A multi-scenario explosion-proof and impact-proof protection device based on Menger sponge fractal structure

Abstract

The present invention belongs to the field of engineering structure protection, and in particular relates to a multi-scenario explosion-proof and impact-resistant protective device based on a Menger sponge fractal structure, wherein the protective device is detachably connected to the surface of the protected structure in a modular assembly form; each protective device includes a surface plate, a back plate, and a core layer bonded therebetween; the surface plate and the back plate are both designed to be high-strength metal plates, serving as the skeleton of the protective device; the core layer is composed of a number of identical Menger sponge fractal structures arranged periodically at equal intervals; each Menger sponge fractal structure utilizes the compression of the core layer under the explosive impact load to absorb energy, reduce the initial peak value of the explosive load applied to the protected structure, prolong the duration of the impact, and thus greatly improve the impact resistance of the structure. The protective device of the present invention can be applied to multi-scenario explosion-proof and impact-resistant protection. When the protective device is installed on a wall, the thermal insulation, sound insulation and noise reduction functions of the Menger sponge fractal structure can be fully utilized.

Description

Technical Field

[0001] The present invention belongs to the field of engineering structure protection, and in particular relates to an anti-explosion and anti-impact protection device for an engineering structure, and specifically relates to a multi-scenario anti-explosion and anti-impact protection device based on a Menger sponge fractal structure. Background Art

[0002] The threat posed by explosions to human life and property cannot be underestimated. Therefore, improving the protective performance of structures under blast impact loads has attracted widespread attention from both the engineering and academic communities. With the continuous advancement of science and technology, the design requirements for engineering structures are constantly increasing. Important engineering structures must not only meet normal service requirements but also possess superior protection under extreme loads (blast or impact).

[0003] Traditional engineering protection mainly includes two design concepts: one is the "rigid protection" design concept, which uses high-strength structural components to improve the bearing capacity of engineering structures, or builds explosion-proof barriers to prevent terrorist attacks such as car bombs; the other is the "flexible protection" design concept, which installs flexible energy-absorbing devices on the outside of the building structure to reduce the load input to the structure by absorbing energy, thereby reducing damage to the engineering structure, such as sandwich structures or sacrificial hanging panels.

[0004] The "rigid protection" design has good explosion and impact resistance, but sometimes the protection structure itself, as part of the structural component, may have a great impact on the integrity of the structure after damage. Sometimes it is necessary to use reinforcement methods to rebuild the damaged components, which has high maintenance costs and a long construction period.

[0005] Protective devices using "flexible protection" designs, such as lightweight, flexible sacrificial cladding, are easy to install and utilize the core's large plastic deformation at relatively low stress levels to absorb significant amounts of energy while simultaneously transmitting controlled forces to the primary structure. Core structures come in a variety of different types, including negative Poisson's ratio, tubular, and corrugated sheet.

[0006] Fractals are self-similar entities at different length scales, following natural hierarchical patterns. Menger sponges are a characteristic fractal topology. Due to their large surface area and compact size, Menger sponge fractals have been applied in various engineering fields, including energy, architecture, biomedicine, manufacturing, and urban design. However, no Menger sponge fractals have yet been applied in explosion and shock resistance. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention proposes a multi-scenario explosion and impact protection device based on the fractal structure of Menger sponge, which can be used to improve the protective performance of engineering structures under blast or impact loads. Natural structures with a latent layered microstructure, such as human bone and wood, are known to possess excellent mechanical properties. Therefore, the protective device proposed in this invention mimics the structure of human bone tissue. Bone tissue consists of cortical bone and cancellous bone. The primary protective mechanism is that cortical bone is hard and dense, highly resistant to compression, and is located on the surface of the bone, providing rigidity. Cancellous bone, on the other hand, is porous and spongy, composed of numerous interwoven trabeculae. It is distributed within the bone, giving the bone its compressive and tensile strength, as well as its elasticity. This structure enables the bone to withstand pressure while maintaining a certain degree of elasticity, effectively absorbing and dissipating impact forces. Trabecular bone, with its highly complex and multi-layered structure, exhibits excellent performance both as a support structure for the human body and as impact protection. The protective device designed in this invention, based on the impact resistance principles of human bone, boasts excellent energy absorption and explosion resistance, is easy to install and replace, and can significantly reduce both economic and time costs.

