阅读说明：本技术 一种高韧性纤维增强泡沫铝梯度抗爆复合结构 (High-toughness fiber-reinforced foamed aluminum gradient anti-explosion composite structure ) 是由 刘雄飞 王楠 郝逸飞 和西民 于 2021-01-13 设计创作，主要内容包括：本发明为一种高韧性纤维增强泡沫铝梯度抗爆复合结构,属于防护结构技术领域。该复合结构,它包含中间层的泡沫铝梯度层,并在泡沫铝层的两侧分别对称粘贴对位芳纶纤维复合板层,夹芯层和面层之间采用胶接制备而成。基于面层大变形特性将爆炸冲击荷载引起的面内均布拉载荷,结合芯层梯度结构主要承担由面层均布荷载引起的剪应力,形成“三明治”式的梯度抗爆耗能复合结构。本发明研制出轻质梯度高强抗爆防护面板结构,解决了军方临时性营地人员与设备抗爆应急防护问题,避免对人员与设施造成损伤与破坏。(The invention relates to a high-toughness fiber-reinforced foamed aluminum gradient anti-explosion composite structure, and belongs to the technical field of protective structures. The composite structure comprises a foamed aluminum gradient layer in a middle layer, para-aramid fiber composite board layers are symmetrically adhered to two sides of the foamed aluminum layer respectively, and the sandwich layer and the surface layer are prepared by glue joint. Based on the large deformation characteristic of the surface layer, tensile loads are uniformly distributed in the surface caused by the explosion impact load, and the sandwich-type gradient antiknock energy-consumption composite structure is formed by mainly bearing the shear stress caused by the uniformly distributed loads of the surface layer by combining the gradient structure of the core layer. The invention develops a light gradient high-strength anti-explosion protection panel structure, solves the anti-explosion emergency protection problem of temporary camp personnel and equipment in the military and avoids the damage and destruction to personnel and facilities.)

1. A high-toughness fiber-reinforced foamed aluminum gradient anti-explosion energy-consumption composite structure is characterized by comprising two para-aramid fiber panels and a foamed aluminum sandwich layer, wherein the foamed aluminum sandwich layer is formed by bonding foamed aluminum with different densities together in the density increasing direction; the cross sections of the foamed aluminum sandwich layer and the para-aramid fiber panels are identical in shape and size, and the two para-aramid fiber panels comprise an upper panel and a lower panel which are respectively adhered to the top surface and the bottom surface of the foamed aluminum sandwich layer by using interface adhesives.

2. The composite structure as claimed in claim 1, wherein the thickness of the foamed aluminum sandwich layer is not more than 90mm, the thicknesses of the foamed aluminum layers with different densities are the same, the thickness of each foamed aluminum layer is not more than 30mm, and the density of the foamed aluminum is not more than 0.55g/cm³。

3. The composite structure of claim 2 wherein the aluminum foam has a thickness of 8mm to 30mm and a density of 0.25 to 0.55g/cm³Within a range.

4. The composite structure of claim 2, wherein the number of the foamed aluminum with different densities in the foamed aluminum sandwich layer is three, and the density value intervals of the three layers of foamed aluminum are respectively as follows: 0.25-0.3g/cm³，0.3-0.4g/cm³、0.4-0.5g/cm³。

5. The composite structure of claim 1, wherein the para-aramid fiber panel is a para-aramid fiber composite material formed by combining para-aramid fibers according to a bonding mode of fibers and a fiber binder, the para-aramid fiber composite material has the tensile strength of 3.0-5.5 GPa, the elastic modulus of 80-160 GPa, the elongation at break of about 5 percent, and the longitudinal thermal expansion coefficient of-4 x 10^-6～-2×10^-6℃^-1A transverse thermal expansion coefficient of 5.9X 10^-5℃^-1。

6. The composite structure as claimed in claim 4, wherein the weaving manner of the para-aramid fiber composite material comprises a two-dimensional and/or three-dimensional weaving manner with the specification of 100-300D; the fiber adhesive is selected from high-strength epoxy resin adhesive and tough epoxy resin adhesive, the ultimate tensile stress and the fracture strain of the high-strength epoxy resin adhesive are respectively 49.2MPa and 0.99 percent, and the ultimate tensile stress and the fracture strain of the tough epoxy resin adhesive are respectively 10.4MPa and 47.2 percent; the relative content volume ratio of the fiber to the resin is 0.4-1.0.

