Composite protection device and preparation method and application thereof

Abstract

The invention provides a composite protection device and a preparation method and application thereof, and relates to the technical field of bulletproof. The composite protection device comprises a closely-laid pattern frame and UHPC-CA units filled in the closely-laid pattern frame. The closely laid pattern frame is laterally spliced with the UHPC-CA unit; the elastic material is silicone rubber or nitrile rubber; the closely laid pattern frame comprises a metal hard framework, and the metal hard framework and the UHPC-CA units are separated through an elastic material. The composite protection device can effectively limit expansion of radial cracks, and through mutual constraint of adjacent units, the overall anti-penetration capacity is improved.

Description

Technical Field

[0001] The present invention relates to the field of bulletproof technology, and in particular to a composite protective device and a preparation method and application thereof. Background Art

[0002] With the advancement of weapon technology, the need for protection of building facilities has become increasingly urgent. Facing increasingly complex external threats, how to enhance the anti-penetration performance of building materials has become an important research direction in the field of protection engineering.

[0003] Ultra-high performance concrete (UHPC) has been widely used in protective engineering due to its excellent mechanical properties, durability, crack resistance and toughness. However, traditional UHPC still has certain limitations when facing strong impact or high-energy penetration. Ultra-high performance concrete (UHPC-CA) containing coarse aggregate has become an effective solution to improve penetration resistance. The introduction of coarse aggregate can not only improve the impact and penetration resistance of building materials through the strength and hardness of the aggregate itself, but also further improve the energy absorption effect through the interface effect between the aggregate and the concrete matrix. Compared with UHPC without coarse aggregate, UHPC-CA exhibits more efficient impact resistance in the impact failure mode.

[0004] Although UHPC-CA has made significant progress in improving its anti-penetration performance, how to further improve its performance by optimizing its structural design remains an important technical challenge in the field of protective materials. Improving the material structure and device to more effectively absorb and disperse the impact energy and limit the damage range when facing more complex and higher energy impacts, thereby improving the overall protective performance, has become a research hotspot in this field. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a composite protective device and a preparation method and application thereof. The UHPC-CA material is separated into multiple independent units through a densely laid splicing structure, and the independent units are separated by elastic materials. The advantages of UHPC-CA and elastic materials can be combined to further improve the anti-penetration performance of the device.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions: The first aspect of the present invention provides a composite protective device, comprising a densely laid pattern frame and UHPC-CA units filled in the densely laid pattern frame; the densely laid pattern frame comprises an elastic material; the densely laid pattern frame is laterally spliced ​​with the UHPC-CA units; the elastic material is silicone rubber or nitrile rubber; The raw materials for preparing the UHPC-CA unit include 360-520 parts of cement, 36-52 parts of silica fume, 36-52 parts of fly ash, 800-1000 parts of fine aggregate, 800-1000 parts of coarse aggregate, 39-78 parts of steel fiber, 120-130 parts of water and 5-10 parts of high-efficiency water reducing agent.

[0007] The second aspect of the present invention provides a method for preparing the composite protective device, comprising the following steps: S1. Prepare a UHPC-CA unit of a set shape; S2, preparing a tessellated graphics framework of a set shape; S3. Assemble the UHPC-CA units into a densely laid pattern frame to obtain the composite protective device.

[0008] In a third aspect, the present invention provides application of the above-mentioned composite protective device in protective facilities.

[0009] The beneficial effects of the present invention are as follows: 1. The present invention proposes a composite protective device based on a bionic structure. Drawing on the splicing structure of polygonal units such as tortoise shells in nature, a modular hexagonal frame unit structure is designed to separate the UHPC-CA material into multiple independent units, each of which is separated by an outer ring of elastic material. This design can effectively limit the expansion of radial cracks and improve the overall anti-penetration capability through the mutual constraints of adjacent units. The close combination of densely laid graphics, especially hexagonal units, disperses external forces in multiple directions, thereby preventing material damage. The elastic material of the densely laid graphics frame has high elasticity and energy absorption characteristics, which significantly slows down the propagation of shock waves and the expansion of cracks. A metal hard skeleton is provided inside the frame unit, and the male and female groove structure increases the contact area between the UHPC-CA unit and the densely laid graphics frame, improves the bonding strength, and the metal hard skeleton improves the stability of the entire structure. The metal hard skeleton and the elastic material form a soft-wrapped hard structure. Thus, the protection performance is further improved through the reasonable layout and interaction of multiple materials and structures.

