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This article investigates the penetration of 4.5g spherical fragments into PE composite materials of various thicknesses. Based on the results of ballistic tests and theoretical analysis, the empirical relationship between the ultimate penetration velocity and areal density was determined. This relationship can be used to assess whether the ballistic resistance performance of the PE composite materials meets the requirements. Next, a lightweight ceramic-PE composite structure was designed using numerical calculation and simulation analysis. This structure can effectively protect against 12.7mm API (armor piercing incendiary) projectiles with an areal density of ≤ 70kg/mm 2 and 100m/0°. The feasibility of the structure was confirmed through target testing.

In the face of the need for soldiers to strike targets behind walls in military activities and counter-terrorism operations, while preventing projectiles from penetrating walls and harming other non military targets, this paper conducts research on brick blocks material models based on Autodyn software to analyze the penetration of pointed oval projectiles into 24cm thick brick walls. This article first studied the material models and obtained two sets of material models suitable for brick blocks, namely the Riedel-Hiermaier-Thomamodel material model and the Drucker Prager material model. Based on material models of different brick blocks, the finite element simulation of the penetration process of a pointed oval shaped projectile into a 24cm thick brick wall was carried out using Autodyn software, and the remaining velocity and offset angle of the projectile after penetrating the wall were obtained. By comparing and analyzing the simulated data with experimental data, it was found that the residual velocity of the brick block calculated using the RHT model had an error of 8.9% compared to the experimental results, and the error between the offset distance and the experimental results was 25%. This can accurately calculate the penetration ability of the projectile into the brick wall, providing guidance for predicting the trajectory of the projectile after penetrating the wall to a certain extent.

Polyurea has gained significant attention in recent years as a functional polymer material, specifically regarding blast and impact protection. The molecular structure of polyurea is characterized by the rapid reaction between isocyanate and the terminal amine component, and forms an elastomeric copolymer that enhances substrate protection against blast impact and fragmentation penetration. At the nanoscale, a phase-separated microstructure emerges, with dispersed hard segment microregions within a continuous matrix of soft segments. This unique microstructure contributes to the remarkable mechanical properties of polyurea. To maximize these properties, it is crucial to analyze the molecular structure and explore methods like formulation optimization and the incorporation of reinforcing materials or fibers. Current research efforts in polyurea applications for protective purposes primarily concentrate on construction, infrastructure, military, transportation and industrial products and facilities. Future research directions should encompass deliberate formulation design and modification, systematic exploration of factors influencing protective performance across various applications and the integration of numerical simulations and experiments to reveal the protective mechanisms of polyurea. This paper provides an extensive literature review that specifically examines the utilization of polyurea for blast and impact protection. It encompasses discussions on material optimization, protective mechanisms and its applications in blast and impact protection.

This research deals with the numerical investigation of ballistic protection proided by a combination of steel and reinforced concrete. Firstly, the parameters of the material model were calibrated based on the experimental data, and numerical simulations were carried out with existing experiments to verify the rationality of the material model and numerical simulation methods. Subsequently, the numerical simulation of the penetration of a typical ground-penetrating projectile into the G50/RC composite target at a velocity of 350m/s was carried out to analyze the stress wave transmission and ballistic performance during the penetration process, and the critical penetration depth was obtained. Finally, by changing the steel type and the number of steel plate layers, the best composite target combination is obtained. The simulation results show that the G50/RC composite target can effectively withstand the impact of conventional ground-penetrating warheads, and make them break or explode outside the shielding layer. At a projectile velocity of 350 m/s, the critical penetration thickness of BLU-109/B, BLU-122 and BLU-137 prototypes is 16, 17 and 19cm, respectively. Under the penetration of BLU-137, 40cm 45# steel can achieve the same protection effect as 19cm G50; The double steel plate composed of 12cm G50 steel and 12cm 45# steel has excellent penetration resistance. By comprehensive analysis, the same composite target using double steel plate can greatly increase the anti-penetration performance of the bomb shield and reduce the cost of engineering construction.

High-entropy alloy (HEA) and graphene have high strength, and both have been explored as shielding materials for impact protection. Very recently, HEA/graphene composites with HEA as the matrix and graphene as reinforcing phase have attracted great interests. Herein, the deformation behavior and penetration resistance of AlCoCuFeNi HEA/graphene composites are studied under ballistic impact loadings using molecular dynamics simulations. It is found that graphene can enhance the impact property of the HEA with graphene on the top surface or inside HEA. The amount of enhancement is proportional to the number of graphene layers from monolayer to trilayer. This enhancement is mainly attributed to the strong load carrying ability of graphene, which significantly increases the penetration resistance when a projectile passes through the graphene layers. However, graphene could also lead to some reduction in the impact force of HEA when it is inside the HEA. This negative effect is because graphene sheets break the structure continuity of HEA, reducing the load carrying ability of the local HEA. Overall, the positive effect of graphene outweighs the negative effect, leading to improved impact performance of the HEA/graphene composites. Besides, graphene considerably affects the magnitude and distribution of stress at the HEA/graphene interface during the impact process, which greatly influences the dislocation nucleation and propagation in the HEA/graphene composites. The present work not only provides insights into the dual role that graphene plays in the impact performance of the HEA/graphene composites, but also is useful for the design of HEA/graphene composites for impact protection.

