11 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 10 / 11
Öğe Behaviour of bi adhesive in double strap joint with embedded to bending(Journal of Theoretical and Applied Mechanics, 2015-06-15) Adin, Hamit; Temiz, Şemsettin; Sülü, İsmail YasinIn this study, behaviour of bi-adhesive used in the repair of damaged parts was analyzed, using the finite element method. In a double-strap joint with an embedded patch, patch is embedded into the adherents for structural requirements. In addition, to increase the strength of the joint, two adhesives are used to bond the adherents. This approach reduces stress concentration at the overlap ends, increases the load capacity and delays the failure. These effects give rise to higher joint strength. For this purpose, a stiff adhesive, FM73 produced by Cytec Fiberite, was applied in the middle portion of the overlap, while a softer adhesive, SBT9244 from 3M, was applied towards the edges, prone to stress concentrations. Non-linear finite element analyses were carried out to predict the failure loads, to assist with the geometric design and to identify effective ratios of sizes to maximize joint strength. Key words: Bi-adhesive, double-strap joints, finite element analysis, mechanical properties, stress analysis, failure loadsÖğe Effect of welding parameters on microstructure and mechanical properties of AA7075/AA5182 alloys joined by TIG and MIG welding methods(SpringerLink, 2020) Çelik, Yahya Hışman; Temiz, Şemsettin; Çetkin, EdipIn this study, V and X welding grooves were opened to the forehead positions of the AA5182 and AA7075 aluminum alloy pairs and these alloy pairs were joined with tungsten inert gas (TIG) and metal inert gas (MIG) methods. Three diferent welding currents were used in joints. Gas fow rates of 12 and 17 l/min at the TIG welding and wire feed rates of 38 and 45 cm/min at MIG welding were selected. The efect of the welding grooves, welding current, gas fow rate and wire feed rate on microstructure and mechanical properties were investigated. Microstructures of welding zones were analyzed by an optical microscope and a scanning electron microscope (SEM). Vickers hardness of these zones was also measured. In addition, tensile and fatigue tests were carried out. Fracture mechanisms of failed specimens were conducted after the tensile tests were examined by using SEM. The highest hardness, tensile and fatigue strengths were obtained from the alloy pairs joined by opening X welding groove with TIG welding method. These values were 89 HV, 262.87 MPa, and 131.5 MPa, respectively. Similarly, the lowest tensile and fatigue strengths were obtained from the alloy pairs joined by opening V welding groove in the TIG welding method. These values were, respectively, 94.48 MPa and 19.1 MPa. However, the minimum hardness value was measured as 58 HV from the alloy pairs joined by opening V welding groove with MIG welding methods. In addition, it was observed on the fracture surfaces that the grain distributions and mechanisms difered depending on the welding methods, welding groove, and welding parameters.Öğe Sürtünme karıştırma kaynak yöntemi ile birleştirilmiş AA5182/AA7075 alaşım bağlantılarının mekanik özelliklerinin incelenmesi(Dicle Üniversitesi, 2019-06-20) Çelik, Yahya Hışman; Temiz, Şemsettin; Çetkin, EdipBu çalışmada farklı özelliklere sahip AA5182 ve AA7075 alüminyum alaşımları, sürtünme karıştırma kaynağı (SKK) yöntemiyle alın pozisyonunda birleştirilmiştir. Yapılan birleştirmelerde karıştırıcı ucun dönme devri, kaynak ilerleme hızı ve karıştırıcı uç geometrisi değiştirilerek farklı mekanik ve mikroyapı özelliklerine sahip birleştirmeler elde edilmeye çalışılmıştır. SKK yöntemi ile birleştirilen kaynaklı bağlantılarda kaynak ilerleme hızının, karıştırıcı ucun dönme devrinin ve uç geometrisinin mekanik davranışlar üzerine olan etkisini tespit etmek amacıyla numunelere çekme testi uygulanmıştır. Ayrıca taramalı elektron mikroskobu (SEM) kullanılarak çekme testi sonucunda kırılan numunelerin yüzey mekanizmaları belirlenmiştir. Çekme test sonuçlarından elde edilen verilerden, AA5182 ve AA7075 alüminyum alaşımlarının SKK yöntemiyle ile birleştirilmesinde, uygun dönme devrinin, ilerleme hızı ve uç geometrisi