Person: EKİCİ, BÜLENT
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EKİCİ
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BÜLENT
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Publication Open Access Ballistic behavior of high hardness perforated armor plates against 7.62 mm armor piercing projectile(ELSEVIER SCI LTD, 2014-11) EKİCİ, BÜLENT; Kilic, Namik; Bedir, Said; Erdik, Atil; Ekici, Bulent; Tasdemirci, Alper; Guden, MustafaIn this paper, some of the important defeating mechanisms of the high hardness perforated plates against 7.62 x 54 armor piercing ammunition were investigated. The experimental and numerical results identified three defeating mechanisms effective on perforated armor plates which are the asymmetric forces deviates the bullet from its incident trajectory, the bullet core fracture and the bullet core nose erosion. The initial tests were performed on the monolithic armor plates of 9 and 20 mm thickness to verify the fidelity of the simulation and material model parameters. The stochastic nature of the ballistic tests on perforated armor plates was analyzed based on the bullet impact zone with respect to holes. Various scenarios including without and with bullet failure models were further investigated to determine the mechanisms of the bullet failure. The agreement between numerical and experimental results had significantly increased with including the bullet failure criterion and the bullet nose erosion threshold into the simulation. As shown in results, good agreement between Ls-Dyna simulations and experimental data was achieved and the defeating mechanism of perforated plates was clearly demonstrated. (C) 2014 Elsevier Ltd. All rights reserved.Publication Metadata only Ballistic resistance of high hardness armor steels against 7.62 mm armor piercing ammunition(ELSEVIER SCI LTD, 2013) EKİCİ, BÜLENT; Kilic, Namik; Ekici, BulentAlthough advanced lightweight composite based armors are available, high hardness steels in military vehicles are often used to provide ballistic protection at a relatively low cost and is an interesting material due to its widespread usage in vehicle structure. In this study, ballistic limit of 500 HB armor steel was determined against 7.62 mm 54R B32 API hardened steel core ammunition. Lagrange and smoothed particle hydrodynamics (SPH) simulations were carried out using 3D model of bullet and high hardness armor target. Perforation tests on 9 and 20 mm thickness armor were performed to validate simulation methodology. Also material tests were performed for armor steel and ammunition hardened steel core to develop Johnson-Cook constitutive relations for both strength and failure models. Finally, results from 3D numerical simulations with detailed models of bullet and target were compared with experiments. The study indicates that the ballistic limit can be quantitatively well predicted independent of chosen simulation methodology, but qualitatively some differences are seen during perforation and fragmentation. As shown in results, good agreement between Ls-Dyna simulations and experimental data was achieved by Lagrange formulation with the full bullet model. (c) 2012 Elsevier Ltd. All rights reserved.Publication Metadata only Optimization of high hardness perforated steel armor plates using finite element and response surface methods(TAYLOR & FRANCIS INC, 2017) EKİCİ, BÜLENT; Kilic, Namik; Ekici, Bulent; Bedir, SaidIn this article, finite element simulations and response surface method are used to optimize perforated plate parameters for ballistic protection. After statistically validating the relationship between residual velocity and geometric parameters, a response optimizer was used to find the best combination of design parameters to stop a threat with less areal density. Finally, the optimized solution was checked both numerically and experimentally to show the effectiveness of the developed methodology. The weight is decreased by 28% when compared with monolithic steel armor having the same antiballistic performance.