Scopus İndeksli Yayınlar Koleksiyonu

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https://hdl.handle.net/20.500.12684/2

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Investigation of the Mechanical Properties of St52 and S460MC Steels by Gas Welding
(Gazi �niversitesi, 2022) Okuro�ullar�, Y.; �avu�o�lu, Oktay; Tutar, M.; Ayd�n, H.
In this study, the effect of the changes in welding parameters on the tensile strength, which is one of the mechanical properties of the steels, was investigated in the robotic gas arc welding method applied to St52 and S460MC steels, which are widely used in the industry. As a result of the experiments carried out within the scope of the study, it was aimed to determine the optimum parameter values for the MAG welding method. St52 and S460MC materials were used in the experiments. An experimental design was created in order to carry out the experiments in the most accurate way. Parameter val-ues are placed in this created experimental design. As a result of the experiments per-formed according to the created the experimental design, the optimum parameter val-ues were examined, welding processes were applied with the selected values, and the improvements in the welding quality were determined by subjecting the welded samples to the tensile test. The optimum welding parameters providing the best mechanical properties were 25 V, 7 mm/sec and 13 mm/sec for the arc voltage, wire feed speed and welding speed, respectively.
Elektrik diren� punta kayna�� ile ��l� birle�tirilen FEP05/DP600/FEP05 �elik saclarda kaynak parametrelerinin mekanik �zelliklere ve mikroyap� �zerindeki etkilerin ara�t�r�lmas�
(Gazi �niversitesi, 2024) Selova, L.; Tun�el, O�uz; �avu�o�lu, Oktay; Dindar, �.; Ayd�n, H.
G�n�m�z otomotiv end�strisinde, farkl� malzemelerin elektrik diren� punta kayna�� ile ikili ve ��l� birle�tirmelerinde yayg�n olarak kullan�lmaktad�r. Araba g�vdelerinin a-, b- ve c s�tunlar�nda �ift fazl� (DP) 600 �elikleri ve FEP05 �elikleri s�kl�kla birbirine kaynaklan�r. Bu �al��mada kaynak ak�m�, kaynak zaman� ve elektrot kuvveti gibi elektrik diren� punta kayna�� proses parametrelerinin y�k ta��ma kapasitesi, uzama, �ekirdek �ap� ve ��l� kaynakl� sac ba�lant�lar�n (FEP05 + DP600 + FEP05) ��kme miktar� �zerindeki etkisi ara�t�r�lm��t�r. Kaynakl� birle�tirmenin mekanik �zelliklerini belirlemek i�in �ekme testleri ve mikrosertlik �l��mleri yap�lm��t�r. Kaynak kalitesini analiz etmek i�in mikroyap�sal karakterizasyon kullan�lm��t�r. Ayr�ca ��l� kaynakl� birle�tirmelerde kaynak zaman�n�n, kaynak ak�m�n�n ve elektrot kuvvetinin �nemli fakt�rler oldu�u g�sterilmi�tir. Sonu� olarak, Kaynak parametreleri uygun se�ilerek FEP05 + DP600 + FEP05 levhalar�n�n elektrik diren� punta kayna�� ile ��l� olarak ba�ar�l� �ekilde birle�tirilebilece�i g�r�lm��t�r.
Mechanical characterization and microstructure of fiber laser welded TWIP980 steel depending on welding speed and focal distance
(Elsevier, 2023) �avu�o�lu, Oktay; Yuce, C.; Ayd�n, H.
The TWIP steels are preferred in the automotive industry due to excellent strength and ductility. In this study, the effect of fiber laser welding parameters has been investigated on the mechanical properties and microstructural points of view twinning-induced plasticity (TWIP) steel. The variation of the mechanical properties depending on fiber laser welding parameters has been determined. The samples were laser-welded with different speeds and focal distances the laser power constant at 4 kW. The stress and elongation decreased when the welding speed increased. The highest stress was obtained at + 1 focal distance. The best energy absorption was seen in b-3 combination (laser power 4 kW, welding speed 130 mm/s, focal distance +1 mm)
Influence of oscillating fiber laser welding process parameters on the fatigue response and mechanical performance of butt-jointed TWIP980 steels
(De Gruyter Brill, 2025) �avu�o�lu, Oktay; Ayd�n, H.; Eroglu, M.; Davut, K.