7. The composite structure of claim 1, wherein the interfacial bonding agent comprises epoxy resin E-51, epoxy resin E-44, curing agent TJ-500, diluent 501, defoamer A530, silane coupling agent KH-560, silica micropowder 400 mesh, toughening agent D-400 and toughening agent D2000, and the weight ratio of each component is as follows: epoxy resin E-51: epoxy resin E-44: curing agent TJ-500: diluent 501: defoaming agent A530: silane coupling agent KH-560: the silicon micropowder is 400 meshes: a toughening agent D-400: toughening agent D2000 ═ 70: 30: 25: 15: 0.7: 1.75: 180: 6: 3.

Technical Field

The invention belongs to the technical field of protective structures. In particular to a gradient anti-explosion energy-consumption composite structure of high-toughness fiber-reinforced foamed aluminum.

Background

The explosion impact load effect is generated by terrorist explosion attack or inflammable material explosion, and a strong compression wave is generated in the explosion process, so that military fighters and equipment are seriously harmed in a limited space and a very short time. The rapid development of modern firearms, missiles and other thermal weapons and the potential safety hazard of flammable and explosive environments cause serious security threats to personnel and equipment in the army on duty, and the rapid construction of temporary defense works with sufficient anti-striking capacity has urgent requirements.

The existing anti-knock composite structures are various in types, and common high-strength concrete, steel structures and the like are available. Although these anti-explosion composite structures also have a certain anti-explosion effect, they all have the problems of low anti-explosion capability, heavy weight of single body, high cost, relatively poor durability and the like, and the anti-explosion reinforcement of the inner and outer walls of the building by using the common engineering material plates not only has the problems of large required plate thickness or volume, more construction materials and the like, but also has low anti-explosion efficiency. Therefore, the method is difficult to be really popularized and applied in the army and public protection.

At present, most of common light panels are formed by combining foamed aluminum serving as an inner core and a metal plate (such as a steel plate and an aluminum plate) with higher rigidity or a carbon fiber reinforced composite material (CFRP), the high dead weight of the metal plate and the brittle failure form of the CFRP greatly reduce the anti-explosion performance of a composite structure, and uniform foamed materials cannot effectively and gradually buffer and absorb explosion energy.

In the existing documents, ceramic panels are mostly adopted as the surface layer of the composite structure, the ceramic panels have large self weight and brittleness and lower strength, good results are not made up till now, and meanwhile, only a certain bulletproof effect can be achieved on the area contacted with the front face of a bullet, but in the design of the bulletproof composite material, the system research of the material failure mechanism under the combined action of explosion and impact penetration because the tensile wave reflected by the shock wave on the free surface can also seriously damage the structure is not considered, so that the bulletproof composite material is not suitable for the design of an anti-explosion structure.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a high-toughness fiber-reinforced foamed aluminum gradient anti-explosion energy-consumption composite structure, which is a light protective panel formed by bonding foamed aluminum with different densities as sandwich layers and para-aramid fiber composite plates on two sides of the gradient foamed aluminum through an interface binder to form the composite structure and is suitable for the anti-explosion and anti-impact field with requirements on high-speed deformation.

In order to achieve the purpose, the invention adopts the technical scheme that:

a high-toughness fiber-reinforced foamed aluminum gradient anti-explosion energy-consumption composite structure is characterized by comprising two para-aramid fiber panels and a foamed aluminum sandwich layer, wherein the foamed aluminum sandwich layer is formed by bonding foamed aluminum with different densities together in the density increasing direction; the cross sections of the foamed aluminum sandwich layer and the para-aramid fiber panels are identical in shape and size, and the two para-aramid fiber panels comprise an upper panel and a lower panel which are respectively adhered to the top surface and the bottom surface of the foamed aluminum sandwich layer by using interface adhesives.

