Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article The Effect of Layered Cover Plate Material on the Ballistic Performance of Ceramic Armors: Experimental and Numerical Study(Pergamon-Elsevier Science Ltd, 2026) Cellek, Seven Burcin; Tasdemirci, Alper; Cimen, Gulden; Yildiztekin, Faki Murat; Toksoy, Ahmet Kaan; Guden, MustafaThis study investigates the ballistic performance of silicon carbide (SiC) ceramic armor systems reinforced with single and hybrid metallic cover plates composed of Ti-6Al-4V (Ti64) and copper. Controlled ballistic experiments combined with validated LS-DYNA simulations were conducted to examine how cover-plate material, thickness, and stacking sequence influence penetration resistance, energy dissipation, and failure mechanisms. The experimental results revealed that metallic cover plates significantly enhance protection by improving projectile erosion and extending dwell time. While both Ti64 and copper single layers increased the antipenetration capability (APC) compared with bare SiC, hybrid configurations achieved the highest performance. The optimal design, consisting of a 2 mm Ti64 plate placed in front of a 1 mm copper plate, produced the greatest reduction in penetration depth and the highest APC value. Numerical analyses closely replicated the experimental trends and provided insight into stress-wave interactions, pressure evolution, and damage progression within the ceramic. The findings demonstrate that hybrid Ti64-Cu systems not only improve initial impact resistance but also redistribute energy toward the front layers, reducing stress transmission to the backing and mitigating catastrophic ceramic failure. The combined experimental and numerical results establish a clear design framework for developing lightweight, high-efficiency ceramic armor through tailored hybrid layering strategies.Article On the Quasi-Static and Dynamic Compressive Behavior of Paper Honeycomb: Experimental and Numerical Study(Pergamon-Elsevier Science Ltd, 2025) Imrag, Berkay Turkcan; Tasdemirci, Alper; Gurler, YigitThis study explores the quasi-static and dynamic compressive behavior of paper-based honeycomb structures, with a focus on quantifying the distinct roles of strain rate sensitivity, microinertia, and entrapped air. While these effects have been broadly recognized in prior work, the novelty of this research lies in the systematic separation and evaluation of their individual contributions using a validated experimental-numerical approach tailored for low-strength, sustainable materials. A custom direct impact test setup was developed to capture dynamic force response with high resolution, overcoming the limitations of conventional high-rate methods such as SHPB, which are not suitable for paper. The material model implemented in LS-DYNA incorporates CowperSymonds parameters derived from relevant high strain-rate data and simulates air interaction using an ALE-based fluid-structure framework. The numerical results closely match the experimental findings across different impact velocities, allowing each mechanism to be isolated and quantitatively assessed. The study shows that microinertia dominates the early deformation response, strain rate sensitivity becomes more pronounced at higher velocities, and entrapped air affects force levels during intermediate compression. These findings offer a practical and validated modeling framework that can support the design of recyclable protective systems, where weight, sustainability, and performance under impact are critical considerations.Article Constitutive Equation Determination and Dynamic Numerical Modelling of the Compression Deformation of Concrete(Wiley, 2021) Seven, Semih Berk; Çankaya, M. Alper; Uysal, Çetin; Taşdemirci, Alper; Saatci, Selçuk; Güden, MustafaThe dynamic compression deformation of an in-house cast concrete (average aggregate size of 2-2.5 mm) was modelled using the finite element (FE), element-free Galerkin (EFG) and smooth particle Galerkin (SPG) methods to determine their capabilities of capturing the dynamic deformation. The numerical results were validated with those of the experimental split Hopkinson pressure bar tests. Both EFG and FE methods overestimated the failure stress and strain values, while the SPG method underestimated the peak stress. SPG showed similar load capacity profile with the experiment. At initial stages of the loading, all methods present similar behaviour. Nonetheless, as the loading continues, the SPG method predicts closer agreement of deformation profile and force histories. The increase in strength at high strain rate was due to both the rate sensitivity and lateral inertia caused by the confinement effect. The inertia effect of the material especially is effective at lower strain values and the strain rate sensitivity of the concrete becomes significant at higher strain values.