Fish-scale-like bulletproof glass based on multi-level energy dissipation mechanism

Abstract

The present invention discloses a fish-scale-like bulletproof glass based on a multi-level energy dissipation mechanism, which relates to the technical field of bulletproof glass. The glass is composed of a crack-stop layer, a bulletproof layer, a protective layer and an adhesive layer. The crack-stop layer, the bulletproof layer and the protective layer are arranged in sequence from the impact surface to the back surface and are bonded together by an adhesive layer. The bulletproof layer includes a cross structure, a laminated structure and a spiral structure formed by a composite of glass and polymethyl methacrylate, and is arranged in sequence along the impact direction. The crack-stop layer and the protective layer are made of polycarbonate, and the adhesive layer is made of polymethyl methacrylate. Existing bulletproof glass has poor impact resistance due to factors such as the inherent brittleness of glass, a relatively simple structure and a single energy dissipation mechanism, which leads to easy expansion of cracks and catastrophic damage when impacted. The present invention includes multiple layered structures, cross structures, overlapping structures and spiral structures, which can induce the generation of multiple energy dissipation mechanisms and effectively improve the impact resistance of bulletproof glass.

Description

Technical Field

[0001] The present invention relates to the technical field of bulletproof glass, and more particularly to a fish-scale-like bulletproof glass based on a multi-level energy dissipation mechanism. Background Art

[0002] Glass, with its exceptional optical clarity, mechanical strength, thermal stability, and impact resistance, holds a crucial position in the security and protection sector. It offers a unique advantage in bulletproof equipment, combining both visual and impact protection capabilities to effectively safeguard personnel and property. Currently, mainstream bulletproof glass utilizes a laminated composite technology, combining multiple layers of glass with a flexible polymer, then laminating them to form a composite system. This structure dissipates energy through interfacial delamination, but due to the inherent brittleness of glass, it experiences significant stress concentration when subjected to high-velocity projectile impacts, which can easily induce microcracks that rapidly propagate and lead to catastrophic failure of the overall structure. To improve the impact resistance of bulletproof glass, increasing the glass thickness is typically employed. However, this increases the glass's weight, complicating installation and use, while also increasing production and operating costs. In recent years, a new type of imitation mother-of-pearl bulletproof glass has been proposed, utilizing a sliding mechanism to induce crack deflection within the glass, thereby improving fracture toughness. This imitation mother-of-pearl bulletproof glass maintains high strength and rigidity, and has higher impact resistance than laminated glass and tempered glass. However, when dealing with high-energy armor-piercing projectiles, it still faces bottlenecks such as a single energy dissipation mechanism and insufficient protective performance.

[0003] like Figure 1 As shown in the figure, fish possess a hard "armor." The overlapping hard scales on their surface provide effective protection, while the soft collagen fibers within allow these scales to move relative to each other, making the overall structure highly flexible. Collagen fibers of the same orientation assemble within a plane to form collagen sheets. Each collagen sheet layer is formed by rotating its adjacent layers at a small angle about the normal, and the first and last collagen sheet layers along the thickness direction complete exactly one rotation, meaning that the collagen fibers within the first and last collagen sheet layers have the same orientation. This helical structure allows the collagen sheet to rotate toward or away from the direction of the applied load, improving fracture toughness through shearing between collagen fibers, stretching of the collagen fibers themselves, separation of gaps between collagen fibers, and rotation between collagen fibers. Therefore, both the overlapping scales on the surface and the internal helical structure undoubtedly provide inspiration for the design of high-performance bulletproof glass. Summary of the Invention

[0004] The purpose of the present invention is to provide a fish-scale-like bullet-proof glass based on a multi-stage energy dissipation mechanism, thereby overcoming the shortcomings of existing bullet-proof glass in the background art, such as the inherent brittleness of the glass, the relatively simple structure and the single energy dissipation mechanism, which lead to easy crack propagation and catastrophic damage when impacted, resulting in poor impact resistance.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention discloses a fish-scale-like bulletproof glass based on a multi-level energy dissipation mechanism, which is composed of a crack-stop layer, a bulletproof layer, a protective layer, and an adhesive layer. The crack-stop layer, bulletproof layer, and protective layer are arranged in sequence from the impact surface to the back surface, and the crack-stop layer, bulletproof layer, and protective layer are bonded together by an adhesive layer.