The thickness of the foamed aluminum sandwich layer is not more than 90mm, the preferable thickness is 20-40mm, the thicknesses of the foamed aluminum with different densities are the same, the thickness of each layer of foamed aluminum is not more than 30mm, and the density of the foamed aluminum is not more than 0.55g/cm³。

The thickness of the foamed aluminum is 8-30 mm, the preferable thickness is 10-20mm, and the density is 0.25-0.55 g/cm³Within a range.

The number of the foamed aluminum with different densities in the foamed aluminum sandwich layer is three, and the density value intervals of the three layers of foamed aluminum are respectively：0.25-0.3g/cm³，0.3-0.4g/cm³、0.4-0.5g/cm³。

The para-aramid fiber panel is formed by combining para-aramid fibers according to a fiber and fiber binder bonding mode to form a para-aramid fiber composite material, the tensile strength of the para-aramid fiber composite material is 3.0-5.5 GPa, the elastic modulus is 80-160 GPa, the elongation at break is about 5%, and the longitudinal thermal expansion coefficient is-4 multiplied by 10^-6～-2×10^-6℃^-1A transverse thermal expansion coefficient of 5.9X 10^-5℃^-1。

The weaving mode of the para-aramid fiber composite material comprises a two-dimensional and/or three-dimensional weaving mode, and the specification is 100-300D; the fiber adhesive is selected from high-strength epoxy resin adhesive and tough epoxy resin adhesive, the ultimate tensile stress and the fracture strain of the high-strength epoxy resin adhesive are respectively 49.2MPa and 0.99 percent, and the ultimate tensile stress and the fracture strain of the tough epoxy resin adhesive are respectively 10.4MPa and 47.2 percent; the relative content volume ratio of the fiber to the resin is 0.4-1.0.

The interface binder comprises epoxy resin E-51, epoxy resin E-44, a curing agent TJ-500, a diluent 501, a defoaming agent A530, a silane coupling agent KH-560, silica powder of 400 meshes, a toughening agent D-400 and a toughening agent D2000, and the weight ratio of each component is as follows: epoxy resin E-51: epoxy resin E-44: curing agent TJ-500: diluent 501: defoaming agent A530: silane coupling agent KH-560: the silicon micropowder is 400 meshes: a toughening agent D-400: toughening agent D2000 ═ 70: 30: 25: 15: 0.7: 1.75: 180: 6: 3.

compared with the prior art, the invention has the following beneficial effects:

the invention relates to a novel light and composite structure which is formed by compounding an upper panel and a lower panel made of para-aramid fibers and a middle light porous foamed aluminum core body through an interface binder. It has several advantages:

1) the foamed aluminum plywood layer is light, the thickness of the used foamed aluminum is less than or equal to 30mm, and the density is less than or equal to 0.55g/cm³The foamed aluminum has a relatively low density, and the density of the foamed aluminum with the porosity of 65-90 percent is 0.25g/cm³～0.55g/cm³The foamed aluminum sandwich plate taking foamed aluminum as the core also has light weightQualitative characteristics. The foamed aluminum sandwich layer has higher specific strength, namely the bearable weight can reach more than 60 times of the self weight. When the foamed aluminum sandwich plate is subjected to bending deformation, the foamed aluminum sandwich plate has the bending rigidity which is about 1.5 times that of steel; the foamed aluminum sandwich layer does not have the ductility as that of a compact metal, and can not deform under strong impact when the pore structure of the core foamed aluminum is not damaged, and the anti-explosion performance is excellent under the thicker foamed aluminum sandwich layer.

