WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 1Interfacial Properties of Aluminum/Glass-fiber Reinforced Polypropylene Sandwich Composites(Springer Verlag, 2013) Baştürk, S. B.; Guruşçu, A.; Tanoğlu, MetinAluminum/glass-fiber-reinforced polypropylene (Al/GFPP) laminates were manufactured by using various surface pretreatment techniques. Adhesion at the composite/metal interface was achieved by a surface pretreatment of Al sheets with amino-based silane coupling agents, incorporation of a polyolefin-based adhesive film and modification with a PP-based film containing 20 wt.% of maleic-anhydride-modified polypropylene (PP-g-MA). In order to increase the effect of bonding between components of the laminates, the combination of silane treatment and the addition of the PP-based film was also investigated. The mechanical properties (shear, peel, and bending strengths) of adhesively bonded Al/GFPP laminates were examined to evaluate the effects of the surface treatments mentioned. It was revealed that the adhesion in the laminated Al/GFPP systems could be improved by the treatment of aluminum surface with an amino-based silane coupling agent. Judging from the results of peel and bending strength, with incorporation of polyolefin-based films, adhesion in the Al/GFPP laminates increased significantly. The modification of Al/GFPP interfaces with a PP-g-MA/PP layer led to the highest improvement in their adhesion properties. The combination of surface modification with silane and addition of PP-based films did not yield the high bending strength desired. This may be due to the insufficient bonding between silane groups and PP-based films.Article Citation - WoS: 21Citation - Scopus: 24Development and Mechanical Behavior of Fml/Aluminium Foam Sandwiches(Springer Verlag, 2013) Baştürk, Suat Bahar; Tanoğlu, MetinIn this study, the Fiber-Metal Laminates (FMLs) containing glass fiber reinforced polypropylene (GFPP) and aluminum (Al) sheet were consolidated with Al foam cores for preparing the sandwich panels. The aim of this article is the comparison of the flexural properties of FML/Al foam sandwich panels bonded with various surface modification approaches (silane treatment and combination of silane treatment with polypropylene (PP) based film addition). The FML/foam sandwich systems were fabricated by laminating the components in a mould at 200 A degrees C under 1.5 MPa pressure. The energy absorbtion capacities and flexural mechanical properties of the prepared sandwich systems were evaluated by mechanical tests. Experiments were performed on samples of varying foam thicknesses (8, 20 and 30 mm). The bonding among the sandwich components were achieved by various surface modification techniques. The Al sheet/Al foam sandwiches were also consolidated by bonding the components with an epoxy adhesive to reveal the effect of GFPP on the flexural performance of the sandwich structures.Article Citation - WoS: 8Citation - Scopus: 8The Effect of Single-Walled Carbon Nanotube (swcnt) Concentration on the Mechanical and Rheological Behavior of Epoxy Matrix(Springer Verlag, 2020) Ay, Z.; Tanoğlu, MetinThe improvement of Mode I fracture toughness of epoxy by the addition of single-walled carbon nanotubes (SWCNTs) is considered. To prepare nanocomposites, chemical-vapor-deposition-grown SWCNTs noncovalently functionalized with an ethoxylated alcohol was used as the additive and a diglycidyl ether of bisphenol-A-based epoxy as the matrix material. The SWCNTs were dispersed in the epoxy matrix via a mechanical stirrer and a 3-roll mill. The effect of their concentration (0.0125, 0.025, 0.05, 0.1, 0.3, and 0.5 wt.%) on the mechanical properties of the nanocomposites was investigated, and the optimum concentration was determined. Mode I fracture toughness (single-edge-notch 3-point bending) and tensile tests were carried out on neat epoxy and SWCNT-reinforced epoxy nanocomposites. The fractured surfaces of fracture toughness and tensile test specimens were examined by the SEM to reveal the effect of SWCNTs on their failure modes.Conference Object Citation - WoS: 2Citation - Scopus: 2Function Generation Synthesis of Planar Slider-Crank Linkages for Given 3 Positions and a Dead-Center Position(Springer Verlag, 2020) Kiper, Gokhan; Gorgulu, Ibrahimcan; Kucukoglu, Sefa FurkanFunction generation for finitely many positions and dead-center design problems are generally separately handled in the literature. This paper presents a mixed formulation for planar slider-crank linkages where three precision points and a folded or extended dead-center position are to be satisfied. The formulation results in an 8th degree univariate. Examples show that generally there are four real solutions, only two of which result in distinct solutions.Article Citation - WoS: 47Citation - Scopus: 46Surface Charge-Dependent Transport of Water in Graphene Nano-Channels(Springer Verlag, 2018) Çelebi, Alper Tunga; Barışık, Murat; Beşkök, AliDeionized water flow through positively charged graphene nano-channels is investigated using molecular dynamics simulations as a function of the surface charge density. Due to the net electric charge, Ewald summation algorithm cannot be used for modeling long-range Coulomb interactions. Instead, the cutoff distance used for Coulomb forces is systematically increased until the density distribution and orientation of water atoms converged to a unified profile. Liquid density near the walls increases with increased surface charge density, and the water molecules reorient their dipoles with oxygen atoms facing the positively charged surfaces. This effect weakens away from the charged surfaces. Force-driven water flows in graphene nano-channels exhibit slip lengths over 60 nm, which result in plug-like velocity profiles in sufficiently small nano-channels. With increased