Browsing by Author "Hakeem, I.Y."

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Corrigendum To “Experimental Investigation and Analytical Verification of Buckling of Functionally Graded Carbon Nanotube-Reinforced Sandwich Beams” [Heliyon Volume 10, Issue 8, April 2024, Article E28388](s2405844024044190)(10.1016/J.heliyon.2024.e28388)
(Elsevier Ltd, 2025) Madenci, E.; Özkılıç, Y.O.; Bahrami, A.; Aksoylu, C.; Asyraf, M.R.M.; Hakeem, I.Y.; Fayed, S.
In this article, reference [52] was included in error: [52] E. Payton, J. Khubchandani, A. Thompson, J.H. Price, Parents’ expectations of high schools in firearm violence prevention, J. Community Health 42 (2017) 1118–1126. The correct version of the reference is as below: [52] Senjanović, I., Vladimir, N., Hadžić, N., & Tomić, M. (2016). New first order shear deformation beam theory with in-plane shear influence. Engineering Structures, 110, 169-183. https://doi.org/10.1016/j.engstruct.2015.11.032 The authors apologize for the error. © 2025
Citation - WoS: 9
Citation - Scopus: 9
Crashworthiness Performance of Filament Wound Gfrp Composite Pipes Depending on Winding Angle and Number of Layers
(Elsevier Ltd, 2024) Hakeem, I.Y.; Özkiliç, Y.O.; Bahrami, A.; Aksoylu, C.; Madenci, E.; Asyraf, M.R.M.; Beskopylny, A.N.
The main goal of this study is to enhance the crashworthiness performance of tubular composites to absorb more energy by optimizing the winding angle of their fibers. The crashworthiness performance of glass fiber-reinforced polymer composite pipes manufactured using the filament winding is investigated in detail. The effects of the winding angle of the fibers and thickness of the tube wall on the energy absorption were examined through quasi-static compression tests. The composite pipes were produced with 1200 tex E-glass fibers and Epikote 828 resin as the matrix material. The winding angles of ± 30°, ± 45°, ± 55°, ± 75°, and ± 90° were evaluated, and the number of the winding layers, ranged from 1 to 3, was also assessed. Quasi-static axial compressive loading was applied to 15 specimens using a hydraulic actuator. The results revealed that the one-layer specimens experienced buckling damage at low load levels, while an increase in the number of the layers led to higher load-carrying capacity and different types of damages. Furthermore, as the number of the layers increased, the load-carrying capacity and energy absorption of the specimens significantly improved. Progressive failure was observed in the specimens [± 90] for all the layers' configurations, with the specimen [± 90]3, having three layers, exhibiting the highest performance in terms of the load-carrying capacity and energy absorption. The failure modes indicated a combination of the fibers' separation, buckling, diagonal shear failure, and crushing in the upper and lower heads. © 2023 The Authors
Citation - WoS: 1
Citation - Scopus: 1
Effects of the Location and Size of Web Openings on Shear Behavior of Clamped-Clamped Reinforced Concrete Beams
(Techno-Press, 2024) Aksoylu, C.; Özkiliç, Y.O.; Hakeem, I.Y.; Kalkan, I.
The present study pertains to the effects of variations in the location and size of drilled web openings on the behavior of fixed-fixed reinforced concrete (RC) beams. For this purpose, a reference bending beam with a transverse opening in each half span was tested to failure. Later, the same beam was modeled and analyzed with the help of finite element software using ABAQUS. Upon achieving close agreement between the experimental and numerical results, the location and size of the web opening were altered to uncover the effects of these factors on the shear strength and load-deflection behavior of RC beams. The experimental failure mode of the tested beam and the numerical results were also verified by theoretical calculations. In numerical analysis, when compared to the reference (D0) specimen, if the distance of the opening center from the support is 0 or h or 2h, reduction in load-bearing capacity of 1.5%-22.8% or 2.0%-11.3% or is 4.1%-40.7%. In other words, both the numerical analyses and theoretical calculations indicated that the beam behavior shifted from shear-controlled to flexure-controlled as the openings approached the supports. Furthermore, the deformation capacities, energy absorption values, and the ductilities of the beams with different opening diameters also increased with the decreasing distance of the opening from supports. Web compression failure was shown to be the predominant mode of failure of beams with large diameters due to the lack of sufficient material in the diagonal compression strut of the beam. The present study indicated that transverse openings with diameters, not exceeding about 1/3 of the entire beam depth, do not cause the premature shear failure of RC beams. Finally, shear damage should be prevented by placing special reinforcements in the areas where such gaps are opened. © 2024 Techno-Press, Ltd.
Citation - WoS: 5
Citation - Scopus: 5
Experimental Investigation and Analytical Verification of Buckling of Functionally Graded Carbon Nanotube-Reinforced Sandwich Beams
(Elsevier Ltd, 2024) Madenci, E.; Özkılıç, Y.O.; Bahrami, A.; Aksoylu, C.; Asyraf, M.R.M.; Hakeem, I.Y.; Beskopylny, A.N.
Carbon nanotube (CNT) reinforcement can lead to a new way to enhance the properties of composites by transforming the reinforcement phases into nanoscale fillers. In this study, the buckling response of functionally graded CNT-reinforced composite (FG-CNTRC) sandwich beams was investigated experimentally and analytically. The top and bottom plates of the sandwich beams were composed of carbon fiber laminated composite layers and hard core. The hard core was made of a pultruded glass fiber-reinforced polymer (GFRP) profile. The layers of FG-CNTRC surfaces were reinforced with different proportions of CNT. The reference sample was made of only a pultruded GFRP profile. In the study, the reference sample and four samples with CNT were tested under compression. The largest buckling load difference between the reference sample and the sample with CNT was 37.7%. The difference between the analytical calculation results and experimental results was obtained with an approximation of 0.49%–4.92%. Finally, the buckling, debonding, interlaminar cracks, and fiber breakage were observed in the samples. © 2024 The Authors