Yazar "Erbayrak, Engin" seçeneğine göre listele

Listeleniyor 1 - 11 / 11
  • Küçük Resim Yok
    Öğe
    Determination of flexural properties of hybrid composite using Cowper-Symonds rate-dependent material model
    (Sage Publications Ltd, 2021) Erbayrak, Engin
    This study addressed to determine the flexural properties of hybrid composite laminates (HCAFRE) under the strain rate sensitivity. The hybrid composite laminate was formed as consecutive stacking of a sequence of plain woven carbon fiber reinforced epoxy (CFRE) and a plain-woven aramid fiber reinforced epoxy (AFRE) laminates. The flexural tests were carried out at four different strain rates (0.01, 0.11, 0.55, 1.1 s(-1)) to determine the strain rate sensitivity of the HCAFRE. Moreover, the strain rate sensitivity of CFRE and AFRE was also determined individually. The effect of different fiber orientations (0 degrees, 45 degrees, and 90 degrees) on the flexural properties of the composite laminates were also investigated at the scope of this study. In numerical analysis, composite laminates (CFRE, AFRE, and HCAFRE) were constituted in LS-DYNA finite element program using the Cowper-Symonds material model (MAT 112) which includes strain rate dependency. Consequently, it was seen that the experimental and numerical results were indicated a similar tendency to each other. Therefore, it was understood that the Cowper-Symonds material model is suited for the flexural behavior model of composite laminates under different strain rates.
  • Küçük Resim Yok
    Öğe
    Determination of the impact damage threshold point of composite material using fuzzy-base taguchi method
    (University of Kuwait, 2020) Erbayrak, Seda; Erbayrak, Engin
    In this study, the impact damage threshold point of composite materials was determined using the optimum design parameters obtained from the Fuzzy Based Taguchi Method (FBTM). It is known that both Taguchi and Fuzzy methods provide optimization of design parameters yet, in Taguchi method, optimization of design parameters is not sufficient in solving multi response optimization problem. Therefore, Fuzzy Logic system was combined with the Taguchi system for working out the multi-response optimization problem. In this study, the low velocity impact damage analyses were performed in an LS-DYNA 3D explicit finite element program. ASTM D7136/D7136M standard was used during the low velocity impact analyses. In explicit finite element analyses, contact algorithms were executed to observe better damage zone shapes. Furthermore, the control parameters (termination and computation time step) were tuned to provide perfect correlation with the force-energy-time histories. The study concluded that Fuzzy Based Taguchi Method (FBTM) is much more capable of optimizing the design parameters that predict the impact damage threshold point of the composite material. © 2020 University of Kuwait. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Determination of the Impact Damage Threshold Point of Composite Material Using Fuzzy-Base Taguchi Method
    (Academic Publication Council, 2020) Erbayrak, Seda; Erbayrak, Engin
    In this study, the impact damage threshold point of composite materials was determined using the optimum design parameters obtained from the Fuzzy Based Taguchi Method (FBTM). It is known that both Taguchi and Fuzzy methods provide optimization of design parameters yet, in Taguchi method, optimization of design parameters is not sufficient in solving multi response optimization problem. Therefore, Fuzzy Logic system was combined with the Taguchi system for working out the multi-response optimization problem. In this study, the low velocity impact damage analyses were performed in an LS-DYNA 3D explicit finite element program. ASTM D7136/D7136M standard was used during the low velocity impact analyses. In explicit finite element analyses, contact algorithms were executed to observe better damage zone shapes. Furthermore, the control parameters (termination and computation time step) were tuned to provide perfect correlation with the force-energy-time histories. The study concluded that Fuzzy Based Taguchi Method (FBTM) is much more capable of optimizing the design parameters that predict the impact damage threshold point of the composite material.
