Search Results (55)

Recent technological advances have expanded the use of 3D-printed polymer components across industries, including a growing interest in military applications. The effective defensive use of such materials depends on a thorough understanding of polymer properties, printing techniques, structural design, and influencing parameters. This paper analyzes the ballistic resistance of 3D-printed polymer structures against 9 × 19 mm projectiles. Cuboid targets with different infill patterns—cubic, grid, honeycomb, and gyroid—were fabricated and tested experimentally using live ammunition. Post-impact, CT scans were used to non-destructively measure projectile penetration depths. The honeycomb infill demonstrated superior bullet-stopping performance. Additionally, mechanical properties were experimentally determined and applied in FEM simulations, confirming the ability of commercial software to predict projectile–target interaction in complex geometries. A simplified analytical model also produced satisfactory agreement with experimental observations. The results contribute to a better understanding of impact behavior in 3D-printed polymer structures, supporting their potential application in defense systems. Full article

This study considers the impact and penetration of composite targets by steel projectiles. Firstly, experiments on the impact of homogeneous polymethyl methacrylate (PMMA) targets were simulated using the finite element method (FEM) and the incubation time fracture criterion (ITFC). Next, targets were assumed to be composed of cells with weakened mechanical properties, forming a composite barrier. The composite impact problems were then used to demonstrate an approach, which can be applied to overcome the typical difficulties for impact simulations—high demands on computing resources, long computation times, and potential numerical instabilities arising from high stresses in the contact zone and high strain rates. The approach is based on the use of artificial neural networks (ANNs) trained on arrays of numerical results obtained via finite element method. Full article

With the advancement of high-velocity kinetic energy weapons, the impact velocity encountered by concrete protective structures has evolved from low to high velocity ranges, rendering traditional rigid projectile penetration theories inadequate for accurately describing the physical mechanisms of deformation and erosion coupling during penetration. This study establishes a theoretical analytical framework for penetration dynamics under high-velocity conditions with coupled deformation and erosion effects: the critical velocity threshold distinguishing between rigid projectile penetration and hydrodynamic penetration modes is precisely defined based on the initial impact velocity V₀. By integrating empirical mass erosion formulas with cavity expansion theory, a theoretical model encompassing coupled deformation and erosion effects has been developed, incorporating both projectile cross-sectional area evolution and penetration depth prediction. Comparative analysis with published experimental data (small-scale projectiles vertically impacting concrete targets) demonstrates the model’s predictive accuracy, showing maximum errors of 9.5% in critical velocity prediction, 17.89% in projectile cross-sectional area prediction, and 24.4% in penetration depth prediction. Full article

Ti-Al₃Ti metal–intermetallic laminate (MIL) composites with microscale layer thickness have attracted attention in aerospace applications. However, whether millimeter-thick Ti layers can enhance the anti-penetration of Ti-Al₃Ti MIL composites under 400–1000 m/s impact velocities remains unclear. In this study, a Ti-Al₃Ti MIL composite target was prepared by hot press sintering, and the 2D finite element model validated by anti-penetration testing was used to prove that increasing the thickness of the Ti layer significantly increases the stress level and anti-penetration limit of the target. Simulations show that compared with a 0.1 mm Ti layer, a 2.5 mm Ti layer reduces the projectile residual velocity by 100% (600 m/s), 72% (800 m/s), and 38.5% (1000 m/s). With a total thickness difference of 0.1 mm, the crack propagation angles increase by 4° (0.06 mm Ti) and 14° (2.5 mm Ti) compared to a 0.4 mm Ti layer. By analyzing stress wave propagation and energy absorption during penetration, this work reveals that millimeter-thick Ti layers improve anti-penetration performance by controlling heterogeneous interface failure and the crack propagation direction through increased ductile layer thickness. These findings provide data for MIL composites and offer potential cost reductions for high-performance anti-penetration materials. Full article