[0007] The bulletproof layer is composed of a cross structure, a laminated structure and a spiral structure arranged in sequence along the impact direction; the cross structure is composed of a plurality of cross composite layers and bonding layers distributed at intervals, the laminated structure is composed of a plurality of homogeneous layers and bonding layers distributed alternately, and the spiral structure is composed of a plurality of spiral composite layers and bonding layers distributed at intervals;

[0008] The cross composite layer and the spiral composite layer are both composed of a plurality of unit bodies and the cohesion of the gaps between them; the unit body is an oblique hexahedron, the front and rear faces are parallelograms, and the remaining faces are rectangular, and a plurality of the unit bodies with the same inclination direction form a row;

[0009] In the same cross-composite layer, the inclination directions of the unit cells in adjacent rows differ by 90 degrees, forming a cross; taking the first cross-composite layer close to the impact surface as a reference, the remaining cross-composite layers are formed by rotating the normal of the previous cross-composite layer by 90 degrees.

[0010] In the same layer of the spiral composite layer, the inclination directions of the unit bodies are all the same. Taking the first layer of the spiral composite layer close to the impact surface as a reference, the remaining layers of the spiral composite layer are formed by rotating the normal of the previous spiral composite layer as the axis by the same angle, and the rotation angle is 18.95 degrees. The inclination directions of the unit bodies in the first layer of the spiral composite layer and the last layer of the spiral composite layer along the impact direction are exactly the same.

[0011] Preferably, the materials of the crack-stop layer and the protective layer are both polycarbonate, the material of the bonding layer is polymethyl methacrylate, the material of the unit body in the bulletproof layer is glass, the material of the cohesive body is polymethyl methacrylate, and the material of the homogeneous layer is glass.

[0012] Preferably, the thickness of the crack-stop layer is 2-3 mm, the thickness of the bulletproof layer is 30-33 mm, and the thickness of the protective layer is 4-6 mm.

[0013] Preferably, the cross structure, the stacked structure and the spiral structure in the bulletproof layer have the same thickness.

[0014] Preferably, the cross structure includes 10 cross composite layers and 10 bonding layers; the laminated structure includes 10 homogeneous layers and 10 bonding layers; and the spiral structure includes 20 spiral composite layers and 20 bonding layers.

[0015] Preferably, the minimum thickness of the bonding layer in the bulletproof layer is 0.0055 mm and the maximum thickness is 0.0625 mm.

[0016] Preferably, the inclination angle of the unit body along the thickness direction is 45 degrees.

[0017] Preferably, the volume fraction of polymethyl methacrylate in the cross-composite layer has a minimum value of 0.18% and a maximum value of 6.8%.

[0018] Preferably, the minimum volume fraction of polymethyl methacrylate in the spiral composite layer is 0.74% and the maximum volume fraction is 1.78%.

[0019] Preferably, the volume fraction of polymethyl methacrylate in the bulletproof layer is 6% to 15%.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This design utilizes fish-scale-like bulletproof glass, enhancing its energy dissipation mechanism. This design includes multiple layered, cross-laminated, overlapping, and spiral structures, inducing a variety of energy dissipation mechanisms and effectively improving the impact resistance of the bulletproof glass. The overlapping distribution of glass within the cross-laminated and spiral layers allows for stress transfer, helping to improve the stress field distribution near the bullet impact point, expanding the strain energy storage area and thereby enhancing energy absorption capacity. The cross-laminated structure near the impact surface of the bulletproof layer exhibits higher rigidity, while the spiral structure near the back surface exhibits higher toughness. This design achieves rigid-flexible coupling, simultaneously improving both strength and toughness. This coupling effect is reinforced by the linear gradient structural design. Furthermore, the stacked structure, located in the middle of the bulletproof layer, generates greater shear stress and strain, maximizing energy dissipation. The spiral structure, located at the bottom of the layer, induces a spatial distortion effect in the crack, resulting in a longer propagation path compared to cracks that only deflect in-plane, thus increasing the fracture energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1This is a schematic diagram of the overlapping scales on the surface of fish, the collagen fibers inside, and the spiral structure described in the background technology.