  • Küçük Resim Yok
    Öğe
    Determination of the Natural Frequency Change of Different Bayburt Stone (Tüfit) Sizes During the Transportation in the Screw Conveyor
    (2023) Erbayrak, Engin; Kırar, Burhan
    The mechanism that carries the powder or tiny granular particles with the rotational movement of the spiral shaft is called the screw conveyor. The working principle of screw conveyors is transporting dust particles due to rotating the screw shaft placed in a cylindrical pipe with engine power. The transport process transfers the powder particles to the conveyor from the feed pipe at the top of the mechanism to the wings (helix) of the helix shaft. In this study, a scaled prototype of the screw conveyor was produced. Different Bayburt stone (Tüfit) sizes were transported utilizing the prototype, and changes in the natural frequency of the screw conveyor were measured during particle transportation. The natural frequency value of the fine particles of Bayburt stone is determined as the lowest (15.67 Hz), and the natural frequency value is determined as high in the coarse particles (20.32 Hz). This is expected for this test, which is an example of forced vibration. The increase in the weight of the particles with increasing volumetric size also causes an increase in the external force values they create. The increase in mass value and the change in dynamic loads increased the natural frequency value for forced vibration. It has been observed that the natural frequency values increase in the range of 10-15 percent with the increase in particle sizes from fine to coarse. As a result, it has been determined that the size of the particles carried on the conveyor is important in determining the natural frequency of the system.
  • Küçük Resim Yok
    Öğe
    Effect of loading rate on cohesive parameters of the adhesive Araldite 2015
    (Carl Hanser Verlag, 2020) Erbayrak, Engin; Ozer, Halil
    This study addresses the effect of loading rates on cohesive parameters and microstructural composition of the Araldite 2015 adhesive. Double Cantilever Beam (DCB) samples were tested under the loading rates of 1, 5, 10, 20, 100 and 200 mm x min(-1). The Park-Paulinho-Roeser model (PPR model) was used to get cohesive parameters. In modelling of the softening behavior, inverse analyses were performed using the date obtained from the PPR softening curves. It was seen that the fracture energy and cohesive parameters are decreasing with increasing the loading rate. However, there seems to be a transition region where the fracture energy nearly remains constant. Microstructural analyses were implemented in order to study the effects of the loading rates on the characteristics of the fracture surfaces. It was concluded that the loading rates greatly influence the distribution of micro-voids in the epoxy matrix. Moreover, the presence of voids in epoxy matrix improved the plastic deformation around the crack tip and increased the fracture toughness.
  • Küçük Resim Yok
    Öğe
    An Experimental and Numerical Determination on Low-Velocity Impact Response of Hybrid Composite Laminate
    (Springer, 2021) Erbayrak, Engin; Yuncuoglu, Ercument Ugur; Kahraman, Yusuf; Gumus, Beril Eker
    In this study, experimental and numerical investigations were carried out in order to determine the mechanical properties and impact response of hybrid composite laminate. The hybrid composite laminate was formed from plain woven carbon fiber reinforced epoxy (CFRE) and plain woven glass fiber reinforced epoxy (GFRE) fiber using VARTM (vacuum-assisted resin transfer molding) process. The mechanical properties of the hybrid composites were determined using tensile test device with a 1 mm/min loading rate at room temperature. In addition, hybrid composites were subjected to low-velocity impact test under different impact energy levels (10, 20, 30, 40 J) for determining the impact response. Moreover, mechanical properties and impact responses of CFRE and GFRE laminates were also determined to compare to those of hybrid composite (HCGFRE). Microstructure analysis was performed to investigate the damage surfaces of the fiber and matrix in the composite material subjected to impact and tensile forces. In numerical analyses, composite damage model (Mat 54) was utilized in LS-DYNA(R)explicit finite element program to simulate the impact behavior of CFRE, GFRE and HCGFRE laminates. Consequently, the tensile test results showed that hybrid composite laminate behaved more ductile than carbon composite laminate and it exhibited more brittle behavior than glass composite laminate. Also, it was determined that absorbed energy and impact load capacity of HCGFRE composite laminate are between absorbed energy and impact load capacity of CFRE and GFRE composite laminate. It was determined that numerical results indicate a similar tendency with the experimental results.
