.an armor structure

Abstract

.This invention relates to an armored structure (1) developed to provide ballistic protection when used in all appropriate vehicles in the defense sector — air, land, and sea platforms — along with modifications to the necessary parameters, and having a plate layer (3) made of 304 stainless steel, which stands out for its light weight and availability, a honeycomb-shaped core sandwich panel (2) formed by joining sinusoidal trapezoidal sheet metal plates, and a boron carbide ceramic coating (4) applied to the outer surface to absorb impact.

Description

[0001] AN ARMOR STRUCTURE

[0002] Technical Field

[0003] This invention relates to an armored structure developed to provide ballistic protection when used in all appropriate defense vehicles — air, land, and sea platforms — along with modifications to meet the necessary parameters and having a surface plate made of 304 stainless steel, which stands out for its light weight and affordability, a honeycomb-shaped core panel formed by joining sinusoidal trapezoidal sheet metal plates, a boron carbide ceramic coating applied to the outer surface to absorb impact, and a protective plate made of aramid fiber on the inner surface to secure the components.

[0004] Background

[0005] In the state of the art, vehicles use RHA structures with voids as armor. In such previous technical applications, weight and ballistic protection levels pose a significant disadvantage, Specific Energy Absorption (SEA) values are low, and they result in substantial cost requirements.

[0006] RHA — Rolled Homogeneous Armor is a type of high-strength armor used primarily for military vehicles and structures. RHA is manufactured from high-strength steel alloys and is referred to as “homogeneous” because it has a uniform structure. MIL-DTL- 12560 and MIL-DTL-46100 standards are military specifications that govern the different types and applications of RHA. MIL-DTL-12560 is an armor specification included in U.S. military standards and is widely used for RHA steel. This standard is particularly suitable for use in ground vehicles, fixed structures, and armored platforms. To provide STANAG 4569 Level-3 protection (against 7.62 mm armor-piercing (AP) rounds), rolled homogeneous armor (RHA) with a hardness of approximately 380 Brinell Hardness Units (BHN) must be approximately 14.5 mm thick. The areal density of rolled homogeneous armor (RHA) with a hardness of 380 BHN is approximately 113.8 kg / m2for a thickness of 14.5 mm. This is calculated based on the armor’s density and thickness. RHA is widely recognized as a standard in armor technology. Modem armor designs are evaluated relative to this steel, and their durability isexpressed using terms such as “RHA equivalent” or “RHA replacement”. For example, the effectiveness of more advanced armor systems, such as composite armor or reactive armor, is measured by comparing them to the protection provided by RHA of a specific thickness. In this way, the durability of RHA serves as a benchmark in the field of armor. With the advancement of composite and reactive armor technologies today, RHA is often combined with these systems to achieve higher levels of protection. In sources regarding armor materials, steel materials are classified into forged armor steels, cast armor steels, and perforated steel armor. When discussing perforated steel armor, it is designed using high-hardness steel plates with holes arranged in a specific pattern on their surface. These holes are calculated based on the targeted threat type and are generally no larger than half the diameter of the expected penetrator. To reduce the weight and density of the armor, the positions and sizes of the holes are determined based on the order specifications. It has been observed that the holes cause an armor-piercing (AP) round to lose its balance or fragment by disrupting its trajectory.

[0007] Perforated steel armor is designed using high-hardness steel plates with perforations arranged in a specific pattern on their surface. These perforations are optimized through engineering calculations based on the type of threat they are intended to counter and are typically designed to be less than half the diameter of the expected penetrating bullet. This ensures effective protection while reducing unnecessary material weight. The size, shape, and arrangement of the perforations are customized to match the armor’s protection level and intended use. Additionally, it has been observed that the perforations have a dual effect on armor-piercing (AP) rounds. By disrupting the round’s linear motion, they cause rotational instability, leading to the round’s fragmentation or a reduction in its effectiveness. This property enables perforated steel armor to offer advantages in both weight and protection.

