Comparison of Numerical Simulation Techniques of Ballistic Ceramics under Projectile Impact Conditions

This article presents an analysis of the effectiveness of available numerical techniques in mapping the characteristic behavior of ballistic ceramics under projectile impact conditions. As part of the work, the ballistic tests were performed on the layered ceramic/steel composite armor and tested with the 7.62 × 39 mm, armor-piercing incendiary (API) BZ projectile. The experimental tests were then mapped using computer simulations. In numerical analyses, four different techniques were used to describe cubic ceramic tiles Al2O3 placed on the ARMOX 500T steel backing plate, i.e.,: the Finite Element Method without Erosion (FEM), Finite Element with erosion (FEM + Erosion), Smoothed Particles Hydrodynamics (SPH) and a hybrid method that converts finite elements to SPH particles after exceeding the defined failure criteria (FEM to SPH conversion). The effectiveness of the individual methods was compared in terms of quality (mapping of characteristic phenomena occurring during the penetration process), quantity (bulge height of the backing plate) and time needed to complete the calculations. On the basis of the results of the experiments and numerical simulations, it was noticed that the most accurate reproduction of the phenomenon of ballistic impact of AP projectiles on ceramic/steel composite armor can be obtained by using a hybrid method, incorporating the conversion of finite elements into SPH particles. This method should be used in cases where accuracy of the results is more important than the time required to complete the calculations. In other situations where the purpose of the calculation is not to determine, for example, the exact value of penetration depth but only to observe a certain trend, the FEM method with defined erosion criteria (variant 2), which is more than 10 times faster, can be successfully used.

CIRCUITRY , STRUCTURE AND PROPERTIES OF HETEROGENEOUS MATERIALS

Currently, heterogeneous materials based on titanium and aluminum alloys are widely used as promising armor materials. When a ballistic object is exposed to the armor material, brittle cracks that occur at the contact point spread in such a way that composite material is in state of decay both deep into and along the interlayer boundaries of the joint, while there is a violation of the composite structure and loss of the mechanical strength of the armor element. In this regard, the task of developing new reinforcement schemes for composite armor is urgent. One of the most promising technologies in the field of creating and developing new composite non-metallic armor materials is explosion bonding. The authors of the work proposed a new scheme for reinforcing a heterogeneous metal material by means of explosion bonding, which uses internal perforated reinforcing layers that serve as elements preventing the development of brittle fracture at the point of ballistic contact. To increase the efficiency of the destruction of a ballistic object in the composite structure, the authors proposed the formation of highly solid intermetallic compounds at the boundary between the metal of the base of a viscous metal matrix and the reinforcing element by subsequent heat treatment of the material. The conducted micro-X-ray spectral analysis of intermetallic compounds showed their correspondence to the chemical compound α-titanium (TiAl3). Comparison of the obtained level of physical and mechanical properties of the developed heterogeneous armored material with analogues suggests that the expected level of the composite protection class against small arms is in the range from Br4 to Br5 according to GOST R 50963-96 with an armor thickness of 40 to 60 mm, which makes it possible to reduce the weight of armored vehicles significantly and, as a result, increase its tactical and technical characteristics.

Ballistic performance of powder metal Al5Cu-B4C composite as monolithic and laminated armor

In this study, ballistic performances of x wt.-% B4C (x = 5, 10, and 20) reinforced Al5Cu matrix composite samples were investigated as a monolithic and laminated composite armor component. Composite armor plates were produced by the powder metallurgy method. The prepared powders were pressed under 400 MPa pressing pressure. Green compacts were pre-sintered at 400 °C for 30 minutes in order to blow the lubricant. Subsequently, liquid phase sintering was performed at 610 °C for 210 minutes. In ballistic tests, 7.62 mm caliber armor-piercing bullets were used as the ballistic threat. In the ballistic tests of monolithic armors, only 10 mm thick powder metal composite plates were tested. In the ballistic tests of laminated composite armors, these powdered metal plates were layered with 10 mm thick alumina ceramic plate front layers and 10 mm thick AA5083 plates. Although all of the monolithic powder metal composite armors were penetrated, they showed multi-hit capability. All of the laminated composite armors provided full ballistic protection. It was determined that with the increase in B4C reinforcement rate, the ballistic resistance also increased due to the improvement in strength, hardness, and abrasive feature.

Numerical study of theanti-penetration performance of sandwich composite armor containing ceramic honeycomb structures filled with aluminum alloy

The aim of this work was to study the anti-penetration effect of sandwich composite armor with ceramic honeycomb structures filled with aluminum alloy under the impact of high-speed projectiles. The finite element software ABAQUS was used to conduct numerical simulation research on the process of a standard 12.7-mm projectile penetrating sandwich composite armor. The armor-piercing projectile model was simplified as a rigid body. The numerical simulation models were applied to three different sandwich composite armor structures (A, B, and C), each with a total armor thickness of 25 mm. The penetration resistance of the three kinds of composite armor was studied. We obtained velocity curves for the rigid projectile penetrating the different structures. The failure forms and penetration resistance characteristics of the three composite armor structures adopted in this paper were analyzed. In addition, the velocity reduction ratio is proposed as an index to evaluate the penetration resistance performance of the armor. The simulation results revealed decreasing rates of projectile speed in the structures A, B, and C of 69.6%, 91.1%, and 100%, respectively. The third composite armor (structure C) designed here has excellent penetration resistance and can block the penetration of a high-speed (818m/s) rigid projectile. This study can provide some reference for the application of laminated armor material in anti-penetration protection structures.

Study on the Penetration Performance of a 5.8 mm Ceramic Composite Projectile

The penetration ability of a 5.8 mm standard projectile can be improved by inserting a ZrO2 ceramic ball with high hardness, high temperature, and pressure resistance at its head. Thereby, a ceramic composite projectile can be formed. A depth of penetration (DOP) experiment and numerical simulation were conducted under the same condition to study the armor-piercing effectiveness of a standard projectile and ceramic composite projectile on 10 mm Rolled Homogeneous Armor (RHA) and ceramic/Kevlar composite armor, respectively. The results show that both the ceramic composite and standard projectiles penetrated the armor steel target at the same velocity (850 m/s). The perforated areas of the former (φ5 mm & φ2 mm) were 2.32 and 2.16 times larger, respectively, than those of the latter. The residual core masses of these two projectiles (φ5 mm & φ2 mm) were enhanced by 30.45% and 22.23%. Both projectiles penetrated the ceramic/Kevlar composite armor at the same velocity (750 m/s). Compared with the standard projectile, the residual core masses of the ceramic composite one (Ø5 mm & Ø2 mm) were enhanced by 12.4% and 3.6%, respectively. This paper also analyzes the penetration mechanism of the ceramic composite projectile on target plates by calculating its impact pressure. The results show that the ceramic composite projectile outperformed the standard projectile in penetration tests. The research results are instructive in promoting the application of the ZrO2 ceramic composite in an armor-piercing projectile design.

Numerical simulation of multi-hit impact on Ceramic/Composite armor

The numerical simulation of ballistic multi-hit impact on ceramic/composite armors is very challenging. The damage introduced by the previous hit affects the performance of the armor. In composite backings the damage is often more diffused than for metallic backings. Moreover, different sources of damage can intervene within the composite material. The present work proposes a mesoscopic scale approach to assess these issues. The 2D woven material is modelled with beams elements embedded in volume elements. Each component has its own material constitutive law and its damaging law. This approach allows to better model the damaging of the material, but also to better identify the material parameters from a set of basic experiments.