In this study, the effect of laser power, welding speed, linear heat inputs on the mechanical performance of TWIP980 steels joined by oscillating fiber laser welding in butt welding configuration was investigated. Oscillating fiber laser welding were changed: laser power from 1.2 to 1.6?kW, welding speed from 20 to 30?mm?s?1, linear heat input from 40 to 80?J?mm?1. The tensile, hardness and fatigue tests were carried out to determine mechanical performance. A significant improvement in weld penetration, fatigue performance and mechanical properties was detected at linear heat inputs above 53.33?J?mm?1. The best mechanical properties were obtained at 1.6?kW laser power and 25?mm?s?1 welding speed. The study reveals that linear heat inputs, laser power, and welding speed have significant effects on mechanical performance and weld geometry. Furthermore, the results demonstrate that oscillating fiber laser welding enables good weldability even at low laser power.
Microstructural features and mechanical properties of 22MnB5 hot stamping steel in different heat treatment conditions
(Elsevier, 2020) �avu�o�lu, Oktay; �avu�o�lu, Oktay; Y�lmazo�lu, A. G.; �zel, U.; Ayd�n, H.; G�ral, A.
In this study, the microstructure and mechanical properties of the 22MnB5 steel sheet were investigated in different heat treatment conditions. The steel sheet heated to 700?�C, 800?�C, and 900?�C was subjected to air cooling, water quenching, and water quenching?+?tempering procedures. Microstructural properties post-heat treatment were analyzed under an optical microscope. To determine the mechanical properties, uniaxial tensile tests, and hardness measurements were performed. The highest mechanical properties were achieved with the water quenching from 800?�C and 900?�C. The elongation value was ranged of 2-4% with the water quenching. Also, the tempering process slightly increased the elongation value.
Triple joining of different sheets with self-pierce riveting method
(SAGE, 2022) �avu�o�lu, Oktay; Bak�rc�, A.; Dink�i, H.; Y�lmazo�lu, A. G.
Self-piercing riveting (SPR) is a high-speed mechanical joining technique for sheet metal materials. In this study, the mechanical properties of DC04 steel and AA5182 aluminium alloy in triple combinations joined by the SPR method were investigated. For this purpose, triple-joining processes were performed in different combinations, and macro-structural analysis and tensile shear tests were carried out by comparing their mechanical properties. As a result of the study, the highest shear forces were obtained in FFA (DC04-DC04-AA5182) and AFF (AA5182-DC04-DC04) combinations. As the number of aluminium layers increases, the probability of tearing increases in triple joining. Higher spread ratios were generally measured under conditions with hard materials in the upper layers and soft materials in the lower layers
Using Metakaolin In High Strength White Cementitious Composites,
(2014) Suba��, Azime; Emiro�lu, Mehmet
Farkl� renk ve doku �zelliklerine sahip �imentolu kompozitlerin �retilebilmesi i�in �zellikle mimari beton uygulamalar�nda kullan�labilecek y�ksek dayan�ml� beyaz �imentoya ihtiya� duyulmaktad�r. Bu �al��mada mimari beton uygulamalar�nda y�ksek dayan�ml� beyaz portland �imentosu (BP�) ile birlikte puzolan olarak kullan�labilecek metakaolinin (MTK) �imentolu kompozit davran��na etkisi ara�t�r�lm��t�r. �al��ma kapsam�nda MTK, a��rl�k�a %0, %5, %10, %15, %20, %25 ve %30 oranlar�nda CEM I 52,5 R BP� yerine ikame edilmi�tir. Haz�rlanan numuneler �zerinde MTK�n�n, BP� nin bas�n� dayan�m�na, priz s�resine, su ihtiyac�na ve hacim genle�mesine etkisini belirlemeye y�nelik deneyler yap�lm��t�r. Sonu� olarak, y�ksek dayan�ml� BPǒlerde MTK ikamesinin su ihtiyac� ve priz s�resinde, %20 den sonraki ikame oranlar�nda �nemli bir etkiye sahip oldu�u belirlenmi�tir. MTK ikame oran� artt�k�a 28 g�nl�k dayan�m de�erlerinde bir azalma oldu�u, ancak 56. ve 90. g�nlerde MTK ikameli �rneklerin puzolanik etkiden dolay� dayan�m de�erlerinin artt�� g�r�lm��t�r. Ayr�ca MTK ikameli �imento har�lar�n�n bas�n� dayan�mlar�n�n %20 oran�nda MTK ikamesine kadar standart de�erler aras�nda oldu�u belirlenmi�tir.
