Browsing by Author "Çevik, Mehmet"

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Diameter and pattern effects of Al₂O₃ balls on ballistic strength of metal–ceramic composites
(İzmir Katip Çelebi Üniversitesi Yayınları - 6th International Students Science Congress, 2022) Aktaş, Latif Tibet; Çevik, Mehmet
In composite materials made from metals and ceramics, a metallic substrate material is reinforced with ceramic hardened particles. This combination makes it possible to combine the low weightiness of the metal with the resistance of ceramics. Used metals in those types of composites have greater density than the ceramics, so relatively, metals are heavier than ceramics, but in metal-ceramic composite applications, the metal parts are used in small quantities as in thin slices. These types of composites can combine attractive properties of both a ceramic, such as high temperature resistance and hardness, and those of a metal, such as the ability to undergo plastic deformation. Metal-ceramic armors are used in the fields where the weight factor is not crucial yet important for mobilization. Metal-ceramic composites show their unique values in armor technologies especially in vehicle protection applications. Ceramic balls offer advantages such as being lightweight, lower friction resistance, high temperature resistance, higher rigidity, higher hardness, and higher corrosion resistance than metallic composite core, but these properties belong to the material nature. In ballistic applications like high velocity impact situations, spherical shape, theoretically must have an effect on bullet trajectory. Because of the curved surface of a sphere, chances are a projectile hits any spherical surface obliquely. That means the projectile loses some of its kinetic energy by transferring it into the sphere and changing course into another trajectory axis. Shao et al. showed this trajectory deflection effect vividly.
Finite element analysis of material and parameter effects in ballistic armors
(İzmir International Student Association - 2nd International Students Science Congress, 2018) Aktaş, Latif Tibet; Çevik, Mehmet
The literature about the ballistic armors are mostly focused on 2 or 3 different parameter effects. The aim of this study, differently, is to find and compare the effects of specific materials on protection of composite ballistic armor plates against high-velocity projectile impact. The effects of stacking sequence for different materials, projectile type, target plate shape and impact obliquity are investigated individually. It is shown that the proposed stacking sequence decelerates the residual velocity of the projectile better than the other considered arrangements. The average percentage of kinetic energy absorption of rectangular shaped Kevlar 29/epoxy plate is considerably higher than that of circular shaped Kevlar 29/epoxy plate.
Impact location effects on ballistic performance of checkerboard-formation ceramic sphere armor
(ITU Press - International Congress on New Trends in Mechanics, 2025) Aktaş, Latif Tibet; Çevik, Mehmet
This study explores the influence of localized impact positions on the ballistic performance of modular ceramic armor systems. Utilizing a previously validated finite element model based on experimental data, simulations were conducted on an armor panel composed of alumina ceramic spheres arranged in a checkerboard configuration. The selected sphere diameter and layout had been previously identified as optimal for energy dissipation in high-velocity projectile impacts. In this extended analysis, the effect of varying projectile impact locations across the ceramic surface was evaluated. Rather than assuming central impacts, the study considered more realistic scenarios where projectiles may strike the edges of ceramic elements, vertical and horizontal locations between them, or the interstitial voids that naturally occur in such configurations. The findings indicate that the location of impact significantly alters the armor’s ability to absorb and dissipate kinetic energy. Certain locations were found to enhance resistance, while others allowed more efficient projectile penetration. These results underscore the importance of incorporating spatial variability into the design of advanced ceramic-based protective structures and highlight the need for optimizing geometric configurations not only by material and layout, but also by accounting for the probabilistic nature of real-world ballistic interactions.