Browsing by Author "Kaybal, Halil Burak"

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Citation - WoS: 25
Citation - Scopus: 27
The Effect of Nanoclay Particles on the Incubation Period in Solid Particle Erosion of Glass Fibre/Epoxy Nanocomposites
(ELSEVIER SCIENCE SA, 2020) Bağcı, Mehmet; Demirci, Musa; Şükür, Emine Feyza; Kaybal, Halil Burak
During erosion tests of glass fibre/epoxy nanocomposites, an incubation period emerged because of the embedding of abrasive particles into the target material. In this study, the effect of this period on solid particle erosion behaviour was investigated for glass fibre/epoxy composites with the addition of nanoclay. The surface erosion characteristics of the composites were obtained by solid particle erosion tests using angular alumina particles with a size on the order of 400 mu m as the erodent. The tests were conducted using impact velocities of similar to 23 or similar to 34 m/s and impingement angles of 30 degrees, 60 degrees or 90 degrees as operating conditions. The eroded surfaces were examined using a scanning electron microscope to characterise the incubation mechanisms taking place in the nanocomposites. The glass fibre/epoxy composite without nanoclay (the pure test specimen) had the highest erosion resistance when compared to the composites with a nanoclay additive in ratios between 1% and 3% by weight. The findings of this study indicate that the agglomeration and weak compatibility of nanoclay, glass fibre and epoxy affected the results.
Citation - WoS: 48
Citation - Scopus: 48
Enhanced Salty Water Durability of Halloysite Nanotube Reinforced Epoxy/Basalt Fiber Hybrid Composites
(KOREAN FIBER SOC, 2019) Ulus, Hasan; Kaybal, Halil Burak; Eskizeybek, Volkan; Avcı, Ahmet
In this study, we report the effect of halloysite nanotube (HNT) modification on salty water aging durability of epoxy (Ep)/basalt fiber (BF) hybrid composites. For this, various amounts of HNTs were introduced into the Ep matrix, and the HNTs/Ep mixture was used to impregnate basalt fabrics to fabricate hybrid laminated composites. The hybrid composites were exposed substantial increases in the tensile strength and the fracture toughness. Besides, after salty water aging for 6 months, the hybrid composites exhibited remarkably improved aging performance with almost 10 % less reduction in both tensile and flexural strengths and fracture toughness compared to the neat basalt-epoxy composites. SEM analysis showed relatively less number of cracks, micro-voids and better interfacial bonding for the 2 wt% HNTs reinforced hybrid composite specimens in comparison to the neat counterpart, similarly conditioned in all cases. The consequences of salty water aging on micro-scale morphology were discussed based on the fracture morphologies to reveal degradation mechanisms in the existence of HNTs reinforcement.
Citation - WoS: 29
Citation - Scopus: 26
An Experimental Evaluation on the Dynamic Response of Water Aged Composite/Aluminium Adhesive Joints: Influence of Electrospun Nanofibers Interleaving
(ELSEVIER SCI LTD, 2022) Ulus, Hasan; Kaybal, Halil Burak; Berber, Nihat Erdem; Tatar, Ahmet Caner; Ekrem, Mürsel; Ataberk, Necati; Avcı, Ahmet
The impact response of adhesives is a critical design parameter considering their lifetime. Additionally, environmental effects such as water or moisture may cause to degrade of the polymer-based adhesive and shorten its service life. This study aimed to investigate the impact response of water-aged aluminium-composite adhesively bonded single lap joints (SLJs). Nylon 6.6 nanofibers modified with graphene nanoplatelets (GNPs) were introduced in the adhesion areas to increase adhesive performance. The water aging resulted in decreased impact resistance in all cases. However, nanofiber-modified SLJs exhibited comparatively higher impact performance under both non-aged and water-aged conditions. Further, the GNP reinforced nylon 6.6 nanofibers increased the maximum impact load by 15 and 19% compared to neat nanofibers before and after aging, respectively. The fracture surfaces were examined via scanning electron microscopy (SEM) to understand damage and toughness mechanisms. A schematic model has been developed to explain the mechanisms leading to improved bonding performance by applying N6.6 nanofiber reinforcement to the adhesion zone.