The production of glass fiber reinforced polymer pipes, application areas in the sector and performance evaluation
(2014) Suba��, Serkan; Eren, �.; Suba��, Azime; G�ner, �.
Otomotiv, havac�l�k, uzay ve savunma end�strilerindeki h�zl� geli�im hafif ve y�ksek mukavemetli malzemelerin kullan�m�n� gerekli k�lm��t�r. Bu ama�la cam elyaf takviyeli plastik kompozit malzemeler �retilmeye ba�lanm�� ve yayg�n bir �ekilde kullan�lm��t�r. CTP�nin farkl� y�klere kar�� dayan�m�, �ok y�ksek korozyon dayan�m� (yap�sal olarak �elik ve ah�ap malzemeye g�re ��r�me ve paslanma olmamas�ndan dolay� periyodik bak�ma ihtiya� duyulmamas�), hafifli�i, montaj ve i��ilik kolayl��, k�sa zamanda imalat� gibi �zelliklere sahip olmas� bu malzemelerin yap�larda kullan�l�rken di�er geleneksel malzemelere kar�� st�nl��n�n bir g�stergesidir. B�t�n bu �zelliklerinin bir sonucu olarak CTP�ler y�ksek bas�n�l� boru �retiminde de kullan�lmaktad�rlar. Bu ara�t�rmada, CTP�lerin boru �retimindeki yeri ve �nemine de�inilmi�, CTP boru �retiminde kullan�lan hammaddeler ve �zelliklerinden bahsedilmi�tir. Bunun yan�nda, CTP boru �retim y�ntemleri a��klanm�� ve �retilen CTP borular�n s�n�fland�r�lmas�, teknik �zellikleri, k�sa d�nem performans deney y�ntemleri belirtilmi�tir. Ayr�ca farkl� projeler i�in tasarlanabilecek ve �e�itli ihtiya�lara cevap verebilen daha y�ksek performansl� CTP boru �retimine y�nelik �nerilerde bulunulmu�tur
Mechanical characterization and microstructure of fiber laser welded TWIP980 steel depending on welding speed and focal distance
(Elsevier, 2023) Çavuşoğlu, Oktay; Yuce, C.; Aydın, H.
The TWIP steels are preferred in the automotive industry due to excellent strength and ductility. In this study, the effect of fiber laser welding parameters has been investigated on the mechanical properties and microstructural points of view twinning-induced plasticity (TWIP) steel. The variation of the mechanical properties depending on fiber laser welding parameters has been determined. The samples were laser-welded with different speeds and focal distances the laser power constant at 4 kW. The stress and elongation decreased when the welding speed increased. The highest stress was obtained at + 1 focal distance. The best energy absorption was seen in b-3 combination (laser power 4 kW, welding speed 130 mm/s, focal distance +1 mm)
Investigation of the Mechanical Properties of St52 and S460MC Steels by Gas Welding
(Gazi Üniversitesi, 2022) Okuroğulları, Y.; Çavuşoğlu, Oktay; Tutar, M.; Aydın, H.