surface charge density, the slip length decreases and the apparent viscosity of water increases, leading to parabolic velocity profiles and decreased flow rates. Results of this study are relevant for water desalination applications, where optimization of the surface charge for ion removal with maximum flow rate is desired.Article Citation - WoS: 35Citation - Scopus: 39Development of Graphene Nanoplatelet-Reinforced Az91 Magnesium Alloy by Solidification Processing(Springer Verlag, 2018) Kandemir, SinanIt is a challenging task to effectively incorporate graphene nanoplatelets (GNPs) which have recently emerged as potential reinforcement for strengthening metals into magnesium-based matrices by conventional solidification processes due to their large surface areas and poor wettability. A solidification processing which combines mechanical stirring and ultrasonic dispersion of reinforcements in liquid matrix was employed to develop AZ91 magnesium alloy matrix composites reinforced with 0.25 and 0.5 wt.% GNPs. The microstructural studies conducted with scanning and transmission electron microscopes revealed that fairly uniform distribution and dispersion of GNPs through the matrix were achieved due to effective combination of mechanical and ultrasonic stirring. The GNPs embedded into the magnesium matrix led to significant enhancement in the hardness, tensile strength and ductility of the composites compared to those of unreinforced AZ91 alloy. The strength enhancement was predominantly attributed to the grain refinement by the GNP addition and dislocation generation strengthening due to the coefficient of thermal expansion mismatch between the matrix and reinforcement. The improved ductility was attributed to the refinement of β eutectics by transforming from lamellar to the divorced eutectics due to the GNP additions. In addition, the strengthening efficiency of the composite with 0.25 wt.% GNP was found to be higher than those of the composite with 0.5 wt.% GNP as the agglomeration tendency of GNPs is increased with increasing GNP content. These results were compared with those of the GNP-reinforced magnesium composites reported in the literature, indicating the potential of the process introduced in this study in terms of fabricating light and high-performance metal matrix composites.Conference Object Citation - Scopus: 1Structural Compliance Effects on the Accuracy and Safety of a R-Cube Haptic Device(Springer Verlag, 2019) Carbone, Giuseppe; Acinapura, Antonio; Mundo, Domenico; Görgülü, İbrahimcan; Dede, Mehmet İsmet CanThis paper addresses the contribution of structural compliance on stiffness and safety of a R-CUBE Haptic Device. Structural compliance is determined in several poses via FEM analysis and addressed by referring to local and global indices of performance. Results are also compared with evidences from experimental tests. Comparison of numerical and experimental data allows to identify and separate the contributions to the overall compliance that are due to the structural stiffness, and other contributions such as joint clearance, pose and loading conditions.Conference Object Low-Power and Low-Cost Stiffness-Variable Oesophageal Tissue Phantom(Springer Verlag, 2017) Thorn, Alexander; Afacan, Dorukhan; Ingham, Emily; Kavak, Can; Miyashita, Shuhei; Damian, Dana D.Biological tissues are complex structures with changing mechanical properties depending on physiological or pathological factors. Thus they are extendible under normal conditions or stiff if they are subject to an inflammatory reaction. We design and fabricate a low-power and low-cost stiffness-variable tissue phantom (SVTP) that can extend up to 250% and contract up to 5.4% at 5 V (1.4 W), mimicking properties of biological tissues. We investigated the mechanical characteristics of SVTP in simulation and experiment. We also demonstrate its potential by building an oesophagus phantom for testing appropriate force controls in a robotic implant that is meant to manipulate biological oesophageal tissues with changing stiffness in vivo. The entire platform permits efficient testing of robotic implants in the context of anomalies such as long gap esophageal atresia, and could potentially serve as a replacement for live animal tissues.Conference Object Citation - Scopus: 2A Critical Review of Unpowered Performance Metrics of Impedance-Type Haptic Devices(Springer Verlag, 2019) Görgülü, İbrahimcan; Kiper, Gökhan; Dede, Mehmet İsmet CanA kinesthetic haptic device’s performance relies on unpowered, powered and controlled system characteristics. In this paper, a critical review is carried out for the well-known metrics for kinematics, stiffness and dynamic aspects of robots that can be applied in evaluating the unpowered system performance of kinesthetic haptic devices. The physical meanings of these metrics are discussed and the important factors that affect the unpowered system performance of a kinesthetic haptic device are revealed.Conference Object Citation - WoS: 1Citation - Scopus: 2Synthesis of Scalable Planar Scissor Linkages With Anti-Parallelogram Loops(Springer Verlag, 2019) Gür, Şebnem; Karagöz, Cevahir; Kiper, Gökhan; Korkmaz, KorayScissor linkages are commonly used as mechanisms for scaling objects. They constitute a significant portion of deployable structures. Since 1960s many researchers sought to form novel structures using the scissor units. In 1990s Hoberman brought a new perspective to the field when he used the loops, not the units to form linkages. Starting from mid 2000s, other researchers joined into this new approach of design. One of the latest researches presented a design for scaling a circular forms with anti-parallelogram loops. This study shows that an anti-parallelogram loop assembly can also be used for scaling planar curves with variable curvature.