[0023] Figure 2 Schematic diagram of the explosion of fish-scale bulletproof glass.

[0024] Figure 3 A side view of the bulletproof layer.

[0025] Figure 4 A side view of the cross structure.

[0026] Figure 5 Schematic diagram of the explosion of the cross composite layer.

[0027] Figure 6 Schematic diagram of the distribution of adjacent cross-composite layers.

[0028] Figure 7 A side view of the stacked structure.

[0029] Figure 8 A side view of the spiral structure.

[0030] Figure 9 Schematic diagram of the explosion of the spiral composite layer.

[0031] Figure 10 Schematic diagram of the distribution of adjacent spiral composite layers.

[0032] Figure 11 is the distribution diagram of the bonding layer thickness.

[0033] Figure 12 The distribution diagram of the volume fraction of polymethyl methacrylate in the cross-composite layer and the spiral composite layer.

[0034] In the figure: 1. Crack-arresting layer; 2. Bulletproof layer; 3. Protective layer; 4. Adhesive layer; 5. Cross structure; 6. Laminated structure; 7. Spiral structure; 8. Cross composite layer; 9. Unit body; 10. Cohesive body; 11. Homogeneous layer; 12. Spiral composite layer. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] Figures 2 to 12 This is an embodiment of the present invention, and the following Figures 2 to 12 The present invention is further described.

[0037] like Figure 2 As shown, a fish-scale-like bulletproof glass based on a multi-level energy dissipation mechanism is composed of a crack-stop layer 1, a bulletproof layer 2, a protective layer 3 and an adhesive layer 4. The crack-stop layer 1, the bulletproof layer 2 and the protective layer 3 are arranged in sequence from the impact surface to the back surface, and the crack-stop layer 1, the bulletproof layer 2 and the protective layer 3 are bonded together by the adhesive layer 4. The bulletproof layer 2 is a composite structure composed of glass and polymethyl methacrylate. The materials of the crack-stop layer 1 and the protective layer 3 are both polycarbonate, and the material of the adhesive layer 4 is polymethyl methacrylate. The function of the crack-stop layer 1 and the protective layer 3 is to prevent glass fragments of the bulletproof layer 2 from flying out from the impact surface and the back surface respectively. The thickness of the protective layer 3 is greater than that of the crack-stop layer 1. The protective layer 3 has a certain elasticity and can use its own flexible deformation to further absorb the impact energy of the bullet and wrap the bullet head, playing a good protective role.

[0038] like Figures 3 to 10 As shown, the bulletproof layer 2 comprises a cross structure 5, a laminated structure 6, and a spiral structure 7, arranged sequentially along the impact direction. The cross structure 5 comprises a plurality of spaced-apart cross composite layers 8 and an adhesive layer 4; the laminated structure 6 comprises a plurality of alternating homogeneous layers 11 and adhesive layers 4. The homogeneous layers 11 are made of glass. The laminated structure 6 is located near the neutral layer of the bulletproof layer 2 and experiences minimal tensile and compressive deformation. The energy dissipation mechanism is primarily shear deformation of the adhesive layer 4 upon impact, generating significant shear stress and strain, thereby maximizing energy dissipation; the spiral structure 7 comprises a plurality of spaced-apart spiral composite layers 12 and an adhesive layer 4.