[0010] 2. The structure provided by the present invention adopts a modular design, which is convenient for mass production and rapid on-site assembly. Each UHPC-CA unit is fixed to each other through the embedded structure of the close-laid graphic frame, and a complete protection system is formed by pouring and hardening the UHPC-CA slurry. This assembled structure not only improves the construction efficiency, but also facilitates the later inspection and maintenance, and has good operability.

[0011] 3. The composite protective device provided by the present invention can reduce the amount of UHPC-CA and reduce the weight of the overall structure while achieving the same anti-penetration performance. This lightweight design can reduce the deadweight of the building and improve the material utilization rate without affecting the protective performance, and is suitable for protective facilities with strict weight restrictions. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0013] In order to show the positions of various parts, the distances or sizes between them are exaggerated in the figure, and the schematic diagram is for illustration only.

[0014] Figure 1 It is a schematic diagram of the design concept of the composite protective device in Example 1.

[0015] Figure 2 It is a schematic diagram of the connection structure of the molding die in Example 1.

[0016] Figure 3 It is a structural schematic diagram of the densely-paved graphics framework in Example 1.

[0017] Figure 4 It is a schematic diagram of the structure of the composite protective device in Example 1.

[0018] Figure 5 It is a schematic diagram of the cross-sectional structure of the composite protective device in Example 4.

[0019] Figure 6 It is a schematic diagram of the cross-sectional structure of the composite protective device in Example 5.

[0020] Among them, 1. densely laid graphic frame; 11. groove; 12. elastic material; 2. UHPC-CA unit; 3. projectile; 4. metal hard skeleton; 41. hexagonal frame. DETAILED DESCRIPTION

[0021] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] A composite protective device, comprising a densely laid pattern frame and UHPC-CA units filled in the densely laid pattern frame; the densely laid pattern frame comprises an elastic material; the densely laid pattern frame and the UHPC-CA units are laterally spliced; the elastic material is silicone rubber or nitrile rubber; the densely laid pattern frame comprises a metal hard skeleton, and the metal hard skeleton and the UHPC-CA units are separated by an elastic material; The raw materials for preparing the UHPC-CA unit include 360-520 parts of cement, 36-52 parts of silica fume, 36-52 parts of fly ash, 800-1000 parts of fine aggregate, 800-1000 parts of coarse aggregate, 39-78 parts of steel fiber, 120-130 parts of water and 5-10 parts of high-efficiency water reducing agent.

[0025] Through the above design, the geometric arrangement of the densely laid pattern can effectively disperse the external impact force, and delay the structural damage through the mutual constraint between the densely laid pattern frame and the UHPC-CA unit. The buffering effect of the elastic material and the high strength performance of UHPC-CA are used to achieve stress dispersion and energy dissipation when the material is subjected to impact or penetration, effectively improving its overall anti-penetration performance. The UHPC-CA unit prepared from the above raw materials has a high anti-penetration ability, and the coarse aggregate and steel fiber included therein can effectively reduce its shrinkage degree, so that the prepared UHPC-CA unit can conform to the spatial shape in the densely laid pattern frame.

[0026] Optionally, the elastic modulus of the elastic material is between 0.1 MPa and 10 MPa, and the Shore hardness ranges from A30 to A80, so that it has good energy absorption effect, good toughness, can effectively absorb and disperse energy under impact, and its rigidity can firmly fix and support the UHPC-CA unit laterally spliced ​​therein.

[0027] Optionally, the densely laid graphic frame includes a metal hard skeleton, and the metal hard skeleton is separated from the UHPC-CA unit by an elastic material to ensure the stability of the entire structure when subjected to impact; the metal hard skeleton is made of high-strength steel, and the tensile strength of the high-strength steel is 600~1200MPa and the yield strength is 500~1000MPa.

