A dendritic skeleton reinforced force-thermal decoupling integrated satellite structure panel and manufacturing method

Abstract

The application discloses a dendritic skeleton reinforced force-thermal decoupling integrated satellite structure plate and a manufacturing method. The structure plate comprises an upper plate, a lower plate, a heat pipe system arranged between the upper plate and the lower plate, and a dendritic load-bearing skeleton for supporting the upper plate and the lower plate. The dendritic load-bearing skeleton forms a trunk and multiple levels of branches along a main load direction. Local gradient lattices are arranged at branch nodes, hole peripheries or mounting connection areas. The structure plate is internally provided with a heat pipe system comprising a main vein heat pipe, branch heat pipes and a return pipe. Structure isolation areas are arranged between the heat pipe system and the dendritic load-bearing skeleton, and the heat pipe system is connected with the plates through heat-conducting bridges with compliant sections, so that direct rigid connections between the heat pipe system and the plates are avoided. Through the above configuration, the load-bearing path and the heat transfer path are separated from each other in the structural connection relationship, so that the light weight, the local connection reliability, the heat flow organization capability and the additive manufacturing adaptability are considered.

Description

Technical Field

[0001] This invention belongs to the technical fields of metal additive manufacturing, lightweight load-bearing structures and integrated structural thermal control. It relates to a dendritic skeleton-reinforced integrated force-thermal decoupling satellite structural plate and its manufacturing method, and more particularly to a locally lattice dendritic load-bearing skeleton-reinforced integrated force-thermal separation structural plate and its manufacturing method and application. Background Technology

[0002] Structural panels are widely used in spacecraft platforms, electronic equipment mounting bases, high-power device support frames, and other equipment with comprehensive requirements for lightweighting, rigidity, and thermal management. Existing structural panels mostly employ solid panels, stiffened panels, honeycomb sandwich panels, or uniform lattice sandwich structures, and achieve thermal management through heat pipes, heat transfer tapes, cold plates, or radiators. As equipment develops towards lightweighting, high integration, and high heat flux density, structural panels not only bear load-bearing and connection functions but also need to consider heat transfer, equipment installation, and multifunctional integration requirements.

[0003] However, the existing solutions still have the following shortcomings: Firstly, load-bearing structures and thermal control structures are typically connected by rigid superposition, embedding, or shared walls. When the structural panel is subjected to vibration, impact, assembly preload, and thermal deformation, the load can easily be directly transferred to the thin-walled thermal control components through the rigid connection, causing localized stress concentration, interface damage, sealing failure, or reduced fatigue life. At the same time, the thermal expansion of the thermal control components can conversely affect the dimensional stability of the structural panel. Secondly, existing lightweight structures often use regular stiffeners, honeycomb cores, or uniform lattices, which makes it difficult to simultaneously meet the requirements of optimizing the main load-bearing path and strengthening local connection areas. This can easily lead to problems such as insufficient local stiffness, high stress peaks, and poor mass utilization efficiency around bolt holes, equipment installation areas, load input areas, and bifurcation nodes of the frame. Third, existing thermal control solutions mostly use straight heat pipes, parallel heat pipes, or in-plane uniform heat conduction layers, which are insufficient for organizing heat flow under non-uniform heat source distribution and complex boundary conditions. Fourth, for the integrated complex configuration of metal additive manufacturing, existing designs often do not fully consider manufacturing constraints such as support removal, channel cleaning, internal channel forming, wall thickness transition and residual stress control, which affects engineering applications.

[0004] Therefore, it is necessary to propose a structural plate configuration that enables the load-bearing path and heat transfer path to be optimized collaboratively under a unified design framework, so as to achieve a clear main load-bearing path, reinforced local connection areas, relatively independent heat flow transmission paths, and an overall structure suitable for additive manufacturing. Summary of the Invention

[0005] To improve the above-mentioned technical problems, the present invention provides a force-thermal separation integrated structural plate reinforced with a locally lattice dendritic load-bearing skeleton and its manufacturing method, so as to solve the problems of rigid coupling between load-bearing structure and thermal control structure, insufficient reliability of local connection area, limited heat flow organization efficiency, and poor adaptability of additive manufacturing of complex integrated components in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides an integrated structural plate, including an upper panel, a lower panel, a heat pipe system disposed between the upper panel and the lower panel, and a branched load-bearing frame for supporting the upper panel and the lower panel.

[0007] According to an embodiment of the present invention, the branched load-bearing skeleton includes at least one main load-bearing segment and multiple sub-load-bearing segments connected to the main load-bearing segment; the main load-bearing segment extends along the main direction of the structural slab and is used to form the main area for load transfer and support of the structural slab; the multiple sub-load-bearing segments branch from the main load-bearing segment to the load input area, interface connection area, or panel support area to form a continuous main load transfer path. The equivalent cross-sectional dimensions of each sub-load-bearing segment can gradually decrease along the load diffusion direction, and the branching nodes are provided with continuous fillets or gradual curvature transitions.

[0008] In some implementations, the sub-supporting force section includes a primary sub-supporting force section and a secondary sub-supporting force section; the primary sub-supporting force section is arranged bifurcated on both sides of the main support force section; the secondary sub-supporting force section is located at the end of the primary sub-supporting force section or in a local area with insufficient support.

[0009] According to an embodiment of the present invention, the contact portion between the dendritic load-bearing skeleton and the upper panel and the lower panel is provided with a local gradient lattice reinforcement structure, and the upper panel, the dendritic load-bearing skeleton, the local gradient lattice reinforcement structure and the lower panel are integrally formed.

[0010] According to an embodiment of the present invention, the locally gradient lattice reinforcement structure can also be disposed at the bifurcation nodes, trunk connection areas, node regions, bolt-fixed reinforcement points, or local reinforcement locations of the dendritic load-bearing skeleton, without requiring uniform distribution throughout the entire structural plate. Further, the lattice reinforcement structure includes node region reinforcement lattices and connection region reinforcement lattices. A gradual transition region is provided between the locally gradient lattice reinforcement structure and the solid skeleton, wherein at least one of the following continuously changes: lattice unit cell size, rod diameter, wall thickness, relative density, or rod connection angle.

[0011] By setting lattice reinforcement structures at key stress-bearing parts of the dendritic load-bearing skeleton, the deformation resistance and connection reliability of local areas of the skeleton can be improved, and the overall load-bearing performance can be enhanced.

