Yazar "Turan, Kadir" seçeneğine göre listele

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    Buckling behavior of adhesively patch-repaired composite plates
    (Sage Publications Ltd, 2014) Turan, Kadir
    In this study, buckling behavior of adhesively patch repaired composite plates was investigated experimentally and numerically. Unidirectional carbon/epoxy composite plates with circular cutout were repaired with an adhesively bonded patch. Critical buckling loads of composite plates were researched without cutout, circular cutout, single patch-repaired, and double patch-repaired conditions. In addition to circular hole dimensions, patch length and adhesive thickness were used as geometrical parameters. Numerical study was performed in ANSYS finite element software three dimensionally. As a result, the critical buckling loads of single and double patch-repaired composite plates were increased from 96 and 263 ratios higher than circular-cutout composite plates. The percentile errors between experimental and numerical studies were determined from 2 to 11.5.
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    Çentikli kompozit levhaların hasar davranışlarının incelenmesi
    (Dicle Üniversitesi Mühendislik Fakültesi, 2015) Çelik, Abdullah; Turan, Kadir
    Bu çalışmada, çentikli kompozit levhaların hasar davranışları statik çekme testleriyle deneysel olarak araştırılmıştır. Sekiz tabakalı örgülü cam elyaf takviyeli epoksi reçine matrisli kompozit levhalar kullanılmıştır. Levhaya kenarlarından ve ortasından açılan çentiklerin ve fiber takviye açısı değişiminin levhanın çekme mukavemeti üzerine etkileri incelenmiştir. Fiber takviye açısının etkileri [0o ]8, [15o ]8, [30o ]8, ve [45o ]8, tabaka dizilimine sahip levhalar için araştırılmıştır. Çentik türü değişimi ise levha ortasında radyal delik (Tip 1), levha kenarında yarım daire çentik (Tip 2), levha merkezinde dairesel delik (Tip 3) ve levha kenarında u çentik (Tip 4) olmak üzere 4 farklı çentik türü için incelenmiştir. Fiber takviye açısına bağlı olarak tüm çentik türleri için hasar yüklerinin azaldığı gözlemlenmiştir. Buna ek olarak çentik türü değişiminin hasar yükleri üzerinde oldukça etkili olduğu deneysel çalışma sonuçlarından görülmektedir.
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    Design and production of new type reinforced U-profile composite panels
    (Toros University, 2024) