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: 39Citation - Scopus: 38Loading-Rate Effect on Tensile and Bending Strength of 3D-Printed Polylactic Acid Adhesively Bonded Joints(Taylor & Francis Ltd, 2021-05-18) Atahan, M. Gokhan; Apalak, M. KemalAdditive manufacturing provides the production of many machine parts and components with complex geometries. The adhesive bonding technique can be alternative method for joining parts produced with additive manufacturing. This experimental study investigates the applicability of the adhesive bonding technique for PLA (polylactic acid) adherends produced with additive manufacturing and especially the effects of loading rate on the strength of 3D-printed PLA adhesive single-lap joints under tensile, three-point bending (with shear) and four-point bending (no shear effect) loadings. Both PLA and adhesive tensile test specimens exhibited a better strength but lower failure strain with increasing loading rate. PLA had better mechanical behaviour in the raster orientation than those in the layer-build direction. The strength of adhesive single-lap joints improved slightly with increasing loading rate for the tensile and three-point bending tests whilst a decrease of strength and an improvement of bending stiffness were observed for the four-point bending test. Failure initiated at the free edge of the top adherend-adhesive interface for all tests, and propagated along this interface for both bending tests whilst a sudden through-the-thickness failure of top adherend occurred for tensile load after a small interfacial damage propagation. The failure propagation appeared in a wavy form for the three-point bending test whilst it was along the top adherend-adhesive interface for the four-point bending test. Digital Image Correlation (DIC) method for tensile tests showed that the peeling and shear strains were more critical and concentrated around both free edges of adherend-adhesive interfaces; thus, at the right free edge of the top adherend-adhesive interface and at the left free edge of the bottom adherend-adhesive interface.Article Citation - WoS: 2Citation - Scopus: 2Compression Performance of 3D-Printed Ant-Inspired Lattice Structures: An Innovative Design Approach(Sage Publications Ltd, 2025-01-12) Atahan, Mithat Gokhan; Saglam, SelmanIn this study, three different ant-inspired lattice design types: single, double, and inverted double structures were considered due to ants' excellent load-carrying weight ratio. Lattice structures were fabricated using the 3D printing method and polylactic acid filament was used as a printing material. The true blueprint images of the ant were used to obtain the parametric dimensions of the ant-inspired lattice structure. Hence, the presented innovative method for designing lattice structures can be a promising option for industrial sectors requiring high-strength structures. The quasi-static axial compression tests were conducted to evaluate the compression performance of the novel lattice structures. The compression performance of ant-inspired single lattice structures was compared based on specific force, specific energy absorption, and specific stiffness at different height values. The deformation stages and damage regions of ant-inspired lattice structures were analyzed to identify their critical regions during compression tests. The results indicated that as the height value increased, there was a notable decrease in specific force, specific energy absorption, and specific stiffness, along with buckling damage in the ant-inspired single lattice structures. Among the three design types, the ant-inspired inverted double lattice structure showed better compression performance compared to the ant-inspired double lattice structure; however, the ant-inspired single lattice structure with a height of 30 mm exhibited the highest overall compression performance.Article Citation - WoS: 5Citation - Scopus: 5A Rational Utilization of Reinforcement Material for Flexural Design of 3D-Printed Composite Beams(Sage Publications Ltd, 2019-08-05) Ciftci, Cihan; Sas, Hatice S.Recent developments in composite industry address the adaptation of 3D printing technology to overcome the design and manufacturing challenges of the traditional composite processing techniques. This adaptation can be performed with the development of design methodologies corresponding to the type of structural load-carrying members in a structure. Considering the frequently use of beams in structures, the development of the design methodology of beams is essential for the adaptation of the additive manufacturing. Therefore, in this paper, the flexural loading concept is analytically formulated to derive moment capacity for the flexural behavior of 3D-printed composite beams. Then, the formulation is adapted to develop a design methodology of 3D-printed laminates under flexural loading. Additionally, the analytical solutions developed for the design methodology presented in this paper were verified with a good agreement with experimental studies.