  • Küçük Resim Yok
    Öğe
    Experimental study of adhesively bonded joints with dissimilar composite laminates under different loading rates and ambient temperatures
    (Springer Heidelberg, 2023) Erbayrak, Engin; Gumus, Beril Eker; Yuncuoglu, Ercument Ugur
    An experimental study of the single-lap joints at different loading rates and ambient temperatures was investigated. In the experiment, a single lap joint was formed using plain woven glass fiber reinforced epoxy (GFRE) laminates, plain woven aramid fiber reinforced laminates (AFRE), and Araldite 138 M / HV998 epoxy adhesive. The composite laminates were produced using Vacuum-Assisted Resin Transfer Molding (VARTM) process. Adhesively bonded joints were created using similar and dissimilar adherends. Experiments were carried out under different loading rates (1 mm/min, 10 mm/min, 50 mm/min, 100 mm/min) and ambient temperatures (23 degrees C,60 degrees C,100 degrees C). Stress-strain graphs were obtained for each experimental condition. It is seen that the maximum stress values increase as the loading rate increases in all single lap joints at all different temperatures. However, in all single lap joints, at all different loading rates, the maximum stress value decreases as the ambient temperature increases.
  • Küçük Resim Yok
    Öğe
    Investigations of low-velocity impact behaviour of single-lap joints having dissimilar hybrid composite adherends through cohesive zone model approach
    (Taylor & Francis Ltd, 2022) Erbayrak, Engin
    The low-velocity impact behavior of single-lap joints was investigated in this study. In single-lap joints, woven carbon fiber reinforced epoxy (CFRE) and plain woven glass fiber reinforced epoxy (GFRE) laminates as well as a hybrid composite laminate (HCGFRE), which is formed by stacking carbon and glass composite laminates, are used as adherends. Araldite 2011 and Araldite 138 M/HV998 epoxy adhesives were used with different mechanical properties for joining similar and dissimilar composite adherends. Low-velocity impact tests were carried out with 40 J impact energy. Reaction force-time and impact energy-time graphs were obtained from the experimental study as impact response. In numerical analyses, the damage approach of composite adherend was modeled using composite stress-based failure model (Mat 59) and adhesives were modeled utilizing a mixed-mode cohesive zone model (Mat 138) that existed in LS-DYNA explicit finite element software. It was seen that the numerical results indicated a similar tendency with the experimental results due to the modeling of the adhesives using the proper cohesive zone model, the application of correct boundary conditions, and the selection of the correct contact type.
  • Küçük Resim Yok
    Öğe
    Investigations of Strain Rate Effects on the Mechanical Properties of Hybrid Composite Laminate Under Varying Temperatures
    (Springer Heidelberg, 2020) Erbayrak, Engin; Gumus, Beril Eker; Yuncuoglu, Ercument Ugur; Kahraman, Yusuf
    The mechanical behavior of hybrid composite laminates under varying strain rates and temperatures was investigated in this study. The hybrid composite laminate is constituted as a sequential stacking sequence of plain-woven carbon-fiber-reinforced epoxy (CFRE) and plain-woven glass-fiber-reinforced epoxy (GFRE) laminates. Vacuum-assisted resin transfer molding (VARTM) process was used to fabricate the composite laminates. Hybrid composite laminates (HCGFRE) were tested under four different strain rates (0.05 min(-1), 0.5 min(-1), 2.5 min(-1), 5 min(-1)) and three different temperatures (RT, 60 degrees C, 100 degrees C). Microstructure analysis was performed to observe the voids, fiber delamination and matrix failure occurring in the composite laminate. In numerical analyses, continuum damage mechanics material model (MAT 58) was utilized in LS-DYNA(R)explicit finite element program to simulate the mechanical properties of CFRE, GFRE and HCGFRE laminates. It was determined that the tensile strength of all composite laminates is increasing by increasing the strain rates in all temperatures. The continuous damage mechanics material model (MAT 58) was found to be suitable for simulating woven composite laminate under different strain rates and temperatures. In microstructural study, it was not observed significant changes in the microstructure of composite laminates by changing strain rates.