[0012] According to an embodiment of the present invention, the heat pipe system is a two-phase (vapor-liquid) heat transfer channel network. Preferably, the heat pipe system includes a main pulse heat pipe, a primary branch heat pipe, a secondary branch heat pipe, a liquid return pipe communicating with a condensation section and at least a portion of the primary branch heat pipe, and a working medium sealed within the heat pipe; at least a portion of the primary branch heat pipe and the secondary branch heat pipe are located near the heat source area, and at least a section of the main pulse heat pipe or a condensation branch (primary branch heat pipe and secondary branch heat pipe) communicating with it constitutes the condensation section.

[0013] Preferably, the inner wall of the liquid return pipe or the first-stage branch heat pipe and the second-stage branch heat pipe is provided with a capillary liquid return structure, so that the working medium absorbs heat and vaporizes in the evaporation section, flows along the vapor passage to the condensation section, and returns to the evaporation section through the liquid return pipe and the capillary structure after condensation.

[0014] According to an embodiment of the present invention, the capillary liquid return structure can be a microgroove formed along the inner wall of the channel, an additively manufactured porous layer, a metal mesh, a sintered powder layer, a foamed metal layer, or a combination thereof. For structural plates that need to operate under microgravity or arbitrary orientation, it is preferable that the capillary liquid return structure is continuously or overlappingly connected between the evaporation section, the liquid return channel, and the condensation section.

[0015] According to an embodiment of the present invention, the heat pipe system is located within a clearance space formed by a branched load-bearing frame, and a structural isolation zone is provided between the heat pipe system and the branched load-bearing frame to avoid a direct rigid connection between the heat pipe system and the branched load-bearing frame. The structural isolation zone can be a cavity gap, a non-contact clearance zone, a low-contact-rate support zone, a low-stiffness transition zone, or a combination thereof.

[0016] According to an embodiment of the present invention, one end of the flexible thermal bridge forms a thermally conductive connection with the upper or lower panel, and the other end forms a thermally conductive connection with the main heat pipe, branch heat pipe, or its outer thermal conductive base. Preferably, the flexible thermal bridge includes at least one thin-walled, corrugated, zigzag, arc-shaped, or slotted flexible section, used to absorb thermal expansion mismatch, structural micro-deformation, and assembly deviation while maintaining the continuity of heat transfer.

[0017] According to an embodiment of the present invention, a floating guide structure is provided at the end or a local location of the main pulse heat pipe to allow the heat pipe system to undergo adaptive displacement while maintaining its guiding position. Thus, a thermally conductive connection is formed between the main pulse heat pipe and the upper panel via a flexible thermal bridge, reducing structural load transfer and thermal deformation coupling while ensuring continuous heat transfer.

[0018] In some implementations, a heat spreader or a high thermal conductivity mounting base is provided between the heat source and the top panel; the heat is spread from the heat source through the heat spreader and the top panel, and then transferred to the adjacent heat pipe branches through multiple flexible thermal bridges, thereby avoiding the main heat pipe from bearing the local heat absorption function alone.

[0019] The present invention also provides a design and manufacturing method for the above-mentioned structural plate, comprising the following steps: S1, Working Condition Analysis and Functional Zoning: Based on the service environment, installation method and functional requirements of the structural plate, determine the static load, vibration load, impact load and assembly preload of the structural plate, determine the heat source location, heat flux density and heat sink boundary, and set the mass constraints of the structural plate; on this basis, divide the structural plate into the main load-bearing area, heat source area, interface connection area, assembly area and multi-functional area. S2, Determination of regional main control objectives: Based on the role of each functional area, determine at least one main control objective among load-bearing stiffness, structural stability, temperature uniformity, heat transfer capacity, local connection reliability, dimensional accuracy and lightweighting degree, and establish design constraints corresponding to each main control objective; S3, Design of branched load-bearing frame: Determine the arrangement, extension direction and cross-sectional dimensions of the main load-bearing section, first-level sub-supporting section and second-level sub-supporting section of the branched load-bearing frame according to the load boundary conditions and load transfer path, so that the main load-bearing section extends along the main load transfer direction and the sub-supporting sections of each level are arranged in a branched manner along the load diffusion direction. S4, Local gradient lattice reinforcement structure design: Based on the stress distribution, stiffness requirements and connection forms of each functional area, a lattice reinforcement structure is set at least once in the node area, trunk connection area, around bolt holes and local high stress area of ​​the dendritic load-bearing skeleton, and the lattice topology, cell size, rod diameter, relative density and its gradation method are determined. S5, Heat pipe system design: Based on the location of the heat source, the heat flux density distribution and the heat sink boundary, determine the layout path of the main pulse heat pipe, the first-level branch heat pipe, the second-level branch heat pipe and the return pipe, and optimize the branch level, pipe diameter, pipe wall thickness, branch spacing and flow channel cross section of the heat pipe system so that heat is gradually collected from the local heat source area and transferred to the heat sink area. S6, Decoupling Structure Design of Force and Heat Path: A structural isolation zone is set between the heat pipe system and the branched load-bearing frame to reduce the structural load transmitted from the branched load-bearing frame to the heat pipe system; a flexible heat-conducting bridge is set between the heat pipe system and the upper or lower panel to compensate for the relative displacement caused by thermal expansion mismatch, structural deformation and assembly deviation while maintaining the continuity of heat transfer. S7, Additive Manufacturing and Performance Verification: Based on the main control objectives of each functional area, determine the corresponding forming parameters and scanning strategies, and perform additive manufacturing on the structural panels.

[0020] According to an embodiment of the present invention, in step S3, the cross-sectional dimensions of each branch of the branched load-bearing skeleton decrease gradually along the load transmission direction, and a transition fillet is provided at the bifurcation point.

[0021] According to an embodiment of the present invention, in step S4, the local gradient lattice reinforcement structure is arranged in such a way that the lattice cell size, rod diameter or density gradually changes outward from the connection center.

[0022] According to an embodiment of the present invention, in step S5, the number of branches, branch levels, pipe diameter and branch spacing of the heat pipe system are adjusted according to the heat flux density of different regions; according to the requirements of low temperature start-up, anti-freezing or temperature stability, an auxiliary heating unit and a temperature detection unit can also be set in the condensation section of the heat pipe system.

