3D printed multi-modal vibration isolation structure for spacecraft component connections

Abstract

The application discloses a 3D printing multi-modal vibration isolation structure for spacecraft component connection, and relates to the technical field of three-dimensional printing structure.The structure can optimize spacecraft vibration reduction and isolation performance, improve spacecraft sensor working performance, and is relatively simple and compact compared with a component structure manufactured by a traditional method.The multi-modal vibration isolation structure comprises a multilayer structure, each layer comprising a plurality of lattice units in an array distribution and having the same shape; the lattice unit comprises a force bearing base and three elastic networks, the three elastic networks are nested with each other from inside to outside, and the three elastic networks are fixedly connected with the force bearing base.The working performance of the spacecraft vibration isolation component is improved, and the application of additive manufacturing in the field of aviation and aerospace is expanded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of three-dimensional printing structure, in particular to the structure design and processing method of the connecting section of the spacecraft parts. BACKGROUND

[0002] With the development of aerospace industry, people have higher and higher requirements for the integration of flight parts, especially in the design of spacecraft vibration isolation units. With different flight attitudes of spaceflight, the spacecraft requires different stiffness of the structure. For example, in the take-off stage of the spacecraft, a vibration isolation unit with small stiffness is needed to alleviate the damage of spacecraft vibration in the take-off stage to sensitive parts. When the aircraft reaches a certain height, especially during the normal working stage of the spacecraft carrying system, the vibration isolation unit that is too sensitive will affect the normal work of various mechanical sensors, so the stiffness of the vibration isolation unit needs to be improved to ensure the normal work of the spacecraft. Metal additive manufacturing is widely concerned in the aerospace industry because of its freedom of forming. It is obvious that there is a good application prospect for using three-dimensional printing technology to manufacture vibration isolation connecting units with controllable gradient stiffness.

[0003] In the process of metal additive manufacturing, various supports are often needed to ensure the forming rate of the parts, but the existence of the support will affect the mechanical properties of the metal material, especially the closed grid unit. The support is easy to remain inside the formed part, affecting the normal work of such a grid, and in severe cases, it may even cause the part to be scrapped. Therefore, when designing the additive manufacturing vibration isolation unit, the machinability of the part also needs to be considered, and the best printing method is to use less support or no support. SUMMARY

[0004] The present application proposes a 3D printed multi-modal vibration isolation structure for spacecraft part connection to optimize the vibration reduction and isolation performance of the spacecraft, improve the working performance of the spacecraft sensor, and the structure of the parts manufactured by the traditional method is relatively simple and compact. And provide a manufacturing method of the above structure, solve the manufacturing and post-processing problem of the grid structure, improve the processing feasibility and working reliability of the structure.

[0005] The technical scheme of the present application is that the multi-modal vibration isolation structure includes a multi-layer structure, each layer includes a plurality of lattice units with the same shape arranged in an array;

[0006] The lattice unit includes a force bearing base and three elastic networks, the three elastic networks are nested with each other from the inside to the outside, and the three elastic networks are fixedly connected with the force bearing base.

[0007] In one lattice unit, the top and bottom ends of the elastic network are force ends, a gap is left between the top ends of adjacent elastic networks, and the bottom ends of three elastic networks are sequentially fixedly connected, and the top end of the outermost elastic network is fixedly connected with the force bearing base. In this way, the overall structure designed has movable end surfaces on the upper and lower surfaces, and the pre-tightening force can be adjusted by adjusting the upper and lower end surfaces to obtain different initial stiffnesses.

[0008] Each lattice unit has three layers of nested elastic grid structures, three elastic grids share one force bearing base, but gaps and force bearing platforms are left between the elastic grids. When compressed, the first-order elastic structure deforms, and the remaining second-order structure does not work, so that a working interval with a first-order fixed elastic modulus is obtained; after adjusting the pre-tightening force, the bottom of the first-order elastic unit and the top of the second-order elastic unit are in rigid contact, so that the first-order and second-order elastic units work together to obtain a working interval with a second-order fixed elastic modulus; with the loading of the pre-tightening force, the bottom of the second-order elastic unit and the top of the third-order elastic unit are in contact, so that a working interval with a third-order elastic modulus is obtained. In practical application of the structure, the stiffness of the structure can be controlled by adjusting the pre-tightening force, so as to adapt to different working conditions of the spacecraft connecting piece and obtain good vibration isolation and reduction effect.

