Papers by Keyword: Composite Armor

Abstract: The effect of steel, copper and aluminum interlayer on the stress wave propagation of ceramic/ Ti6Al4V armors were studied by traditional Split Hopkinson Pressure Bar system in this paper. Based on the SHPB experimental results, the stress wave propagation mechanism and energy absorption in tri-layered structure were discussed. Compared to ceramic/Ti6Al4V structure without interlayer, the steel, copper and aluminum interlayer could attenuate the transmission stress level and greatly increase the energy absorption of the structure. Due to the high acoustic reluctance of steel and copper interlayer, the reflected shock wave was in compressed situation and extended a tri-axial compressive stress within the ceramic which could improve the anti-penetration properties of ceramic plate. The numerical modeling studies of ballistic testing were carried on, and then the energy densities were compared. The results showed the steel and copper interlayer could increase the energy absorption of ceramic and improve the anti-penetration of ceramic plate. The three kinds of interlayer structures all could attenuate transmitted energy and decrease the residual penetration.

Abstract: The ballistic properties of different thickness combinations of ceramic/UHMWPE composite armors were studied in this paper, in order to find a better ballistic property structure subject to 12.7mm bullet. Powder-gun ballistic testing system was used to carry out the normal impact tests to determine the response and the ballistic limit of these combinations of ceramic/UHMWPE composite armors subject to impact loading. Compared with the test, an explicit finite element (FE) model was built with LS-DYNA Code to simulate the impact process. The influence of different parameters on the impact behavior was considered analytically. Results show very good agreement with the experimental data.

Abstract: The multi-hit of armor piercing projectiles (APPs) is one of the main treats to lightweight vehicles. Based on published ballistic experiments of Al2O3/Al2024 laminated composite armors against 7.62mm APP, the debonding of ceramic tiles was successfully simulated by setting reasonable material model and contact algorithm. A method named Geometric Intervals Method (GIM) was developed for simulation of multi-hit and its feasibility and rationality were investigated with the finite element code LS-SYNA. The numerical results shows that GIM has taken into account the effects of target damage caused by former APP impact on the target responds to later APP penetration. GIM can be used to simulate composite amours against multi-hit.

Abstract: This study presents an effective methodology for the optimum design of two-component armor. The armor consists of two plates: one is boron carbide ceramic and the other is kevlar/epoxy composites. The effect of the thickness of two plates on the ballistic limit velocities of the armor was investigated by Florence model. A finite element model was created using MSC.DYTRAN to simulate the impact of a rigid projectile on the composite armor. The optimum thickness of the ceramic and composite was obtained by evaluating the ballistic resistance efficiency.

Abstract: The paper presents a numerical study of a double layer composite panels impacted by a AP (Armor Piercing) 51WC projectile. The standard panel is built with aluminum and Al2O3 ceramic continuum layers while the studied model consists of the same aluminum plate but the front one is built with a set of hexagonal ceramic bars. The bar width and the impact position influence on the ballistic resistance are analyzed and compared with the reference solution. The problem has been solved with the usage of the modeling and simulation methods as well as finite elements method implemented in LS-DYNA software. Space discretization for each option was built by three dimension elements guarantying satisfying accuracy of the calculations. For material behavior simulation specific models including the influence of the strain rate and temperature changes were considered. Projectile Tungsten Curbide and aluminum plate material were described by Johnson-Cook model and ceramic target by Johnson-Holmquist model. In the studied panels the area surrounding back edges was supported by a rigid wall. The obtained results show interesting properties of the examined structures considering their ballistic resistance. All tests has given clear results about ballistic protection panel response under WC projectile impact. Panels consisting of sets of hexagonal ceramic bars are slightly easier to penetrate, reference model is stronger by 19% for smaller bars and by only 7% for bigger rods. Despite this fact, the ceramic layer is much less susceptible to overall destruction what makes it more applicable for the armor usage. Furthermore, little influence of the projectile impact point and consequently a part of the bar which is first destroyed is proved.

Abstract: Numerical investigations were performed to determine the influence of the spherical convex shape ceramic - alumina composite in reference to the standard double layer panel. All versions of the target were verified in an impact test including influence upon the position of the AP (Armor Piercing) 7,62x51HHS impact. The crucial parameter which was used for this verification was change in time of the PROJECTILE kinetic energy. The problem has been solved with the usage of the modeling and simulation methods as well as finite elements method implemented in LS-DYNA software. Space discretization for each option was built by three dimension elements guarantying satisfying accuracy of the calculations. For material behavior simulation specific models including the influence of the strain rate and temperature changes were considered. Projectile’s core made of HHS and aluminum plate material were described by Johnson-Cook model and ceramic target with Johnson-Holmquist model. In the studied panels the area surrounding back edges was supported by rigid wall. The obtained results show interesting properties of the new structures considering their ballistic resistance. However only certain places were chosen for tests, the protection ability against projectile attack is in general higher than the reference model. What is particularly interesting during the 6.6mm from the sphere center impact the sphere surface trajectory deviation effect is present. A projectile is not stopped here by material strength but the front layer shape. Moreover it can be assumed that this phenomenon will take place on majority of points on the sphere surface. Despite this fact, a ceramic multi sphere layer is less susceptible to overall destruction, depending on the impact point. The results of those numerical simulations can be used for designing of modern armor protection systems against hard kinetic projectiles.