[0023] According to an embodiment of the present invention, in step S7, the additive manufacturing process is any one of selective laser melting, electron beam melting, or directional energy deposition.

[0024] According to an embodiment of the present invention, after step S7, the process further includes stress-relieving heat treatment, support removal, local machining of the mounting surface and sealing port, internal channel cleaning and drying, vacuuming, working medium filling and sealing, and performing at least one of industrial CT inspection, helium mass spectrometry leak detection, dimensional inspection, thermal resistance test, temperature uniformity test, static loading test, modal test, vibration test and thermal cycling test.

[0025] The present invention also provides the application of the above-mentioned structural plate in spacecraft structural plates, electronic equipment mounting plates, high heat flux density lightweight load-bearing components, and other structural components with comprehensive requirements for load-bearing, thermal conductivity and lightweight.

[0026] The beneficial effects of this invention are: (1) The present invention constructs the main load-bearing path through a branched load-bearing skeleton, which is conducive to the graded transmission and dispersion of loads and improves the problem of local stress concentration in traditional uniform plate or regular stiffened plate structures under complex load conditions.

[0027] (2) By arranging local gradient lattices only as needed in high-stress areas such as bifurcation nodes, hole periphery and installation connections, this invention can improve the stiffness, fatigue reliability and load diffusion capability of the connection area while reducing the mass input of non-critical areas.

[0028] (3) By setting up a structural isolation zone between the heat pipe system and the branched load-bearing frame, and establishing a thermal connection between the heat pipe system and the panel through a flexible thermal bridge, the load-bearing path and the heat transfer path can be relatively decoupled in terms of connection relationship, thereby reducing the adverse effects of vibration, impact, assembly pre-tightening force and thermal expansion mismatch on the thin-walled heat transfer channel, and maintaining the continuity of heat conduction.

[0029] (4) By adopting a heat pipe system with a hierarchical and branched arrangement, the present invention improves the reliability of heat flow collection and return under multiple heat sources and different installation conditions, and enhances the adaptability of heat flow organization under complex thermal boundary conditions.

[0030] (5) The present invention, through structural design and manufacturing method that match the constraints of additive manufacturing, makes the complex integrated configuration more in line with the actual manufacturing capability of powder bed melting equipment, and improves the manufacturability and engineering application adaptability of the complex integrated configuration. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the integrated structural plate of the present invention; Figure 2 This is a partial structural diagram of the integrated structural plate of the present invention; Figure 3 This is a schematic diagram of the structure of the branched load-bearing frame of the present invention; Figure 4 This is a schematic diagram of a locally gradient lattice-enhanced structure. Figure 5 This is a schematic diagram of a heat pipe system. Figure 6 This diagram illustrates the connection relationships between the flexible thermal bridge, heat pipe system, and panel. Figure 7 A schematic cross-sectional view of the local lattice support relationship; Figure 8 This is a schematic diagram of the functional areas of the structural panel; Figure 9 A schematic diagram illustrating the modular and expandable structure of the structural panel and its application status. Figure 10 This is a schematic diagram of the regional parameter design and partitioned manufacturing of the present invention; Figure 11 This is a flowchart of the "five-zone, four-parameter" additive manufacturing closed-loop control process of the present invention; The definitions of the reference numerals in the figures are as follows: 1. Top panel; 101. Heat source area; 102. Main load-bearing area; 103. Multifunctional area; 104. Interface connection area; 105. Assembly area; 2. Bottom panel; 3. Heat pipe system; 301. Main pulse heat pipe; 302. Primary branch; 303. Secondary branch; 304. Return pipe; 4. Branched load-bearing frame; 41. Main load-bearing section; 42. Sub-load-bearing section; 421. Primary sub-load-bearing section; 422. Secondary sub-load-bearing section; 43. Locally gradient lattice reinforced junction 5. Heat spreader; 6. Flexible thermal bridge; 601. Top panel thermal bridge connection area; 602. Locally compliant structure (corrugated / grooved / zigzag); 603. Heat pipe thermal bridge connection area; 604. Structural isolation area (dashed line); 605. Floating guide structure; 701. Mechanical connector; 702. Elastic compression joint; 801. Load-bearing strengthening parameter design; 802. Thermal control optimization parameter design; 803. Lightweight parameter design; 804. Connection enhancement parameter design. Detailed Implementation

[0032] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0033] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0034] Example 1 like Figure 1-2 As shown, the present invention provides an integrated structural panel, including an upper panel 1, a lower panel 2, a heat pipe system 3 disposed between the upper panel 1 and the lower panel 2, and a branched load-bearing frame 4 for supporting the upper panel 1 and the lower panel 2. The upper panel 1 and the lower panel 2 constitute the outer surface of the structural panel and the assembly reference, and the branched load-bearing frame 4 is disposed between the two and forms the main support. The heat pipe system 3 is arranged within the clearance space reserved in the branched load-bearing frame 4.

[0035] The upper panel 1, the lower panel 2, and the branched load-bearing frame 4 can be integrally formed using aluminum alloy, titanium alloy, magnesium alloy, high-temperature alloy, or other metal materials suitable for additive manufacturing.

[0036] [Branched load-bearing framework] like Figure 3 As shown, the branched load-bearing frame 4 includes at least one main load-bearing section 41 and multi-level sub-load-bearing sections 42 connected to the main load-bearing section 41; the main load-bearing section 41 extends along the main load transmission direction of the structural plate and is used to form the main area for load transmission and support of the structural plate; the sub-load-bearing sections 42 branch from the main load-bearing section 41 to the load input area, interface connection area or panel support area.

[0037] Furthermore, the sub-support section 42 includes a primary sub-support section 421 and a secondary sub-support section 422; the primary sub-support section 421 is arranged in a bifurcated manner on both sides of the main support section 41; the secondary sub-support section 422 is located at the end of the primary sub-support section 421 or in a local area with insufficient support.

[0038] The dendritic load-bearing framework 4 is based on the dendritic lattice, taking into account the principal stress directions obtained from finite element analysis, topology optimization results, and manufacturing constraints. The intersections of the main load-bearing segment 41 and the first-level sub-support segment 421, and the first-level sub-support segment 421 and the second-level sub-support segment 422, adopt rounded corners, spline surfaces, or continuous curvature transitions; the branch cross-sections gradually decrease along the load diffusion direction to avoid abrupt changes in stiffness and reduce ineffective mass.