2) According to the invention, three layers of foam aluminum layers with different pores are arranged between two layers of para-aramid fiber layers to form a light gradient anti-explosion protection panel structure, and a large amount of explosion energy is gradually dissipated through a gradient structure constructed by foam aluminum with different densities by utilizing the large deformation energy absorption capacity of the foam aluminum. The explosive load is transferred to the front panel of the sandwich structure, the front panel instantly obtains an initial impact velocity, and the middle sandwich layer and the structural back panel are kept in a static state. The intermediate aluminum foam sandwich layer is compressed to plastically deform and absorb a large amount of impact energy, while the back plate remains stationary. When the deformation of the panel and the crushing of the sandwich layer completely consume explosion energy, the back plate (the para-aramid fiber layer) does not deform, and when the explosion impact energy cannot be completely absorbed by the front panel and the sandwich layer, the back plate also consumes energy through self bending deformation. The anti-explosion performance of the composite anti-explosion structure is ensured, the overall quality of the composite anti-explosion structure is greatly reduced, and the requirements of anti-explosion and light weight are met.

3) The composite structure is formed by compounding the para-aramid fiber serving as the panel and the gradient foamed aluminum serving as the sandwich, has stronger bearing capacity compared with pure foamed aluminum, can fully exert the wave-absorbing performance of the gradient foamed metal and the wave-absorbing coating, and has stronger wave-absorbing performance. The electromagnetic interference can be reduced by more than 80% in the electromagnetic wave high frequency region, and the electromagnetic wave high frequency filter can be used in electromagnetic shielding rooms, radio recording rooms, electromagnetic shielding and other occasions.

4) The invention has the advantages of light weight, strong designability, accurate and controllable content, controllable product thickness and fiber volume fraction, stable product quality, high product quality consistency and reliability and the like, and has the advantages of simple forming process, performance far higher than that of the traditional glass fiber reinforced plastic and metal materials and the like, light weight, high strength, environmental protection, realization of light weight on the premise of meeting the material performance requirements, and great application potential and market value.

5) The high-toughness reinforced foamed aluminum gradient anti-explosion energy-consumption composite structure comprehensively considers the influence of explosion load and impact penetration load on material failure, and fully exerts the mechanical property of the composite foamed aluminum structure under the action of high-speed impact. The peak stress of the material is improved along with the increase of the initial impact speed of the drop hammer, the stress peak value is improved from 99MPa to 135MPa and is improved by 35.6 percent, and the mechanical property of the composite foamed aluminum structure is fully exerted under the impact action of higher speed; the energy peak value of the composite foamed aluminum is increased from 76J to 185J, which is 2.4 times of that of the former, and the energy peak value is greatly increased under different drop hammer speeds.

6) The composite structure fully analyzes the influence of material parameters and environment influence parameters (different interface binder types and binding performances) on the strength, toughness and anti-explosion performance of the light panel, considers different weaving modes of para-aramid fibers and relative content ratios of the para-aramid fibers and the binders, considers factors in multiple layers, multiple mechanism energy absorption principles and other aspects, develops the light gradient high-strength anti-explosion protection panel structure, and finds out the dynamic response and impact damage mechanism of the light panel. The weaving mode with the minimum strength anisotropy and the cooperation of the weaving mode with the minimum strength anisotropy meet the parameter conditions of the optimal tensile strength and the optimal deformability, and the composite structure with light weight, good absorption performance, excellent anti-explosion performance and excellent anti-ballistic performance is obtained. The invention selects the para-aramid fiber with excellent thermal stability, high crystallinity, high orientation structure, high tensile property, low density and other excellent properties as the panel, and the material and the foamed aluminum sandwich layer act synergistically, can fully exert the energy absorption and buffering properties of the foamed aluminum, and effectively attenuate the explosion shock wave, and has remarkable effect.

Drawings

FIG. 1 is a physical sectional structural view of the different density gradient foamed aluminum material of the antiknock composite structure of the present invention;

FIG. 2 is a schematic diagram of three components of a high-toughness fiber-reinforced foamed aluminum gradient anti-explosion energy-dissipation composite structure according to the present invention;

FIG. 3 is a stress-strain plot of a foam aluminum sandwich layer with a drop weight velocity of 4m/s in example 1;

FIG. 4 is a stress-strain plot of a foam aluminum sandwich layer having a drop weight velocity of 6m/s in example 1;

FIG. 5 is a graph of the 4m/s impact energy absorption time course of the foamed aluminum sandwich layer in example 1;