[0028] Optionally, the outer periphery of the metal rigid skeleton is coated with elastic material, so that the densely packed graphic frame becomes a soft-wrapped hard structure, so as to enhance the energy absorption and energy dispersion effects of the densely packed graphic frame and limit the expansion of cracks; or, the metal rigid skeleton includes a plurality of polygonal frames spliced ​​to each other, and the polygonal frames are separated from the internal UHPC-CA units by elastic material, so that a large number of polygonal frames can more flexibly form a protective device.

[0029] Optionally, the shape of the densely packed graphic frame is one or more of a triangle, a quadrilateral and a hexagon, and can be spliced ​​into a plane through multiple graphics. The shape of the densely packed graphic frame is formed by combining multiple straight line segments, so that the edges of the UHPC-CA units are straight, and the overall structural design of the composite protective device is convenient and easy to manufacture, and the proportion of the elastic material in the composite protective device can be regulated by adjusting the number of graphic edges.

[0030] Optionally, the densely-paved pattern frame and the UHPC-CA unit are spliced ​​via lateral male and female grooves, the male and female grooves comprising grooves and bosses, the height of the bosses being the same as the depth of the grooves, and the lateral male and female groove structure can increase the contact area between the UHPC-CA unit and the densely-paved pattern frame, and the snap-fit ​​structure formed by the cooperation of the grooves and bosses can enhance the splicing strength, thereby ensuring the stability of the overall structure.

[0031] The side length of the UHPC-CA unit is 10 to 20 times the side spacing of adjacent UHPC-CA units. The side spacing is the wall thickness of the dense pattern frame. Combined with the shape design of the dense pattern, the proportion of elastic material and UHPC-CA material in the plane can be flexibly adjusted to meet different anti-penetration performance requirements.

[0032] Optionally, the composite protective device is a structure of equal thickness and can be set as armor on the outer surface of a building.

[0033] Optionally, the height of the densely packed pattern frame and the UHPC-CA unit is 30-100 mm, that is, the overall thickness of the composite protective device is 30-100 mm, and its plane size can be expanded by increasing the number of densely packed patterns; when the densely packed pattern is a regular hexagon, the side length of the UHPC-CA unit is 100-200 mm, the spacing between the opposite sides of adjacent UHPC-CA units is 5-20 mm, the depth of the groove in the male and female grooves is 3-5 mm, and the height of the boss is the same as the groove, so that the two can be spliced ​​with each other, so that the two can be deformed synergistically, thereby effectively exerting the elasticity and energy absorption characteristics of the densely packed pattern frame, significantly slowing down the propagation of shock waves and hindering the expansion of cracks in different UHPC-CA units.

[0034] Optionally, compared with the raw materials for preparing the above-mentioned UHPC-CA units, the UHPC material does not add coarse aggregate and steel fiber, and can fill the space between the UHPC-CA units and the densely laid pattern frame to improve the lateral splicing strength; other raw materials are the same as the raw materials for preparing the UHPC-CA units, which can improve the connection strength between the UHPC material as an adhesive material and the UHPC-CA units.

[0035] Optionally, the coarse aggregate is one or more of basalt, sintered bauxite and corundum, which has a relatively high hardness and is used to enhance the anti-penetration effect of the composite protective device.

[0036] The preparation method of the composite protective device comprises the following steps: S1. Prepare a UHPC-CA unit of a set shape; S2, preparing a tessellated graphics framework of a set shape; S3. Assemble the UHPC-CA units into a densely laid pattern frame to obtain the composite protective device.

[0037] Optionally, in S1, a UHPC-CA unit is cast in a hard mold, the inner cavity of the hard mold has the same shape as the inner cavity of the dense pattern frame, and the UHPC-CA unit obtained after solidification and curing has the same assembly space size as the dense pattern frame; the hard mold is made of hard plastic or metal, and its inner cavity size is equal to the inner cavity shape size of the dense pattern frame; UHPC-CA shrinks relatively little due to the influence of coarse aggregate, so the inner cavity shape size basically does not need to consider the shrinkage of UHPC-CA.

[0038] Optionally, the preparation method of the UHPC-CA unit includes: S11, dry-mixing cement, fly ash, silica fume, fine aggregate and coarse aggregate to obtain a dry mix; S12, adding water and a water reducing agent to the dry mix, preliminarily stirring, and then adding steel fibers and stirring evenly; S13. Pour the UHPC-CA slurry into a hard mold, remove bubbles, and perform curing.