[0039] The branched load-bearing frame 4 forms a continuous connection with the upper panel 1 and the lower panel 2. The cross-section of the branched load-bearing frame 4 can be circular, elliptical, box-shaped, I-shaped, open slot-shaped, or a variable cross-section optimized according to the load direction.

[0040] The branched load-bearing frame 4 adopts a branched support frame structure to form continuous support and load transfer path between the upper panel 1 and the lower panel 2. Through the above configuration, the upper panel 1, the lower panel 2 and the branched load-bearing frame 4 form an integrated structural panel, thereby achieving a synergistic unity of the overall stiffness, load-bearing capacity and lightweight performance of the structural panel.

[0041] Local gradient lattice enhancement structure like Figure 4 As shown, the local gradient lattice reinforcement structure 43 can also be set at the bifurcation node, trunk connection area, node area, bolt hole periphery load diffusion area or other local reinforcement positions of the dendritic load-bearing skeleton 4.

[0042] Furthermore, the local gradient lattice reinforcement structure 43 includes a node region reinforcement lattice and a connection region reinforcement lattice. The local gradient lattice reinforcement structure 43 is integrally formed with the surrounding solid structure and is connected to the dendritic load-bearing frame 4 through a gradient transition region, which can improve the deformation resistance and connection reliability of the local area of ​​the dendritic load-bearing frame 4 and enhance the overall load-bearing performance.

[0043] The local gradient lattice reinforcement structure 43 can adopt a Kagome lattice, TPMS lattice, chiral honeycomb lattice or other three-dimensional lattice topology suitable for additive manufacturing, and preferably adopts a gradual transition configuration at the boundary connected with the dendritic load-bearing skeleton 4 to reduce abrupt stiffness changes and stress concentration.

[0044] The locally gradient lattice reinforcement structure 43 is not post-assembled into the dendritic load-bearing frame 4, but is integrally formed with the dendritic load-bearing frame 4 during additive manufacturing. Specifically, a structural reinforcement cavity can be set inside the main load-bearing section 41, and the locally gradient lattice reinforcement structure 43 is filled in the structural reinforcement cavity and metallurgically connected to the inner wall of the structural reinforcement cavity; a node reinforcement region is set at the intersection of the sub-support section 42 and the first-level sub-support section 421, and the first-level sub-support section 421 and the second-level sub-support section 422, and the locally gradient lattice reinforcement structure 43 forms the node reinforcement core, which is integrally connected to the sub-support section 42, the first-level sub-support section 421 and the second-level sub-support section 422 respectively; a solid reinforcing ring is set around the bolt hole or mounting hole, and the locally gradient lattice reinforcement structure 43 is located between the solid reinforcing ring and the dendritic load-bearing frame 4 to form a load diffusion region around the hole. Except for the above-mentioned areas, the locally gradient lattice reinforcement structure 43 is not set in other areas of the structural plate to avoid mass redundancy caused by uniform reinforcement throughout the entire area.

[0045] A gradient transition configuration is preferably provided between the locally gradient lattice reinforcement structure 43 and the dendritic load-bearing skeleton 4. The gradient transition configuration refers to the provision of a gradient transition region between the locally gradient lattice reinforcement structure 43 and the dendritic load-bearing skeleton 4. Within this gradient transition region, at least one of the following parameters—lattice unit cell size, lattice rod diameter, relative density, and rod connection angle—changes continuously along the direction from the locally gradient lattice reinforcement structure 43 to the dendritic load-bearing skeleton 4, so that the locally gradient lattice reinforcement structure gradually transitions from a low-density porous state to a high-density load-bearing skeleton state.

[0046] In a preferred embodiment, the length of the gradient transition region is 1 to 3 times the characteristic diameter of the adjacent dendritic support frame 4; the lattice rod diameter gradually increases from 0.6 to 1.2 mm to 1.2 to 2.5 mm, the lattice unit cell size gradually decreases from 6 to 10 mm to 3 to 6 mm, and the lattice relative density gradually increases from 15% to 25% to 35% to 60%. Through this gradient transition configuration, the abrupt change in stiffness between the locally gradient lattice reinforcement structure 43 and the dendritic support frame 4 can be reduced, stress concentration can be decreased, and the connection stability during additive manufacturing can be improved.

[0047] Heat pipe system like Figure 5 As shown, the heat pipe system 3 includes a main pulse heat pipe 301, a primary branch heat pipe 302, a secondary branch heat pipe 303, and a liquid return pipe 304 connected to the condensation section and at least a portion of the primary branch heat pipe 302. The primary branch heat pipe 302 extends from the main pulse heat pipe 301 towards the heat source region, and the secondary branch heat pipe 303 is located at the end of the primary branch heat pipe 302 and / or in a local high heat flux density region. The main pulse heat pipe 301, the primary branch heat pipe 302, and the secondary branch heat pipe 303 are interconnected, supplying gaseous working medium from the local heat source region to the condensation section of the main pulse heat pipe 301.

[0048] The main heat pipe 301 extends along the length of the structural plate, forming the main heat transfer channel of the heat pipe system 3. The primary branch heat pipe 302 and the secondary branch heat pipe 303 correspond to the heat source areas within the structural plate. The working medium absorbs heat and vaporizes in the evaporation of the primary branch heat pipe 302 and the secondary branch heat pipe 303. The vapor is collected from the secondary branch heat pipe 303 to the primary branch heat pipe 302 and further enters the main heat pipe 301, subsequently being transported along the main heat pipe 301 to the condensation section.

[0049] The graded heat pipe system 3 of the present invention can adapt to the heat dissipation needs of multiple dispersed heat sources and local high heat flux density heat sources in the structural plate, so that the heat generated in different areas can be concentrated and transported to the main pulse heat pipe 301 through the corresponding branch heat pipes, thereby improving the heat flow organization, temperature uniformity and overall heat dissipation efficiency inside the structural plate.

[0050] At least one end of the main pulse heat pipe 301 and / or near the edge of the structural plate or the lower panel 2 of the structural plate constitutes a condensation section, which is thermally connected to an external radiator, cold plate, radiant heat dissipation surface or other heat dissipation components. After entering the condensation section, steam releases heat to the outside and condenses to form a liquid working medium.

