CN107140238B - High-efficiency kinetic energy dissipation protective screen - Google Patents

Abstract

The invention discloses a kinetic energy high-efficiency dissipation protective screen, which comprises a high-performance wave impedance gradient material, a porous material and a back plate which are sequentially welded or adhered, wherein the high-performance wave impedance gradient material is formed by arranging two or more material components in a sequence from high wave impedance to low wave impedance; the porous material of the second layer has a cellular or foam porous structure and can further absorb the kinetic energy of the fragments; the back plate of the third layer is an alloy back plate, which mainly plays a role in fixing and simultaneously dissipates the kinetic energy of the fragments again. The protective structure has the characteristics of light weight, high integration level, small occupied space, flexible use and the like, can efficiently dissipate and disperse the kinetic energy of space debris, and greatly improves the capacity of resisting the space debris of the spacecraft on the premise of not increasing the weight and the occupied space.

Description

High-efficiency kinetic energy dissipation protective screen

technical field

The invention relates to the technical field of space debris protection, in particular to a space debris protection structure that dissipates kinetic energy efficiently.

Background technique

The extremely high pressure generated by the impact of space debris exceeds the yield strength of the spacecraft material by tens to hundreds of times, which will penetrate the surface of the spacecraft, destroy the internal devices and systems, cause serious damage to the function of the spacecraft, and even lead to the complete disintegration of the spacecraft/ Explosive failure. In the 1940s, astrophysicist F.L. Whipple proposed to place a layer of metal sheet at a certain interval outside the spacecraft to break the projectile, consume the kinetic energy of the projectile, and change the point load of the incident projectile into a surface load, thereby reducing the amount of space required by the spacecraft. Damaged by the impact of a micrometeoroid, the structure is known as the Whipple Shield. The commonly used space debris protection structures in the world are developed and evolved on the basis of the Whipple protection structure, including: single protection screen reinforced protection structure, multi-layer impact protection structure and filled Whipple protection structure.

Material properties have a great influence on the protective ability of protective structures. For the selection of spacecraft protective materials, it is required that it can effectively shatter the incoming space debris, and transmit and dissipate more of its impact energy, so as to achieve the purpose of resisting impact and effectively protecting the spacecraft. Compared with foreign countries, due to the limitation of the ability to prepare advanced protective materials, there is a big gap in spacecraft protection in China. Some protective screens improve the crushing ability of space debris by sacrificing surface flatness and through surface profile treatment [CN102514737A, CN102490912A], or adopt two-layer or multi-layer protective screen design [CN102514737A, CN105109709A, CN103466104A], to resist the impact of space debris , which complicates the structure and occupies a lot of valuable space resources on the spacecraft.

Due to the harsh requirements of aerospace material engineering applications, it is of great significance to develop a protective structure with low density, simple structure, small volume, and flexible application.

SUMMARY OF THE INVENTION

Aiming at the severe situation of the space debris environment and the urgent need for spacecraft debris protection, the present invention proposes a novel space debris protection structure with the characteristics of efficient dissipation of kinetic energy, which improves the safety and reliability of the spacecraft.

The invention takes limiting the surface density of the protective screen as a constraint condition to ensure the lightweight of the protective structure, adopts an integrated plane single protective screen structure, reduces the distance between it and the bulkhead, and releases more usable space.

The present invention adopts the following technical scheme to realize:

High-efficiency kinetic energy dissipative protective shield, including high-performance wave impedance gradient material, porous material and back plate welded or adhesively connected in sequence, wherein the high-performance wave impedance gradient material of the first layer is composed of two or more material components in wave form. The impedance is arranged in order from high to low. The outer surface, as the impacted surface, has the highest wave impedance, which fully breaks the space debris. The subsequent low-impedance part changes the shock wave transmission path and time, and fully disperses and dissipates the kinetic energy of the debris. The porous material has the porous structure of honeycomb or foam, which can further absorb the kinetic energy of debris; the back plate of the third layer is an alloy back plate, which mainly plays a role of fixing and dissipates the kinetic energy of debris again.

Among them, the high-performance wave impedance gradient material includes alloy materials such as titanium alloy, aluminum alloy or magnesium alloy.

Wherein, the high-performance wave impedance gradient material is prepared by rolling or powder metallurgy method.

Further, the surface of the high-performance wave impedance gradient material is treated by surface strengthening treatment.

Wherein, the surface strengthening method includes micro-arc oxidation or surface shot peening to improve the hardness and strength of the windward surface of the protective screen.

Wherein, the porous material is aluminum honeycomb panel, foamed aluminum, foamed magnesium and/or polyurethane foam.

Wherein, the back plate is a light alloy back plate of aluminum alloy or magnesium alloy.

