Sürdürülebilir Kalkınma Amaçları

• 2
• 1

Araştırmacılar(3)

• Çolak, Murat
• Gavgalı, Esma
• Sekban, Hayriye Tuğba

• MakaleYalnız künye2026Scopus SJRQ2/r/bayburt/12819
  Comparative investigation of composite-metal lap joints with mono-adhesive and thermoplastic-reinforced mixed adhesive at elevated temperatures

  Erbayrak, Engin; Eker, Beril; Colak, Murat

  This study primarily examines the strength of a single lap joint having a mixed adhesive overlap consisting of a single adhesive and its thermoplastic reinforced state under varying temperatures. In the single lap joint, Titanium-Boron reinforced A356 aluminum was employed as the metal adherend, while plain woven glass fiber-reinforced epoxy (GFRE) was employed as the composite adherend. In the application of the mixed adhesive overlap, the brittle adhesives were employed in the middle section of the lap joint, while the reinforcement of the thermoplastics was employed on the adhesives at both sides of the lap joint. The single lap joints were subjected to tensile tests at 1 mm/min loading rates under room temperature and 120 °C, which is the melting point of the copolyester. In the numerical analysis, the cohesive zone model was applied in order to define the adhesives; however, elastic isotropic and orthotropic material behaviors were employed for the metal and composite adherends, respectively. Eventually, it is determined that the strength of a mixed adhesive lap joint consisting of a single adhesive and its thermoplastic reinforced state is better than a lap joint made with the mono-adhesive alone. Although literature suggests that mixed adhesive overlaps can be formed using at least two different adhesives (one ductile and one brittle), this study demonstrated that a mixed adhesive zone can be created using a single adhesive and thermoplastic reinforcement.

  İncele
• MakaleAçık Erişim2026Scopus SJRQ2/r/bayburt/11576
  Low-velocity impact analysis of metal-composite joints with grain-refined A356 and reinforced epoxy adhesive using six node pentahedron cohesive elements

  Erbayrak, Engin; Colak, Murat; Noberi, Cansu

  This study evaluates the strength of double lap joints composed of metal composite adherends and epoxy adhesive subjected to low impact energies (20 J, 40 J). The study was carried out through experimental and numerical methods to understand the strength of lap joints comprehensively. In the production of double lap joints, A356 aluminum and grain-refined aluminum adherends were used as the metal components. To refine the grain structure, titanium (Ti) and boron (B) were added to the liquid metal at a rate of 0.01% of the total metal weight (A356-TiB). The composite laminates consisted of glass/epoxy and aramid/epoxy, made with unidirectionally oriented fibers. Araldite 2015 epoxy adhesive, available in both unreinforced and copolyester-reinforced forms, was utilized to bond the metal and composite materials. In the numerical analysis of double-lap joints, the metal and composite adherends are modeled using 8-node solid elements, while the adhesive is represented by 6-node pentahedron cohesive elements. Furthermore, a surface-to-surface, two-way treatment of contact was created between the impactor and the metal adherend. Consequently, the maximum impact loads obtained from the numerical analysis are in good agreement with the experimental results for both impact energies.

  AtıfScopus4·WoS5·OpenAlex4

  İncele
• MakaleYalnız künye2026Scopus SJRQ2/r/bayburt/11231
  Identifying the optimal flexural performance of metal-composite single-lap joints with copolyester-reinforced epoxy adhesive under various loading rates using the Grey Relation Analysis

  Erbayrak, Engin; Erbayrak, Seda; Eker, Beril; Colak, Murat

  This study examines the best flexural performance of metal composite single-lap joints fabricated with copolyester-reinforced epoxy adhesives at various loading rates using the Grey Relation Analysis (GRA). The study consists of three parts. The first part involves the formation of metal composite single-lap joints and their experimental approach under different loading rates. In the experimental approach, A356 aluminum was used as the metal material with the addition of titanium (Ti) and boron (B) additives. Plain-woven glass fiber-reinforced epoxy (GFRE) and plain-woven carbon fiber-reinforced epoxy (CFRE) were served as the composite materials. The lap joints were tested in three-point bending tests under loading rates of 1, 10, and 50 mm/min, respectively. In the second part, a numerical analysis was conducted using boundary conditions similar to the experimental conditions. In the numerical analysis, a 6-node pentahedral cohesive element was utilized, representing a novel approach for modeling adhesives in finite element analysis (FEA). When experimental and numerical results were compared, a difference of 4.36% was observed between the maximum load values and 6.80% between the failure displacements. Based on these results, it can be said that the experimental results converge with the numerical results. In the last part of the study, performance rankings of metal composite joints were determined using the Grey Relational Analysis (GRA) method, which enabled us to identify the optimum joint. This systematic approach facilitated the scientific design of joints that demonstrate optimal flexural performance under various loading conditions.