[0051] One end of the return pipe 304 is connected to the condensate collection area of ​​the condensation section of the main pulse heat pipe 301, and the other end is connected to the evaporation section of the first-stage branch heat pipe 302. The condensate returns from the condensation section of the main pulse heat pipe 301 to the evaporation sections of the first-stage branch heat pipe 302 and the second-stage branch heat pipe 303. The condensate enters the return pipe 304 from the condensate collection area, is transported to the first-stage branch heat pipe 302 through the return pipe 304, and is further distributed to the second-stage branch heat pipe 303 to replenish the liquid working medium consumed by vaporization, thereby completing the closed phase change cycle of the working medium.

[0052] The reflux pipe 304 preferably serves as the main channel for the condensate to return from the condensation section to each evaporation section. At least a portion of the inner wall of the reflux pipe 304, the main pulse heat pipe 301, the first-stage branch heat pipe 302, and the second-stage branch heat pipe 303 is provided with a capillary return structure to adsorb, retain, transport, and distribute the condensate. The capillary return structure can be an axial microgroove integrally formed with the channel, a cross-groove formed by the intersection of axial and circumferential grooves, a porous layer, a porous lattice layer, or a combination of the above structures.

[0053] For microgravity applications such as spacecraft, the capillary return structure between the condensation section of the main pulse heat pipe 301, the condensate collection area, the return pipe 304, the first-stage branch heat pipe 302, and the second-stage branch heat pipe 303 is preferably continuously overlapped to avoid capillary interruption and to allow the condensate to continuously return from the condensation section to each evaporation section under the action of capillary pressure difference.

[0054] For gravity-assisted applications with a stable installation orientation, the return pipe 304 can be arranged at an angle from the condensation section of the main pulse heat pipe 301 to the evaporation section of the first-stage branch heat pipe 302, allowing the condensate to return to the evaporation section under the combined action of gravity and capillary force. For applications with microgravity, changes in orientation, or where the condensation section is lower than the evaporation section, the condensate return is mainly driven by the capillary pressure difference generated by the continuous capillary return structure.

[0055] The working medium is determined based on the operating temperature of the heat pipe system 3, the channel material, and the compatibility between the working medium and the channel material. It can be water, ammonia, acetone, ethanol, methanol, or other phase change working fluids suitable for the corresponding operating temperature range.

[0056] In one example, the main heat pipe 301 has an outer diameter of 10–14 mm and a wall thickness of 0.6–1.0 mm; the first-stage branch heat pipe 302 has an outer diameter of 6–8 mm and a wall thickness of 0.5–0.8 mm; and the second-stage branch heat pipe 303 has an outer diameter of 3.5–5 mm and a wall thickness of 0.4–0.7 mm. The connection between the main heat pipe 301, the first-stage branch heat pipe 302, and the second-stage branch heat pipe 303 employs a continuous diameter transition structure. The axial length of this continuous diameter transition structure is not less than 1.5 times the larger outer diameter of the two connected heat pipes, in order to reduce flow resistance and local stress concentration at the connection point.

[0057] [Structural isolation zone, floating guide structure, and flexible thermal bridge] like Figure 6 As shown, the heat pipe system 3 is located within the clearance space formed by the branched load-bearing frame 4. A structural isolation zone 604 is provided between the heat pipe system 3 and the branched load-bearing frame 4 to avoid a direct rigid connection between them. The structural isolation zone 604 can be a cavity gap, a non-contact cavity area, a low contact rate support area, a low modulus transition area, or a combination thereof. By forming a structural isolation relationship, the risk of structural loads, vibration loads, and assembly loads being directly transmitted to the heat pipe system 3 can be reduced.

[0058] A floating guide structure 605 is positioned at the end or middle of the main pulse heat pipe 301 to allow the heat pipe system 3 to undergo adaptive displacement while maintaining its guiding position. This creates a thermally conductive connection between the main pulse heat pipe 301 and the upper panel 1 via a flexible thermal bridge 6, ensuring continuous heat transfer while reducing structural load transfer and thermal deformation coupling.

[0059] The flexible thermal bridge 6 includes a panel-thermal bridge connection area 601, a heat pipe-thermal bridge connection area 603, and a locally compliant structure 602 disposed between the two; wherein, the panel-thermal bridge connection area 601 is connected to the upper panel 1, the heat pipe-thermal bridge connection area 603 is connected to the main pulse heat pipe 301, and the locally compliant structure 602 is used to provide the thermal bridge with the ability to adapt to deformation in the thickness direction or in the in-plane direction.

[0060] A flexible thermal bridge 6 is provided between the heat pipe system 3 and the upper panel 1 and / or the lower panel 2. The flexible thermal bridge 6 is a bridging thermally conductive component with a compliant structure. One end of it forms a thermally conductive connection with the upper panel 1 or the lower panel 2, and the other end forms a thermally conductive connection with the main pulse heat pipe 301, the branch heat pipe, or its outer thermally conductive seat. It is used to absorb relative displacement caused by thermal expansion mismatch, structural micro-deformation, or assembly deviation while ensuring the continuity of heat transfer.

[0061] The flexible heat-conducting bridge 6 can be made of thin-walled metal heat-conducting sheets, corrugated heat-conducting sheets, zigzag heat-conducting sheets, partially slotted heat-conducting sheets, or other bridging heat-conducting components with flexible sections.

[0062] The flexible thermal bridge 6 can be integrally formed with the heat pipe system 3, the panel or the branched load-bearing frame 4 during the additive manufacturing process, or it can be set as an independent component between the heat pipe system 3 and the panel after the structural plate is formed.

[0063] When the flexible heat-conducting bridge 6 is integrally formed with the heat pipe system 3, the panel or the branched load-bearing frame 4, the flexible heat-conducting bridge 6 is a thin-walled metal heat-conducting component that is metallurgically connected to the outer wall of the heat pipe and the inner side of the panel. It includes at least one of thin-walled metal heat-conducting sheets, corrugated heat-conducting sheets, zigzag heat-conducting sheets, partially slotted heat-conducting sheets or other bridging heat-conducting components with flexible sections.

[0064] When the flexible thermal bridge 6 is set as an independent component, the structural plate has a pre-reserved installation groove between the heat pipe system 3 and the panel. The flexible thermal bridge 6 is embedded in the installation groove and forms a thermally conductive connection with the heat pipe system 3 and the panel through welding, brazing, diffusion connection, mechanical pressing or thermal interface material.