Given the significantly large deformation and high strain exhibited by explosively formed projectiles (EFP) in penetration, their penetration performance into multi-layer targets differs from that of ordinary bullets or rigid projectiles. Therefore, it is necessary to investigate the ballistic performance and the damage mechanism of target deformation when an EFP penetrates a multi-layer target. This study conducted high-velocity impact tests of EFPs on four types of multi-layer steel targets, analyzing the damage morphology and deformation characteristics of multi-layer steel targets subjected to EFP penetration from both macro and micro levels. To investigate the anti-penetration performance of more target combinations at different EFP velocities, an accurate symmetrical finite element model of EFP penetration into multi-layer targets was established using Autodyn 16.0 finite element software and the SPH-FEM algorithm based on the symmetrical characteristics of the EFP and target structure. The experimental and simulation results showed that for a three-layer composite target, when the thickness of the middle layer remained constant, using the target layers with a front–rear target thickness ratio of less than one was beneficial for enhancing the anti-penetration performance of the targets against EFPs; when the EFP velocity was low and the residual velocity for penetrating a single-layer target was no more than 200 m/s, the anti-penetration performance of the two-layer target was optimal. When the EFP velocity exceeded 1500 m/s, the single-layer target exhibited the best anti-penetration performance to the EFP, and the more layers, the smaller the ballistic resistance. When the number of layers was more than six, the ballistic resistance of the multi-layer targets gradually tended to remain constant. Full article

The choice of constitutive model significantly affects the accuracy of concrete perforation simulation. This study analyzes four concrete constitutive models, HJC, RHT, KCC, and TCK, focusing on their strength models, damage evolution, and strain rate effects. Combining the damage pattern and erosion cracks, the effectiveness of the four constitutive models in simulating the penetration of reinforced concrete targets is evaluated using LS-DYNA 11.0. The results indicate that the RHT and TCK models accurately depict the concrete damage and failure modes under the same test conditions. In contrast, the KCC and HJC models demonstrate superior capability in predicting the residual velocity of the projectile. Additionally, this study highlights the significant impact of the erosion parameters on the simulation results. This study offers a valuable reference for the application and parameter set of constitutive models in simulating concrete target perforation. Full article

A numerical method has been presented to simulate hypervelocity impacts on metal targets. The target is a rectangular prism and is positioned at various inclined angles relative to the impact direction, while four different projectiles such as square prism, triangular prism, truncated cone, and ogival shape are chosen. This numerical model employs an open-source code, MPM3D-F90, which is based on the Material Point Method. In order to enhance flexibility of the code for defining projectiles and target bodies in the material domain, a preprocessor is developed to create a variety of geometrical shapes for a given volume. In addition to supplementing and defining various geometrical bodies, this tool also simplifies the preprocessing process to create the user’s specific preferences for the problem. To demonstrate the utility of the preprocessor tool and investigate the influence of geometry on hypervelocity impacts, simulations are conducted using various projectile and target configurations. The analysis results reveal that the structure of the debris cloud formations, scattering behavior of the ejected particle from both front and rear faces, and penetration depth measures are significantly influenced by the projectile shape and impact angles. Full article

Tunnels are underground infrastructures intended for diverse community applications as well as military applications. During impact loading due to high-velocity projectiles such as ballistic missiles, materials experience a high strain rate. Moreover, there is a superficial augmentation of the dynamic strength when geomaterials such as rock are subjected to a high strain rate. Despite this strength enhancement, tunnels can get damaged by the impact load of a projectile hitting at a high velocity if they are present at a shallow depth. The present study is an effort to comprehend the response of a shallow tunnel in soft sandstone due to the impact load by a ballistic projectile using the FEM-based software ABAQUS/CAE 6.11. The Drucker–Prager damage model and the Johnson–Cook damage model were used to define the properties of the rock mass and steel tunnel lining, respectively. The crown of the 3 m diameter tunnel was kept at different depths from 1 m to 5 m from the surface. A striking velocity of 1000 m/s at a normal position to the target was given to the projectile. The projectile caused noticeable damage to the tunnel lining up to 3 m crown depth. Increasing the crown depth had a positive effect on the maximum depth of the projectile penetration up to 4 m tunnel crown depth, after which the effect reversed, making the tunnel safer. The maximum von Mises stress on the tunnel lining reduced in a logarithmic trend with an increase in the crown depth, gradually lowering to an impact load lesser than the yield stress of the tunnel lining material after a crown depth of 4.5 m. Full article