[0039] Optionally, the dry mixing time in S11 is 1-2 min, and the stirring speed is 60 r / min; the initial stirring time in S12 is 2-4 min, and the stirring speed is 120 r / min; the stirring speed after adding steel fiber is 120 r / min, and the stirring time is 2.5-4 min; the stirring speed before pouring in S13 is 150 r / min, and the stirring time is 2-3 min.

[0040] Optionally, in S13, a scraper and a vibrator are used to remove bubbles and improve the density; the vibrator vibrates at a frequency of 30 Hz for 3 minutes; the curing conditions are standard curing, the temperature is 20±2°C, and the humidity is ≥95%; after demolding, a concrete grinder is used for grinding to eliminate surface defects and adjust the size to prepare a UHPC-CA unit with a dense structure.

[0041] Optionally, in S2, a metal hard skeleton is first prepared, and then a densely laid graphic frame is prepared on the periphery of the metal hard skeleton by injection molding, which is a conventional forming method of wrapping the hard skeleton with an elastic material.

[0042] Optionally, in S3, after the densely packed pattern frame is elastically deformed to expand the inner cavity size, it is assembled into the UHPC-CA units one by one through the male and female grooves, and then the densely packed pattern frame is restored to its shape to complete the assembly of the two.

[0043] Optionally, in S3, UHPC slurry is filled in the gap between the UHPC-CA unit and the densely laid pattern frame, and the composite protective device is obtained after the slurry is cured. The UHPC-CA unit and the densely laid pattern frame become a tightly integrated whole that can synergistically resist impact and deformation.

[0044] Example 1 A composite protective device, the overall size is about 800mm×800mm×50mm, such as Figure 1 As shown, the densely-paved pattern frame includes 7 regular hexagonal cavities of the same size, and the cavities are respectively filled with UHPC-CA units of the same size; the densely-paved pattern frame is silicone rubber, and its elastic modulus is 3 MPa and its Shore hardness is A70. like Figure 1 As shown, the tessellated pattern simulates the hexagons of biological structures such as turtle shells, and the interlocking and restraint mechanism of the multi-units designed based on this bionic design can enhance the overall protection capability, thereby improving the protection capability of the projectile 3.

[0045] like Figure 1As shown, the height of the closely laid pattern frame 1 and the UHPC-CA unit 2 is 50 mm, that is, the overall thickness of the composite protective device is 50 mm, the side length of the regular hexagonal UHPC-CA unit 2 is 150 mm, and the narrowest distance between the opposite sides of adjacent UHPC-CA units 2 is 10 mm, that is, the narrowest part of the wall thickness of the closely laid pattern frame 1 is 10 mm; The paved pattern frame and the UHPC-CA unit are spliced ​​through lateral male and female grooves, such as Figure 3 As shown, the groove 11 in the male and female grooves is arranged on the side of the dense pattern frame 1, the depth of the depression from the side is 5mm, the length of the groove 11 is the same as that of the regular hexagon, the width of the groove 11 is 20mm, and the groove 11 is located in the middle position of the side of the paved pattern frame 1. The boss is arranged on the side of the UHPC-CA unit 2. The size of the boss is the same as that of the groove 11, and the shape and position are matched with the UHPC-CA unit. Then, the wall thickness of the dense pattern frame 1 is more than 15mm, and the wall thickness of the groove depression is 10mm.

[0046] The raw materials for the preparation of the UHPC-CA unit include 400 parts of cement, 40 parts of silica fume, 40 parts of fly ash, 900 parts of river sand, 900 parts of basalt coarse aggregate, 39 parts of steel fiber, 120 parts of water and 8 parts of water reducing agent.

[0047] The gaps between the closely laid pattern frame and the UHPC-CA units are filled with UHPC materials. Compared with the raw materials for preparing the above-mentioned UHPC-CA units, the filled UHPC materials do not contain coarse aggregates and steel fibers.

[0048] The cement is 52.5 ordinary Portland cement.

