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Ballistic limit thickness for Stanag 4569 level 3 threat: (a) full bullet model with Lagrange discretization, (b) steel core model with Lagrange discretization and (c) steel core model with SPH discretization.
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Although advanced lightweight composite based armors are available, high hardness steels in military vehicles are often used to provide ballistic protection at a relatively low cost and is an interesting material due to its widespread usage in vehicle structure. In this study, ballistic limit of 500 HB armor steel was determined against 7.62 mm 54R...
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Citations
... Gara et al. 15 studied the impact behaviour of alloy aluminium (Al)2024-T351 using finite element (FE) analysis performed in LS DYNA software, and the simulation results on the residual velocities had a perfect agreement with the analytical models. Kiliç and Ekici 16 utilized the Lagrangian framework in conjunction with smoothed particle hydrodynamics (SPH) to numerically evaluate the ballistic limit thickness of Secure 500 armor steel, achieving a high degree of correlation between the computational predictions and experimental observations. Tria and Trębiński 17 developed a finite element (FE) model to simulate the impact of a 7.62 mm armour-piercing (AP) projectile on 30 p.m. armour steel, employing a modified Johnson-Cook material model. ...
Sandwich structures composed of top and bottom face sheets and an inner core are commonly used for energy-absorbing applications, mainly because of their superior stiffness-to-weight ratio and crashworthiness. Despite extensive studies on the ballistic behavior of monolithic and composite materials, limited research has focused on hybrid sandwich structures combining lightweight and ductile materials like thermoplastic polyurethane (TPU) with high-strength aluminum. This study aimed to numerically establish the ballistic limit velocities and the penetrating and perforation resistances of composite sandwich structures to address this gap. The sandwich panels were manufactured from thermoplastic polyurethane (TPU) and aluminum (Al) 2024-T351 as core and face sheets/skins, respectively. The panels were subjected to an impact to investigate the effects of various thicknesses of their face skins and core on high-speed impact resistance. From the results obtained, it was evident that the numerical models simulated experiments with high accuracy. The impact and damage resistances of the composite sandwich structures increased with the thicknesses of their core and face sheets. The resistance of the structure increased by 19% by increasing the thickness of face sheets from 1.2 to 2.0 mm. Similarly, the resistance of the composites can be increased by 44% by increasing the core thickness from 20 to 50 mm. Therefore, it can be established that the impact resistance of the composite sandwich structures depended on the thicknesses of their core and skins. The investigated performances of the different composite sandwich structures should guide their choice for various industrial applications.
... Erraticism of the ballistic impacts and J o u r n a l P r e -p r o o f their tendency to display stochastic behavior further enhances those issues as it facilitates the need to conduct a significantly greater number of tests in order to obtain valid experimental data. For example, in the research of Kilic and Ekici [1] it was observed that only one out of five firings achieved a perpendicular intrusion into the target plate, while in the rest of the firings unwanted obliquity was detected. Conversely, ballistic parameters may also be evaluated by the utilization of predictive models, in a relatively simple and fast manner and without the need for extensive number of ballistic tests. ...
This paper proposes a modification of the Forrestal-Warren perforation model aimed at extending its applicability range to intermediately-thick high-hardness armor steel plates. When impacted by armor-piercing projectiles, these plates tend to fail through adiabatic shear plugging which significantly reduces their ballistic resistance. To address this effect, an approach for determining effective thickness was defined and incorporated into the predictive model. Ballistic impact tests were performed to assess the modification’s validity, in which ARMOX 500T steel plates were subjected to perpendicular impacts from 7.62×39 mm steel-cored rounds under various velocities. Frequent target failure by soft plugging was observed, as well as the brittle shatter of the hard steel core. Key properties of the recovered plugs including their mass, length and diameter were measured and reported along with the projectiles' residual velocities. Additionally, independent data from the open literature were included in the analysis for further validation. The original Forrestal-Warren model and the novel effective thickness modification were then used to establish the relationship between impact and residual velocities, as well as to determine the ballistic limit velocity. The comparison revealed that the proposed approach significantly improves the model's accuracy, showing a strong correlation with experimental data and reducing deviations to within a few percent. This enhancement highlights the potential of the effective thickness term, which could also be applied to other predictive models to extend their applicability range. Further exploration into other armor steels and impact conditions is recommended to assess the method's versatility
... To prevent movement at the edges, the six degrees of freedom for the nodes at the edges were constrained. Eroding_Nodes_to_Surface contact [13] was defined between the hail and the plate (Fig. 1). The hail model consists of 14,328 Smooth Particle Hydrodynamics (SPH) elements [14,15]. ...
