Papers by Author: Sebastian Stanislawek

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.