[0049] The silica mass percentage of silica ash is not less than 97%, the volcanic ash activity index is greater than 95%, the specific surface area is greater than 21.0m² / g, and the density is 2.20g / cm³.

[0050] The fly ash is Class I fly ash, with a loss on ignition of less than 3.0%, a specific surface area of ​​more than 1000cm² / g, and mainly contains silicon oxide and aluminum oxide.

[0051] The fine aggregate is natural river sand with a fineness modulus of 2.3 and a maximum particle size of 4.75 mm.

[0052] The coarse aggregate is high-strength and high-hardness basalt coarse aggregate with a particle size of 5~8mm.

[0053] The steel fiber is a straight steel fiber with a length of 13 mm.

[0054] The water reducing agent is polycarboxylic acid water reducing agent, and the water reducing rate is more than 30%.

[0055] The preparation method comprises the following steps: S1. Use hard plastic to prepare the molding mold of UHPC-CA unit, such as Figure 2 As shown, the inner cavity of the molding die is a regular hexagon, and grooves are provided on the side for forming the bosses in the male and female grooves. The inner cavity of the molding die is consistent with the shape of the UHPC-CA unit.

[0056] Then, the raw materials of the UHPC-CA unit are proportioned, poured into the molding mold, and cured, which includes the following steps: S11, mixing cement, fly ash, silica fume, fine aggregate and coarse aggregate, and dry mixing at a speed of 60 r / min for 2 min to obtain a dry mix; S12, adding water and water reducing agent to the dry mix, preliminarily stirring at a speed of 120r / min for 4min, so that the mixture shows good uniformity and operability, gradually and evenly sprinkle steel fibers and stir at a speed of 120r / min for 4min to obtain UHPC-CA slurry; S13. Stir the UHPC-CA slurry at a speed of 150r / min for 3 minutes, pour it into a hard mold, use a scraper and vibrator to remove bubbles and improve density; vibrate the vibrator at a frequency of 30Hz for 3 minutes; the standard curing temperature is 20±2℃, and the humidity is ≥95%; after curing and demoulding, perform surface treatment and size adjustment, and use a concrete grinder to polish and eliminate surface defects.

[0057] S2. Prepare a close-packed graphic frame made of silicone rubber by injection molding.

[0058] S3. The densely laid pattern frame is elastically deformed to expand the inner cavity size, and the UHPC-CA units are assembled one by one. Then, the gaps are filled with UHPC slurry to ensure the firmness and stability of the overall structure, and finally the assembly of the composite protective device is completed.

[0059] Example 2 A composite protective device, wherein a densely laid pattern frame comprises a plurality of equilateral triangular cavities of the same size, and the cavities are respectively filled with UHPC-CA units of the same size; the densely laid pattern frame is made of nitrile rubber, and its elastic modulus is 8MPa and its Shore hardness is A80.

[0060] The raw materials for preparing the UHPC-CA unit include 360 ​​parts of cement, 36 parts of silica fume, 36 parts of fly ash, 800 parts of fine aggregate, 800 parts of coarse aggregate, 39 parts of steel fiber, 120 parts of water and 5 parts of high-efficiency water reducing agent. The specifications of each raw material are the same as those in Example 1, and the preparation method is the same as that in Example 1.

[0061] Example 3 A composite protective device, wherein a densely laid pattern frame includes a plurality of quadrilateral cavities, and the cavities are respectively filled with UHPC-CA units of the same size; the densely laid pattern frame is silicone rubber, and its elastic modulus is 1 MPa and the Shore hardness is A30; the overall thickness of the device and the shape of the male and female grooves are the same as those in Example 1.

[0062] The raw materials for preparing the UHPC-CA unit include 520 parts of cement, 52 parts of silica fume, 52 parts of fly ash, 1000 parts of fine aggregate, 1000 parts of coarse aggregate, 78 parts of steel fiber, 130 parts of water and 10 parts of high-efficiency water reducing agent. The specifications of each raw material are the same as those in Example 1, and the preparation method is the same as that in Example 1.