[0008] The present invention is achieved in that:

[0009] A multi-scenario explosion- and impact-resistant protective device based on a Menger sponge fractal structure, wherein the protective device is detachably connected to the surface of the protected structure in a modular assembly form;

[0010] Each guard consists of a face plate, a core layer, and a back plate;

[0011] The core layer is bonded between the front panel and the back panel using epoxy resin. The core layer is composed of a number of identical Menger sponge fractal structures arranged periodically at equal intervals. The fractal structures are generated by replicating structures of the same shape or by continuously removing structures of the same shape, and are periodic and self-similar. Each Menger sponge fractal structure is considered a self-recovering toughness unit of the protective device.

[0012] The front plate and the back plate are both high-strength metal plates; the back plate is detachably connected to the protected structure.

[0013] Furthermore, the pores of the Menger sponge fractal structure are square, circular, diamond, cross, or a mixture of pores of different shapes.

[0014] Furthermore, the materials used for the surface plate and back plate are low carbon steel plate, stainless steel plate, alloy steel and plastic steel.

[0015] Furthermore, the material of the Menger sponge fractal structure is one of polylactic acid material, shape memory alloy, and melamine foam.

[0016] Furthermore, the Menger sponge fractal structure is any fractal level.

[0017] Furthermore, all components of the protective device are prefabricated components, prepared by 3D printing technology, and each component is connected using a modular assembly method.

[0018] The present invention also discloses a method for installing the multi-scenario explosion-proof and impact-proof protective device based on the Menger sponge fractal structure, comprising the following steps:

[0019] Step 1: Clean the outer surface of the engineering structure wall and set bolt holes at the four corners of the back plate surface;

[0020] Step 2: Modeling the Menger sponge fractal structure in 3D modeling software, wherein the fractal structure is generated by replicating the same shape structure or by continuously removing the same shape structure;

[0021] Step 3: Import the designed Menger sponge fractal structure model into the 3D printing slicing software. According to the selected 3D printing material and printer type, set the appropriate printing parameters. Transfer the print file generated by the slicing software to the 3D printer to complete the printing.

[0022] Step 4: evenly apply polyurethane coating on the front and back surfaces of the front panel and back panel to form an anti-corrosion protective layer;

[0023] Step 5: Prepare a number of Menger sponge fractal structures according to the geometric dimensions of the front panel or the back panel, arrange the Menger sponge fractal structures periodically at equal intervals, and bond them between the front panel and the back panel respectively.

[0024] Furthermore, the modeling analysis method in step 2 includes: creating an initial cube unit, and then subdividing the cube into 3 n equal small cubes, and remove the small cubes in the center and six surfaces of the cube, leaving 3 n -7 small cubes, place the remaining 3 n -7 small cubes are divided according to the above operation; the side length of each small cube is 1 / n of the size of the previous cube, so after k iterations, the side length of the cube is 1 / n of the side length of the initial cube k ; According to the recursive rule of Menger sponge, multiple iterations are performed to eventually form a Menger sponge fractal structure of the nth fractal level.

[0025] The technical effects of the present invention are as follows:

[0026] (1) The protective device proposed in the present invention is composed of a surface plate, a core layer, and a back plate, and its structural features are designed to imitate the human skeleton. The surface plate and the back plate are similar to the cortical bone in bone tissue, and use the hard, dense, and high pressure-resistant material properties to provide "rigid protection" and provide the required rigidity for the protective device. Several Menger sponge fractal structures serve as the core layer to provide "flexible protection" by absorbing energy through compression. The protective device proposed in the present invention is a "rigid and flexible" protective device that can achieve hierarchical protection for the protected structure, and the protective effect is better than single rigid protection or flexible protection.

[0027] (2) The protective device proposed in the present invention can not only be used for explosion and impact protection of above-ground engineering structures, but can also be used as an energy sink in underground engineering structures to suppress and absorb ground impacts. In addition, the core layer of the protective device proposed in the present invention has the characteristics of an elastic wave band gap, which prevents elastic waves within a specific frequency range from propagating, thereby reducing the vibration of people or equipment inside the underground structure.

[0028] (3) The present invention can change the energy consumption performance of the protective device by adjusting various parameters of the protective device, such as the geometric parameters, relative density, pore shape and size, and fractal grade of the Menger sponge fractal structure. Therefore, the protective device can be optimized and designed considering the actual engineering conditions, thereby maximizing practicality and economy.