[0039] Both the cross-composite layer 8 and the spiral composite layer 12 are composed of several unit cells 9 and the intervening cohesive bodies 10. Unit cells 9 are oblique hexahedrons formed by tilting and deforming a rectangular parallelepiped. The front and rear faces are parallelograms, and the remaining faces are rectangles. Several unit cells 9 with the same tilt direction form a row. Unit cells 9 are made of glass. When an impacting bullet contacts a unit cell 9, stress is transferred through the overlapping units 9, thereby expanding the strain energy storage area and improving energy absorption capacity. Cohesive bodies 10 are made of polymethyl methacrylate, which increases the deformation capacity of brittle glass, improves the stress field distribution within the bulletproof layer 2, reduces stress concentration, effectively avoids catastrophic failure modes in the bulletproof layer 2, and increases the energy storage area.

[0040] In the same cross-composite layer 8, the inclination directions of adjacent rows of unit cells 9 differ by 90 degrees, forming a cross; adjacent layers of cross-composite layers 8 are different. Taking the first layer of cross-composite layer 8 close to the impact surface as the benchmark, the remaining layers of cross-composite layers 8 are formed by rotating 90 degrees around the normal of the previous cross-composite layer 8 as the axis. This multi-level cross design ensures that the cross-composite layer 8 has sufficiently high rigidity and a certain toughness.

[0041] Within the same spiral composite layer 12, the tilt directions of the unit cells 9 are all the same, which makes the spiral composite layer 12 have lower stiffness and higher toughness than the cross composite layer 8. Taking the first spiral composite layer 12 close to the impact surface as the reference, the remaining spiral composite layers 12 are formed by rotating the normal of the previous spiral composite layer 12 at the same angle of 18.95 degrees. Along the impact direction, the first and last spiral composite layers 12 rotate exactly one circle, that is, the tilt directions of the unit cells 9 in the first and last spiral composite layers 12 along the impact direction are exactly the same. This spiral structure 7 at the bottom of the bulletproof layer 2 can induce a spatial distortion effect in the crack, resulting in a longer propagation path than cracks that only deflect within the surface, thereby increasing the fracture area and thus improving the fracture energy.

[0042] In a specific embodiment, Figures 11-12 As shown, the thickness of the adhesive layer 4 in the cross structure 5 and the laminate structure 6 increases linearly from the impact surface to the back surface, while the thickness of the adhesive layer 4 in the spiral structure 7 remains constant, numerically equal to the maximum thickness of the adhesive layer 4 in the laminate structure 6. The volume fraction of the cohesive layer 10 in the cross composite layer 8 and the spiral composite layer 12 increases linearly from the impact surface to the back surface. These two gradient designs enhance the rigid-flexible coupling effect and improve energy absorption.

[0043] In a specific embodiment, the thickness of the crack-arresting layer 1 is 2-3 mm, the thickness of the bulletproof layer 2 is 30-33 mm, and the thickness of the protective layer 3 is 4-6 mm.

[0044] In a specific embodiment, the cross structure 5 , the laminated structure 6 and the spiral structure 7 in the bulletproof layer 2 have the same thickness, which is beneficial to enhance the synergistic effect between the different structures.

[0045] In a specific embodiment, the cross structure 5 includes 10 cross composite layers 8 and 10 bonding layers 4; the laminated structure 6 includes 10 homogeneous layers 11 and 10 bonding layers 4; and the spiral structure 7 includes 20 spiral composite layers 12 and 20 bonding layers 4.

[0046] In a specific embodiment, the minimum thickness of the adhesive layer 4 in the bullet-proof layer 2 is 0.0055 mm, and the maximum thickness is 0.0625 mm.

[0047] In a specific embodiment, the unit body 9 has an inclination angle of 45 degrees along the thickness direction, which effectively extends the crack propagation path and prevents the crack from directly passing through the glass material.

[0048] In a specific embodiment, the volume fraction of polymethyl methacrylate in the cross-composite layer 8 has a minimum value of 0.18% and a maximum value of 6.8%.

[0049] In a specific embodiment, the volume fraction of polymethyl methacrylate in the spiral composite layer 12 has a minimum value of 0.74% and a maximum value of 1.78%.

[0050] In a specific embodiment, the volume fraction of polymethyl methacrylate in the bulletproof layer 2 is 6% to 15%, which can ensure that the bulletproof glass has a certain toughness without reducing its strength.