kombinasyonunun kaynak kalitesini arttırdığı görülmüştür. Ayrıca konik helisel uç kullanılarak 980 dev/dk dönme devri ve 108 mm/dk ilerleme kaynak parametreleri ile birleştirilen numunelerin çekme test deneylerinde en yüksek hasar kuvveti 16468 N olarak elde edilmiştirÖğe Experimental determination of the static and fatigue strength of theadhesive joints bonded by epoxy adhesive including different particles(Elsevier, 2018-12) Adin, Hamit; Saraç, İsmail; Temiz, ŞemsettinBecause of their many advantages, adhesively bonded joints are intensively used in many engineeringfields. So,the mechanical research of the adhesively bonded joints is very important to use these joints safely. There aremany studies performed by researchers to investigate the mechanical properties of the adhesive joints. There hasbeen a considerable interest in nanoparticles added to structural adhesives recently because nanoparticles im-prove the mechanical properties of adhesives and joints. In this paper, different nanoparticles reinforced byepoxy adhesive, and neat adhesive were used to produce single lap joints. The static and fatigue strengths ofsingle lap joints incorporating nanoparticles were compared to those without nanoparticles. Experiments wereperformed at 20 mm overlap length. DP460 epoxy was used as the adhesive material, and nano-Al2O3, nano-TiO2and nano-SiO2were used as the nanoparticles; and AISI 304 stainless steel plates were used as the adherents. Theresults of the experimental research revealed that average failure load increased significantly in nanoparticle-reinforced adhesive joints. The highest average failure load was obtained with 4 wt% nano-Al2O3in epoxyadhesive. Fatigue tests were performed at 10 Hz frequency, and 0.1 loading ratio (R). When the fatigue testresults were examined, it was observed that the addition of the nano-Al2O3and nano-SiO2to the adhesiveincreased fatigue strength of the adhesive joints, on the other hand, the addition of the nano-TiO2to the adhesivereduced fatigue strength of the adhesive joints.Öğe Experimental determination of the mechanical properties of adhesive joints bonded epoxy adhesive included Al2O3 nanoparticule(European Journal of Technic, 2016-08-01) Adin, Hamit; Saraç, İsmail; Temiz, ŞemsettinYapıştırma bağlantılarında, yapıştırıcı içerisine katılan nanopartiküllerin, bağlantıların mekanik özelliklerine etkisi ile ilgili araştırmalar son zamanlarda dikkat çekmektedir. Bu çalışmada; epoksi yapıştırıcı içerisine % 2 oranında Al2O3 nanopartikül katılarak ve katkısız epoksi yapıştırıcı kullanılarak tek tesirli bindirme bağlantıları oluşturulmuş ve bağlantıların mekanik özellikleri çekme yükü altında 20 mm, 25 mm ve 30 mm bindirme boylarında deneysel olarak incelenmiştir. Deneysel çalışmalarda DP460 epoksi yapıştırıcısı, Al2O3 nanopartikülleri ve yapıştırılan malzeme olarak St-37 çeliği kullanılmıştır. Deneylerden elde edilen sonuçlar incelendiğinde; % 2 Al2O3 nanopartikül katkılı yapıştırıcıların kullanılmasıyla 20 mm ve 30 mm bindirme boylu bağlantılarda genel olarak hasar yükü azalmıştır. Ancak 25 mm bindirme boyunda % 5 oranında bir artış görülmüştür. Ayrıca nanopartikül ilavesi bağlantıların uzama kapasitelerine azaltıcı yönde etki yapmıştır.Öğe Kompozit yama ile tamir edilen eliptik delikli alüminyum levhalarda yama boyutu etkisinin araştırılması(Kilis 7 Aralık Üniversitesi, 2016) Adin, Hamit; Temiz, Şemsettin; Şişman, Abdullah; Ergün, Raşit KorayÖğe A research on the fatigue strength of the single-lap joint joints bonded with nanoparticle-reinforced adhesive(Welding in the World, 2021-01) Adin, Hamit; Saraç, İsmail; Temiz, ŞemsettinNano-technological developments, which have made significant progress in recent years, have significant impact on the science of adhesives. Therefore, in our study, the static and fatigue strengths of single-lap joints (SLJs) incorporating nanoparticles were compared to those without nanoparticles. Steel plates were used in the adhesive joints. The results revealed that average damage load increased significantly in nanoparticle-reinforced adhesive joints. The highest damage load was obtained with 4 wt% nanoAl2O3 in epoxy adhesive. As the average damage load increased, the locus of damage changed from interfacial to the mixture of interfacial and cohesive. Also, fatigue strengths of the joints increased when the adhesive joint had nano-Al2O3 and nano-SiO2, and decreased when the adhesive joint had nano-TiO2.