Citation - WoS: 45
Citation - Scopus: 48
Halloysite Nanotube Reinforcement Endows Ameliorated Fracture Resistance of Seawater Aged Basalt/Epoxy Composites
(SAGE PUBLICATIONS LTD, 2020) Ulus, Hasan; Kaybal, Halil Burak; Eskizeybek, Volkan; Avcı, Ahmet
Seawater aging-dominated delamination failure is a critical design parameter for marine composites. Modification of matrix with nanosized reinforcements of fiber-reinforced polymer composites comes forward as an effective way to improve the delamination resistance of marine composites. In this study, we aimed to investigate experimentally the effect of halloysite nanotube nanoreinforcements on the fracture performance of artificial seawater aged basalt-epoxy composites. For this, we introduced various amounts of halloysite nanotubes into the epoxy and the halloysite nanotube-epoxy mixtures were used to impregnate to basalt fabrics via vacuum-assisted resin transfer molding, subsequently. Fracture performances of the halloysite nanotubes modified epoxy and basalt/epoxy composite laminated were evaluated separately. Single edge notched tensile tests were conducted on halloysite nanotube modified epoxy nanocomposites and the average stress intensity factor (K-IC) was increased from 1.65 to 2.36 MPa.m(1/2) (by 43%) with the incorporation of 2 wt % halloysite nanotubes. The interlaminar shear strength and Mode-I interlaminar fracture toughness (G(IC)) of basalt-epoxy hybrid composites were enhanced from 36.1 to 42.9 MPa and from 1.22 to 1.44 kJ/m(2), respectively. Moreover, the hybrid composites exhibited improved seawater aging performance by almost 52% and 34% in interlaminar shear strength and G(IC) values compared to the neat basalt-epoxy composites after conditioning in seawater for six months, respectively. We proposed a model to represent fracture behavior of the seawater aged hybrid composite based on scanning electron microscopy and infrared spectroscopy analyses.
Citation - Scopus: 4
Influence of Seawater on Mechanical Properties of Sio2-Epoxy Polymer Nanocomposites
(2019) Kaybal, Halil Burak; Ulus, Hasan; Tatar, Ahmet Caner; Demir, Okan; Avcı, Ahmet
In this study, dispersion of nano SiO2 in epoxy composite aged in seawater and its effect on mechanical properties were studied. The SiO2-epoxy polymer nanocomposite materials were kept in seawater for a total of six months to be tested every two months. Tensile and bending tests were applied to composite materials as a mechanical test. According to the mechanical test results, there was less decrease in strength in SiO2-epoxy polymer nanocomposite material compared to unmodified material. In usage of seawater, the mechanical properties were observed to be the best in 3 % added SiO2-epoxy nanocomposite material.
Tuzlu Su Yaşlandırmasının Cıvata Bağlantılı Halloysit Nanotüp–epoksi/bazalt Fiber Nanokompozitlerin Düşük Hızlı Darbe Davranışlarına Etkisi
(Konya Teknik Üniversitesi, 2019) Kaybal, Halil Burak; Avcı, Ahmet
Bu tez çalışmasında, bazalt fiber takviyeli epoksi matris (epoksi/BF) kompozit ve halloysit nanotüp (HNT) katkılı bazalt fiber takviyeli epoksi matris (HNT-epoksi/BF) nanokompozit malzeme üretimi hem el yatırması hem de vakum infüzyon yönteminin birlikte kullanılmasıyla gerçekleştirilmiştir. Ayrıca epoksi matris içinde kullanılan HNT 'nin en verimli oranı, epoksi nanokompozit numunelerin çekme testi sonucunda ağırlıkça % 2 oranında bulunmuştur. ASTM standartlarına göre malzemelerin uygun cıvata bağlı montajları yapılmıştır. Cıvata bağlı epoksi/BF kompozit ve HNT-epoksi/BF nanokompozit malzemeler, 2, 4 ve 6 ay tuzlu suya maruz kalacak şekilde yaşlandırmaya bırakılmıştır. Yaşlandırma sonrasında numunelerin yük altındaki davranışlarını incelemek, meydana gelen hasar türlerini görmek ve yük taşıma kapasitelerini bulmak için çekme testi uygulanmış ve yaşlandırılmamış numuneler ile kıyaslanmıştır. Numunelere 15 J, 20 J ve 25 J enerji seviyelerinde vurucunun cıvata bağlı numuneler üzerine iki farklı bölgeye düşürülmesiyle düşük hızlı darbe testi oda sıcaklığında yapılmış ve birbirleriyle kıyaslanmıştır. Kompozit ve nanokompozit numunelerin çekme ve darbe testleri sonrası tuzlu suyun etkisi numuneler üzerinde araştırılmıştır. Numunelerin yüzeylerinde ve kırılma bölgelerinde oluşan hasarlar optik ve SEM görüntüleri alınarak incelenmiştir. HNT 'nin epoksi polimer içerisine takviye edilmesiyle, epoksi nanokompozit malzemenin çekme dayanımı, elastiklik modülü ve tokluk özelliklerinde artış olmuştur. Bu durum, bazalt fiberlerin HNT takviyeli epoksinin, bazalt fiberlere matris olarak taşınması ile devam etmiştir. Cıvata bağlantılı HNT-epoksi/BF nanokompozit malzemeler gerçekleştirilen çekme ve darbe testi sonrasında epoksi/BF kompozit malzemeye göre daha üstün bir performans göstermiştir. HNT takviyesi ile HNT-epoksi/BF nanokompozit malzemenin yaşlandırma sonrasında tuzlu sudan etkilenmesi epoksi/BF kompozit malzemeye nispeten daha az olmuştur. Bu durum, HNT 'nin tuzlu suya karşı tampon vazifesi gördüğünü ön plana çıkarmıştır. Ayrıca optik ve SEM görüntüleri incelendiğinde epoksi/BF kompozit numunelerde aynı şartlar altında daha fazla hasar yoğunluğu meydana gelmiştir.