  İncele
• MakaleAçık Erişim2026Scopus SJRQ3/r/bayburt/11135
  Optimization of Rotary Degassing Parameters to Improve Melt Cleanliness and Mechanical Properties in A356 Aluminum Alloy

  Kutsal, U.; Çolak, M.; Sağnak, Y.; Bardakci, S.; Ammas, G.; Sarper, G.

  Melt cleanliness is a critical factor that directly affects the quality of aluminum castings and becomes even more significant in recycling-oriented production, where high scrap utilization is inevitable. Increasing the proportion of scrap intensifies the risk of oxide films, inclusions, and gas porosity in the molten metal; therefore, efficient refining techniques are essential. In this study, the effects of rotary degassing parameters—including rotor speed, rotation time, and gas flow rate—on melt cleanliness of A356 aluminum alloy were systematically investigated. Experimental melts containing 20% primary and 80% scrap aluminum were treated under various degassing conditions using a commercial flux cleaning flux. Characterization was performed through the Reduced Pressure Test (RPT), bifilm index analysis, fluidity measurements, microstructural examinations, and mechanical testing (tensile test and Brinell hardness measurement). The results demonstrated that increasing the rotor speed from 200 rpm to 500 rpm significantly reduced both the density and bifilm indices, indicating a notable improvement in melt cleanliness. Furthermore, higher gas flow rate (10 L/min) and longer rotation time (10 min) provided additional but secondary improvements. Consequently, the optimization of rotary degassing parameters enhanced not only melt quality but also tensile strength and ductility. These findings offer practical insights for optimizing process control in recycling-based aluminum foundries.

  İncele
• MakaleAçık Erişim2025Scopus SJRQ3/r/bayburt/11721
  Effect of Fe Amount on Microstructure and Fluidity of A356 Alloy

  Durmus, M.; Dispinar, D.; Gavgali, M.; Colak, M.

  The most important factor affecting the production of quality parts with aluminum alloys is the quality of molten metal. One of the determining factors in molten metal quality is the minimization of trace impurity elements in the alloy. One of the most harmful impurities among these elements is Fe, and its amount is a determining factor in its negative effect. It is known that Fe negatively affects the quality of aluminum, causing a decrease in mechanical properties. Most of the Fe in the alloy forms intermetallic from needle-like to complex Chinese-script structures. In this study, carbon steel and stainless-steel rods were immersed in the liquid metal at casting temperatures of 700°C and 750°C in A356 aluminum casting alloy and were subjected to diffusion for 1, 2 and 5 hours. Subsequently, a 4-channel flow test mold with various section thicknesses was used. All samples were measured by measuring the liquid metal advance distances of all sections in mm. Then, microstructure analyses were performed on the obtained sections. As a result, it is observed that as Fe diffusion increases, liquid metal advancement distances decrease and Fe intermetallics form in the microstructure. © The Author(s) 2025. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

  İncele
• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/11513
  Investigation of the Effects of Filling Speed, Casting Temperature and Metallurgical Quality on Fluidity of Lamellar Graphite Cast Iron at Different Section Thicknesses

  Köse, Sami; Çolak, Murat; Şüküroğlu, Ebru Emine

  In this study, the fluidity properties of the alloy were investigated at different casting temperatures, different section thicknesses, and varying casting parameters of lamellar graphite cast iron materials. To achieve our goal, we utilized sand molds that were created with specific parameters including pouring temperature, metallurgical quality, section thickness, and fluidity test model. These molds were used for casting. Thus, the effect of fluidity properties in changing casting conditions and liquid metal advance distances at determined section thicknesses was investigated. Modeling was carried out with FlowCast casting simulation software by determining the liquid metal advance distance depending on the section thickness in the castings made in sand molds under changing casting conditions. The fluidity and advance distance of the liquid metal was determined comparatively with experimental and modeling techniques under the changing casting conditions in the parameters determined in this study. When the outcomes were examined; it was observed that different liquid metal advance distances occur at different cross-section thicknesses depending on the changing conditions.

  AtıfScopus8·WoS8·OpenAlex7

  İncele
• MakaleAçık Erişim2024/r/bayburt/16429
  A356 alüminyum alaşımının dökümünde katılaşma zamanı ve Nb ilavesinin mikroyapıya etkisinin incelenmesi

