Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Failure Analysis of Fused Deposition Modeling 3D Printed Poly Lactic Acid Polymer(Sage Publications Ltd, 2025-10-04) Yilmaz, Cagatay; Eltahir, Sara Saeed AbdulrahmanAdditive manufacturing, commonly known as 3D printing (AM), has emerged as one of the most transformative technological advances in the last few decades in global manufacturing, as it allows for the production of intricate components without the use of costly molds. Fused Deposition Modeling (FDM) is widely adopted among various AM techniques due to its accessibility and effectiveness. FDM 3D-printed PLA (Poly Lactic Acid) shows a transversely isotopic symmetry similar to laminated composite structures. Therefore, classical lamination theory can be applied to FDM 3D-printed PLA. This study attempts to expand the knowledge by relying on classical lamination theory and several imposed failure theories like maximum stress, Tsai-Hill, Tsai-Wu, and Hashin to determine how FDM 3D printing of PLA fails. We investigate eight different raster orientations (0 degrees, 10 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, and 90 degrees) and compare the theoretical prediction of strength with experimental findings. With this comprehensive analysis, we are seeking to better understand the failure analysis of FDM 3D printed PLA. The maximum stress, Tsai-Wu, Tsai-Hill, and Hashin failure theories show good agreement with experimental findings for 0 degrees and 90 degrees raster orientations. As the raster orientation shifts from 0 degrees, the discrepancy between experimental results and theoretical predictions increases, peaks at mid-angles, and then decreases, becoming negligible at 90 degrees.Article Citation - WoS: 1Citation - Scopus: 2The Impact of Knitted Linked Seams on Comfort and Friction Perception(Taylor & Francis Ltd, 2024-08-29) Temel, Mevra; Scott, Eleanor; Cain, Rebecca; Johnson, Andrew A.Friction from knitted clothing can cause discomfort and skin issues, underscoring the importance of tactile comfort for wearers. Seamless knitted garments are assumed to be comfortable to wear, yet there is little understanding of their tactile comfort in comparison to linked seams - the most common form of knitted garment. This novel study examines the influence of a garments knitted structural architecture on clothing comfort and wearability by investigating skin friction and tactile perception across ten body regions in both male and female participants, using two commonly utilised materials and seam designs: cotton and merino wool with plain and linked seams. The impact of seam design and regional factors on skin friction and tactile perception was analysed, revealing varying levels across tested body regions. Removing seams exposed a greater surface area to skin contact, leading to higher perceived friction levels. As such, structural elements in knitted garments enhance wearer comfort. Seamless knitwear manufacturing offers a more environmentally conscious option compared to traditional cut-and-sew processes. This study investigated the impact of knitted garment material and structure on wearer comfort by analysing skin friction and tactile perception across ten upper body regions. Removing seams increased garment-to-skin contact leading to wearer discomfort.Article Citation - WoS: 1Citation - Scopus: 2Effect of Multi-Cell Approach on Crashworthiness Performance of 3D-Printed Thin-Walled Structures Under Lateral Compression Loading for Unmanned Aerial Vehicle Applications(Sage Publications Ltd, 2025-06-02) Atahan, M. Gokhan; Zeybek, Halil; Gokhan Atahan, M.Recent technological advancements in unmanned aerial vehicles have led to their use in various military and civilian applications. However, weather conditions, operator faults, and electronic or mechanical problems can result in unmanned aerial vehicle accidents. In the event of an accident, energy-absorbing structures can be placed in specific regions of vehicles to protect sensitive and costly cameras, sensors, and cargo from damage, while also preserving the vehicle's structural integrity. In this study, thin-walled energy absorbers with circular, square, hexagonal, and reentrant geometries were proposed, and the experimental investigation focused on the effect of increasing the number of cells on their crashworthiness performance and deformation mechanisms. Lateral compressive load was applied to thin-walled structures produced by fused deposition modeling technology using advanced polylactic acid filament. Experimental results showed that the triple-cell reentrant thin-walled structure demonstrated promising results for unmanned aerial vehicle applications, as it exhibited the highest mean crushing force, energy absorption, and specific energy absorption values. Thanks to the unique geometry of the reentrant structure, a gradual collapse mode was observed, and as a result, the triple-cell reentrant structure exhibited high energy absorption performance.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.