[0063] Example 4 A composite protective device, comprising a densely laid pattern frame and a UHPC-CA unit, having the same shape, structure and size as Example 1, and having the same appearance as Example 1 Figure 4 Same; in Figure 4 The cross section at the AA position in Figure 5 As shown, the cross-section of the densely laid graphic frame includes a metal hard skeleton 4 and an elastic material 12. The material of the metal hard skeleton 4 is high-strength steel, and the outer periphery of the metal hard skeleton is coated with the same elastic material 12 as in Example 1. The narrowest distance between the opposite sides of adjacent UHPC-CA units 2 is 10 mm, and the average thickness of the metal hard skeleton 4 in this direction is 5 mm.

[0064] The raw materials for preparing the UHPC-CA unit are the same as those in Example 1.

[0065] In the preparation method, a metal hard skeleton 4 is first prepared, and then the elastic material 12 is added to the periphery of the metal hard skeleton 4 by injection molding to prepare a densely laid graphic frame.

[0066] The other steps are the same as those in Example 1.

[0067] Example 5 A composite protective device, including a densely laid pattern frame and a UHPC-CA unit, has the same shape structure and size as Example 1, such as Figure 6 In the cross-section shown, the closely laid graphic frame includes a metal hard skeleton, which includes 7 hexagonal frames 41. Two adjacent hexagonal frames 41 are connected by a mortise and tenon structure. The material of the hexagonal frames 41 is the same as that of the metal hard skeleton 4 of Example 4. The hexagonal frames 41 and the internal UHPC-CA units 2 are separated by an elastic material 12 that is the same as that of Example 1. The narrowest distance between the opposite sides of adjacent UHPC-CA units 2 is 10 mm, and the average thickness of the hexagonal frames in this direction is 4 mm. There are two side walls of the hexagonal frames 41 between adjacent UHPC-CA units 2.

[0068] In the preparation method, a hexagonal frame 41 is first prepared, and then the elastic material 12 is added to the inner side of the hexagonal frame 41 by injection molding, and multiple hexagonal frames 41 are connected to obtain a densely laid graphic frame.

[0069] The other steps are the same as those in Example 1.

[0070] Comparative Example 1 A composite protective device includes a densely laid pattern frame and a UHPC-CA unit, having the same shape, structure and size as those in Example 1, and the material of the densely laid pattern frame is the same as that in Example 1.

[0071] The raw materials for preparing the UHPC-CA unit are 590 parts of cement, 150 parts of silica fume, 150 parts of fly ash, 1100 parts of river sand, 39 parts of steel fiber, 222 parts of water, and 15 parts of water reducing agent. The coarse aggregate is not included, and the specifications of other raw materials are the same as those in Example 1.

[0072] The preparation method was the same as in Example 1, but no coarse aggregate was added during the preparation of the UHPC-CA unit.

[0073] Comparative Example 2 A protective device has the same shape, structure and size as Example 1, but does not include a densely laid pattern frame. The entire device is a plate formed by one-time integral casting of UHPC-CA material.

[0074] The raw materials for preparing the UHPC-CA material of this comparative example are the same as those in Example 1.

[0075] Comparative Example 3 A protective device has the same shape, structure and size as those of Example 1, except that: thermoplastic resin is used as adhesive in S3.

[0076] Experimental example The performance test of high-speed projectile penetration resistance includes: 1) The composite protective device of Example 1, the composite protective device of Comparative Example 1 and the protective device of Comparative Example 2 were respectively used to prepare a target body, with a thickness of 50 mm in the ballistic direction, i.e., a single-layer device; a pointed egg-shaped projectile with a diameter of 8 mm was selected, and the projectile material was 30CrMnSiNi2A high-strength alloy steel (yield strength of 1370-1466 MPa, ultimate strength of 1770 MPa, Rockwell hardness of 55 HRC).

[0077] 2) Use a cannon to launch an egg-shaped projectile, hitting the target at a target speed of 400m / s, and use a high-speed camera on the side of the trajectory to capture the movement of the projectile and collect corresponding data.

[0078] 3) The degree of damage to the high-speed projectile target was evaluated by measuring the penetration depth, crater diameter and crater volume of the target. The results are shown in Table 1. Figure 4 The protective device shown includes a tessellated pattern frame and UHPC-CA units; the penetration depth refers to the distance from the impact surface of the target to the deepest point of the crater; the crater diameter is the diameter of an equivalent circle with the same area as the target crater; the crater volume refers to the volume of the target crater.

