WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Crashworthiness Evaluation of 3D-Printed Hybrid-Design Multi-Cell Energy Absorbers Under Lateral Compression for Unmanned Aerial Vehicles(Springer Heidelberg, 2025-11-25) Atahan, M. Gokhan; Zeybek, Halil; Ozturk, SezginEnergy absorbers can be strategically integrated into critical areas of unmanned aerial vehicles to protect their structural integrity and electronic components in the event of an accident. In this study, hybrid-design multi-cell energy absorber configurations were proposed, and their crashworthiness performance and collapse mechanisms were comparatively analyzed. Hybrid energy absorbers were designed considering circular, square, hexagonal, and re-entrant unit cell geometries. The energy absorber configurations were produced via additive manufacturing. Compared to the single-cell circular energy absorber, the hybrid-design multi-cell approach resulted in a higher peak crushing force value, while offering considerable enhancements in other crashworthiness parameters. Configuration 3 is recommended for use in energy absorber applications in unmanned aerial vehicles due to its superior crashworthiness performance. Moreover, in hybrid-design multi-cell energy absorbers, the selection of layer geometries significantly influences deformation capability. Compared to the single-cell circular configuration (Configuration 1), Configuration 3 demonstrated superior crashworthiness performance by increasing the MCF, EA, and SEA values by 7.47, 4.47, and 1.41 times, respectively.Article Citation - WoS: 4Citation - Scopus: 3Low-Speed Oblique Impact Response of Adhesively Bonded Dissimilar Single-Lap Joints(ASCE-Amer Soc Civil Engineers, 2022-09) Atahan, M. Gokhan; Apalak, M. KemalAdhesively bonded joints are widely preferred for joining similar and dissimilar materials due to the mechanical advantages they provide. As the demand for the adhesively bonded method increases, it is necessary to determine the behavior of joints under impact loads for joint design. The aim of this study was to investigate the low-speed oblique impact behavior of dissimilar single-lap joints and the effect of plastic deformation ability and strength of the adherends [(Top) Al 2024-T3-(Bottom) Al 5754-0, (Top) Al 5754-0-(Bottom) Al 2024-T3], overlap lengths (25, 40 mm), and impact energy (3, 11 J) on adhesive damage. The behavior of the joints determined by the numerical model under low-speed oblique impact was compared with experimental results. Considering the contact force-time, contact force-displacement, and adhesive damage, the numerical model was reasonably compatible with the experimental results. The damage initiation and propagation in the adhesive layer were determined by three-dimensional explicit finite-element analysis. In order to obtain suitability for the damage mechanism by observing the experimental bonding damage surfaces, the adhesive region was divided into three zones, the upper and lower adhesive interfaces and a middle adhesive layer between them. The different strength and plastic deformation ability of the adherends had a significant effect on the adhesive damage initiation and propagation. In the case of high strength and low deformation ability of the adherend material (Al 2024-T3) contacting with the impactor, a reduction of the adhesive damage occurred due to the deformation of the adherend material (bottom adherend) with low strength and high deformation capability. The oblique impact load and the different mechanical properties of the adherends greatly affected the adhesive damage initiation and propagation of single-lap joints.