This study investigates the mechanical performance of bio-inspired honeycomb sandwich structures under high-speed hail impacts. A detailed Ls-Dyna model was developed and validated using experimental results from hail impact tests on Carall composite structures from the literature, with the model’s accuracy confirmed through alignment of post-impact damage patterns, z-axis displacement values, and initial energy absorption with experimental data. Mesh refinement techniques, ranging from coarse to fine elements, were applied, revealing that smaller mesh sizes provided more detailed damage representation and improved accuracy in critical areas. Various impact angles (22.5°, 45°, 67.5°, and 90°) were analyzed to simulate real-world conditions, demonstrating that higher angles, particularly 90°, resulted in the most severe damage. Additionally, eight different honeycomb configurations, including hexagonal and bio-inspired designs, were incorporated into the sandwich structure model. The results showed that hexagonal, re-entrant, wavy, and SI honeycombs sustained substantial damage, while spider web, bamboo, pomelo peel, and grass stem designs exhibited superior resistance. Among all, the wavy honeycomb model achieved the highest specific energy absorption (sEA), showing a 5.62% improvement over the hexagonal model. This research underscores the potential of bio-inspired honeycomb structures in enhancing impact resistance, offering valuable insights for future design strategies in impact-critical applications.
... The armor material of traditional vehicles mainly uses homogeneous armor steel. Due to its poor resistance to multiple rounds, improving its ballistic protection ability is mainly achieved by increasing the thickness, but this seriously affects the mobility of armored vehicles [1,2]. To achieve the lightweight and multi-bullet resistance performance of the armor module, researchers have carried out a lot of research on the perforated armor plate. ...
To compare the ballistic protection characteristics of perforated plates made of different steel materials against 12.7 mm perforating ammunition, the ballistic gun, light curtain velocity measurement system, and high-speed camera were used to study its ballistic performance, and the ballistic protection, perforated plate damage area, core fracture and core deflection characteristics of perforated plates made of different armor steel materials were compared. The results show that the ballistic protection performance of C-2 and H-1 perforated plates is better than that of C-1 and C-3 perforated plates, the protection performance of C-1 and C-3 is equivalent, and the protection coefficient of H-1 can reach or even exceed that of C-2. The hole damage area of an H-1 perforated plate is larger than that of a circular perforated plate, and the number of bullet core fractures is more, but its crack arrest performance is poor. The damage area of a single interconnection hole in perforated plates of different armor steel materials meets the linear relationship, and its linear slope can characterize the degree of hole loss. The damage of a single interconnection hole with hexagonal holes is greater than that of perforated plates with circular holes. At the same time, the projectile deflection angle of perforated plates made of different armor steel materials also conforms to the linear relationship, and the fitting linear slope can measure the degree of core deflection. The higher the hardness of perforated plates with circular holes, the greater the core deflection, while the degree of core deflection of hexagonal holes is greater than that of perforated plates with circular holes.
... Considerable research has been conducted by scholars 26,27 to determine the material constants of the bullet. A comparative analysis reveals that the simulation results obtained using the projectile parameters reported in Kilic's study 26 align well with the shooting results. ...
... Considerable research has been conducted by scholars 26,27 to determine the material constants of the bullet. A comparative analysis reveals that the simulation results obtained using the projectile parameters reported in Kilic's study 26 align well with the shooting results. Consequently, the parameters reported by Kilic 26 are selected for this study, and their values are listed in Table 2. ...