FIG. 6 is a graph of the impact energy absorption time course of 6m/s for the foamed aluminum sandwich layer of example 1;

FIG. 7 is a stress-strain plot of a conventional adhesive aluminum foam sandwich layer with a drop weight velocity of 4m/s in example 2;

FIG. 8 is a stress-strain plot of a conventional adhesive aluminum foam sandwich layer with a drop weight velocity of 6m/s in example 2;

FIG. 9 is a graph of the 4m/s impact energy absorption time course of a conventional adhesive foamed aluminum sandwich layer in example 2;

FIG. 10 is a graph of the 6m/s impact energy absorption time course of a conventional adhesive foamed aluminum sandwich layer in example 2.

Detailed Description

The present invention is further explained by the following examples, which should not be construed as limiting the scope of the present invention.

The invention relates to a high-toughness fiber-reinforced foamed aluminum gradient anti-explosion energy-consumption composite structure which comprises two para-aramid fiber panels (having an anti-explosion effect and a bulletproof effect simultaneously) and a foamed aluminum sandwich layer, wherein the foamed aluminum sandwich layer is a gradient structure formed by multiple layers of foamed aluminum with the same thickness and different densities, the cross sections of the foamed aluminum sandwich layer and the para-aramid fiber panels are completely the same in size, the foamed aluminum sandwich layer is formed by bonding foamed aluminum with different densities in the increasing direction, the two para-aramid fiber panels comprise an upper panel and a lower panel, and interface bonding agents are respectively used for bonding the top surface and the bottom surface of the foamed aluminum sandwich layer to form a light high-strength protective panel structure.

Foamed aluminum: the thickness is 10 mm-30 mm, and the density is 0.25-0.55 g/cm³The porosity: 63-90 percent and the aperture is 0.3-7 mm.

Alignment ofThe aramid fiber panel is made of para-aramid fiber composite materials, and the para-aramid fiber composite materials comprise: the weaving mode comprises a two-dimensional and/or three-dimensional weaving mode, and the specification is 100D-300D, such as 100D, 200D or 300D; the fiber adhesive is selected from high-strength epoxy resin adhesive and tough epoxy resin adhesive, the ultimate tensile stress and the fracture strain of the high-strength epoxy resin adhesive are respectively 49.2MPa and 0.99 percent, and the ultimate tensile stress and the fracture strain of the tough epoxy resin adhesive are respectively 10.4MPa and 47.2 percent; the relative content volume ratio of the fiber to the resin is 0.4-1.0, such as 0.4, 0.6, 0.8 and 1.0. The tensile strength of the para-aramid fiber composite material is 3.0-5.5 GPa, the elastic modulus is 80-160 GPa, the elongation at break is about 3 percent, and the longitudinal thermal expansion coefficient is-4 multiplied by 10^-6～-2×10^-6℃^-1A transverse thermal expansion coefficient of 5.9X 10^-5℃^-1。

Interface adhesive: the adhesive is composed of epoxy resin (E-51, E-44), a curing agent TJ-500, a diluent 501, a defoaming agent A530, a silane coupling agent KH-560, a silica micropowder 400 mesh, a toughening agent D-400 and a toughening agent D2000, and the adhesive comprises the following components in parts by weight: epoxy resin E-51: epoxy resin E-44: curing agent TJ-500: diluent 501: defoaming agent A530: silane coupling agent KH-560: the silicon micropowder is 400 meshes: a toughening agent D-400: toughening agent D2000 ═ 70: 30: 25: 15: 0.7: 1.75: 180: 6: 3.

example 1

The high-toughness fiber-reinforced foamed aluminum gradient anti-explosion energy-consumption composite structure comprises the following components:

foamed aluminum: each layer is 10mm thick and the density is 0.25-0.55 g/cm³The porosity: 63-90 percent and the aperture is 0.3-7 mm. The density of the multilayer foamed aluminum is 0.26g/cm in sequence³，0.38g/cm³、0.44g/cm³In this embodiment, the total three-layer is lighter, can avoid bonding too much, guarantees antiknock effect.

