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18th European Conference on Composite Materials, ECCM 2018; 24 June 2018 through 28 June 2018, Weight, 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.

Power transmitted from the engine to the final drive where useful work is applied through a system consisting of a gearbox, clutch, drive shaft and a differential in the rear-wheel-drive automobiles. It is well-known that the steel drive shaft is usually manufactured in two pieces to increase the fundamental bending natural frequency to ensure safe operation conditions. In this work, hybrid one-piece propeller shafts composed of carbon/epoxy and glass/epoxy composites have been designed for a rear wheel drive automobile satisfying three design specifications, such as static torque transmission capability, torsional buckling and the fundamental natural bending frequency. Hybridization of carbon and glass fibers is being studied to optimize the cost/performance requirements. Composites shaft materials with various fiber orientation angles and stacking sequences are being fabricated and analyzed using finite element analysis (FEA).

Beylergil, Bertan/0000-0002-3204-6746; Aktas, Engin/0000-0002-5706-2101 WOS: 000464609300001 In this study, carbon fiber/epoxy (CF/EP) composites were interleaved with aramid nonwoven veils with an areal weight density of 8.5 g/m(2) to improve their Mode-I fracture toughness. The control and aramid interleaved CF/EP composite laminates were manufactured by VARTM in a [0]4 configuration. Tensile, three-point bending, compression, interlaminar shear, Charpy impact and Mode-I (DCB) fracture toughness values were determined to evaluate the effects of aramid nonwoven fabrics on the mechanical performance of the CF/EP composites. Thermomechanical behavior of the specimens was investigated by Dynamic Mechanical Analysis (DMA). The results showed that the propagation Mode-I fracture toughness values of CF/EP composites can be significantly improved (by about 72%) using aramid nonwoven fabrics. It was found that the main extrinsic toughening mechanism is aramid microfiber bridging acting behind the crack-tip. The incorporation of these nonwovens also increased interlaminar shear and Charpy impact strength by 10 and 16.5%, respectively. Moreover, it was revealed that the damping ability of the composites increased with the incorporation of aramid nonwoven fabrics in the interlaminar region of composites. On the other hand, they caused a reduction in in-plane mechanical properties due to the reduced carbon fiber volume fraction, increased thickness and void formation in the composites.

Fiber reinforced composites are beingextensively used in many applications such as aerospace and automotivestructural components due to their specific strength and stiffness.Delamination is the most common and critical failure mode observed in thesecomposites. Many different methods such as epoxy toughening by nanofillers,stitching, z-pinning and micro/nanofiber interleaving have been developed toimprove their delamination resistance. In this study, the Mode-I delaminationresistance of carbon fiber/epoxy composites toughened by polyamide 6/6 (PA 66)microfibers has been statistically analyzed using Weibull distribution. Thestatistical analyses of the test data showed that the use of PA 66 microfiberscould improve Mode-I fracture toughness by as much as 445% at a 90% confidencelevel., Fiber takviyeli kompozitler, ağırlıklarınaoranla yüksek mukavemet ve rijitlikleri nedeniyle uzay ve otomotiv yapısalparçalarında yaygın olarak kullanılmaktadır. Delaminasyon, bu kompozitlerdegörülen en yaygın ve kritik hasar modudur. Bu kompozitlerin delaminasyon direnciniarttırmak amacıyla, nanokatkılar ile epoksi toklaştırması, dikişleme, z-pimlerve arayüzeyde mikro/nanofiber kullanılması gibi pek çok sayıda teknikgeliştirilmiştir. Bu çalışmada, poliamid 6/6 (PA 66) mikrofiberler iletoklaştırılmış karbon fiber/epoksi kompozitlerin Mode-I delaminasyon direnciWeibull dağılımı kullanılarak istatiksel olarak analiz edilmiştir. Testverilerinin istatiksel olarak değerlendirilmesi sonucunda PA 66 mikrofiberlerinkullanılmasının %90 güven seviyesinde kırılma tokluğunu yaklaşık %445mertebesinde arttırdığı gözlemlenmiştir.

Fiber-reinforcedcomposite materials are used in various applications in aviation,maritime, sport, automotive, and defense industry due to theirseveral advantages. Beside this, they have some disadvantages. Thebehavior of hybrid composites is a weighed sum of the individualcomponents in which there is a more favorable balance between theinherent advantages and disadvantages. Theaim of this study is to develop of the carbon-glass fabric reinforcedpolyester hybrid composites. PA66 nonwoven fabrics were alsoincorporated within the composite laminates to modify interlaminarregion. The results show the addition of the PA66 nonwoven fabricsaffects the mechanical properties in hybrid composite.