  Colak, Murat; Tokatlı, Mehmet; Yalçın, Önder; Tigli, Ahmet

  Alüminyum alaşımları hafiflik, korozyon direnci, elektrik ve ısı iletkenliğinin yüksek olması yüksek dayanım, sünek olması gibi özelliklerinde dolayı oldukça önemli bir mühendislik malzemesidir. Bu sebeple; otomotiv, havacılık, savunma, uzay endüstrisi, makine imalat, gıda endüstrisi gibi birçok alanda yaygınca kullanım bulmaktadır. Özellikle otomotiv sanayi ve yüksek teknoloji gereksinimi olan birçok sektörde kullanımı artmakla birlikte kalite gereksinimleri de artmaktadır. Alüminyum döküm alaşımlarından kalite beklentisindeki artışa bağlı olarak farklı alaşım elementi ilaveleri ile dökümler yapılması ve üretimde yeni teknoloji kullanımları üzerinde çalışmalar devam etmektedir. Bu çalışmada A356 alüminyum döküm alaşımına %0.03, %0.06 ve %0.1 Niyobyum ilavesinin değişen kesitler içeren kokil kalıba dökümünde mikroyapı üzerindeki etkileri incelenecektir. Çalışmada ergitme, sıvı metal temizleme, kokil kalıba döküm, metalografik numune hazırlama, mikroyapı inceleme ve imaj analiz teknikleri kullanılmıştır. Sonuçlar incelediğinde katılaşma zamanına ve Nb ilave miktarına bağlı olarak döküm mikro yapılarında değişimler olduğu gözlenmiştir.

  AtıfOpenAlex1

  İncele
• MakaleAçık Erişim2024/r/bayburt/16380
  Investigation of The Effect of Molding Material Difference on Design in GGG70 Ductile Cast Iron Production

  Colak, Murat; Keskin, Muhammet Emin; Durmuş, Melek; Şekerden, Mete

  The casting process involves filling a prepared mould cavity with molten metal, which takes the shape of the container. While the liquid metal takes the shape of the container it is in, the method is attractive, while the volumetric changes during the liquid-solid transformation reveal the importance of moulding design for the manufacture of solid parts. Especially in cast irons, moulds with the same design may produce different results depending on the changing casting and foundry conditions because the volumetric change that occurs during the solidification of ductile cast irons is affected by many parameters and develops differently than in steel and aluminium castings. This study used model wet and resin molding materials to create single and double-riser moulding and castings with different section thicknesses. The importance of the type of mold material used in castings and the number of feeders for the robust production of the cast part was evaluated using experimental and modeling techniques. When the results were examined, it was seen that the shrinkage risk was lower with resin mould than with green sand moulding. In addition, depending on the riser connection point, the importance of the riser neck has emerged.

  İncele
• Kitap BölümüAçık Erişim2023/r/bayburt/11808
  Trajectory Tracking Control of an Unmanned Ground Vehicle Based on Fractional Order Terminal Sliding Mode Controller

  Sekban, Hayriye Tuğba; Başçi, Abdullah

  In this chapter, fractional order terminal sliding mode control (FOTSMC) method, which is a hybrid control approach, is used to improve the trajectory tracking control performance of an unmanned ground vehicle (UGV). First, a kinematic controller design has been carried out to estimate the linear and angular velocities that will stabilize the vehicle asymptotically. Then, FOTSMC, which is a hybrid control method that combines the advantages of fractional control and terminal sliding mode control methods, is proposed to perform vehicle reference velocities tracking. In addition, terminal sliding mode control (TSMC) and sliding mode control (SMC) methods are used for trajectory tracking control of the same vehicle to demonstrate the performance of the proposed controller. Simulation results show that the proposed controller performs trajectory tracking with smaller error and lower amplitude chattering compared to TSMC and SMC.

  • 
  İncele
• MakaleAçık Erişim2023Scopus SJRQ3/r/bayburt/11751
  Correlation Between K-value, Density Index and Bifilm Index in Determination of Liquid Al Cleanliness

  Tigli, A.; Tokatli, M.; Uslu, E.; Colak, M.; Dispinar, D.

  Aluminum alloys are widely used in the industry thanks to its many advantages such as light weight and high strength. The use of this material in the market is increasing day by day with the developing technology. Due to the high energy inputs in the primary production, the use of secondary ingots by recycling from scrap material are more advantageous. However, the liquid metal quality is quite important in the use of secondary aluminum. It is believed that the quality of recycled aluminum is low, for this purpose, many liquid metal cleaning methods and test methods are used in the industry to assess the melt cleanliness level. In this study, it is aimed to examine the liquid metal quality in castings with varying temperature using K mold. A206 alloy was used, and the test parameters were selected as: (i) at 725 °C, 750 °C and 775 °C casting temperatures, (ii) different hydrogen levels. The hydrogen level was adjusted as low, medium and high with degassing, as-cast, and upgassing of the melt, respectively. The liquid metal quality of the cast samples was examined by the K mold technique. When the results were examined, it was determined that metal K values and the number of inclusions were high at the as-cast and up-gas liquid with increasing casting temperatures. It has been understood that the K mold technique is a practical method for the determination of liquid metal quality, if there is no reduced pressure test machine available at the foundry floor.

  AtıfScopus7·WoS6·OpenAlex7

  İncele