Para-aramid fiber composite material: the weaving mode comprises two-dimensional and three-dimensional weaving modes, and the specification of the para-aramid fiber is 100D; the fiber binder is selected from high-strength epoxy resin glue and tough epoxy resin glue, and the ultimate tensile stress and fracture of the high-strength epoxy resin glueThe strain is 49.2MPa and 0.99 percent respectively, and the ultimate tensile stress and the fracture strain of the tough epoxy resin adhesive are 10.4MPa and 47.2 percent respectively; the relative content volume ratio of the fiber to the resin (high-strength epoxy resin glue and tough epoxy resin glue) is 0.8. The tensile strength of the para-aramid fiber composite material is 4.5GPa, the elastic modulus is 102GPa, the elongation at break is about 3 percent, and the longitudinal thermal expansion coefficient is-3.4 multiplied by 10^-6A transverse thermal expansion coefficient of 5.9X 10^-5℃^-1。

Interface adhesive: the adhesive is composed of epoxy resin (E-51, E-44), a curing agent TJ-500, a diluent 501, a defoaming agent A530, a silane coupling agent KH-560, a silica micropowder 400 mesh, a toughening agent D-400 and a toughening agent D2000, and the adhesive comprises the following components in parts by weight: epoxy resin E-51: epoxy resin E-44: curing agent TJ-500: diluent 501: defoaming agent A530: silane coupling agent KH-560: the silicon micropowder is 400 meshes: a toughening agent D-400: toughening agent D2000 ═ 70: 30: 25: 15: 0.7: 1.75: 180: 6: 3.

the preparation method comprises the following steps: the structure comprises two para-aramid fiber panels and a foamed aluminum panel, wherein the cross sections of the foamed aluminum panel and the para-aramid fiber panels are completely the same in shape and size, foamed aluminum with different porosity is arranged in the thickness direction in the direction of increasing the density to prepare a multilayer foamed aluminum structure with different densities, the two para-aramid fiber panels comprise an upper panel and a lower panel, and the upper panel and the lower panel are respectively adhered to the top surface and the bottom surface of a foamed aluminum sandwich layer by adopting adhesives to form a light high-strength protective panel structure.

The blast and impact resistance properties of the composite structure of the present application are described below in conjunction with specific tests.

The experiments were divided into 2 groups: the initial speed of the set 1 drop hammers was 4m/s and the initial speed of the set 2 drop hammers was 6 m/s. The other components are the same as the preparation process and the construction method.

The test adopts a pendulum impact test, different loading rates (namely pendulum height and mass) are set, the pendulum impact test is adopted to measure the impact energy absorption time-course curve of the composite structure according to the dynamic compression test method of the buffer material for packaging (GB8167-87), and a strain gauge and a high-speed camera are adopted to record and obtain a stress-strain curve, so that the deformation and stress process of the composite material can be seen. The stress-strain curves of the foamed aluminum sandwich structure with the drop weight speeds of 4m/s and 6m/s are shown in fig. 3 and fig. 4, and the impact stress-strain curves of the foamed aluminum sandwich structure under different drop weight initial speeds are compared, so that the peak stress of the material is improved along with the increase of the drop weight initial impact speed, the stress peak value is improved from 99MPa to 135MPa, and is improved by 35.6%. The mechanical property of the composite foamed aluminum structure is fully exerted under the impact action of higher speed, and the composite foamed aluminum structure is suitable for the anti-explosion and anti-impact field with requirements on high-speed deformation.

FIGS. 5 and 6 are graphs of the impact energy absorption time courses of the foamed aluminum sandwich layers at 4m/s and 6 m/s: comparing the curves at different initial drop hammer speeds, the energy absorption capacity of the syntactic foam aluminum is enhanced along with the increase of the impact speed, the peak value of the energy of the syntactic foam aluminum is 76J at the impact speed of 4m/s, and the peak value of the energy of the syntactic foam aluminum structure is 185J at the impact speed of 6m/s, which is 2.4 times that of the former.

Example 2

The composition and preparation method of each material in this example are the same as those in example 1, except that the interfacial adhesive in this example is selected from conventional epoxy resin adhesive (composed of epoxy resin E44 and polyamide resin 650), and other conditions are unchanged.