... J-C parameters for the target plate and AP bullet26 . ...
In order to establish a connection between the ballistic performance and mechanical properties of armor steel, a ballistic simulation model was developed and subsequently validated for accuracy and reliability. The mechanical properties of the target plate were described using the Johnson–Cook constitutive relation. An analysis was conducted to investigate the impact of the J–C parameters of the target plate on its ballistic performance, revealing a strong linear relationship between them. Subsequently, a mathematical model represented as H = 14.82 − 0.0048A − 0.0023B + 5.95n − 81.3C was derived, and its accuracy was demonstrated to exceed 90%. This mathematical model can effectively predict the ballistic performance of the armor steel, even when its mechanical properties undergo variations during the production process. This prediction capability significantly contributes to reducing research costs and time.
... Considering penetration mechanism simulations, Namik and Bulent numerically investigated the perforation of 7.62 mm AP projectiles in high-strength steel armour. They concluded that the strain rate parameters in the projectile model must be modified to eliminate premature erosion of the projectile tip during simulations [5]. ...
The ballistic performance and penetration capabilities of armour piercing (AP) projectiles have attracted considerable interest, especially with the development of personal body armour. This paper presents the steps for converting conventional 7.62x51 mm AP projectiles into advanced ones provided with tungsten carbide cores. Designing, finite element modeling and testing procedures have been studied to enhance the penetration capability of developed projectiles. The internal ballistic parameters were calculated for these projectiles to ensure barrel safety. PRODAS ballistic software is used to predict the stability of developed projectiles during flight. The penetration ability in armour steel with a hardness of 450–500 HB for all the designed projectiles as well as the traditional NATO AP projectile is evaluated both numerically using ANSYS software and experimentally by fining. In conclusion, the penetration capability of the best configuration of the developed projectiles is almost twice that of the NATO AP projectile.
... Fras et al. examined the defeat mechanism of a 20 mm thick super bainitic plate with 4 mm diameter array of holes and compared it with Mars 190 armour plate. They concluded that Mars 190 armour plate with an areal weight of 129.7 kg/m 2 can be substituted by perforated super-brainitic plate with a weight of 85.2 kg/m2 [61]. In this study, areal weights were calculated between 97.70 and 88.10 kg/m 2 and considering the high density of armour steels, the method and welding consumables used stand out as promising alternatives. ...
The aim of this study was to develop plates resistant to ballistic limits by welding on S355JR steel plate with Fe-Cr-C and austenitic electrodes. A total of four different weld coated materials were prepared for ballistic testing. For these four different coatings, E Z Fe 14 (Fe 14), E Fe 16 (Fe16) hardfacing electrodes and E 18 8 Mn R 3 2 (307) austenitic stainless steel electrode were selected, respectively. The coatings were made in the electric arc welding machine, with two different coatings on the surface for each material. These are Fe 14 – Fe 14, Fe 16 – Fe 16, 307-Fe 14 and 307-Fe 16, as the first layer and the second layer, respectively. In all coatings, the welding current was kept constant at 150 A and the welding voltage was kept constant at 27 V. The microstructure, hardness, and ballistic properties of the hardfacing surfaces were investigated using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) to analyze the phases and components. The hardnesses of the hardfacing surfaces were determined by Vickers methods from the weld metal to the base metal. Ballistic tests were conducted according to NIJ Level III standards, firing 7.62×51 mm AP bullets from a distance of 10 m to calculate the effects of the bullets on the plates, the kinetic energy of the bullet, and the amount of energy absorbed by the plates. Welding for hard surface coating achieved with the combination of 307 - Fe 14 electrodes provides the highest ballistic limit velocity at 830 m/s, while the lowest limit is observed in the material welded with Fe16-Fe16 electrodes at 747 m/s. Fe-Cr-C electrodes were found to be effective as main or auxiliary components when designing armor plates. This study highlights the potential of hardfacing techniques to improve the ballistic properties of steel surfaces, with implications for the development of protective materials across various industries.
