearly arrayed in the second direction and the third direction, and the second spatial spiral unit is linearly arrayed in the first direction and the third direction. The spiral rods between adjacent array units are connected to each other at spatial intersection nodes to form a three-dimensional network structure. The third direction is perpendicular to the first direction and the second direction, respectively.

[0052] The following will provide a detailed description through different embodiments.

[0053] Example 1

[0054] like Figure 1 As shown, a bidirectional helical structure in three-dimensional space is disclosed, which is actually a bidirectional single helical structure, and each of the helical rods is a single helical rod.

[0055] Specifically, the bidirectional helical structure includes an X-axis helical structure arranged along the X-axis and a Y-axis helical structure arranged along the Y-axis. In the spatial rectangular coordinate system O-XYZ, the X-axis helical structure includes four X-axis helical rods, each extending along the positive X-axis, corresponding to helical rods X1, X2, X3, and X4. The Y-axis helical structure includes four Y-axis helical rods, each extending along the positive Y-axis, corresponding to helical rods Y1, Y2, Y3, and Y4. Wherein:

[0056] For the X-axis helical structure, the starting point of both the X1 and X2 helical rods is the origin O, and the ending point is point O. Furthermore, the X2 helical rods are arranged in the Y direction of the X1 helical rod and are interconnected with the X1 helical rod; the X3 helical rods are arranged in the Z direction of the X1 helical rod and are interconnected with the X1 helical rod, with the starting point of the X3 helical rod being... The destination is The X4 helical rods are arranged on the line connecting the X2 helical rod in the Z direction and the X3 helical rod in the Y direction, and are interconnected with the X2 and X3 helical rods respectively. The starting point of the X4 helical rod is... The destination is ;

[0057] For the Y-axis helical structure, the starting points of both the Y1 and Y2 helical rods are located at the origin O, and the ending points are located at... Furthermore, the Y2 helical rods are arranged in the X direction of the Y1 helical rod and are interconnected with the Y1 helical rod; the Y3 helical rods are arranged in the Z direction of the Y1 helical rod and are interconnected with the Y1 helical rod, with the starting point of the Y3 helical rod located at... The finish line is located at The Y4 helical rods are arranged on the line connecting the Y2 helical rod in the Z direction and the Y3 helical rod in the X direction, and are interconnected with the Y2 and Y3 helical rods respectively. The starting point of the Y4 helical rod is located at... The destination is Where d is the mean diameter of the screw.

[0058] Linearly arraying the X-axis helical structure along the Y and Z directions yields array structure A; linearly arraying the Y-axis helical structure along the X and Z directions yields array structure B; then, using Boolean operations built into the 3D software, all the helical rods of array structures A and B are combined to expand and form structures such as... Figure 2 The diagram shows a lightweight spiral structure integrating load-bearing and thermal protection. During expansion, the surrounding spiral lines of adjacent spiral structures overlap and intersect in space, forming constraints. Through Boolean operations, members in different directions are combined to ensure corresponding nodes coincide, thus forming two types of spiral units. In this embodiment, the size of the spiral unit is... .

[0059] In this embodiment, both the X-axis and Y-axis helical rods are circular helical rods with the same diameter (0.6 mm), a mean diameter (2 mm), and a pitch (6 mm). Adjacent helical rods are offset at the initial angle by 180° to ensure mutual connection. Furthermore, the X-axis helical rod is a left-handed helical rod, while the Y-axis helical rod is a right-handed helical rod.

[0060] Example 2

[0061] This embodiment discloses another bidirectional helical structure in three-dimensional space, which is actually a bidirectional double helical structure. The difference between this bidirectional helical structure and Embodiment 1 is that each of the helical rods included in this bidirectional helical structure is a double helical rod. The double helical rod is formed by two helical rods with different directions of rotation connected in parallel. That is, one helical rod is a left-hand threaded rod, and the other helical rod is a right-hand threaded rod.

[0062] Specifically, the bidirectional double helix structure described in this embodiment includes eight helical rods in both the X and Y directions. Of these eight helical rods, four are left-handed helices, and the remaining four are right-handed helices connected to the left-handed helical rods. See the attached diagram for details. Figure 3 , 4 .

[0063] Specifically, when arranged to form an X-axis helical structure, each of the X1, X2, X3, and X4 helical rods comprises two helical rod segments, one of which is a left-handed helix and the other a right-handed helix. Similarly, each of the Y1, Y2, Y3, and Y4 helical rods also comprises two helical rod segments, one of which is a left-handed helix and the other a right-handed helix.