[0009] In one lattice unit, the top and bottom ends of the elastic network are fixedly connected through a plurality of side strip supports, and the shape of the side strip support can be a broken line, an arc, a semicircle, an ellipse, or other units with elastic deformation function.

[0010] The angle of the side wall of the elastic network is not less than 45 degrees with the bottom surface, and the span of the part with a small angle plane is small during printing, so that it can be basically printed without support, avoiding damage to the structure caused by removing the support.

[0011] The force bearing base is in the shape of a cross. In this way, the lattices are connected through cross-shaped lattice ear-shaped supports, and when the part is compressed, there is enough deformation space between the adjacent lattices, which is constrained by the ear-shaped supports. The width of the structure in the horizontal direction basically does not change, and a macroscopic zero Poisson's ratio effect is produced.

[0012] The lattice unit is formed by laser selective melting of 316L stainless steel, and the processing parameters are: laser spot diameter 70 μm, scanning speed 1000 mm / s, laser power 180 w, and powder layer thickness 30 μm.

[0013] The lattice unit is formed by laser selective melting of 316L stainless steel, and after the part is processed, stress annealing is performed at a medium temperature of 400℃ in a muffle furnace for two hours, and then the part is cut off from the substrate using a wire cutting.

[0014] The surface of the lattice unit is processed by using plasma polishing or chemical polishing means to remove the surface residual powder and smooth the surface, so that the structure has good fatigue performance.

[0015] The application can be applied to the aerospace industry and other parts requiring vibration isolation flexible connection. The overall unit of any spatial shape can be formed by a plurality of lattice units, and the array and Boolean operation method can be used to fill the inside of any cavity in need of vibration reduction and isolation.

[0016] Preferably, the structure is integrally formed with two parts to be connected, and the distance between the two parts is designed to be adjustable in design, so that the connection stiffness between the two parts is changed by adjusting the distance between the parts, thereby achieving good vibration isolation effect.

[0017] Preferably, the side strip-shaped support shape of the structure can be changed to semicircular, elliptical, etc. with elastic deformation function.

[0018] Preferably, chemical polishing or ion polishing means can be used to smooth the surface of the part after processing to improve the fatigue performance of the structure.

[0019] Preferably, multiple layers of grids can be nested in the structure to realize variable multi-gradient stiffness.

[0020] Preferably, the orientation of the lattice unit of the structure can be adjusted to realize the manufacturing of a multi-angle gradient stiffness vibration isolation system.

[0021] The application has the following beneficial effects:

[0022] 1. The method of the application is beneficial to the integrated forming design and manufacturing of spacecraft parts, improves the working performance of the spacecraft vibration isolation parts, and expands the application of additive manufacturing in the field of aerospace.

[0023] 2. The application uses three-dimensional printing technology to manufacture an integrated elastic grid structure that is difficult to manufacture by traditional processing methods, and the manufacturing and assembly are simple, which is beneficial to reducing the overall volume of spacecraft parts and improving the carrying efficiency of spacecraft.

[0024] 3. The application realizes the support-free printing of spacecraft parts, simplifies the processing procedure, and accelerates the update iteration rate of spacecraft parts. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of the basic lattice unit structure of the application;

[0026] Figure 2 is a schematic diagram of the array arrangement and combination of the lattice unit in the embodiment of the application;

[0027] Figure 3These are three-view diagrams showing the array arrangement of lattice units in an embodiment of the present invention. Detailed Implementation

[0028] To clearly illustrate the technical features of this patent, the following detailed description is provided through specific embodiments and in conjunction with the accompanying drawings.

[0029] This invention is produced using laser selective melting forming technology, and its basic lattice unit is as follows: Figure 1 As shown, the gradient elastic modulus function of the structure is achieved through the internal design of multi-layered elastic support units and load-bearing platforms. The overall structure obtained by arraying these units exhibits zero Poisson's ratio characteristics. Figure 2 As shown, the lateral dimension of this structure remains essentially unchanged when it is compressed.