In this study, the effect of the changes in welding parameters on the tensile strength, which is one of the mechanical properties of the steels, was investigated in the robotic gas arc welding method applied to St52 and S460MC steels, which are widely used in the industry. As a result of the experiments carried out within the scope of the study, it was aimed to determine the optimum parameter values for the MAG welding method. St52 and S460MC materials were used in the experiments. An experimental design was created in order to carry out the experiments in the most accurate way. Parameter val-ues are placed in this created experimental design. As a result of the experiments per-formed according to the created the experimental design, the optimum parameter val-ues were examined, welding processes were applied with the selected values, and the improvements in the welding quality were determined by subjecting the welded samples to the tensile test. The optimum welding parameters providing the best mechanical properties were 25 V, 7 mm/sec and 13 mm/sec for the arc voltage, wire feed speed and welding speed, respectively.
Influence of oscillating fiber laser welding process parameters on the fatigue response and mechanical performance of butt-jointed TWIP980 steels
(De Gruyter Brill, 2025) Çavuşoğlu, Oktay; Aydın, H.; Eroglu, M.; Davut, K.
In this study, the effect of laser power, welding speed, linear heat inputs on the mechanical performance of TWIP980 steels joined by oscillating fiber laser welding in butt welding configuration was investigated. Oscillating fiber laser welding were changed: laser power from 1.2 to 1.6?kW, welding speed from 20 to 30?mm?s?1, linear heat input from 40 to 80?J?mm?1. The tensile, hardness and fatigue tests were carried out to determine mechanical performance. A significant improvement in weld penetration, fatigue performance and mechanical properties was detected at linear heat inputs above 53.33?J?mm?1. The best mechanical properties were obtained at 1.6?kW laser power and 25?mm?s?1 welding speed. The study reveals that linear heat inputs, laser power, and welding speed have significant effects on mechanical performance and weld geometry. Furthermore, the results demonstrate that oscillating fiber laser welding enables good weldability even at low laser power.
Elektrik direnç punta kaynağı ile üçlü birleştirilen FEP05/DP600/FEP05 çelik saclarda kaynak parametrelerinin mekanik özelliklere ve mikroyapı üzerindeki etkilerin araştırılması
(Gazi Üniversitesi, 2024) Selova, L.; Tunçel, Oğuz; Çavuşoğlu, Oktay; Dindar, Ç.; Aydın, H.
Günümüz otomotiv endüstrisinde, farklı malzemelerin elektrik direnç punta kaynağı ile ikili ve üçlü birleştirmelerinde yaygın olarak kullanılmaktadır. Araba gövdelerinin a-, b- ve c sütunlarında çift fazlı (DP) 600 çelikleri ve FEP05 çelikleri sıklıkla birbirine kaynaklanır. Bu çalışmada kaynak akımı, kaynak zamanı ve elektrot kuvveti gibi elektrik direnç punta kaynağı proses parametrelerinin yük taşıma kapasitesi, uzama, çekirdek çapı ve üçlü kaynaklı sac bağlantıların (FEP05 + DP600 + FEP05) çökme miktarı üzerindeki etkisi araştırılmıştır. Kaynaklı birleştirmenin mekanik özelliklerini belirlemek için çekme testleri ve mikrosertlik ölçümleri yapılmıştır. Kaynak kalitesini analiz etmek için mikroyapısal karakterizasyon kullanılmıştır. Ayrıca üçlü kaynaklı birleştirmelerde kaynak zamanının, kaynak akımının ve elektrot kuvvetinin önemli faktörler olduğu gösterilmiştir. Sonuç olarak, Kaynak parametreleri uygun seçilerek FEP05 + DP600 + FEP05 levhalarının elektrik direnç punta kaynağı ile üçlü olarak başarılı şekilde birleştirilebileceği görülmüştür.
Triple joining of different sheets with self-pierce riveting method
(SAGE, 2022) Çavuşoğlu, Oktay; Bakırcı, A.; Dinkçi, H.; Yılmazoğlu, A. G.
