Browsing by Author "Kartav, Osman"

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Citation Count: 1
A Comprehensive Study on Burst Pressure Performance of Aluminum Liner for Hydrogen Storage Vessels
(Asme, 2021) Kangal, Serkan; Say, A. Harun; Ayakda, Ozan; Kartav, Osman; Aydin, Levent; Artem, H. Secil; Beylergil, Bertan
This paper presents a comparative study on the burst pressure performance of aluminum (Al) liner for type-III composite overwrapped pressure vessels (COPVs). In the analysis, the vessels were loaded with increasing internal pressure up to the burst pressure level. In the analytical part of the study, the burst pressure of the cylindrical part was predicted based on the modified von Mises, Tresca, and average shear stress criterion (ASSC). In the numerical analysis, a finite element (FE) model was established in order to predict the behavior of the vessel as a function of increasing internal pressure and determine the final burst. The Al pressure vessels made of Al-6061-T6 alloy with a capacity of 5 L were designed. The manufacturing of the metallic vessels was purchased from a metal forming company. The experimental study was conducted by pressurizing the Al vessels until the burst failure occurred. The radial and axial strain behaviors were monitored at various locations on the vessels during loading. The results obtained through analytical, numerical, and experimental work were compared. The average experimental burst pressure of the vessels was found to be 279 bar. The experimental strain data were compared with the results of the FE analysis. The results indicated that the FE analysis and ASSC-based elastoplastic analytical approaches yielded the best predictions which are within 2.2% of the experimental burst failure values. It was also found that the elastic analysis underestimated the burst failure results; however, it was effective for determining the critical regions over the vessel structure. The strain behavior of the vessels obtained through experimental investigations was well correlated with those predicted through FE analysis.
Desing and production of light-weight pressure resistant composite tank materials and systems for hydrogen storage
(Izmir Institute of Technology, 2020-07) Kartav, Osman; Tanoğlu, Metin; Tanoğlu, Metin
This thesis focuses on the development of high-pressure resistant composite tanks for hydrogen storage. For this aim, composite tanks with aluminum liners were designed and manufactured by filament winding technique with various lay-up configurations and tested. The main objective of this study was to develop composite tanks with 700 bar working pressure and 1400 bar burst pressure. Furthermore, composite doily layers were incorporated into the filament winding technique and inserted at the front and end dome sections of the composite tanks to improve the burst pressure performance of the composite tanks and to develop the manufacturing process. Before the manufacturing process, the winding simulations were completed using CADWINDTM CAM software. The manufactured composite tanks were hydrostatically loaded with increasing internal pressure up to the burst pressure. During loading, the deformations over the composite tanks and liners were measured locally using strain gauges. Besides, composite plates were manufactured by filament winding technique to determine the mechanical and the thermo-mechanical properties, and the fiber mass fractions of composite sections were determined. Additionally, a preliminary study was carried out to investigate the effect of hybrid fiber usage on the burst pressure performance of steel liner based composite tanks. The effect of filament winding parameters on the burst pressure performance of composite tanks was investigated experimentally. The aimed burst pressure value of more than 1400 bar was obtained in this study for aluminum liner-based carbon fiber reinforced composite tanks. Also, a desired safe burst mode that is expected to occur in the mid-region of the composite tanks was successfully obtained. This study may be useful for the development of composite tanks for high-pressure hydrogen storage especially for the automotive industry and can be helpful to decrease the usage of fossil fuels.
Citation Count: 8
Development and analysis of composite overwrapped pressure vessels for hydrogen storage
(Sage Publications Ltd, 2021) Kartav, Osman; Kangal, Serkan; Yuceturk, Kutay; Tanoglu, Metin; Aktas, Engin; Artem, H. Secil; Tanoğlu, Metin
In 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.
Citation Count: 0
Enhancement of filament wound glass fiber/epoxy-based cylindrical composites by toughening with single-walled carbon nanotubes
(Sage Publications Ltd, 2022) Solak, Zeynep Ay; Kartav, Osman; Tanoglu, Metin; Tanoğlu, Metin
In 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.
Citation Count: 16
Investigation of interlayer hybridization effect on burst pressure performance of composite overwrapped pressure vessels with load-sharing metallic liner
(Sage Publications Ltd, 2020) Kangal, Serkan; Kartav, Osman; Tanoglu, Metin; Aktas, Engin; Artem, H. Secil; Tanoğlu, Metin
In 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.
Citation Count: 16
Investigation of interlayer hybridization effect on burst pressure performance of composite overwrapped pressure vessels with load-sharing metallic liner
(Sage Publications Ltd, 2020) Kangal, Serkan; Kartav, Osman; Tanoglu, Metin; Aktas, Engin; Artem, H. Secil; Tanoğlu, Metin
In 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.
Vibration analysis of rotating curved beams with variable cross-section
(Izmir Institute of Technology, 2014-07) Kartav, Osman; Yardımoğlu, Bülent
In this study, in-plane free vibration characteristics of rotating curved beams are investigated by Finite Difference Method and Finite Element Method since the mathematical model of the present problem is based on the differential eigenvalue problem with variable coefficients. A computer program regarding the titled problem is developed in Mathematica and this program is verified by using results available in the literature. The effects of taper parameters of the curved beam and rotation speed on natural frequencies are investigated.