[0051] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A fish-scale bulletproof glass based on a multi-level energy dissipation mechanism, characterized in that: It consists of a crack-stop layer, a bullet-proof layer, a protective layer and a bonding layer, wherein the crack-stop layer, the bullet-proof layer and the protective layer are arranged in sequence from the impact surface to the back surface, and the crack-stop layer, the bullet-proof layer and the protective layer are bonded together by the bonding layer; The bulletproof layer is composed of a cross structure, a laminated structure and a spiral structure arranged in sequence along the impact direction; the cross structure is composed of a plurality of cross composite layers and bonding layers distributed at intervals, the laminated structure is composed of a plurality of homogeneous layers and bonding layers distributed alternately, and the spiral structure is composed of a plurality of spiral composite layers and bonding layers distributed at intervals; The cross composite layer and the spiral composite layer are both composed of a plurality of unit bodies and the cohesion of the gaps between them; the unit body is an oblique hexahedron, the front and rear faces are parallelograms, and the remaining faces are rectangular, and a plurality of the unit bodies with the same inclination direction form a row; In the same cross-composite layer, the inclination directions of the unit cells in adjacent rows differ by 90 degrees, forming a cross; taking the first cross-composite layer close to the impact surface as a reference, the remaining cross-composite layers are formed by rotating the normal of the previous cross-composite layer by 90 degrees. In the same spiral composite layer, the inclination direction of the unit bodies is the same. Taking the first spiral composite layer close to the impact surface as a reference, the remaining spiral composite layers are formed by rotating the normal of the previous spiral composite layer as an axis by the same angle, and the rotation angle is 18.95 degrees. The inclination directions of the unit bodies in the first spiral composite layer and the last spiral composite layer along the impact direction are exactly the same. The material of the unit body is glass, the material of the cohesive body is polymethyl methacrylate, and the material of the homogeneous layer is glass.

2. The fish-scale-like bulletproof glass based on a multi-level energy dissipation mechanism according to claim 1, characterized in that: The materials of the crack-stop layer and the protective layer are both polycarbonate, and the material of the bonding layer is polymethyl methacrylate.

3. The fish-scale-like bullet-proof glass based on a multi-level energy dissipation mechanism according to claim 1, characterized in that: The thickness of the crack-stop layer is 2-3 mm, the thickness of the bulletproof layer is 30-33 mm, and the thickness of the protective layer is 4-6 mm.

4. The fish-scale-like bullet-proof glass based on a multi-level energy dissipation mechanism according to claim 1, characterized in that: The cross structure, the stacked structure and the spiral structure in the bulletproof layer have the same thickness.

5. The fish-scale-like bullet-proof glass based on a multi-level energy dissipation mechanism according to claim 1, characterized in that: The cross structure includes 10 cross composite layers and 10 bonding layers; the laminated structure includes 10 homogeneous layers and 10 bonding layers; and the spiral structure includes 20 spiral composite layers and 20 bonding layers.

6. The fish-scale-like bullet-proof glass based on a multi-level energy dissipation mechanism according to claim 1, characterized in that: The minimum thickness of the bonding layer in the bulletproof layer is 0.0055 mm, and the maximum thickness is 0.0625 mm.

7. The fish-scale-like bullet-proof glass based on a multi-level energy dissipation mechanism according to claim 1, characterized in that: The inclination angle of the unit body along the thickness direction is 45 degrees.

8. The fish-scale-like bullet-proof glass based on a multi-level energy dissipation mechanism according to claim 1, characterized in that: The minimum volume fraction of polymethyl methacrylate in the cross-composite layer is 0.18%, and the maximum volume fraction is 6.8%.

9. The fish-scale-like bullet-proof glass based on a multi-level energy dissipation mechanism according to claim 1, characterized in that: The minimum volume fraction of polymethyl methacrylate in the spiral composite layer is 0.74%, and the maximum volume fraction is 1.78%.

10. The fish-scale-like bullet-proof glass based on a multi-level energy dissipation mechanism according to claim 1, characterized in that: The volume fraction of polymethyl methacrylate in the bulletproof layer is 6% to 15%.

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