[0065] This invention, through the cooperation of the structural isolation zone 604 and the flexible thermal bridge 6, ensures that the load-bearing path is mainly transmitted along the dendritic load-bearing frame 4, while the heat transfer path is mainly transmitted along the heat pipe system 3 and the flexible thermal bridge 6. The flexible thermal bridge 6 can connect the panel and the heat transfer channel at multiple discrete locations, and the locally gradient lattice reinforcement structure 43 is arranged at the edges and connection areas to ensure panel support and local load diffusion. The number and spacing of the flexible thermal bridges are determined according to the heat source distribution, ensuring that the in-plane distance from any major heat source point to the nearest thermal bridge meets the thermal resistance requirements.

[0066] like Figure 7 As shown, bolt-fixed reinforcement zones are set on both sides of the structural plate or at the connection edges. A local gradient lattice reinforcement structure 43 (i.e., a node region lattice reinforcement structure) is set inside the bolt-fixed reinforcement zone to assist the bolted connections in bearing assembly preload and external loads. Load transfer is achieved between the bolt-fixed reinforcement zone and the internal support structure through local support units and reinforced connections, allowing the concentrated load generated by the bolt connection to gradually diffuse from the connection zone into the interior of the structural plate. This improves the local load-bearing capacity, deformation resistance, and connection stability of the bolt-fixed area, and enhances the overall reliability of the structural plate in both assembled and service conditions.

[0067] Heat transfer A heat source is positioned above the upper panel 1, with a heat spreader 5 positioned between the heat source and the upper panel 1. The heat generated by the heat source is first transferred to the heat spreader 5, which is used to expand the localized concentrated heat flow in-plane. The heat first expands in-plane within the heat spreader 5 and the upper panel 1, and then enters the heat pipe system 3 via multiple flexible heat-conducting bridges 6. Finally, the heat dissipates along the surface and edge areas of the structural panel, thus forming a heat flow convergence path that sequentially transfers heat from the heat source to the heat spreader 5, the upper panel 1, and the heat pipe system 3. This configuration enhances the heat diffusion capability under single heat source conditions and improves the overall thermal management efficiency of the structural panel 1.

[0068]

Functional Areas

[0069] In the heat source zone 101, priority is given to increasing the branch coverage and the number of flexible thermal bridges; in the main load-bearing zone 102, priority is given to increasing the continuity and density of the skeleton; in the interface connection zone 104, solid reinforcing rings and local gradient lattices are set; in the assembly zone 105, edge reinforcing strips are set and warping is controlled; in the multifunctional zone 103, the hollowing rate is increased while meeting the minimum stiffness and reflow connectivity requirements.

[0070] Example 2 like Figure 9 As shown, the upper panel 1 and the lower panel 2 constitute the upper and lower boundaries of the structural plate module. The main heat pipe 301 is arranged inside the structural plate module and is set along the extension direction of the module. Adjacent structural plate modules are connected by mechanical connectors 701 to ensure the structural installation and positioning between the modules. The main pulse heat pipe 301 is equipped with a resilient compression fitting 702 at its connection end, enabling detachable connection of the main pulse heat pipe 301 in a modular assembly state. The resilient compression fitting 702 may include a high thermal conductivity sleeve, a resilient pre-tightening element, and a thermally conductive interface layer, ensuring stable contact between the ends of the two independently sealed channels while compensating for assembly deviations and differences in thermal expansion. This design avoids the risks of working fluid leakage and air ingress caused by detachable fluid joints. The resilient compression fitting 702 can adaptively compensate for assembly deviations, differences in thermal expansion, and minor displacements during the connection process. Therefore, multiple structural plate modules can be spliced ​​and expanded according to actual application requirements, maintaining structural connection reliability to form a scalable modular structure and its application configuration.

[0071] Example 3 like Figure 10-11 As shown, this invention, based on the functional zoning of the structural panel, further establishes a regionalized parameter design and zoning manufacturing scheme. According to the differences in the roles of different regions in load-bearing, heat conduction, connection, and auxiliary functions, different structural parameter design and manufacturing control requirements are assigned to each region of the structural panel. Among them, the large area located in the middle of the structural panel is the main load-bearing zone 102, which is the main channel for structural load transfer; therefore, a load-bearing strengthening parameter zone 801 is designed to ensure its high load-bearing capacity and structural stability.

[0072] The manufacturing method of the structural plate in Example 1 includes the following steps: S1: Establish functional partitions and boundary conditions for the structural plate Based on the service environment, installation method, and functional requirements of the structural plate, the static load, vibration load, impact load, and assembly preload load on the structural plate are determined. The location of the heat source, heat flux density, and heat sink boundary are also determined, and mass constraints on the structural plate are set. On this basis, the structural plate is divided into a heat source area 101, a main load-bearing area 102, a multi-functional area 103, an interface connection area 104, and an assembly area 105. Corresponding mechanical boundary conditions, thermal boundary conditions, mass constraints, and manufacturing constraints are established for each area.

[0073] Based on the equipment mass and its dynamic environment, equivalent inertial loads are applied to each equipment installation location. For the i-th equipment installation location, the equivalent inertial load is expressed as: F i = m i ·a In the formula, F i Let m be the equivalent inertial load exerted by the i-th device on the structural plate. i Let be the mass of the equipment, and 'a' be the equivalent acceleration in the corresponding direction.

[0074] Based on the device power consumption and contact area, the thermal boundary conditions are determined. For the i-th heat source region, its equivalent heat flux density is: q i = P i / A i In the formula, q i Let P be the heat flux density of the i-th heat source region. i For device power consumption, A i This refers to the contact area between the heat source and the structural plate. The heat sink boundary is located on the heat dissipation surface of the structural plate, in the edge heat dissipation area, or at the location of the heat pipe condensation section.

[0075] Simultaneously, a mass constraint condition for the structural plate is set. Let the mass of the solid structural plate be M0, and the mass of the structural plate after lightweight design be M. Then, the following conditions are satisfied: M ≤ ηM0 In the formula, η is the mass constraint coefficient, preferably 0.55 to 0.80.