[0008] An ideal armor system must strike a balance between effectiveness and lightness and be as practical as possible. For this reason, the most effective system consists of materials that are low in density but have high penetration resistance. The materials used in passive armor are selected based on the requirements of engineers and can be divided into two main categories: energy “dispersing” and energy “absorbing” materials. Dispersing (destructive) materials, which cause deformation in the penetrator, are typically made of hard and durable materials such as high-strength steel or ceramics and reduce the penetrator’ s effectiveness by wearing it down. If the penetrator fragments (or takes on a mushroom shape), the hard surface dispersesthese fragments into the surrounding area, diverting and dissipating kinetic energy. As a result, the penetrator struggles to penetrate subsequent plates or areas due to this deformation and erosion. Destructive components are typically made of hard materials such as ceramics or high-hardness steel.

[0009] Energy-absorbing materials, on the other hand, absorb incoming energy through significant plastic deformation, thereby converting the energy into a small amount of heat and reducing the impact of the penetrator. Energy-dissipating components, meanwhile, are materials capable of undergoing significant plastic deformation, thereby providing protection against explosions.

[0010] Summary of the Invention

[0011] The object of this invention is to realize an armor structure that offers significant cost and weight advantages due to its layered design — composed of lightweight materials with complementary technical properties — which enhances energy absorption through a hybrid structural configuration achieved by combining multiple layers.

[0012] Another object of the invention is to develop an armor structure that provides protection at the NATO STANAG 4569 Level 3 standard, as demonstrated by field tests.

[0013] Detailed Description of the Invention

[0014] The “armor structure” designed to achieve the object of this invention is shown in the attached figures, in which:

[0015] Figure 1. A schematic representation of the positioning of the layers that make up the armor structure described in the invention.

[0016] (Based on the dimensions designed within the scope of the invention:

[0017] • the thickness of the ceramic coating (tk): 10 mm,

[0018] • the thickness of the core sandwich panel (He): 30 mm, and

[0019] • the total thickness of the core region and plate layers (H) is 35 mm, and;

[0020] • the surface area of the layers (L) is 150 mm x 150 mm; however, these values may vary depending on the intended application of the product)Figure 2. A perspective view of the sinusoidal-shaped core component forming the core sandwich panel in the armor structure of the invention.

[0021] Figure 3. A representation of the formation of the honeycomb structure possessed by the core sandwich panel, resulting from the honeycomb -like assembly of the sinusoidal plates that constitute the core sandwich panel in the armor structure of the invention.

[0022] Figure 4. A top view of the core sandwich panel positioned on the plate layer in the armor structure of the invention.

[0023] Figure 5. A comparative representation of ballistic limit velocities according to penetrator types, with the value for the multi-layered armor structure of the invention

[0024] shown in the far-right column.

[0025] • S: Uncoated corrugated core sandwich panel [Wang X, Yue, Z., Xu, X.,

[0026] Zhao, Z, Ji, H., Zhu, M., Wan, P., Zhang, Q., Lu, T.J.: Ballistic impact

[0027] response of elastomer-retrofitted corrugated core sandwich panels. Int. J.

[0028] Impact Eng 175, 104545(2023)]

[0029] • RP: Rigid bullet,

[0030] • DP: Deformable bullet

[0031] • PS: 15 mm polyurethane-coated corrugated core sandwich panel [Wang et al., 2023] • HC: Honeycomb sandwich panel,

[0032] • B4CHC: 6 mm B4C-coated honeycomb sandwich panel

[0033] Figure 6. Representation of the precision analysis results for different types of applications during the development process of the invention. Among these;Simulation Bullet Impact Model Details

[0034] Number Location

[0035] 1 Blow to the 30 mm core height, 1 mm core wall thickness, uncoated Honeycomb sandwich panel, standard size

[0036] Joint

[0037] 2 Striking the 30 mm core height, 1 mm core wall thickness, uncoated Honeycomb sandwich panel, standard size

[0038] Space

[0039] 3 Blow to the 30 mm core height, 1 mm core wall thickness, sandwich Honeycomb panel with a 0.3 mm B4C-coated core (inside the core)