Self-piercing riveting (SPR) is a high-speed mechanical joining technique for sheet metal materials. In this study, the mechanical properties of DC04 steel and AA5182 aluminium alloy in triple combinations joined by the SPR method were investigated. For this purpose, triple-joining processes were performed in different combinations, and macro-structural analysis and tensile shear tests were carried out by comparing their mechanical properties. As a result of the study, the highest shear forces were obtained in FFA (DC04-DC04-AA5182) and AFF (AA5182-DC04-DC04) combinations. As the number of aluminium layers increases, the probability of tearing increases in triple joining. Higher spread ratios were generally measured under conditions with hard materials in the upper layers and soft materials in the lower layers
Microstructural features and mechanical properties of 22MnB5 hot stamping steel in different heat treatment conditions
(Elsevier, 2020) Çavuşoğlu, Oktay; Çavuşoğlu, Oktay; Yılmazoğlu, A. G.; Üzel, U.; Aydın, H.; Güral, A.
In this study, the microstructure and mechanical properties of the 22MnB5 steel sheet were investigated in different heat treatment conditions. The steel sheet heated to 700?°C, 800?°C, and 900?°C was subjected to air cooling, water quenching, and water quenching?+?tempering procedures. Microstructural properties post-heat treatment were analyzed under an optical microscope. To determine the mechanical properties, uniaxial tensile tests, and hardness measurements were performed. The highest mechanical properties were achieved with the water quenching from 800?°C and 900?°C. The elongation value was ranged of 2-4% with the water quenching. Also, the tempering process slightly increased the elongation value.
Using Metakaolin In High Strength White Cementitious Composites,
(2014) Subaşı, Azime; Emiroğlu, Mehmet
Farklı renk ve doku özelliklerine sahip çimentolu kompozitlerin üretilebilmesi için özellikle mimari beton uygulamalarında kullanılabilecek yüksek dayanımlı beyaz çimentoya ihtiyaç duyulmaktadır. Bu çalışmada mimari beton uygulamalarında yüksek dayanımlı beyaz portland çimentosu (BPÇ) ile birlikte puzolan olarak kullanılabilecek metakaolinin (MTK) çimentolu kompozit davranışına etkisi araştırılmıştır. Çalışma kapsamında MTK, ağırlıkça %0, %5, %10, %15, %20, %25 ve %30 oranlarında CEM I 52,5 R BPÇ yerine ikame edilmiştir. Hazırlanan numuneler üzerinde MTK’nın, BPÇ nin basınç dayanımına, priz süresine, su ihtiyacına ve hacim genleşmesine etkisini belirlemeye yönelik deneyler yapılmıştır. Sonuç olarak, yüksek dayanımlı BPÇ’lerde MTK ikamesinin su ihtiyacı ve priz süresinde, %20 den sonraki ikame oranlarında önemli bir etkiye sahip olduğu belirlenmiştir. MTK ikame oranı arttıkça 28 günlük dayanım değerlerinde bir azalma olduğu, ancak 56. ve 90. günlerde MTK ikameli örneklerin puzolanik etkiden dolayı dayanım değerlerinin arttığı görülmüştür. Ayrıca MTK ikameli çimento harçlarının basınç dayanımlarının %20 oranında MTK ikamesine kadar standart değerler arasında olduğu belirlenmiştir.
The production of glass fiber reinforced polymer pipes, application areas in the sector and performance evaluation
(2014) Subaşı, Serkan; Eren, Ş.; Subaşı, Azime; Güner, Ö.