Further, the thickness ranges of the high-performance wave impedance gradient material, the porous material and the back plate are 0.5-2.0 mm, 1.5-5.0 mm and 0.2-0.5 mm, respectively.

Further, the limited surface density of the protective screen is used as a constraint condition to ensure that the weight of the protective structure does not increase.

Wherein, the areal density of the protective structure is equal to that of 1 mm thick aluminum alloy.

The protective structure of the present invention integrates high-performance wave impedance gradient material, porous material and back plate, and is placed at a certain distance in front of the bulkhead, which can replace the protective screen of a typical aluminum alloy Whipple structure. The protective structure of the present invention has the characteristics of light weight, high integration, small occupied space, flexible use, etc., can efficiently dissipate and disperse the kinetic energy of space debris, and greatly improves the resistance of the spacecraft without increasing the weight and occupied space. Space debris capabilities. The proposed protective structure ensures the flatness of the surface, reduces the distance between the protective screen and the bulkhead, and releases more usable space,

Description of drawings

FIG. 1 is a schematic structural diagram of the space debris protection structure of the present invention for efficient dissipation of kinetic energy.

Among them, 1. high-performance wave impedance gradient material layer; 2. porous material layer; 3. back plate; 4. bulkhead.

Detailed ways

The following introduces specific embodiments as the content of the present invention, and the content of the present invention will be further clarified below through specific embodiments. Of course, the following specific embodiments are described only to illustrate different aspects of the present invention and should not be construed as limiting the scope of the present invention.

The space debris protection structure for efficiently dissipating kinetic energy of the present invention, as shown in FIG. 1 , is composed of a protective screen, a distance S and a bulkhead 4, and the key lies in the protective screen for efficient kinetic energy dissipation. The high-efficiency kinetic energy dissipation protective screen is composed of a high-performance wave impedance gradient material 1, a porous material 2 and a back plate 3, and the thickness of the high-performance wave impedance gradient material, the porous material and the back plate is limited by the limited surface density of the protective screen. Optimized design to keep the structure lightweight while improving the protection performance.

The first layer is a high-performance wave impedance gradient material, which is composed of two or more material components arranged in the order of wave impedance from high to low. The impacted surface has the highest wave impedance, which can fully break the space debris. The subsequent low impedance part changes the shock wave transmission path and time, increases the internal energy conversion of the shock wave, and disperses and dissipates the initial kinetic energy of the space debris. In addition, according to the shock wave principle, when the shock wave propagates from the high-impedance material to the low-impedance material, a shock wave and a rarefaction wave are transmitted and reflected at the interface, respectively. This reflected rarefaction wave can further fragment and disperse space debris. In the selection of material components, the influence of other space environmental effects, such as atomic oxygen, space irradiation, etc., should be avoided, and commonly used aerospace metal materials, such as titanium alloys, aluminum alloys, and magnesium alloys, should be used. The wave impedance gradient material is prepared by methods such as rolling or powder metallurgy. The hardness and strength of the windward side of the protective screen can be improved by surface strengthening treatments, such as micro-arc oxidation, surface shot peening, etc., or ceramics and amorphous alloys can be generated to increase the ability to break space debris.

The second layer is a porous material, which is composed of cellular or foamed porous structures, and the material can be aluminum honeycomb panels, foamed aluminum, foamed magnesium, and polyurethane foam. This kind of loose porous material can play a buffering role, change the transmission path of the shock wave again, increase the transmission time, and improve the fragmentation degree of space debris. At the same time, due to the large-scale plastic deformation of the porous material, a large amount of heat is accumulated to make the material melt or even gasify, and the kinetic energy is converted into internal energy to achieve the effect of dissipating kinetic energy. It can be combined with the low-impedance surface of the first layer of wave impedance gradient material by welding or adhesion.

The third layer is the back plate, which plays a fixed role, so that the protective screen maintains a high integrity after being hit. It can also play the role of blocking space debris again and improving the protective performance. Lightweight alloys such as aluminum alloys or magnesium alloys can be used as the backplane. It is combined with the second layer of porous material by welding or adhesion to form an integrated protective screen structure.

After the protective screen is formed, place it at a certain distance in front of the bulkhead (or important parts such as components, pipelines, subsystems, etc. that need to be protected). The spacing can be optimized and adjusted for different spacecraft and different parts according to the actual engineering application. .

Example:

The protective structure consists of:

The first layer: wave impedance gradient material composed of 0.3mm thick TC4 titanium alloy and 0.2mm thick 6061 aluminum alloy;

Second layer: 1.7mm PR-6710 polyurethane foam;

The third layer: 0.2mm thick 6061 aluminum alloy.