[0076] S2: Determine the main control objectives for each functional area Based on the role of each functional area, at least one of the following main control objectives is determined: load-bearing stiffness, structural stability, temperature uniformity, heat transfer capacity, local connection reliability, dimensional accuracy, and lightweighting degree. Design constraints corresponding to each main control objective are then established. Specifically, the main load-bearing zone 102 has the main control objectives of load-bearing stiffness, structural strength, buckling stability and fatigue reliability; the heat source zone 101 has the main control objectives of heat diffusion capacity, equivalent thermal resistance and temperature uniformity; the interface connection zone 104 has the main control objectives of local connection strength, perimeter load-bearing capacity and fatigue reliability; the assembly zone 105 has the main control objectives of dimensional stability, assembly datum retention capacity and local stiffness; and the multi-functional zone 103 has the main control objectives of structural weight reduction, auxiliary return flow connection and integration of circuit or detection functions.

[0077] S3: Design of branched load-bearing frame: Determine the arrangement, extension direction and cross-sectional dimensions of the main load-bearing section, first-level sub-supporting section and second-level sub-supporting section of the branched load-bearing frame according to the load boundary conditions and load transfer path, so that the main load-bearing section extends along the main load transfer direction and the sub-supporting sections at each level are arranged in a branched manner along the load diffusion direction. S4: Arrange local gradient lattice reinforcement structures according to local stress characteristics. Based on the stress distribution, stiffness requirements and connection forms of each functional area, a local gradient lattice reinforcement structure 43 is set at least once in the node area, main connection area, around bolt holes and local high stress area of ​​the branched load-bearing skeleton 4, and the lattice topology, cell size, rod diameter, relative density and its gradation method are determined. Specifically, based on the nodal stress, peripore stress, local buckling modes, fatigue-prone locations, and panel deformation distribution obtained from finite element analysis, the local lattice reinforcement region and the relative lattice density are determined. Load-bearing lattice structures, using maple leaf or star lattices, are embedded in the main load-bearing region 102 and the interface connection region 104. A thermally conductive lattice structure is embedded in the heat source region 101, and a chiral honeycomb lattice structure is embedded in the assembly region 105. A gradual transition connection is used between the local gradient lattice reinforcement structure 43 and the dendritic load-bearing skeleton 4 to reduce abrupt changes in stiffness and local stress concentration.

[0078] S5: Arrange the heat pipe system according to the location of the heat source and the boundary of the heat sink. Based on the location of the heat source, the distribution of heat flux density, and the boundary of the heat sink, the arrangement paths of the main heat pipe 301, the first-level branch heat pipe 302, the second-level branch heat pipe 303, and the return pipe 304 are determined. The branching level, pipe diameter, pipe wall thickness, branch spacing, and flow channel cross-section of the heat pipe system are optimized so that heat is gradually collected from the local heat source area and transferred to the heat sink area. S6: Decoupling structure design of force and heat path: A structural isolation zone 604 is set between the heat pipe system 3 and the branched load-bearing frame 4 to reduce the structural load transmitted from the branched load-bearing frame 4 to the heat pipe system 3; A flexible heat-conducting bridge 6 is set between the heat pipe system 3 and the upper panel 1 or the lower panel 2, so that the flexible heat-conducting bridge 6 can compensate for the relative displacement caused by thermal expansion mismatch, structural deformation and assembly deviation while maintaining the continuity of heat transfer. S7: Determine the manufacturing control parameters for each region based on its functions. Based on the main control objectives of each functional area, the corresponding forming parameters and scanning strategies are determined, and the structural plate is formed by additive manufacturing. Specifically, based on the different requirements of each region for density, strength, thermal conductivity and deformation control, four types of process parameters are called according to the principle of zoning and merging, and forming parameters and scanning strategies are assigned to them respectively, including: load-bearing strengthening parameter design 801, thermal control optimization parameter design 802, lightweight parameter design 803, and connection strengthening parameter design 804; at the same time, the forming parameters and scanning strategy elements such as laser power, scanning speed, scanning spacing and scanning sequence are determined.

[0079] The heat source area 101 and its adjacent area are key areas for heat flow convergence and diffusion. Thermal control optimization parameters are designed 802 to improve local heat conduction efficiency and heat diffusion capacity. The main load-bearing zone 102 is designed with load-bearing strengthening parameters 801 to improve density, strength and fatigue reliability, and is formed with higher volumetric energy density. The multi-functional area 103 is mainly used for auxiliary layout, circuit integration and testing functions. Therefore, a lightweight parameter design 803 is adopted to reduce the structural weight while meeting basic usage requirements. The interface connection area 104 and the assembly area 105 mainly undertake the functions of installation, fixing and external connection. Therefore, the connection enhancement parameter design 804 is adopted to improve the strength, rigidity and assembly reliability of the local connection area.

[0080] A parameter transition zone is set between adjacent functional areas to allow the laser power, scanning speed, scanning spacing and scanning strategy to change continuously or in stages, so as to reduce residual stress and interface defects caused by sudden changes in thermal input.

[0081] S8: Post-processing, heat pipe encapsulation, and performance verification Based on the functional partitioning of the current slice layer, the corresponding process parameters and scanning strategies are invoked to implement partitioned forming. During the forming process, coaxial optics, melt pool monitoring, infrared thermography, or layer morphology detection methods are used to collect melt pool state, temperature distribution, and powder spreading quality, and to extract abnormal features such as porosity, lack of fusion, over-melting, and spheroidization. When the monitoring results meet the preset criteria, forming of the current area or the next layer continues; when the criteria are not met, the laser power, scanning speed, scanning spacing, or scanning sequence is adjusted, and the current area is rescanned or subsequent layers are compensated and corrected. The above process is repeated until all layers are manufactured.

[0082] S9: Post-processing, heat pipe encapsulation, and performance verification. After additive manufacturing, residual powder inside the heat pipe system 3 is cleaned through pre-reserved powder removal holes, vacuum holes, or process ports. Cleaning methods include one or more of vibration powder removal, compressed gas purging, vacuum suction, ultrasonic-assisted cleaning, or abrasive flow cleaning. After powder removal, the structural plate undergoes stress-relieving heat treatment; for aluminum-silicon-magnesium alloys or aluminum-based composite materials, a holding time of 300℃~400℃ for 1~3 hours is preferred. Subsequently, the mounting surface, bolt holes, assembly reference surface, and heat pipe encapsulation ports are locally machined. After machining, helium mass spectrometry leak detection, dimensional inspection, industrial CT inspection, thermal resistance testing, thermal cycling testing, static loading, modal testing, and vibration testing are performed to verify the airtightness, structural load-bearing capacity, and thermal control performance of the structural plate.