Öğe Farklı çentik geometrisine sahip alüminyum levhaların alüminyum yamalarla tamirinin araştırılması(Batman Üniversitesi, 2016-12-28) Ergün, Raşit Koray; Temiz, Şemsettin; Çetkin, EdipYapıştırma kaynak, lehim, perçin ve cıvata gibi farklı birleştirme yöntemlerine alternatif olarak kullanılan bir imalat yöntemidir. Özellikle bağlantı güvenirliliğinin önemli olduğu havacılık, uzay, otomotiv, inşaat ve deniz endüstrilerinde yapıştırıcıların kullanımı giderek artmaktadır. Yapıştırma yöntemi ile farklı özellik ve kalınlıklardaki malzemelerin bağlantılarında düzgün bir gerilme dağılımı sağlanarak, daha ekonomik ve daha hafif bir şekilde birleştirilebilir. Bu çalışmada, yapıştırma yöntemi ile farklı çentik geometrisine sahip parçaların tamirinin yapılması amaçlanmıştır. Bu amaçla, 2mm kalınlık, 25mm, 30mm, 35mm genişlik ve 112.5mm uzunluğa sahip alüminyum levhaların çentik ağız derinliği a=2mm, 4mm, 6mm ve çentik ağız yüksekliği b= 8mm olarak çentikler açılmış, daha sonra bu çentikli numuneler ebatları 40mm-25mm, 40mm-30mm, 40mm-35mm olan alüminyum yamalarla tamir edilmiştir. Elde edilen levhaların mekanik davranışları deneysel olarak incelenmiştir. Yama ile tamir edilmiş malzemelerin hasar yüklerinin yamasız malzemelerden daha fazla olduğu tespit edilmiştir.Öğe Microstructure and mechanical properties of AA7075/AA5182 jointed by FSW(Journals & Books, 2019-06) Çelik, Yahya Hışman; Çetkin, Edip; Temiz, ŞemsettinIn this study, AA7075 and AA5182 aluminium alloys were joined using different rotation speeds (980, 1325 and 1800 rpm), feed rates (108 and 233 mm/min) and stirred pins having two different geometries (conical helical and triangular). Microstructures of welding joints were examined by an optical microscope and a scanning electron microscope (SEM). Vickers hardness measurements were performed in the welding zone of samples removed from each welded plate. Tensile and fatigue tests were also applied to the test specimens taken from the welded plates. After the tensile tests, the surface fractures and possible welding defects were scanned via SEM. The best mechanical properties were obtained when conical helical shape stirrer pins were used. The values were 265 MPa for tensile test and 159 MPa for fatigue test. The hardness value was very close to each other and varied depending on the rotation speed. The highest hardness value was determined as 87 HV in the weld center at 1325-rpm rotation speed.Öğe Investigation of the effect of use of Nano-Al2O3, Nano-TiO2 and Nano-SiO2 powders on strength of single lap joints bonded with epoxy adhesive(Elsevier, 2019-06) Adin, Hamit; Temiz, Şemsettin; Saraç, İsmailIn this study, single lap joints were formed by adding nano-Al2O3, nano-TiO2and nano-Al2O3powders in variousproportions to the epoxy adhesive and using the additive-free epoxy adhesive; and also the mechanical prop-erties of the connections were experimentally investigated at 20, 25, 30, 50 and 70 mm overlap lengths undershear load. In the experimental work, DP460 epoxy adhesive was used as adhesive and AISI 304 stainless steelplate as adherent material. When the results obtained from the experiments were examined, it was revealed thatthe average damage load in connection with the use of nanoparticle-added adhesives increased considerably ingeneral. As a result of the experiments, the most effective nanoparticle in increasing the failure strength of theadhesive joints with nano-Al2O3particles and the maximum failure strength increase rate was 20 mm in overlaplength and 97% in 4 wt% nano-Al2O3reinforced specimens. It was also found that the nanoparticle strain was animportant parameter in the tensile strength of the adhesive joints. In addition, it has been found that the additionof nanoparticles into the adhesive increases the elongation of the joints. When the adhesion surfaces of thesamples were examined as in the case of plain adhesives, damage was observed as adhesion separation whilenanoparticle reinforcement was observed as a mixture of adhesion and cohesion.