[0079] Table 1 Test results of high-speed projectile penetration resistance

[0080] It can be seen from Table 1 that the penetration depth of Example 1 is 23.5 mm, which is significantly better than 42.7 mm of Comparative Example 1, 35.3 mm of Comparative Example 2, and 40.5 mm of Comparative Example 3. In Example 1, bionic structure splicing is adopted, and a high elastic polymer energy absorption frame is combined, which greatly improves the anti-penetration performance of the material. Through this bionic design, the regular hexagonal UHPC-CA units can limit the lateral displacement of each other, reduce the transmission of the impact energy of the projectile, and further reduce the penetration depth by paving the graphic frame (energy absorption material). Although the appearance of Comparative Example 2 is similar to that of the embodiment, due to the lack of energy absorption material and the use of integrated casting, the stress transfer path is single, there is no advantage of the bionic structure, and the anti-penetration performance is significantly reduced.

[0081] The area and volume of the pit on the impact surface of Example 1 are 60,820 mm² and 91,250 mm³, respectively, which are much smaller than 78,460 mm² and 120,550 mm³ of Comparative Example 1, 67,900 mm² and 108,300 mm³ of Comparative Example 2, and 75,300 mm² and 115,000 mm³ of Comparative Example 3. This shows that the spliced ​​bionic structure and energy absorption frame in Example 1 can not only effectively prevent the deep penetration of the projectile, but also significantly reduce the range and volume of the pit on the impact surface. The highly elastic polymer frame can absorb part of the energy during the impact, reduce the concentration of the impact force in the local area, and keep the damage range to a minimum. Although Comparative Example 2 is consistent with the embodiment in appearance, due to the lack of energy absorbing material, the integrated casting causes the impact force to spread over a larger range, and the local energy absorption effect of the spliced ​​bionic design cannot be achieved, and the damage range is larger. Comparative Example 3 uses thermoplastic resin as a binder. Due to its weak bonding performance, the force transmission efficiency between the unit and the frame is low, and the force cannot be effectively dispersed to the energy absorbing material of the frame, resulting in stress concentration in local areas, further expanding the scope of damage.

[0082] The area and volume of the pit on the back surface reflect the degree of local damage to the target. The area of ​​the pit on the back surface of Example 1 is 20100mm² and the volume is 13600mm³, which is significantly smaller than that of Comparative Example 1 (33650mm² and 22950mm³) and Comparative Example 2 (28750mm² and 18800mm³). The energy absorption frame in the spliced ​​bionic design plays an important role in resisting impact, and can effectively prevent the cracks from expanding outward and be confined to the local area affected by the impact. In Comparative Example 2, although the appearance is the same as that of the embodiment, due to the use of integrated casting, the lack of local splicing and energy absorption frame, the cracks are easy to spread to the surrounding area, causing greater damage. In Comparative Example 3, although the thermoplastic resin can tightly bond the UHPC-CA unit and the frame, due to its poor bonding performance compared to UHPC, each unit and the frame cannot transmit the force well, resulting in uneven stress distribution and obvious stress concentration, which in turn increases the scope of damage.

[0083] The design concept of the bionic structure is derived from the polygonal protection system in nature, such as the scales of tortoise shells and pangolins. Through the splicing of regular hexagonal units and the application of energy-absorbing materials, a significant improvement in anti-penetration performance is achieved. The bionic structure in Example 1 can not only reduce the transmission of lateral stress through the constraints at the joints during impact, but also further weaken the impact of the impact through the energy absorption of the highly elastic polymer frame. This design enables the material to exhibit excellent performance when resisting the impact of high-speed projectiles, and is particularly suitable for use in the fields of military protection and protection of critical infrastructure.

[0084] In contrast, although Comparative Example 2 imitates the bionic structure in appearance, due to its integrated casting design, it does not effectively limit the expansion of radial cracks and lacks the advantage of energy absorbing materials, resulting in a large-scale diffusion of stress in the impact area, reducing the overall anti-penetration performance. Therefore, it can be concluded that the real advantage of the bionic structure lies in its splicing design and local energy absorption frame, which can not only improve the anti-penetration capability, but also reduce the area and volume of damage.