[0083] The lattice-dendritic load-bearing skeleton-reinforced integrated structural plate of this invention is formed integrally or in stages using metal additive manufacturing processes such as partitioned laser melting, electron beam melting, and directional energy deposition, demonstrating practical manufacturing feasibility. The structural plate of this invention allows for adjustments to the dendritic load-bearing skeleton, localized lattice reinforcement regions, heat pipe system configuration, structural isolation zone form, and flexible thermal bridge parameters according to different application scenarios, exhibiting strong engineering adaptability. This structural plate can be used not only in satellite platforms, aerospace electronic equipment mounting plates, and other applications requiring lightweight, localized reinforcement, and efficient thermal control, but can also be extended to other lightweight load-bearing components with high requirements for structural-thermal control integration, thus possessing excellent industrial practicality.

[0084] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. 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 structural panel, characterised in that, It includes a top panel, a bottom panel, a heat pipe system disposed between the top panel and the bottom panel, and a branched load-bearing frame for supporting the top panel and the bottom panel.

2. The structural panel of claim 1, wherein, The branched load-bearing frame includes at least one main load-bearing section and multiple sub-load-bearing sections connected to the main load-bearing section; the main load-bearing section extends along the main direction of the structural plate and is used to form the main area for load transfer and support of the structural plate; the multiple sub-load-bearing sections branch from the main load-bearing section to the load input area, interface connection area or panel support area.

3. The structural panel of claim 2, wherein, The sub-supporting force section includes a primary sub-supporting force section and a secondary sub-supporting force section; the primary sub-supporting force section is arranged bifurcated on both sides of the main bearing force section; the secondary sub-supporting force section is located at the end of the primary sub-supporting force section.

4. A structural panel as claimed in any one of claims 1 to 3, wherein, The dendritic load-bearing skeleton is provided with a local gradient lattice reinforcement structure at the contact points with the upper panel and the lower panel, and the upper panel, the dendritic load-bearing skeleton, the lattice reinforcement structure and the lower panel are integrally formed.

5. A structural panel as claimed in any one of claims 1 to 4, wherein, The local gradient lattice reinforcement structure can also be set at the branching nodes, trunk connection areas, node areas, bolt-fixed reinforcement points, or local reinforcement locations of the dendritic load-bearing skeleton.

6. A structural panel as claimed in any one of claims 1 to 5 wherein, The heat pipe system includes a main pulse heat pipe, a primary branch heat pipe, a secondary branch heat pipe, a liquid return pipe connected to the condensing section and at least a portion of the primary branch heat pipe, and a working medium sealed inside the heat pipe; at least a portion of the primary branch heat pipe and the secondary branch heat pipe are located near the heat source area, and at least a section of the main pulse heat pipe or a condensing branch connected to it constitutes the condensing section.

7. A structural panel as claimed in any one of claims 1 to 6 wherein, The heat pipe system is located within the clearance space formed by the branched load-bearing frame, and a structural isolation zone is set between the heat pipe system and the branched load-bearing frame; a floating guide structure is set at the end or local position of the main pulse heat pipe.

8. The structural plate according to any one of claims 1-6, characterized in that, The heat source is located above the top panel, and a heat spreader or a high thermal conductivity mounting base is provided between the heat source and the top panel.

9. A method for manufacturing a structural plate according to any one of claims 1-8, characterized in that, Includes the following steps: S1, Working Condition Analysis and Functional Zoning: Based on the service environment, installation method and functional requirements of the structural plate, determine the static load, vibration load, impact load and assembly preload of the structural plate, determine the heat source location, heat flux density and heat sink boundary, and set the mass constraints of the structural plate; on this basis, divide the structural plate into the main load-bearing area, heat source area, interface connection area, assembly area and multi-functional area. S2, Determination of regional main control objectives: Based on the role of each functional area, determine at least one main control objective among load-bearing stiffness, structural stability, temperature uniformity, heat transfer capacity, local connection reliability, dimensional accuracy and lightweighting degree, and establish design constraints corresponding to each main control objective; S3, Design of branched load-bearing frame: Determine the arrangement, extension direction and cross-sectional dimensions of the main load-bearing section, first-level sub-supporting section and second-level sub-supporting section of the branched load-bearing frame according to the load boundary conditions and load transfer path, so that the main load-bearing section extends along the main load transfer direction and the sub-supporting sections of each level are arranged in a branched manner along the load diffusion direction. S4, Local gradient lattice reinforcement structure design: Based on the stress distribution, stiffness requirements and connection forms of each functional area, a lattice reinforcement structure is set at least once in the node area, trunk connection area, around bolt holes and local high stress area of ​​the dendritic load-bearing skeleton, and the lattice topology, cell size, rod diameter, relative density and its gradation method are determined. S5, Heat pipe system design: Based on the location of the heat source, the heat flux density distribution and the heat sink boundary, determine the layout path of the main pulse heat pipe, the first-level branch heat pipe, the second-level branch heat pipe and the return pipe, and optimize the branch level, pipe diameter, pipe wall thickness, branch spacing and flow channel cross section of the heat pipe system so that heat is gradually collected from the local heat source area and transferred to the heat sink area. S6, Decoupling of mechanical and thermal paths: A structural isolation zone is set between the heat pipe system and the branched load-bearing frame to reduce the structural load transmitted from the branched load-bearing frame to the heat pipe system. A flexible thermal bridge is set between the heat pipe system and the upper or lower panel, so that the flexible thermal bridge can compensate for the relative displacement caused by thermal expansion mismatch, structural deformation and assembly deviation while maintaining the continuity of heat transfer. S7, Additive Manufacturing and Performance Verification: Based on the main control objectives of each functional area, determine the corresponding forming parameters and scanning strategies, and perform additive manufacturing on the structural panels.

10. The application of the structural plate according to any one of claims 1-8 in spacecraft structural plates, electronic equipment mounting plates, high heat flux density lightweight load-bearing components, and other structural components with comprehensive requirements for load-bearing, thermal conductivity, and lightweighting.

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