The experiments were divided into 2 groups: the initial speed of the set 1 drop hammers was 4m/s and the initial speed of the set 2 drop hammers was 6 m/s. The other components are the same as the preparation process and the construction method. The pendulum impact test is adopted, different loading rates (namely pendulum height and mass) are set, the pendulum impact test is adopted to measure the impact energy absorption time-course curve of the composite structure according to the dynamic compression test method of the buffer material for packaging (GB8167-87), and a strain gauge and a high-speed camera are adopted to record and obtain a stress-strain curve, so that the deformation and stress process of the composite material can be seen.

FIGS. 7 and 8 are stress-strain curves of a common adhesive foamed aluminum sandwich structure with a drop weight velocity of 4m/s and 6m/s, and comparing the impact stress-strain curves of the foamed aluminum sandwich structure and the common adhesive foamed aluminum sandwich structure at different drop weight initial velocities, it can be seen that the stress peak value of the common adhesive foamed aluminum sandwich layer is reduced by 11.1% compared with the stress peak value of the composite foamed aluminum sandwich layer of example 1 at an impact velocity of 4 m/s; at an impact velocity of 6m/s, the peak stress value of the conventional adhesive foamed aluminum sandwich layer was reduced by 21.5% from that of the composite foamed aluminum sandwich layer of example 1. The invention is more suitable for the anti-knock and anti-impact fields with requirements on high-speed deformation compared with the common binder foamed aluminum sandwich structure in the composite foamed aluminum structure of the example 1.

FIGS. 9 and 10 are the time-course curves of 4m/s and 6m/s impact energy absorption of the conventional adhesive foamed aluminum sandwich layer, and it can be seen from the above figures that, compared with the syntactic foamed aluminum sandwich layer of example 1, the energy peak value of the conventional adhesive foamed aluminum sandwich layer is 10.5% lower than that of the syntactic foamed aluminum sandwich layer of the present invention at an impact speed of 4 m/s; at an impact velocity of 6m/s, the energy peak of the conventional adhesive aluminum foam sandwich layer was 13.6% lower than that of the composite aluminum foam sandwich layer of example 1. Therefore, compared with the embodiment 2, the embodiment 1 has the advantages that the energy peak value is greatly improved under different drop hammer speeds, and the method is more suitable for being applied to an anti-explosion energy consumption structure.

The experimental results can be obviously seen that: within the patent requirement range, the yield strength and the compressive strength of the composite foamed aluminum at a higher strain rate are both greatly improved, and the greater the impact speed is, the more the energy absorption capacity is fully exerted. The composite structure is an effective and simple anti-explosion energy-consumption composite structure and can be popularized and used.

The combination of the gradient foamed aluminum and the para-aramid fiber composite board is adopted in the invention, under the impact action of explosion energy, based on the ultrahigh strength and toughness of the outer para-aramid fiber composite board, the explosion impact and fragment penetration action is converted into distributed load, and a large amount of explosion energy is gradually dissipated through a gradient structure constructed by foamed aluminum with different densities. If the outer side para-aramid fiber composite board and the foamed aluminum are penetrated, the residual kinetic energy is completely absorbed by the inner side para-aramid fiber composite board. The invention combines foamed aluminum and para-aramid fiber to form a sandwich-shaped combined structure, namely, the para-aramid fiber is used as a surface layer, the foamed aluminum is used as a core material, and the foamed aluminum and the core material are combined into a sandwich plate through an interface adhesive, the firm connection effect between the sandwich material and the plate is the key for preparing the high-performance foamed aluminum sandwich material, so that the sandwich plate has certain strength and rigidity, can be used as a structural member bearing use load, can exert the buffering and energy-absorbing characteristics of the foamed aluminum and effectively attenuate explosion shock waves, and the novel sandwich plate taking the foamed aluminum as the core plate has reasonable manufacturing cost, convenient construction and installation and great application prospect in the field of engineering structure anti-explosion.

Nothing in this specification is said to apply to the prior art.