The first layer is made of TC4 titanium alloy (4.17g/cm3) and 6061 aluminum alloy (2.69 g/cm3) into a wave impedance gradient material by rolling compound method, and the second layer is made of polyurethane foam with two-component epoxy resin adhesive. Adhere to the low impedance surface of the wave impedance gradient material, and then use a two-component epoxy resin adhesive to adhere the third layer of aluminum alloy to the polyurethane foam, and finally form a kinetic energy efficient dissipation protective screen.

The surface density of the prepared protective screen is equal to that of 1mm thick aluminum alloy, and the distance between the protective screen and the bulkhead is 100 mm. After verification, compared with the traditional aluminum alloy Whipple structure, the protection performance of this structure is greatly improved at 3.5-6.5km/s.

Rolling preparation process and parameters of wave impedance gradient material:

The plate was cut into 100mm×100mm specifications, and the composite surface was brushed and polished, and then 0.3mm thick TC4 titanium alloy (4.17g/cm3) and 0.2mm thick 6061 aluminum alloy (2.69g/cm3) were stacked, four corners Riveted and then put into a heating furnace for heating.

(1) Surface treatment: The oxide film on the surface of titanium alloy and aluminum alloy is unfavorable for rolling composite, so it is necessary to remove the oxide film on the surface before rolling composite. In this embodiment, the surface oxide film is removed by mechanical polishing, and then the surface is rinsed with alcohol or the like.

(2) Riveting: During the rolling composite process, the surface may be oxidized again due to the different mechanical properties (deformation resistance, plasticity and elongation) of titanium and aluminum, and during hot rolling. Therefore, it is necessary to riveting the plates. One purpose is to fix the two plates so that they can be easily bitten during the rolling process and prevent the dislocation of the rolling piece during the rolling process; the other purpose is to prevent the treated surface from re-oxidizing.

(3) Heating: The purpose of heating is to reduce the deformation resistance and improve the bonding performance of the composite board. The temperature used in this embodiment is 420°C-460°C, and the heating time is 15-30min.

轧制速度0.2-0.6m/s；最大轧制力100t。(4) Hot-rolled composite: The riveted titanium/aluminum plate sample is heated and kept for a certain period of time and taken out, and sent to the roll gap for rolling to generate a certain reduction. The parameters of the two-roll mill in the hot rolling process are:

The rolling speed is 0.2-0.6m/s; the maximum rolling force is 100t.

Although the specific embodiments of the present invention have been described and illustrated in detail above, it should be pointed out that those skilled in the art can make various equivalent changes and modifications to the above embodiments according to the spirit of the present invention, and the resulting All functions and effects shall fall within the protection scope of the present invention as long as they do not exceed the spirit covered by the description and the accompanying drawings.

Claims (6)

1. The kinetic energy efficient dissipation protective screen comprises a planar high-performance wave impedance gradient material, a porous material and a back plate which are sequentially welded or adhered, wherein the high-performance wave impedance gradient material of the first layer is prepared by rolling and compounding two or more material components, the wave impedances are sequentially arranged from high to low, the outer surface as an impacted surface has the highest wave impedance, space debris is fully crushed, the subsequent low impedance part changes the transmission path and time of shock waves, and the kinetic energy of the debris is fully dispersed and dissipated; the porous material of the second layer has a cellular or foam porous structure and can further absorb the kinetic energy of the fragments; the back plate of the third layer is an alloy back plate which mainly plays a role in fixing and simultaneously dissipates the kinetic energy of fragments again, and the high-performance wave impedance gradient material comprises titanium alloy, aluminum alloy or magnesium alloy; and the weight of the protective structure is not increased by taking the limited density of the protective screen as a constraint condition, wherein the surface density of the protective structure is equal to that of the aluminum alloy with the thickness of 1 mm.

2. The kinetic energy efficient dissipation shield of claim 1, wherein the high performance wave impedance gradient material has its surface treated by surface strengthening treatment.

3. The kinetic energy high efficiency dissipative protective shield of claim 2, wherein the surface enhancement comprises micro-arc oxidation or surface peening to increase the stiffness and strength of the windward side of the shield.

4. The kinetic energy high efficiency dissipative protective shield of any of claims 1 to 3, wherein the cellular material is aluminum honeycomb, aluminum foam, magnesium foam, or polyurethane foam.

5. The kinetic energy efficient dissipation shield of claim 1, wherein the back plate is a lightweight alloy back plate of aluminum alloy or magnesium alloy.

6. The kinetic energy high efficiency dissipative protective shield of any of claims 1 to 3, wherein the thickness of the high performance wave impedance gradient material, the porous material, and the backing plate ranges from 0.5 to 2.0mm, 1.5 to 5.0mm, and 0.2 to 0.5mm, respectively.

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