[0029] (4) The material used for the core layer of the present invention is light in weight, energy-saving and environmentally friendly, and simple to manufacture. When the protective device is installed on the wall, the thermal insulation material properties of the Menger sponge fractal structure can be fully utilized, and the Menger sponge fractal structure can form multiple adjustable phonon band gaps, thereby providing the function of sound insulation and noise reduction.

[0030] (5) The protective device of the present invention adopts modular assembly connection, which makes installation, maintenance and reinforcement more convenient, greatly reducing time and economic costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of the protective device of the present invention;

[0032] Figure 2 This is a schematic diagram of the fractal structure of the Menger sponge of the present invention;

[0033] Figure 3 This is the front view of the Menger sponge fractal structure;

[0034] Figure 4 It is a schematic transverse cross-sectional view of the protective device structure of the present invention;

[0035] Figure 5 Schematic diagram of the process of creating the Menger sponge fractal structure;

[0036] Figure 6 Schematic diagram of different pore shapes in the Menger sponge fractal structure;

[0037] Figure 7 Schematic diagram of different pore sizes in the fractal structure of Menger sponge.

[0038] In the figure: 1. Surface plate; 2. Core layer; 21. Menger sponge fractal structure; 211. Pores; 3. Back plate; 4. Bolt hole; 5. High-strength bolt. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] like Figure 1-7 As shown, the present invention discloses a multi-scenario explosion-proof and impact-proof protective device based on a Menger sponge fractal structure, comprising a surface plate 1, a core layer 2, and a back plate 3; the core layer 2 is bonded between the surface plate 1 and the back plate 3 using epoxy resin, and the back plate 3 is connected to the protected structure by bolts. This structure can not only reduce the explosion load transmitted from the core layer to the protected structure, but also realize modular installation of the protective device. The key parts of the protective device are all connected in a modular assembly manner, which makes the installation, maintenance and reinforcement of the protective device more convenient, greatly reducing time and economic costs. Therefore, the purpose of tough protection of local damage and local replacement is achieved through modular design.

[0041] All components of the protective device are prefabricated components, among which the core layer 2 can be prepared by 3D printing technology, and each component is connected in a modular assembly manner so that the protective structure can be assembled on site.

[0042] The surface plate 1 and the back plate 3 are both designed to be high-strength metal plates, serving as the skeleton of the protective device, thereby achieving the purpose of "rigid protection"; preferably, the materials used for the surface plate 1 and the back plate 3 can be low-carbon steel plates, stainless steel plates, alloy steels, plastic steels and other materials. The surface plate 1 can apply the explosion load more evenly to the core layer 2, and at the same time reduce the impact energy input to the core layer 2. The back plate 3 can not only fix the protective device to the protected structure, but also reduce the explosion load transmitted from the core layer 2 to the protected structure.

[0043] The core layer 2 is preferably made of a material with a long stress plateau, which allows it to absorb more energy during compression, further enhancing the protective performance of the structure. The core layer possesses an elastic bandgap, which prevents elastic waves within a specific frequency range from propagating, thereby reducing vibrations to personnel and equipment within the underground structure. Furthermore, the core layer substrate should be easily moldable, convenient to construct, lightweight, and environmentally friendly.

[0044] Furthermore, the core layer 2 consumes the explosion energy through the deformation of the Menger sponge fractal structure 21, so the protective device can protect the above-ground engineering structure; the core layer 2 is composed of several identical Menger sponge fractal structures, each of which can be regarded as a self-recovering toughness unit of the protective device. The compression of the core layer under the explosion impact load absorbs energy, reduces the initial peak value of the explosion load applied to the protected structure, prolongs the duration of the impact, and thus greatly improves the impact resistance of the structure.

[0045] The structural properties of the Menger sponge fractal structure give it excellent energy absorption and shock absorption properties. Each Menger sponge fractal structure, like the trabeculae in the human skeleton, dissipates impact energy through deformation, making this protective device suitable for protecting aboveground engineering structures. Fractal structures are generated by replicating or continuously removing structures of the same shape. Therefore, fractals are multi-layered, complex structures with self-similarity at different scales. Therefore, the Menger sponge fractal structure can be considered periodic and self-similar, possessing wave velocity tuning capabilities and enabling wave manipulation. Protective devices with a Menger sponge fractal structure as their core layer can act as energy sinks to reduce the propagation of ground shock waves, effectively protecting underground engineering structures.