... Steel is the most often used structural material in engineering, and there is currently a considerable demand for studies on its dynamic behavior under impact situations [10][11][12]. Currently, little is known about how strikes, particularly those involving reactive fragment impacts, affect such equidistant steel plate constructions. ...
... where ∆ε eq is the equivalent plastic strain increment for a calculated cycle, and ε f is equivalent fracture strain [12,44,45]. The failure model parameters of Q345S, 304SS, and reactive fragment are shown in Table 6. ...
In this paper, the AUTODYN/Smoothed Particle Hydrodynamics (SPH) method was used to study the impact of reactive fragments on three-layer equidistant steel plates. The perforation characteristics of equidistant three-layer steel plates were investigated along with the parameters of combustion energy release from reactive fragments under varied impact velocities and shape conditions. The modification of the steel plates’ perforation diameter was investigated using the dimensional analysis approach. The shock wave pressure and chemical reaction characteristics were examined using the shock wave theory. The results show that within the examined impact velocity range, the perforation diameter initially increased and then decreased as the impact velocity of the reactive fragment rose. In addition, the perforation diameter was approximately 1.5–3 times the diameter of the reactive fragment. As the impact speed increased, the active reaction generated by the reactive fragments became more sufficient. The energy released contributed to the impact’s pressure rise; in addition, the temperature of the steel plate was raised in part by the reactive fragment impact, making the steel plate more prone to melting. The results of this investigation provide important support for a detailed understanding of the rules governing the failure of steel plates under the impact of reactive fragments as well as the combustion of reactive fragments under impact.
... In order to better represent the dynamic behavior of the core in this study, the hardness, quasi-static compression, and dynamic compression performance of the core were tested in this study (according to national testing standards). The results of the tests are shown in Table 3. Combined with the tensile properties reported by Namık Kılı [20], the JC parameters of the hard steel core were proposed. ...
... Then, Børvik and some authors [6][7][8][9][10][11][12] presented other approaches that examined on ballistic resistance of the aluminium alloy. Kılıç and Ekici [13] conducted research on the degree to which high-hardness armour steels resisted penetration by 7.62 millimetre armour-piercing bullets. Thom and his co-workers [14,15] studied the mechanical behaviour of cracked plate structures made of advanced materials. ...
... This paper studies numerically and experimentally Xar450 and Perform700 target plates with thicknesses varying by 3, 4, and 6 mm each impacted at 0, 15°, 30°, 45°, and 60° of obliquity against a 7.62 × 39 mm API BZ projectile. The material parameters of both targets and bullets for the Johnson-Cook constitutive relation and the Johnson-Cook failure criterion are based on [4][5][6]8,13,16], and [28]. The establishment of material modelling in the simulation software necessitates the use of these specified material attributes. ...
... The core mass of the bullet is somewhat smaller than the required core mass for test level 8 based on VPAM APR 2006, as shown in Table 3. The mechanical properties and material parameters of the bullet can be taken from [4][5][6]8,13,37]. ...
This paper uses numerical and experimental methods to look at how well Xar450 and Perform 700 high-strength steels protect against a 7.62 × 39 mm API BZ projectile. The numerical study of the target thicknesses varies from 3 mm to 4 mm and 6 mm. And they are struck at 0°, 15°, 30°, 45°, and 60° oblique angles. Numerical simulation results show that at a normal impact angle, the bullet can break through the Perform700 targets in all thicknesses; however , the resistance performance of the target plate increases with the rise of oblique angles. The Xar450 target plates of 4 mm and 6 mm can resist the bullet at any oblique angle, but the bullet can easily penetrate 3 mm thickness from 0° to 30° oblique angles. The experiment is based on the VPAM-APR 2006 standard. The experiment results showed that the bullet perforated through the Perform700 target plate with a thickness of 3 mm at 0° and 30° oblique angles. In contrast, the bullet cannot penetrate the Xar450 target thickness of 4 mm at a normal angle. The findings of this research are used in the formulation of the design methodology for a light armoured vehicle. Besides, they have considerable importance in the realm of calculating and developing anti-fracture structures for practical applications. ARTICLE HISTORY