[0040] Joint

[0041] 4 Striking the 2.5 mm core wall thickness, sandwich panel with an uncoated Honeycomb core

[0042] Space

[0043] 5 Blow to the 2.5 mm core wall thickness, sandwich panel with an uncoated Honeycomb core

[0044] Joint

[0045] 6 Blow to the Sandwich panel with a 2.5 mm core wall thickness and a 0.3 Honeycomb mm B4C-coated core (inside the core)

[0046] Joint

[0047] 7 Striking the Sandwich panel with a 2.5 mm core wall thickness and a 0.3 Honeycomb mm B4C-coated core (inside the core)

[0048]

[0049] Space

[0050] The components shown in the figures are numbered individually, and the corresponding numbers are listed below:

[0051] 1. Armor structure

[0052] 2. Core sandwich panel

[0053] 3. Plate layer

[0054] 4. Ceramic coating

[0055] An armor structure (1) of the invention, which is used to provide ballistic protection by modifying the necessary parameters in all suitable defense systems — including air, land, and sea platforms — and which features a hybrid layered configuration obtained by combining layers with different properties to enhance energy absorption, comprises the following:

[0056] at least one honeycomb-shaped core sandwich panel (2), formed by joining sinusoidal trapezoidal sheet metal plates in various configurations and positioned between at least two plate layers (3),

[0057] a ceramic coating (4) applied as a coating to the outer surface of the plate layer (3) on the side of the core sandwich panel (2) facing away from the surface of the vehicle or structure to which the core sandwich panel (2) is applied for protective purposes, and which serves as the first surface contacted by a penetrator striking the surface like abullet.

[0058] In one embodiment of the invention, there is at least one fabric layer positioned between the surface of the vehicle or structure to be protected and the plate layer (3) located near that surface. This fabric layer is made of aramid fiber material, preferably Kevlar®. The fabric layer is an optional component in layered and composite structures; it may not be required in armor systems used in static structures — such as police stations, buildings, etc. The reason for this is that the stainless steel plate layer (3) on the rear surface comes into direct contact with rigid structural elements such as concrete or facade cladding, thereby eliminating the need for an additional ballistic damping layer. In contrast, the presence of the fabric layer is a critical requirement in land, sea, and air vehicles. The fabric layer serves to protect the crew and onboard systems by reducing the spall effect that bullets or shrapnel fragments could create on the rear surface of the armor. A fabric layer made of Kevlar® material can also contribute to the attenuation of electromagnetic effects, thereby enhancing the security of electronic systems.

[0059] In one embodiment of the invention, the plate layers (3) are preferably made of stainless steel — specifically 304 Stainless Steel (304-SS). Alternatively, depending on the application, it is made from at least one of 304 SS (Stainless Steel), aluminum, 301 SS, or 4340 SS. Compared to armor made from traditional aluminum materials, the 304 stainless steel core sandwich panel (2) absorbs less energy because it reaches plastic deformation later due to its high strength. While aluminum material rapidly converts kinetic energy into internal energy, 304 stainless steel dissipates kinetic energy to a lesser extent and exhibits a tendency toward elastic rebound. Aluminum’s lower yield strength, hardening coefficient, and sensitivity to strain rate result in an energy absorption capacity that is more sensitive to strain rate and temperature. Stainless steel’s higher yield strength and hardening coefficient values represent higher strength and lower deformation capacity.

[0060] In one embodiment of the invention, the ceramic coating (4) is made of B4C (boron carbide) material.

[0061] In one application of the invention, epoxy resin, polyurethane adhesive, or methacrylate adhesives are used to bond the layers that are in contact with one another.In one embodiment of the invention, the voids in the core sandwich panel (2) are filled with aluminum foam. Alternatively, these voids are filled with at least one of the fluids that solidify under shear. The fluids used to fill the voids in core sandwich panels play a strategic role, particularly in the defense industry, in terms of damping impact energy and enhancing structural durability. In this context, shear-thickening fluids (STF) are prominent. These fluids exhibit a solid-like behavior by suddenly increasing their viscosity under high impact or shear stress. In particular, polyethylene glycol) (PEG)-based fluids reinforced with silica nanoparticles are widely used in armor systems and ballistic protection. Alternatively, magnetorheological (MR) fluids provide impact damping capability by altering their viscosity under a magnetic field. Additionally, Theologically tunable fluids and silicone-based damping fluids offer advantages in terms of vibration control and thermal stability. The use of these fluids enhances the sandwich panel’s (2) energy dissipation capacity while minimizing deformation, thereby contributing to the preservation of structural integrity.