[0046] Preferably, the structural parameters of the Menger sponge fractal structure have varying degrees of influence on the core layer's impact resistance. By adjusting parameters such as the spacing, geometric dimensions, pore size, shape, and fractal grade of the Menger sponge fractal structure, the energy absorption capacity and wave propagation performance of the Menger sponge fractal structure can be altered. The size of the pores 211 in the Menger sponge fractal structure can be precisely adjusted using additive manufacturing technology. Preferably, the pores 211 in the Menger sponge fractal structure can be arranged in a square, circular, diamond, cross, or mixed configuration.

[0047] Preferably, the Menger sponge fractal structure 21 can be made of materials such as polylactic acid, shape memory alloy, and melamine foam. Due to the controllable physical parameters, the core layer can be adjusted for different operating conditions in practical applications, thereby improving the protective device's ability to withstand explosive shocks. The Menger sponge fractal structure 21 can form multiple tunable phonon band gaps, thereby providing sound insulation and noise reduction.

[0048] The installation steps of a multi-scenario explosion-proof and impact-proof protective device based on Menger sponge fractal structure for engineering structure walls are described as an example.

[0049] Step 1: Clean the outer surface of the engineering structure wall, set bolt holes 4 at the four corners of the back plate 3 surface, and the center of the bolt hole 4 is 40 mm away from the two adjacent sides of the back plate 3. A CNC high-speed drilling machine can be used to complete the precise layout of the bolt holes 4.

[0050] Based on the degree of fractal iteration, the Menger sponge fractal structure 21 can be classified into levels 1, 2, 3, ...n. This embodiment will use the third fractal level as an example to describe the detailed production process of the Menger sponge fractal structure 21. Menger sponge fractal structures 21 of other levels can be produced using the same production method, differing in the number of fractal iterations. The rapid development and continuous improvement of additive manufacturing technology in terms of resolution and build quality have made complex printing architectures possible. Therefore, this patent utilizes 3D printing technology to produce the Menger sponge fractal structure 21.

[0051] Step 2: Select appropriate 3D modeling software to model the Menger sponge fractal structure 21. The fractal structure is generated by replicating the structure of the same shape again or by continuously removing the structure of the same shape. Therefore, in the modeling software, first create an initial cube unit (90 mm × 90 mm × 90 mm), then subdivide the cube into 27 equal small cubes, and remove the small cubes at the center of the cube and the centers of the six surfaces, leaving 20 small cubes. The remaining 20 small cubes are divided according to the above operation. The side length of each small cube is 1 / 3 of the size of the previous divided cube, so after k iterations, the side length of the cube is (1 / 3) of the side length of the initial cube. k According to the recursive rule of Menger sponge, multiple iterations are performed, and finally a Menger sponge fractal structure 21 of the third fractal level with a relative density of 0.4 is formed.

[0052] Fractal topology causes the volume of the cubic structure to continuously decrease while the total surface area continuously increases. As the number of iterative segmentation increases, the surface area of ​​the Menger sponge fractal structure 21 approaches infinity, while its volume approaches zero. Clearly, the Menger sponge fractal structure 21 is a partially complete three-dimensional structure, with a geometric dimension that is a non-integer between 2 and 3. The dimension of the third-level Menger sponge fractal structure 21 is 2.73. As the geometric dimension approaches 2, the pores 211 in the Menger sponge fractal structure become smoother. The closer the geometric dimension is to 3, the greater the complexity of the pore space distribution, which also means that the spatial capacity of the Menger sponge fractal structure pores 211 is enhanced.

[0053] Step 3: Import the designed Menger sponge fractal structure model into 3D printing slicing software. Based on the selected 3D printing material (such as polylactic acid, shape memory alloy, melamine foam, etc.) and printer type, set appropriate printing parameters, including printing speed and temperature. Transfer the print file generated by the slicing software to the 3D printer to complete the printing.

[0054] Step 4: evenly apply polyurethane coating on the front and back surfaces of the surface plate 1 and the back plate 3 to form an anti-corrosion protective layer to block the contact between the external environment and the surface plate 1 and the back plate 3, thereby reducing the occurrence of corrosion.