Ultra-high-performance concrete (UHPC) is a cement-based material with excellent impact resistance. Compared with traditional concrete, it possesses ultra-high strength, ultra-high toughness, and ultra-high durability, making it an ideal material for designing structures with impact resistance. The research on the impact resistance performance of UHPC and its composite structures is of great significance for the structural design of protective engineering projects. However, currently, there is still insufficient research on the impact resistance performance of UHPC composite structures. To study the impact resistance performance, experiments were conducted on UHPC targets using high-speed projectiles. The results were compared with impact tests on granite targets. The results indicated that when subjected to projectile impact, the UHPC targets exhibited smaller surface craters compared with the granite targets, while the penetration depth was lower in the granite targets. Afterwards, the process of a projectile impacting the UHPC composite structure was numerically simulated using ANSYS 16.0/LS-DYNA finite element software. The numerical simulation results of penetration depth and crater diameter were in good agreement with the experimental results, which indicates the rationality of the numerical model. Based on this, further analysis was carried out on the influence of impact velocity, impact angle, and reinforcement ratio on the penetration depth of the composite structure. The results show that the larger the incident angle or the smaller the velocity of the projectile is, the easier it is to deflect the projectile. There is a linear relationship between penetration depth and reinforcement ratio; as the reinforcement ratio increases, the penetration depth decreases significantly. This research is of great significance in improving the safety and reliability of key projects and also contributes to the application and development of ultra-high-performance materials in the engineering field. Full article

Ceramic panel collapse will easily lead to the failure of traditional targets. One strategy to solve this problem is to use separate ceramic units as armor panels. Based on this idea, we propose an aluminum matrix composite using pressure infiltration, containing an array of ceramic balls, the reinforcement of which consists of centimeter-scale SiC balls and micron-scale B₄C particles. Three different array layouts were designed and fabricated: compact balls in the front panel (F-C), non-compact balls in the front panel (F-NC), and compact balls inside the target (I-C). The penetration resistance properties were tested using a 12.7 mm armor-piercing incendiary (API). The results show that there are no significant internal defects, and the ceramic balls are well-bonded with the matrix composite. The F-NC structure behaves the best penetration resistance with minimal overall damage; the I-C structure has a large area of spalling and the most serious damage. Finite element simulation reveals that the ceramic balls play a major role in projectile erosion; in the non-compact structure, the composite materials between the ceramic balls can effectively disperse the stress, thereby avoiding the damage caused by direct contact between ceramic balls and improving the efficiency of ceramic ball erosion projectiles. Furthermore, it is essential to have a certain thickness of supporting materials to prevent spalling failure caused by stress wave transmission during penetration. This multi-scale composite exhibits excellent ballistic performance, providing valuable insights for developing anti-penetration composite armor in future applications. Full article

The penetration of projectiles into targets has a broad background in engineering. In this work, numerical simulations of the projectile-target penetration problem are conducted using the Finite Element Method (FEM), the Smoothed Particle Hydrodynamics (SPH) and the Finite Element–Smoothed Particle Hydrodynamics Adaptive Coupling Method (FE-SPH ACM) based on the LS-DYNA software package. First, the penetration experiments using aluminum targets and ceramic targets are simulated. The experimental and simulation results show that the FE-SPH ACM has the better accuracy in calculating the debris cloud head velocity and interface velocity, with an error of no more than 4%. Furthermore, we use the FE-SPH ACM to investigate the anti-penetration performance of aluminum/ceramic composite targets in different combinations. We find that the reasonable layout can improve the protective performance of multi-layered target, especially composite target plates with ceramic as the front layer. In addition, the ballistic limit velocities for ceramic-aluminum ratios of 3/7, 5/5 and 7/3 are approximately 1300 m/s, 1400 m/s and 1500 m/s, respectively. Obviously, increasing the proportion of ceramic materials can enhance the anti-penetration performance. Full article

The mass erosion of the kinetic energy of projectiles penetrating concrete targets at high speed is an important reason for the reduction in penetration efficiency. The heat generation and heat conduction in the projectile are important parts of the theoretical calculation of mass loss. In this paper, theoretical models are established to calculate the mass erosion and heat conduction of projectile noses, including models of cutting, melting, the heat conduction of flash temperature, and the conversion of plastic work into heat. The friction cutting model is modified considering the heat softening of metal, and a model of non-adiabatic processes for the nose was established based on the heat conduction theory to calculate the surface temperature. The coupling numerical calculation of the erosion and heat conduction of the projectile nose shows that melting erosion is the main factor of mass loss at high-speed penetration, and the mass erosion ratio of melting and cutting is related to the initial velocity. Critical velocity without melting erosion and a constant ratio of melting and cutting erosion exists, and the critical velocities are closely related to the melting temperature. In the process of penetration, the thickness of the heat affected zone (HAZ) gradually increases, and the entire heat conduction zone (EHZ) is about 5~6 times the thickness of the HAZ. Full article