[0085] Example 4 and Example 5 add a metal hard skeleton on the basis of Example 1. This design significantly enhances the structural stability and anti-penetration capability of the composite protective device. The metal hard skeleton effectively disperses the impact force by improving the rigidity of the overall device, reduces local penetration and structural deformation, and at the same time strengthens the connection firmness between each unit to avoid the breakage or falling off of the device under impact. In addition, the metal skeleton can optimize energy absorption and dispersion and limit the expansion of cracks. Compared with Example 1, after adding the metal hard skeleton, the composite protective device has been significantly improved in impact resistance, durability and maintainability, especially when facing high-energy impact, the overall performance has been effectively improved.

[0086] In general, Example 1 greatly improves the impact resistance and penetration resistance of UHPC-CA by combining spliced ​​bionic design with energy absorbing materials. Compared with Comparative Examples 1, 2 and 3, Example 1 not only performs better in terms of penetration depth, impact surface area, volume, etc., but also has more effective control of the back surface. The unique advantages of bionic design lie in local constraints and energy absorption, which give full play to the impact resistance potential of the material, can be applied to the construction of military protection facilities, important infrastructure and high-risk areas, provide a higher level of protection, and have broad engineering prospects in practical applications.

[0087] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A composite protective device, characterized in that: It includes a densely laid graphic frame and UHPC-CA units filled in the densely laid graphic frame; the densely laid graphic frame is laterally spliced ​​with the UHPC-CA units; the elastic material is silicone rubber or nitrile rubber; the densely laid graphic frame includes a metal hard skeleton, and the metal hard skeleton and the UHPC-CA units are separated by an elastic material; The raw materials for preparing the UHPC-CA unit include 360-520 parts of cement, 36-52 parts of silica fume, 36-52 parts of fly ash, 800-1000 parts of fine aggregate, 800-1000 parts of coarse aggregate, 39-78 parts of steel fiber, 120-130 parts of water and 5-10 parts of high-efficiency water reducing agent.

2. The composite protective device according to claim 1, characterized in that: The shape of the tessellated graphic frame is one or more of a triangle, a hexagon and a square.

3. The composite protective device according to claim 1, characterized in that: The outer periphery of the metal rigid skeleton is coated with elastic material; or, the metal rigid skeleton includes a plurality of polygonal frames spliced ​​together, and an elastic material is provided between the polygonal frames and the internal UHPC-CA units.

4. The composite protective device according to claim 1, characterized in that: The elastic modulus of the elastic material is between 0.1 and 10 MPa, and the Shore hardness is between A30 and A80.

5. The composite protective device according to claim 4, characterized in that: The gap between the UHPC-CA unit and the densely laid pattern frame is filled with UHPC material; no coarse aggregate and steel fiber are added to the UHPC material, and other raw materials are the same as those for preparing the UHPC-CA unit.

6. A method for preparing the composite protective device according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Prepare a UHPC-CA unit of a set shape; S2, preparing a densely laid graphic framework of elastic material; S3. Assemble the UHPC-CA units into a densely laid pattern frame to obtain the composite protective device.

7. The method for preparing the composite protective device according to claim 6, characterized in that: In S1, a UHPC-CA unit is cast in a hard mold, wherein the inner cavity of the hard mold has the same shape as the inner cavity of the densely laid pattern frame.

8. The method for preparing the composite protective device according to claim 6, characterized in that: In S1, the preparation method of the UHPC-CA unit includes: S11, dry-mixing cement, fly ash, silica fume, fine aggregate and coarse aggregate to obtain a dry mix; S12, adding water and a water reducing agent to the dry mix, preliminarily stirring, and then adding steel fibers and stirring evenly; S13. Pour the UHPC-CA slurry into a hard mold, remove bubbles, and perform curing.

9. The method for preparing the composite protective device according to claim 6, characterized in that: In S3, UHPC slurry is filled in the gap between the UHPC-CA unit and the densely laid pattern frame, and the composite protective device is obtained after the slurry is cured.

10. An application of the composite protective device according to any one of claims 1 to 5, characterized in that: The applications include applications in protective facilities.

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