[0064] Example 3

[0065] This embodiment provides simulation performance test results of the above-described spiral structure to illustrate the excellent anisotropic performance of the spiral structure described in this invention. Specifically, it uses the bidirectional single spiral structure described in Embodiment 1 (refer to...) Figure 1 The resulting three-dimensional network structure (refer to) Figure 2 Taking (e.g.) as an example, the steps are as follows:

[0066] Step S1: In the finite element analysis software, establish a three-dimensional model of the three-dimensional network structure; in this embodiment, the dimensions of the three-dimensional network structure are... ;

[0067] Step S2: Thin plates are placed at both ends of the 3D network structure along the Y direction to establish a sandwich structure model. When placing the thin plates, it is necessary to ensure that there is surface contact between the 3D network structure and the thin plates, with no sliding constraints. Simultaneously, the thickness of the thin plates is determined based on the dimensions of the 3D network structure. In this embodiment, the thickness of the thin plates is set to 2mm, and the lateral area is... It matches the dimensions of both ends of the three-dimensional network structure in the Y direction.

[0068] Step S3: Apply compressive load along the Y direction of the three-dimensional network structure through a thin plate, obtain the mechanical response under different loading loads, and complete the quasi-static compression simulation analysis of the three-dimensional network structure in the Y direction;

[0069] Following the steps S2 and S3, a quasi-static compression simulation analysis of the three-dimensional network structure in the Z direction is performed.

[0070] Simulation Result Analysis: Simulation analysis revealed that the sandwich structure composed of a bidirectional single-helix structure exhibits significant anisotropic mechanical properties. The compression simulation results show... Figure 7 , 8 As shown:

[0071] Figure 7 The strength-elastic modulus diagram of the plateau region of a sandwich structure composed of a bidirectional single helix structure, obtained through compression simulation, is disclosed. As shown in the figure, along the Y direction (corresponding to the thickness direction of the sandwich structure, refer to…),… Figure 7 When loaded along the BS-XZ section, the elastic modulus of the sandwich structure is 1.83 GPa, and the plateau region strength is 22.6 MPa; when loaded along the Z direction (corresponding to the in-plane direction of the sandwich structure, refer to...), the elastic modulus is 1.83 GPa, and the plateau region strength is 22.6 MPa. Figure 7 (In the BS-XY section), the elastic modulus of the sandwich structure is 0.97 GPa, and the plateau strength is 32.7 MPa. Comparing the plateau strength and elastic modulus of the sandwich structure obtained in the two loading directions, it can be found that the elastic modulus of the sandwich structure decreases by about 47% and the plateau strength increases by about 45% when loaded in the Z direction. Therefore, when high stiffness and moderate load-bearing capacity are required (such as when the sandwich structure is subjected to bending loads), the Y direction should be selected as the main load-bearing direction. In this case, the structure provides a higher elastic modulus and effectively resists elastic deformation.

[0072] Figure 8 The energy absorption-specific energy absorption diagram of a sandwich structure composed of a bidirectional single helix structure, obtained through compression simulation, is disclosed. As shown in the figure, when loaded along the Y direction (refer to…),… Figure 8 When the BS-XZ section is loaded, the energy absorption of the sandwich structure is 59.4 J, and the specific energy absorption (energy absorbed per unit mass) is 14.4 J / g; when loaded along the Z direction (refer to...), the energy absorption of the sandwich structure is 59.4 J, and the specific energy absorption (energy absorbed per unit mass) is 14.4 J / g. Figure 8When loading along the BS-XY direction, the structure's energy absorption is 71.1 J, and its specific energy absorption is 17.2 J / g. Comparing the energy absorption and specific energy absorption of the sandwich structure under the two loading directions, it can be found that the energy absorption of the sandwich structure increases by about 20% and the specific energy absorption increases by about 19% under Z-direction loading, demonstrating excellent energy absorption efficiency. Therefore, when high energy absorption and excellent impact resistance are required, the Z-direction should be selected as the main load-bearing direction. In this case, the structure achieves higher energy absorption density with lower stiffness, making it suitable for impact protection scenarios.

[0073] Example 4

[0074] This embodiment provides a laser additive manufacturing method for the above-described spiral structure, using the bidirectional single spiral structure described in Embodiment 1 (refer to...). Figure 1 The resulting three-dimensional network structure (refer to) Figure 2 Let's take an example to illustrate. The specific steps include:

[0075] Step 1: Create a 3D model:

[0076] A three-dimensional model of the three-dimensional network structure described in Example 1 was created using conventional modeling software, with dimensions of 16×16×16 mm³.

