MONOLİTİK VE KATMANLI METALİK HEDEFLERDE BALİSTİK DARBE TEPKİSİNİN DENEYSEL VE SAYISAL İNCELENMESİ

This thesis investigates the ballistic impact behavior of metallic target plates through experimental testing and numerical modeling. Monolithic and layered configurations consisting of Ti-6Al-4V and Al6061 alloys are examined under high-velocity impact conditions. Ballistic experiments are conducted using 7.62×51 mm armor-piercing ammunition in accordance with the NATO AEP STANAG 4569 standard. Numerical simulations are carried out in LS-DYNA using the finite element method to model the impact event and the resulting deformation of the target plates. The plastic response of the materials is described using the Modified Johnson-Cook constitutive model and its extension with Voce hardening rule, while damage initiation and fracture evolution are modeled using Johnson–Cook damage and Cockcroft-Latham damage models. The effects of target material and stacking sequence on ballistic performance are investigated. In addition to ballistic testing, quasi-static tensile experiments are performed, and surface displacement fields are measured using Digital Image Correlation (DIC). The numerical modeling of the quasi-static tensile tests is carried out in Abaqus, and the displacement data obtained from DIC are used for the calibration of plasticity and damage model parameters employed in the ballistic impact simulations. Moreover, the numerical predictions are compared with experimental results in terms of residual velocity and failure mechanisms. The results demonstrate that both the target material and the stacking sequence in layered configurations have a significant influence on the overall ballistic response of the targets.