Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Experimental Comparative Analysis of Hole-Making Strategies and Cutting Parameters on Flexural Properties and Induced Delamination in S2 Glass and Basalt Fiber-Reinforced Polymers(John Wiley and Sons Inc, 2026) Eltahir, Sara Saeed Abdulrahman; Yilmaz, Cagatay; Kesriklioglu, SinanOpen holes are often required in the applications of fiber-reinforced polymers (FRP). However, machining them leads to fiber and matrix damage, reducing the overall quality of composites. The novelty of this study lies in investigating the influence of multiple hole machining strategies under varying feed rates and cutting speeds on the flexural strength, chord modulus and hole quality for S2-Glass (S2-GFRP) and basalt fiber-reinforced polymers (BFRP), followed by three-point bending tests and statistical analysis to determine the optimum machining parameters in terms of flexural properties, delamination, and time efficiency. Findings indicate that conventional milling yields an increase in the flexural strength and chord modulus by 22.2 MPa and 1.9 GPa, respectively, for S2 GFRP. While climb milling performs best for BFRP, enhancing flexural performance by 7.6 MPa and 0.4 GPa. Direct drilling at high feed rate and cutting speed shows the poorest performance. Hole machining at low feed rate using climb milling minimizes delamination at the entrance by 14.8% for S2 GFRP and by 2.7% for BFRP using conventional milling. At the exit, helical milling at a low feed rate suppresses delamination damage by 58.5% and 10.7% for S2 GFRP and BFRP. The most time-efficient method is direct drilling at a feed rate of 0.075 mm/rev and cutting speed of 75 m/min or climb milling with same feed rate, but 25 m/min cutting speed. Within the tested ranges, the optimized drilling setup significantly improved structural performance of S2-GFRP and GFRP, confirming the effectiveness of the proposed experimental-statistical framework.Article Citation - WoS: 19Citation - Scopus: 19Investigation of the Effect of Surface Crack on Low-Velocity Impact Response in Hybrid Laminated Composite Plates(Springer Heidelberg, 2020-06) Gunes, Aydin; Sahin, Omer SinanComposite materials can be damaged in the environments in which they are used, due to the loads they are exposed to or due to different effects on the production processes. The formation processes of these damages generally develop as crack formation or progress of the existing crack. For this reason, it is very important to investigate the behavior of the crack that occurs after the dynamic loads to which the composite materials are exposed. In this study, the dynamic behaviors of hybrid laminated composites with different surface crack geometries were investigated. Surface cracks with different crack depth-to-thickness (a/t) and crack depth-to-crack width (a/c) ratios were machined upon hybrid composite laminates and subjected to low-velocity impact tests under 2 m/s, 2.5 m/s and 3 m/s impact velocities. The effect of different surface crack geometries upon variation of contact force versus time, variation of contact force versus displacement and variation of absorbed/rebound energy have been evaluated. The effect of surface crack geometry and impact velocity upon contact stiffness and bending stiffness was also evaluated. Damage formation during impact loading was examined by scanning electron microscopy and optical microscopy. After the evaluations, the damage behaviors caused by the dynamic loads depending on the initial surface crack geometry were examined in detail.