Otomotiv, havacılık, uzay ve savunma endüstrilerindeki hızlı gelişim hafif ve yüksek mukavemetli malzemelerin kullanımını gerekli kılmıştır. Bu amaçla cam elyaf takviyeli plastik kompozit malzemeler üretilmeye başlanmış ve yaygın bir şekilde kullanılmıştır. CTP’nin farklı yüklere karşı dayanımı, çok yüksek korozyon dayanımı (yapısal olarak çelik ve ahşap malzemeye göre çürüme ve paslanma olmamasından dolayı periyodik bakıma ihtiyaç duyulmaması), hafifliği, montaj ve işçilik kolaylığı, kısa zamanda imalatı gibi özelliklere sahip olması bu malzemelerin yapılarda kullanılırken diğer geleneksel malzemelere karşı üstünlüğünün bir göstergesidir. Bütün bu özelliklerinin bir sonucu olarak CTP’ler yüksek basınçlı boru üretiminde de kullanılmaktadırlar. Bu araştırmada, CTP’lerin boru üretimindeki yeri ve önemine değinilmiş, CTP boru üretiminde kullanılan hammaddeler ve özelliklerinden bahsedilmiştir. Bunun yanında, CTP boru üretim yöntemleri açıklanmış ve üretilen CTP boruların sınıflandırılması, teknik özellikleri, kısa dönem performans deney yöntemleri belirtilmiştir. Ayrıca farklı projeler için tasarlanabilecek ve çeşitli ihtiyaçlara cevap verebilen daha yüksek performanslı CTP boru üretimine yönelik önerilerde bulunulmuştur
Polyimide strengthened cement mortar
(WALTER DE GRUYTER GMBH, 2024) Poyraz, Bayram; Dayı, Mustafa
This study examined the effects of silane-modified polyimide polymer (PIS) on cement mortar. The PIS was added to replace cement in a specified ratio. Obtained results revealed that the PIS caused retardation on setting time, and accelerated UPV mostly by encapsulating unhydrated cement particles, filling pores, or reacting with C-S-H and Ca(OH)2 with shifting to Si-O vibrations. SEM results showed a good compact interface without forming considerable agglomeration and voids on the microstructure, and this improved flexural and compressive strength properties. In conclusion, silane-modified polyimide as an admixture or cement replacement can be recommended for construction industries to enhance the properties of cement mortar.
Alleviating doxorubicin-induced reproductive toxicity: protective and androgenic effects of drone larvae on sperm morphology and hormonal balance
(Springer, 2025) Ağan, Kağan; Kaya, Salih Tunç; Ağan, Aydan Fulden; Yoldaş, Pınar Ağyar; Yoldaş, Taner; Keleş, Ayşe İkinci; Kekeçoğlu, Meral
Fatty acid composition of stems, leaves, flowers, and seeds of some medicinal plants
(INNOVHUB - Stazioni Sperimentali per l'Industria S.r.l - Area Oli e Grassi, 2023) Kokten, K.; Mokhtarzadeh, S.; Cacan, E.; Kutlu, M.A.; Ozdemir, S.; Ucar, R.; Ekmekci, M.
Medicinal plant species are economically important and have many uses. In this research, the stem, leaves, flowers, and seeds of some medicinal plant species such as Lavandula intermedia, Satureja hortensis and Ocimum basilicum were analysed. The fatty acid compositions of these three different species were determined by gas chromatography of methyl esters of fatty acids. The stem, leaf, flower, and seed oils of L. intermedia contain 44.72%, 45.11%, 29.89% and 8.55% palmitic acid and 16.18%, 23.21%, 34.76% and 39.76% linolenic acid, respectively, as the main component fatty acids, while the stem, leaf, flower and seed oils of S. hortensis contain 23.11%, 11.76%, 13.32% and 6.26% palmitic acid and 31.70%, 51.74%, 47.97% and 43.79% linolenic acid, respectively, as main component fatty acids. On the other hand, stem, leaf, flower, and seed oils of O. basilicum contain 44.72%, 45.11%, 29.89% and 8.55% palmitic acid and linolenic acid 16.18%, 23.21%, 34.76% and 39.76%, respectively, as main component fatty acids. © 2023, INNOVHUB - Stazioni Sperimentali per l'Industria S.r.l - Area Oli e Grassi. All rights reserved.
Preface
(Springer International Publishing, 2022) Gürağaç, Dereli, F.T.; Ilhan, M.; Belwal, T.
[No abstract available]

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