The microorganisms cause some serious infections. It is a requirement and a necessity to create sterile fields such as hospital, food processing and public places. Composite stones are one of the main building materials that have been used in buildings due to their high resistant to abrasives, chemicals and mechanical impacts. The silver (Ag), zinc oxide (ZnO), and also nano Ag loaded ZnO (ZnO/Ag) nanopowders have demonsrated capability for the preparation of the polymer based antibacterial nanocomposite materials. In this study, Ag/polyester, ZnO/polyester, Ag/ZnO/polyester and their nanocomposites were prepared and tested with various weight fractions. The microstructure and surface morphology of these nanocomposites were investigated by means of scanning electron microscopy (SEM/EDX). The thermal properties were analyzed by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Finally, The antibacterial properties of nanocomposites were analyzed against gram positive (Bacillus subtilis) and gram negative bacteria (Escherichia coli)., AKG Yalıtım and Ministry of Science and Technology of Industry, Repuplic of Turkey (SAN-TEZ, Project No. 1209-STZ.2012-1)

We systematically report synthesis, characterization and optical properties of ZnO-CuO-Al2O3 semiconducting thin films on glass substrates in terms of preparation condition such as Cu content for gas sensor applications. In this framework, the thin films were successfully fabricated by sol-gel dip-coating technique using Zn, Cu and Al based precursors as starting materials. Transparent solutions were prepared by dissolving the Zn acetate, Cu and Al chlorides in solutions of methanol and glacial acetic acid. Turbidity, pH values, wettability and rheological properties of the prepared solutions were measured by turbidimeter, pH meter, contact angle ganiometer and rheometer machines before coating process. Turbidity, pH and contact angle values of the solutions were found to be approximately 34 ntu, 4.5 and 18°, respectively. It was determined that viscosities of the solutions slightly changed with increasing Cu concentration. The measured gel points of ZnO-0, 5, 10 and 15% CuO-Al2O3 solutions were approximately determined as 4000, 3500, 3000 and 2500 sec, respectively. The ZnO-CuO-1 wt% Al2O3 composite films with 0, 5, 10 and 15 wt% CuO content were obtained on glass substrate by dipping and the gel films were dried at 300°C for 10 min and followed by heat treating at 500°C for 10 min in air. This process was repeated six cyclics to make thick films. The thick films were annealed at 600°C for 30 min in air. The thermal, structural, microstructural, adhesion and optical properties of the coatings were extensively characterized by using DTA-TG, FTIR, XRD, SEM-EDS, AFM, scratch tester, refractometer and spectrophotometer. The annealing temperature, 600°C, can completely remove all templates from Zn, Cu and Al networks and oxide crystalline structure is completely formed at this temperature. The spectrum of ZnO-CuO-Al2O3 precursor film heat-treated at 500°C and 600°C which shows an absence of absorption bands corresponding to organics and hydroxyls indicating complete removal of organics and hydroxyls. XRD study confirms that the composite films consist of ZnO and CuO phases after annealing process. SEM reveals that dense structures are obtained by increasing CuO content in the composite films. It is clear from EDS analysis that Zn, Cu and Al elements are present in the films and Al peak is very low because it has 1% Al2O3 in the films. It was found that surface roughnesses of the films changed between 90 and 200 nm. The films prepared from 15% CuO have better adhesion strength to the glass substrate among other coatings. Refractive indices of ZnO based sol–gel coatings usually lie within the interval 1.20–1.70. While pure ZnO films has a high porosity, the porosity values of ZnO-5, 10 and 15% CuO-Al2O3 films decrease as a function of CuO content. The film thicknesses for ZnO-0, 5, 10 and 15% CuO-Al2O3 were measured as 852 nm, 478 nm, 518 nm and 695 nm using optical method respectively. The optical direct band gap energies were found to be in the range of 3.18 to 3.15 eV for ZnO-CuO-1 wt% Al2O3 films including 0, 5, 10 and 15 wt% CuO content. The ZnO film shows the transmittance of the order of 44% while that of ZnO-CuO-Al2O3 films was of the order of 55%. It is noticed that the ZnO film has higher absorbance in visible range of spectrum.

Tüp sarma yöntemiyle hazırlanan ince duyarlı cam fiber takviyeli polyester kompozit/Alüminyum ikili tüplerin ezilme davranışları statik basma hızlarında (25 mm/dak) deneysel incelenmiştir. Tüplerde dolgu malzemesi olarak kullanılan Al köpüğün ezilme yük değerlerine ve deformasyon mekanizmalarına etkileri belirlenmiştir., The quas-static (25mm/min) crushing behayior of thin walled rolled tubes of glass fiber reinforced polyester composite/Aluminum hybrid tubes were investigated experimentlly. The effects of AI-foam filler on the crushing loads and deformation mechanisms were determined.

Son yıllarda hafif alüminyum köpük dolu tüplerin çarpışma enerjisi sönümleme amaçlı kullanımı için artan bir ilgi vardır. Tekli veya iç içe geçmiş köpük dolu tüpler bu amaç doğrultusundaki bu uygulamalar için çalışılmasına rağmen altıgen ve kübik paketleme geometrileri henüz araştırılmamıştır. Bu çalışmanın nihai amacı tekli köpük dolu tüplerin enerji emme kapasitesini artıracak çoklu tüp geometrilerini belirlemektir. Dolgu malzemesi olarak kullanılan alüminyum köpük malzemeler toz metalürjisi yöntemi ile hazırlanmıştır. Köpük numuneler blok köpük malzemeden kesilerek hazırlanmıştır. Alüminyum köpük dolu tekli tüpler üzerinde basma testleri yapılmış ve sonuçlar ortalama ezilme kuvveti cinsinden değerlendirilmiştir., TÜBİTAK MİSAG 227