[0077] Step 2, Slice and Layer:

[0078] The 3D model of the 3D network structure is imported into a commonly used slicing software for discretization into layers with a layer thickness of 30 μm, and the cross-sectional profile data of each slice layer is obtained layer by layer.

[0079] Step 3: Laser powder bed melting and forming:

[0080] The cross-sectional contour data of each slice layer is imported into a metal 3D printer (such as an SLM80 device), and the three-dimensional network structure is formed using laser powder bed melting technology. The process parameter range is shown in Table 1 below:

[0081] Table 1. Process Parameter Range

[0082]

[0083] During the printing process, after the powder spreading arm completes the single-layer powder spreading, the metal 3D printer selectively melts the nickel-based superalloy HX powder of the current slice layer according to the cross-sectional contour data of each slice. After the printing of the current slice layer is completed, the forming cylinder descends, and powder is spread again. The above process is repeated until the structure is printed.

[0084] The printed 3D network structure is as follows Figure 9 As shown.

[0085] The performance of the printed 3D network structure was tested, including:

[0086] Mechanical property testing:

[0087] A quasi-static compression test was performed on the three-dimensional network structure using a universal testing machine. The compression rate was set to 2 mm / min. The obtained data was imported into data analysis software to obtain the force-displacement curve of the three-dimensional network structure, as shown in the attached figure. Figure 10 As shown. When the loading direction is Y, the structure exhibits high stiffness and moderate load-bearing capacity, making it suitable for applications requiring resistance to structural deformation; when the loading direction is Z, the structure exhibits high load-bearing capacity and excellent energy absorption performance, making it suitable for applications requiring buffering and energy absorption.

[0088] Thermal protection performance test:

[0089] Thermal conductivity was measured using the transient planar heat source method: The sample was placed in a constant temperature environment, maintaining a room temperature of 25°C. The thermal protection performance of the printed three-dimensional network structure was tested according to the operating specifications of the thermal constant analyzer, and transient temperature response curves were obtained. The transient temperature response curves were analyzed to calculate the thermal conductivity of the three-dimensional network structure at 25°C, and compared with a solid block of the same material to evaluate the thermal protection performance of the obtained three-dimensional network structure sample. The test results showed that for the three-dimensional network structure sample printed under the specified process parameters (laser power 180W, scanning speed 600mm / s, scanning spacing 50μm), its thermal conductivity at 25°C was 0.402 W / (m·K). Compared with a solid block of the same material (thermal conductivity approximately 15W / (m·K)), the thermal conductivity of this spiral structure was reduced by approximately 97%, demonstrating excellent thermal insulation potential (see reference). Figure 11 ).

[0090] In summary, the spiral structure proposed in this invention can be integrally formed using laser powder bed melting technology. It has a lighter weight, smaller data model, controllable mechanical properties, and good anisotropy, and has great potential for engineering applications.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightweight spiral structure integrating load-bearing and thermal protection, characterized in that, It includes several bidirectional helical structures; each bidirectional helical structure consists of two spatial helical units; The two spatial spiral units are referred to as the first spatial spiral unit and the second spatial spiral unit. The first spatial spiral unit extends along a first direction in three-dimensional space, and the second spatial spiral unit extends along a second direction in three-dimensional space. The first direction and the second direction are perpendicular to each other. The starting ends of the first spatial spiral unit and the starting ends of the second spatial spiral unit are fixedly connected. Each spatial spiral unit includes four spiral rods, corresponding to the first to fourth spiral rods; in the same spatial spiral unit, each spiral rod extends in a spiral curve, and the projection of the starting end of each spiral rod in its extension direction onto a plane perpendicular to that extension direction forms a polygon; the second and third spiral rods are replicas of the first spiral rod formed by rotating it 180° along its extension direction; the fourth spiral rod is a replica of the first spiral rod translated along the second and third directions; in the same spatial spiral unit, the first to fourth spiral rods are fixedly connected to each other at spatial intersection nodes; The first spatial spiral unit is linearly arrayed in the second direction and the third direction, and the second spatial spiral unit is linearly arrayed in the first direction and the third direction. The spiral rods between adjacent array units are connected to each other at spatial intersection nodes to form a three-dimensional network structure. The third direction is perpendicular to the first direction and the second direction, respectively.

2. The lightweight spiral structure integrating load-bearing and thermal protection according to claim 1, characterized in that, The helical rod can be a single helical rod or a double helical rod; when the helical rod is a double helical rod, it is formed by connecting two helical rods with different directions of rotation in parallel.

