Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Article Citation - WoS: 3Citation - Scopus: 3Determination of Activation Energy for Carbon/Epoxy Prepregs Containing Carbon Nanotubes by Differential Scanning Calorimetry(SAGE Publications, 2022) Uz, Yusuf Can; Tanoğlu, MetinThe aim of the present study is the thermal characterization of laboratory-scale carbon fiber/epoxy-based prepregs by incorporating single-wall carbon nanotubes (SWCNTs). Investigation of the cure behavior of a prepreg system is crucial for the characterization and optimization of the fiber reinforced polymeric (FRP) composite. To affect dispersion characteristics, SWCNTs were functionalized by oxidizing their surface with carboxyl (-COOH) group using an acid treatment. The modified resin system contained 0.05, 0.1, and 0.2 wt. % functionalized SWCNTs (F-SWCNTs). Carbon fiber (CF) reinforced prepregs containing various amount of F-SWCNTs were prepared using drum-type winding technique. FTIR was performed to identify new bonding groups formed after the functionalization of SWCNTs. Cure kinetics of prepregs prepared with/without F-SWCNTs were investigated using isoconversional methods.Article Citation - WoS: 3Citation - Scopus: 3Enhancement of Filament Wound Glass Fiber/Epoxy-based Cylindrical Composites by Toughening With Single-Walled Carbon Nanotubes(SAGE Publications, 2022) Ay Solak, Zeynep; Kartav, Osman; Tanoğlu, MetinIn this study, the effect of incorporating nano-sized fillers (noncovalently functionalized with ethoxylated alcohol chemical-vapor-deposition-grown SWCNTs) within an epoxy resin on the performance of filament wound glass fiber (GF)-based cylindrical composites (GFCCs) was investigated. For this purpose, SWCNTs were dispersed with the concentration of 0.05 and 0.1 weight percent (wt.%) within an epoxy resin using mechanical stirring and calendaring (3-roll-milling) techniques. The rheological behavior of the SWCNT incorporated epoxy mixture was characterized to determine the suitability of blends for the filament winding process. It was revealed that the viscosity value of the resin was not significantly affected by the addition of SWCNTs in given concentrations. Moreover, contact angle measurements were also performed on the SWCNT/epoxy blends dropped on the GF for the evaluation of the wettability behavior of the GF in the presence of the SWCNTs in relevant concentrations. Eventually, it was observed that the wettability behavior of GF was not reasonably affected by the presence of the SWCNTs. The double cantilever beam (DCB), flexural, and short beam shear (SBS) tests were performed on the reference and SWCNT-modified GFCC specimens to evaluate the effects of the SWCNT presence on the interlaminar fracture toughness and out-of-plane properties of GFCCs. The fractured surfaces after the DCB and SBS tests were analyzed under the scanning electron microscopy to reveal the toughening mechanisms and the filler morphologies. Consequently, although SWCNT incorporation was on the outermost layer of GFCCs, it was found that the interlaminar shear strength (ILSS) values and Mode I interlaminar fracture toughness values of the curved composite samples were improved up to 22 and 216%, respectively, due to the presence of the SWCNTs.Article Citation - WoS: 31Citation - Scopus: 32Development and Analysis of Composite Overwrapped Pressure Vessels for Hydrogen Storage(SAGE Publications, 2021) Kartav, Osman; Kangal, Serkan; Yücetürk, Kutay; Tanoğlu, Metin; Aktaş, Engin; Artem, Hatice SeçilIn this study, composite overwrapped pressure vessels (COPVs) for high-pressure hydrogen storage were designed, modeled by finite element (FE) method, manufactured by filament winding technique and tested for burst pressure. Aluminum 6061-T6 was selected as a metallic liner material. Epoxy impregnated carbon filaments were overwrapped over the liner with a winding angle of +/- 14 degrees to obtain fully overwrapped composite reinforced vessels with non-identical front and back dome layers. The COPVs were loaded with increasing internal pressure up to the burst pressure level. During loading, deformation of the vessels was measured locally with strain gauges. The mechanical performances of COPVs designed with various number of helical, hoop and doily layers were investigated by both experimental and numerical methods. In numerical method, FE analysis containing a simple progressive damage model available in ANSYS software package for the composite section was performed. The results revealed that the FE model provides a good correlation as compared to experimental strain results for the developed COPVs. The burst pressure test results showed that integration of doily layers to the filament winding process resulted with an improvement of the COPVs performance.Article Citation - WoS: 40Citation - Scopus: 37Investigation of Interlayer Hybridization Effect on Burst Pressure Performance of Composite Overwrapped Pressure Vessels With Load-Sharing Metallic Liner(SAGE Publications, 2020) Kangal, Serkan; Kartav, Osman; Tanoğlu, Metin; Aktaş, Engin; Artem, Hatice SeçilIn this study, multi-layered composite overwrapped pressure vessels for high-pressure gaseous storage were designed, modeled by finite element method and manufactured by filament winding technique. 34CrMo4 steel was selected as a load-sharing metallic liner. Glass and carbon filaments were overwrapped on the liner with a winding angle of [+/- 11 degrees/90 degrees(2)](3) to obtain fully overwrapped composite reinforced vessel with non-identical front and back dome endings. The vessels were loaded with increasing internal pressure up to the burst pressure level. The mechanical performances of pressure vessels, (i) fully overwrapped with glass fibers and (ii) with additional two carbon hoop layers on the cylindrical section, were investigated by both experimental and numerical approaches. In numerical approaches, finite element analysis was performed featuring a simple progressive damage model available in ANSYS software package for the composite section. The metal liner was modeled as elastic-plastic material. The results reveal that the finite element model provides a good correlation between experimental and numerical strain results for the vessels, together with the indication of the positive effect on radial deformation of the COPVs due to the composite interlayer hybridization. The constructed model was also able to predict experimental burst pressures within a range of 8%. However, the experimental and finite element analysis results showed that hybridization of hoop layers did not have any significant impact on the burst pressure performance of the vessels. This finding was attributed to the change of load-sharing capacity of composite layers due to the stiffness difference of carbon and glass fibers.Conference Object Citation - Scopus: 1Development of Composite Drive Shaft Tube for Automotive Industry(Applied Mechanics Laboratory, 2019) Arslan Özgen, Gizem; Tanoğlu, Metin; Aktaş, Engin; Yücetürk, KutayWeight, vibration, fatigue, and critical speed limitations have been recognized as serious problems in drive shafts in automotive industry for many years. Conventional drive shaft is made up into two parts to increase its fundamental natural bending frequency. This present work deals with the replacement of conventional steel drive shaft with a composite counterparts. The benefits of eliminating the two piece shafts are significant reductions in weight, noise, vibration and harshness. In this work, one-piece propeller shaft composed of carbon/epoxy and glass/epoxy composites have been designed and manufactured for a rear wheel drive automobile. The performance measures are static torque transmission capability, torsional buckling and the fundamental natural bending frequency. The tubular composite shaft samples are being manufactured by using filament winding technique. To predict the torsional properties, fatigue life and failure modes of composite tubes for different fiber orientation angle and stacking sequence, finite element analysis (FEA) has been used. The predicted and experimental values has been reported for comparison. The next phase of work consists of optimization of shaft for the objective function as weight and fundamental natural frequency considering different stacking sequence and fiber orientation. © CCM 2020 - 18th European Conference on Composite Materials. All rights reserved.