[0030] Structural Working Principle: Because this structure is supported by a complex mesh, it requires metal printing technology primarily based on laser selective melting. Its basic three-view diagram is shown below. Figure 3 As shown, the basic unit structure consists of three platforms that have no contact with each other except for sharing a common support plane. Under compression, the primary elastic structure deforms while the secondary structures remain inactive, resulting in a working range with a first-order fixed elastic modulus. When the preload is adjusted, the bottom of the primary elastic unit makes rigid contact with the top of the secondary elastic unit, thus the primary and secondary elastic units work together to obtain a working range with a second-order fixed elastic modulus. With the application of preload, the bottom of the secondary elastic unit contacts the top of the tertiary elastic unit, resulting in a working range with a third-order elastic modulus. Furthermore, multiple basic unit arrays can form a grid structure with zero Poisson bit properties, which exhibits virtually no lateral deformation during longitudinal compression.

[0031] A 3D-printed multimodal vibration isolation structure for connecting spacecraft components, designed based on the above principles, includes the following steps:

[0032] S1. Analyze the spatial three-dimensional shape of the part that needs to use the connector using three-dimensional modeling software in the computer, and regularize the shape;

[0033] S2. The lattice units designed in this invention are arranged and expanded to fill the working space of the above-mentioned connector. Note that Boolean operations should be avoided directly for filling the lattice units, otherwise the lattice may be damaged.

[0034] S3. During manufacturing, print this structure vertically as much as possible to prevent printing failure of lattice units or reduction of mechanical properties due to printing overhang.

[0035] S4, after printing, first put the parts in the muffle furnace to carry out 400℃ stress relief annealing, the parts are cut by wire cutting, and the residual powder on the surface of the structure is treated by sand blasting and chemical polishing, and the surface is smoothed.

[0036] The present application has many specific implementation approaches, and the above description is only the preferred embodiment of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements can be made, and these improvements should be considered as the protection scope of the present application.

Claims

1. A 3D printed multi-modal vibration isolation structure for spacecraft component connections, characterized by, The lattice unit comprises a force bearing base and a first elastic network, a second elastic network and a third elastic network, which are nested from inside to outside and connected with the force bearing base; The first elastic network has a first force receiving end, and the second elastic network has a second force receiving end, and there is a preset gap between the first force receiving end and the second force receiving end in the initial state; When the load or pre-tightening force of the vibration isolation structure is in the first working interval, only the first elastic network is elastically deformed, so that the vibration isolation structure presents the first order stiffness; When the load or pre-tightening force increases to the second working interval, the first force receiving end and the second force receiving end are in contact and bear force together, so that the structure presents the second order stiffness which is significantly higher than the first order stiffness, thereby realizing the modal switching of the vibration isolation stiffness; The second elastic network and the third elastic network are also provided with a preset gap, and when the load or pre-tightening force further increases to the third working interval, the force receiving end of the second elastic network and the force receiving end of the third elastic network are in contact, so that the vibration isolation structure presents the third order stiffness which is higher than the second order stiffness. In one lattice unit, the bottom ends of the first elastic network, the second elastic network and the third elastic network are sequentially fixed and connected to form a common base, and the force receiving ends of the top ends are separated from each other and form the preset gap.

2. The 3D printed multi-modal vibration isolation structure for spacecraft component connections of claim 1, wherein, In one lattice unit, the top end and the bottom end of the elastic network are fixed and connected through a plurality of side strip supports, and the shape of the side strip support is a broken line or an arc, so as to provide elastic deformation and realize self-supporting in the 3D printing process.

3. The 3D printed multi-modal vibration isolation structure for spacecraft component connections of claim 1, wherein, The force bearing base is in the shape of a cross, which is used to provide deformation space for the elastic networks of adjacent lattice units without interference when bearing compression load, so that the overall structure presents a zero Poisson's ratio effect.

4. The 3D printed multi-modal vibration isolation structure for spacecraft component connections of claim 1, wherein, The surface of the lattice unit needs to be polished or chemically polished to remove surface residual powder and smooth the surface.

5. The 3D printed multi-modal vibration isolation structure for spacecraft component connections of claim 1, wherein, ​

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