[0055] Step 5: Prepare several Menger sponge fractal structures 21 based on the geometric dimensions of the front panel 1 or back panel 3. Arrange these structures 21 periodically and at equal intervals. Each Menger sponge fractal structure 21 can be considered a unit cell, with a spacing of 150 mm between adjacent units. Use epoxy resin to bond each Menger sponge fractal structure 21 between the front panel 1 and back panel 3.

[0056] Step six: fix the 1 mm thick back plate 3 to the outer surface of the wall with high-strength bolts 5. The number of back plates 3 needs to be determined according to the surface area of ​​the wall, thereby completing the modular installation of the protective device.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-scenario explosion and impact protection device based on a Menger sponge fractal structure, characterized by: The protective device is detachably connected to the surface of the protected structure in a modular assembly form; each protective device includes a surface plate, a core layer and a back plate; the core layer is bonded between the surface plate and the back plate using epoxy resin; the core layer is composed of a number of identical Menger sponge fractal structures arranged periodically at equal intervals, and the fractal structure is generated by replicating the structure of the same shape again or by continuously removing the structure of the same shape, and has periodicity and self-similarity; each Menger sponge fractal structure is regarded as a self-recovering toughness unit of the protective device; the surface plate and the back plate are both high-strength metal plates; the back plate is detachably connected to the protected structure.

2. The multi-scenario explosion-proof and impact-proof protective device based on the Menger sponge fractal structure according to claim 1 is characterized in that: The pores of the Menger sponge fractal structure are square, circular, diamond, cross, or a mixture of pores of different shapes.

3. The multi-scenario explosion-proof and impact-proof protective device based on the Menger sponge fractal structure according to claim 1 is characterized in that: The materials used for the surface plate and back plate are low carbon steel plate, stainless steel plate, alloy steel and plastic steel.

4. The multi-scenario explosion-proof and impact-proof protective device based on the Menger sponge fractal structure according to claim 1 is characterized in that: The material of the Menger sponge fractal structure is one of polylactic acid material, shape memory alloy, and melamine foam.

5. The multi-scenario explosion-proof and impact-proof protective device based on the Menger sponge fractal structure according to claim 1 is characterized in that: The Menger sponge fractal structure is any fractal level from 1 to n, where n is a positive integer.

6. The multi-scenario explosion-proof and impact-proof protective device based on the Menger sponge fractal structure according to claim 1 is characterized in that: All components of the protective device are prefabricated components, the core layer is prepared by 3D printing technology, and each component is connected in a modular assembly manner.

7. The installation method of the multi-scenario explosion-proof and impact-proof protective device based on the Menger sponge fractal structure according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: Step 1, cleaning the outer surface of the engineering structure wall, and setting bolt holes at the four corners of the back panel surface; Step 2, modeling the Menger sponge fractal structure in 3D modeling software, wherein the fractal structure is generated by replicating the structure of the same shape again or by continuously removing the structure of the same shape; Step 3, importing the designed Menger sponge fractal structure model into the 3D printing slicing software, setting appropriate printing parameters according to the selected 3D printing material and printer type, and transferring the print file generated by the slicing software to the 3D printer to complete printing; Step 4, evenly applying polyurethane coating on the front and back surfaces of the surface panel and the back panel to form an anti-corrosion protective layer; Step 5, preparing a number of Menger sponge fractal structures according to the geometric dimensions of the surface panel or the back panel, arranging the Menger sponge fractal structures at equal intervals and bonding them between the surface panel and the back panel respectively.

8. The installation method of the multi-scenario explosion-proof and impact-proof protective device based on the Menger sponge fractal structure according to claim 7 is characterized in that: The modeling and analysis method in step 2 includes: creating an initial cube unit, then subdividing the cube into 3n equal small cubes, where n is a positive integer; removing the small cubes at the center and six surfaces of the cube, leaving 3n-7 small cubes, and dividing the remaining 3n-7 small cubes according to the above operations; the side length of each small cube is 1 / n of the size of the previously divided cube, so after k iterations, the side length of the cube is 1 / nk of the side length of the initial cube; performing multiple iterations according to the recursive rule of the Menger sponge, and finally forming a Menger sponge fractal structure of the nth fractal level.

Images