  • Küçük Resim Yok
    Öğe
    Numerical investigation of the Mode I/Mode II fracture behavior of the hybrid composite joints with a hybrid bondline
    (Elsevier B.V., 2023) Erbayrak, Engin
    In this study, the fracture behavior of fracture characterization bonded joints consisting of hybrid composite adherends and hybrid bondlines under Mode I and Mode II loadings were investigated numerically. Numerical analysis was performed using LS-DYNA. Hybrid composite laminates (HCGFRE) obtained by sequencing plain woven glass fiber reinforced epoxy (GFRE) and plain woven carbon fiber reinforced laminates (CFRE) as adherends. Araldite AV138M and Araldite 2015 epoxy adhesives were also used to create the hybrid bondline. Mode I and mode II fracture behaviors were determined by numerical modeling of the Double Cantilever Beam (DCB) and End Notched Flexural (ENF) tests, respectively. In the numerical model, firstly, the fracture parameters of the relevant adhesives were found in the literature, and verification was made utilizing the numerical model. Then, the fracture behavior in both two modes was examined by forming a hybrid bondline. In the literature, there are restricted studies examining the fracture behavior of fracture characterization bonded joints with hybrid bondlines. Additionally, it is not encountered any study determining the both mode I and mode II fracture behavior of composite fracture characterization bonded joints with hybrid bondlines. Therefore, it is thought that this study will gain significant novelties to the existing literature. © 2023 The Author(s)
  • Küçük Resim Yok
    Öğe
    Sandviç Kompozit ve Metal Plakalar ile Oluşturulan Tek Bindirmeli Yapıştırma Bağlantılarının Mekanik Özelliklerinin Deneysel ve Nümerik Yaklaşım ile Belirlenmesi
    (2021) Erbayrak, Engin
    Bu çalışmada, farklı malzemeler kullanılarak oluşturulan tek bindirmeli yapıştırma bağlantılarının mekanik\rözellikleri deneysel ve nümerik yaklaşım ile belirlenmiştir. Tek bindirmeli yapıştırma bağlantılarında\rplaka malzemesi olarak çelik, alüminyum ve alüminyum sandviç kompozit malzeme, yapıştırıcı olarak ise\rAraldite 2015 epoksi yapıştırıcı kullanılmıştır. Aynı malzemeye sahip plakalar kullanılarak elde edilen yapıştırma\rbağlantılarının yanı sıra, farklı malzemelere sahip plakalardan oluşan yapıştırma bağlantıları da bu\rçalışma kapsamında incelenmiştir. Deneysel yaklaşımda çekme testleri 1 mm/dak çekme hızında gerçekleştirilmiştir.\rDeneysel yaklaşım sonunda her bir yapıştırma bağlantısının gerilme-birim şekil değiştirme\rgrafikleri belirlenmiştir. Ayrıca, plaka malzemesi olarak kullanılan alüminyum sandviç kompozit malzeme\rde yer alan polietilen polimerinin XRD testi ile karakterizasyonu yapılmıştır. Nümerik yaklaşımda, deneysel\ryaklaşımda kullanılan tek bindirmeli yapıştırma bağlantı geometrisi Ansys sonlu elamanlar programında\roluşturulmuştur. Model oluşturulurken yapıştırıcı ile plakalar arasında non-lineer kontak kurulmuş ve\rdeney şartlarını karşılayan sınır şartları uygulanmıştır. Bindirme bağlantılarının non-lineer modellenmesi,\rdoğru sınır koşullarının uygulanması ve doğru temas tipinin seçilmesi nedeniyle nümerik sonuçların deneysel\rsonuçlarla benzer bir eğilim gösterdiği görülmüştür.