3. The lightweight spiral structure integrating load-bearing and thermal protection according to claim 2, characterized in that, The bidirectional helical structure includes an X-axis helical structure and a Y-axis helical structure, which are connected as one unit at the origin O of the spatial rectangular coordinate system O-XYZ. The first, second, and third directions are the X, Y, and Z axes of the spatial rectangular coordinate system O-XYZ, respectively. The X-axis spiral structure is the first spatial spiral unit, arranged along the X-axis of the spatial rectangular coordinate system O-XYZ; the Y-axis spiral structure is the second spatial spiral unit, arranged along the Y-axis of the spatial rectangular coordinate system O-XYZ.

4. The lightweight spiral structure integrating load-bearing and thermal protection according to claim 3, characterized in that, The X-axis helical structure includes four helical rods, each extending along the positive X-axis, namely: X1, X2, X3, and X4 helical rods. In the X-axis helical structure, the X2 and X3 helical rods are arranged with the X1 helical rod having a starting rotation angle offset by 180° in the X direction, and the starting rotation angle of the X4 helical rod is the same as that of the X1 helical rod. The Y-axis helical structure includes four helical rods, each extending along the positive Y-axis, namely: Y1, Y2, Y3, and Y4 helical rods. In the Y-axis helical structure, the Y2 and Y3 helical rods are arranged with the initial rotation angles of the Y1 helical rod offset by 180° in the Y direction, and the initial rotation angle of the Y4 helical rod is the same as that of the Y1 helical rod.

5. The lightweight spiral structure integrating load-bearing and thermal protection according to claim 4, characterized in that, In the spatial rectangular coordinate system O-XYZ, the starting point of both helical rods X1 and X2 is the origin O, and the ending point is point A1(a,0,0). Helical rod X2 is aligned along the Y-direction of helical rod X1 and connected to it. Helical rod X3 is aligned along the Z-direction of helical rod X1 and connected to it. The starting point of helical rod X3 is... The destination is The X4 helical rods are arranged on the line connecting the X2 helical rod in the Z direction and the X3 helical rod in the Y direction, and are interconnected with the X2 and X3 helical rods respectively. The starting point of the X4 helical rod is... The destination is ; In the spatial rectangular coordinate system O-XYZ, the starting points of both the Y1 and Y2 helical rods are located at the origin O, and the ending points are located at... Furthermore, the Y2 helical rods are arranged in the X direction of the Y1 helical rod and are interconnected with the Y1 helical rod; the Y3 helical rods are arranged in the Z direction of the Y1 helical rod and are interconnected with the Y1 helical rod, with the starting point of the Y3 helical rod located at... The finish line is located at The Y4 helical rods are arranged on the line connecting the Y2 helical rod in the Z direction and the Y3 helical rod in the X direction, and are interconnected with the Y2 and Y3 helical rods respectively. The starting point of the Y4 helical rod is located at... The destination is d is the mean diameter of the screw.

6. The lightweight spiral structure integrating load-bearing and thermal protection according to claim 3, characterized in that, In a bidirectional helical structure, when the screw is a single helical rod, all the helical rods in the X-direction helical structure are left-handed helices, while all the helical rods in the Y-direction helical structure are right-handed helices.

7. The lightweight spiral structure integrating load-bearing and thermal protection according to claim 3, characterized in that, The screw has a mean diameter of 2 mm, a pitch of 6 mm, and a period of 4.

8. The lightweight spiral structure integrating load-bearing and thermal protection according to claim 3, characterized in that, The spiral rod is a rod structure with a circular cross-section and a diameter of 0.6 mm.

9. A laser additive manufacturing method for a lightweight spiral structure integrating load-bearing and thermal protection, characterized in that, Includes the following steps: Step S1: Establish a three-dimensional model of the integrated lightweight spiral structure for load bearing and thermal protection as described in any one of claims 1 to 8; Step S2: Slice the three-dimensional model into layers to obtain cross-sectional contour data; Step S3: Import the cross-sectional contour data into the laser additive manufacturing equipment, and use laser powder bed melting technology to melt nickel-based superalloy HX powder layer by layer to integrally form the load-bearing and thermal protection integrated lightweight spiral structure; the process parameters of the laser powder bed melting process are: laser energy density 190 J / mm 3 Up to 205 J / mm 3 Laser power 160 W - 200 W, scanning speed 550 mm / s - 650 mm / s.

10. The laser additive manufacturing method for the integrated load-bearing and thermal protection lightweight helical structure as described in claim 9, characterized in that, The laser powder bed melting process employs a unidirectional remelting scanning strategy with an interlayer rotation angle of 67°.

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