[0062] The armor structure (1) of the invention comprises a honeycomb-shaped core sandwich panel (2) positioned between at least two plate layers (3) made of 304 stainless steel — which is distinguished by its lightness and availability — and formed by combining sinusoidal trapezoidal sheet metal plates in various configurations. On the side of the honeycomb-shaped core sandwich panel (2), on the side of the honeycomb-shaped core sandwich panel (2) closest to the surface to which the invention is applied, a fabric layer made of Kevlar® — the most well-known aramid fiber and a material frequently preferred in ballistic protection systems — is provided to protect the area behind the surface (e.g., personnel inside a vehicle) from the spall effect; and on the side of the honeycomb-shaped core sandwich panel (2) and on the side of the core sandwich panel (2) facing away from the applied surface, there is a ceramic coating (4) made of boron carbide (B4C), which serves as the first surface to contact a penetrator — such as a bullet — impacting the surface.

[0063] Within the scope of this invention, in addition to the use of all-metallic sandwich structures, the incorporation of a ceramic coating (4) made from boron carbide (E C) to enhance ballistic resistance is preferred as an innovative and practical technique, particularly for the honeycomb-shaped core sandwich panel (2). Numerical analyses conducted on the ceramic coating (4) made from boron carbide (E C) — used for the first time in this type of panel — demonstrate that reinforcing the surface of the core sandwich panel’s (2) impact zone with a sufficiently thick B4C coating significantly increases the ballistic limit velocity and thepenetration energy threshold. This result can be attributed to the superior mechanical properties and energy dissipation capability of the B4C coating.

[0064] The armor structure (1) of the invention utilizes a fabric layer made of aramid fiber fabric in the section that comes into contact with the surface to which it is applied, thereby further optimizing ballistic performance by leveraging the material’s spall -reducing properties. The spall effect is a threat caused by the dispersion of fragments detached from the rear surface of the armor during an impact; to prevent potential hazards arising from this effect, a fabric layer — preferably made of Kevlar® material — is used as a protective layer on the rear surface of the core sandwich panel (2) where the invention is applied. The high tensile strength and impact energy absorption capability of Kevlar® effectively reduce the kinetic energy of fragments detached from the rear surface and contribute to the overall ballistic resistance of the object of the invention.

[0065] In the experimental studies conducted during the development of the invention, high-accuracy finite element (FE) simulation models were developed for both coated and uncoated core sandwich panels (2) using a user-defined constitutive model for the structure containing a ceramic coating (4) with a E C coating. The fabric layer used as Kevlar® reinforcement was also accounted for in these models, and the contribution of spall effects to dynamic processes was examined in detail. The residual velocity curves, ballistic limit values, penetration energy thresholds, dynamic penetration process, and failure modes obtained from the analyses show a high degree of consistency with experimental results. The results demonstrate that the ceramic coating (4), which consists of a E C layer placed on the impact area, absorbs the impact energy of the penetrators more effectively and thus significantly increases ballistic resistance. Additionally, it is observed that the fabric layer made of Kevlar® fabric further enhances the effectiveness of the invention and personnel safety by minimizing the spall effect that may occur after impact. The complementary effects of the B4C ceramic coating (4) and the fabric layer made of Kevlar® fabric ensure that impact energy is distributed over a wider area and that deformation is controlled. This study demonstrates that the armor structure of the invention is an ultra-lightweight, multifunctional product with advanced ballistic performance. The effective use of this combination enables the development of safer, more durable, and more efficient structures for both military and industrial applications.