The reactive projectile presents a tremendous potential to induce the combined damage effect of kinetic energy and chemical energy to the plate. A series of ballistic impact experiments and numerical simulation studies were carried out to study the penetration behavior of reactive projectile against TC4 plate. The experimental results showed that with the impact velocity of the reactive projectile increasing from 537m/s to 682m/s, the damage mode of the plate gradually changes from bulge, cross crack to plug. According to the experimental results, the ballistic limit velocity of reactive projectile perpendicular penetrating 5mm TC4 is 648.33m/s. The numerical simulation results showed that the reactive projectile reaches GPa high pressure within a few microseconds when it impacted with the plate. During reactive projectile penetrating TC4 plate, the chemical energy release significantly improves the projectile penetrating ability, and the contribution of chemical energy to projectile penetrating can reach 55.07%.

In addressing the penetration resistance of honeycomb sandwich panels, a finite element model is established to simulate the penetration problem. The relationship between initial and residual velocity of the fragments is studied. The effects of angle gradient, height gradient, and thickness gradient structures on the ballistic performance of honeycomb sandwich panels are analyzed. Multi-objective optimization design of honeycomb sandwich panels is conducted, resulting in a thickness gradient honeycomb sandwich panel. The results show that the relationship curve between initial and residual velocities of fragments closely matches the theoretical formula. Different gradient structures exhibit varied protective effects on the honeycomb sandwich panels. Compared to the pre-optimized panels, the optimized thickness gradient honeycomb sandwich panels show a significant improvement in protection, with the residual velocity of fragments reduced by 31.82% and the total mass of the sandwich panel reduced by 16.23%.

In situ femtosecond X-ray diffraction measurements reveal that the dominant mechanism of shock-wave-driven deformation in tantalum changes from twinning to dislocation slip as pressure increases. Deformation caught in the act The effect of shock waves travelling through materials has relevance for various areas of study in geology and materials science. Experiments that probe how materials deform on exposure to shock waves are usually carried out in retrospect of the shock event. This paper reports in situ X-ray diffraction studies of the plastic deformation of textured polycrystalline tantalum on exposure to shock compression with shock pressures ranging from 10 gigapascals to around 300 gigapascals (at which the metal melts). Twinning and slip deformations produce distinct changes to the texture of the tantalum sample and these changes could be observed in the diffraction data. In this way, the researchers observed that the dominant deformation mechanism transitioned from minimal twinning to twinning-dominated to slip-dominated as the shock pressure increased above 150 gigapascals. This dynamic material behaviour would be challenging to observe in experiments carried out after the shock event. Pressure-driven shock waves in solid materials can cause extreme damage and deformation. Understanding this deformation and the associated defects that are created in the material is crucial in the study of a wide range of phenomena, including planetary formation and asteroid impact sites 1 , 2 , 3 , the formation of interstellar dust clouds 4 , ballistic penetrators 5 , spacecraft shielding 6 and ductility in high-performance ceramics 7 . At the lattice level, the basic mechanisms of plastic deformation are twinning (whereby crystallites with a mirror-image lattice form) and slip (whereby lattice dislocations are generated and move), but determining which of these mechanisms is active during deformation is challenging. Experiments that characterized lattice defects 8 , 9 , 10 , 11 have typically examined the microstructure of samples after deformation, and so are complicated by post-shock annealing 12 and reverberations. In addition, measurements have been limited to relatively modest pressures (less than 100 gigapascals). In situ X-ray diffraction experiments can provide insights into the dynamic behaviour of materials 13 , but have only recently been applied to plasticity during shock compression 14 , 15 , 16 , 17 and have yet to provide detailed insight into competing deformation mechanisms. Here we present X-ray diffraction experiments with femtosecond resolution that capture in situ , lattice-level information on the microstructural processes that drive shock-wave-driven deformation. To demonstrate this method we shock-compress the body-centred-cubic material tantalum—an important material for high-energy-density physics owing to its high shock impedance and high X-ray opacity. Tantalum is also a material for which previous shock compression simulations 18 , 19 , 20 and experiments 8 , 9 , 10 , 11 , 12 have provided conflicting information about the dominant deformation mechanism. Our experiments reveal twinning and related lattice rotation occurring on the timescale of tens of picoseconds. In addition, despite the common association between twinning and strong shocks 21 , we find a transition from twinning to dislocation-slip-dominated plasticity at high pressure (more than 150 gigapascals), a regime that recovery experiments cannot accurately access. The techniques demonstrated here will be useful for studying shock waves and other high-strain-rate phenomena, as well as a broad range of processes induced by plasticity.

The uncertain ballistic effects and reliability optimization design of the ceramics composite armors are investigated. Considering the material uncertainty, the ballistic penetration process is analyzed through simulation model. The effects interlayer SiC mass fraction and the matrix thickness gradient ratio are discussed. The optimal parameters of both material and structure are obtained through reliability design methods and verified through ballistic experiments. The results show that the standard deviation can be reduced when interlayer SiC mass fraction increases. The ballistic depth can be reduced by increasing the gradient ratio. Through optimization, the ballistic reliability of the ceramic composite armor is improved.

For the new marine Ti6321 titanium alloy, the penetration tests were carried out under vertical and oblique penetration conditions. The ballistic properties of Ti6321 titanium alloy with different structures and the macro and micro damage characteristics of the target were obtained. The influence of the structure on the ballistic performance and failure mechanism of the titanium alloy target plate was analyzed. The results show that Ti6321 titanium alloy exhibits different properties under vertical and oblique penetration conditions. In the vertical penetration test, the absolute penetration depth and the average crater diameter of the equiaxed target plate are smaller than those of the bimodal and Widmanstatten structure, which show a better resistance to vertical penetration. In the oblique penetration, the safety angle of the bimodal structure was smaller and showed better resistance to the oblique penetration.