To study the ability of shaped charges to penetrate typical ship targets, two shaped charges with the same diameter of 200 mm but different configurations are designed to generate two forms of jetting projectile charge (JPC). Based on the protective structure of typical ship targets, static penetration tests are performed using the two types of a shaped charge with copper liner and 10-layer spaced targets with a total span of 16 m which is made in 921A steel. Numerical simulations under the same working conditions are also carried out. It is found that the simulation results of the penetration depth and the number of layers of target perforated by the JPC are much greater than the experimental results. In fact, the JPC breaks up when moving to a certain distance, and the JPC segments after breakup have a transverse drift velocity, causing the segment to deviate from the original penetrating channel. The influence of drift velocity after JPC fracture cannot be considered in numerical simulation, resulting in significant differences between numerical simulation and experimental results. Thus, this paper proposed a segment-based numerical simulation method and analyzed the penetration process of JPC fragments after JPC fracture. Combined with experimental results, the radial motion after JPC fracture and the final distribution of penetration holes can be well revealed. It is found that the penetration depth and the number of layers of target perforated by the JPC depend on the tip velocity of each segment and the jet length. Full article

A total of 9 tests were carried out with 30 mm and 78 mm caliber scaled projectiles penetrating into granite targets. The penetration depth, crater diameter, and mass loss rate were examined and discussed. The results indicate that the dimensionless penetration depth of large-caliber projectiles is 20% greater than small-caliber projectiles. Based on the description of static resistance R_a in the Forrestal semi-empirical formula, the size effect of dimensionless penetration depth can be attributed to the size effect of static resistance R_a, and it can be seen that the penetration static resistance of projectile A is 40% higher than that of projectile B. Numerical simulations of projectile penetration into granite targets were conducted using the finite element program ANSYS/LS-DYNA. In terms of penetration depth and crater damage, the numerical simulation results agree well with the test data. This suggests that the selection of parameters was reasonable. The influence of compressive strength, projectile striking velocity, mass, diameter, and caliber–radius–head (CRH) ratio on the static resistance R_a were studied by RHT model parameterization. Based on the numerical results from the parametric study, an empirical formula was derived to predict the static resistance R_a. Full article

To understand the influence of the length–diameter ratio (L/D) of explosively formed projectiles (EFPs) on the energy spatial distribution of behind-armor debris (BAD), three EFPs with different L/Ds were designed in this study. The scattering characteristics of the BAD formed by the EFP penetrating a steel target were investigated. High-speed photography was used to observe the shape of the BAD cloud. Fiber and foam plates were sequentially stacked to recover the fragments. The three-dimensional damaged area by the BAD was obtained based on the spatial position information of a large amount of BAD. Finally, the energy spatial distribution characteristics of the EFP and target material fragments were analyzed. The results showed that a large EFP L/D increased the total energy of the BAD, and the proportion of the energy of projectile fragments increased. The difference in the energy spatial distribution between EFPs with varying L/Ds was mainly in the scattering angle range of 3–17°. The total energy of fragments within 17° of scattering angle accounted for 85% of the total energy of all fragments. The BAD energy of the EFP with a large L/D (L/D = 3.86) was concentrated in a small scattering angle range in which the residual projectile was located. The average projectile fragment energy of the EFP with a moderate L/D (L/D = 2.4) was evenly distributed in the scattering angle range of 5–20°. As a result, the energy distribution of the BAD from EFP (L/D = 2.4) shifted towards the large scattering angle, thus leading to a uniform radial distribution of the striking area within the range of 500–1100 mm behind the target. However, with the increase in the distance behind the target, the radial direction of the striking area of the other two EFPs was gradually reduced. The reason was explained according to the force analysis of the fragments resulting from the bulge fracture of target. The spatial energy distribution of BAD is closely related to the damage ability of EFP in relation to the armored target. Thus, it is necessary to design EFPs with appropriate L/Ds in order to maximize the damaging effect behind the armor. Full article