[0066] According to field tests conducted by ROKETSAN A.§., the armor structure (1) of theinvention provides protection at NATO STANAG 4569 Level 3. The technical advantage of the armor structure (1) described in the invention is clearly demonstrated by comparative graphical data (Figures 5 and 6). Graphical analyses show that the B4C-coated honeycomb sandwich panel has a 30% higher energy dissipation capacity during high-velocity bullet impact compared to uncoated panels. Additionally, graphs illustrating the amount of deformation prove that the B4C-coated panel reduces permanent deformation by 40% and significantly preserves structural integrity. Data on penetration depth, meanwhile, reveals that the coated panel experiences 35% less penetration. This graphical data clearly supports the superior performance of our invention in terms of ballistic resistance and structural durability.

[0067] In the experimental studies conducted during the development of the invention, the mechanical performance of B4C-coated honeycomb sandwich panels against high-velocity bullet impact was investigated. Data obtained from comparative graphical representations indicates that the B4C coating minimizes panel deformation by enhancing its energy dissipation capacity.

[0068] Energy Dissipation Capacity:

[0069] When comparing an uncoated sandwich panel with a 30 mm core height and a 1 mm core wall thickness to a B4C-coated sandwich panel, it was found that the B4C coating dissipates 30% more energy. This helps preserve the panel’s structural integrity by dispersing the impact of a bullet strike.

[0070] Deformation Reduction:

[0071] In an impact scenario on the honeycomb joint, a B4C-coated sandwich panel with a 2.5 mm core wall thickness exhibited 40% less permanent deformation compared to an uncoated panel. This demonstrates that the B4C coating increases the panel’s rigidity following an impact.

[0072] Resistance to High-Velocity Penetration:

[0073] In the event of an impact with a honeycomb core, the B4C-coated core reduced the bullet’s penetration depth by 35%. This enhances the panel’s ballistic protection capabilities, therebyincreasing its effectiveness in defense and aerospace applications.

[0074] As a result, the B4C coating significantly enhances the mechanical strength and energy absorption capacity of honeycomb sandwich panels, minimizing deformation and preserving structural integrity. This innovation offers a significant advantage, particularly for applications requiring ballistic protection.

[0075] Based on these fundamental concepts, it is possible to develop a wide variety of implementations related to “an armor structure (1)” of the invention; the invention is not limited to the examples described herein but is essentially as set forth in the claims.

Claims

CLAIMS1. An armor structure (1) having a hybrid layered configuration, in which layers with different properties are combined to provide ballistic protection by modifying the necessary parameters in all suitable vehicles in the defense sector, thereby enhancing energy absorption, and comprising- at least one honeycomb-shaped core sandwich panel (2), formed by joining sinusoidal trapezoidal sheet metal plates in various configurations and positioned between at least two plate layers (3),- a ceramic coating (4) applied as a coating to the outer surface of the plate layer (3) on the side facing away from the surface of the vehicle or structure to which the core sandwich panel (2) is applied for protective purposes, and which serves as the first surface to be struck by a penetrator approaching the surface like a bullet2. The armor structure (1) according to Claim 1, comprising at least one fabric layer positioned between the surface of the vehicle or structure to be protected and a plate layer (3) adjacent to that surface.

3. The armor structure (1) according to Claim 2, comprising a fabric layer made of aramid fiber material.

4. The armor structure (1) according to Claim 3, comprising a fabric layer made of Kevlar® material.

5. The armor structure (1) according to any one of the preceding claims, comprising plate layers (3) made of at least one of 304 stainless steel, aluminum, 301 stainless steel, or 4340 stainless steel, depending on the intended use.

6. The armor structure (1) according to any one of the preceding claims, comprising a ceramic coating (4) made of boron carbide material.

7. The armor structure (1) according to any one of the preceding claims, comprising epoxy resin, polyurethane adhesive, or methacrylate adhesives used to bond layers into contact with each other.The armor structure (1) according to any one of the preceding claims, comprising a core sandwich panel (2) with voids filled with at least one of aluminum foam or a liquid to be injected.

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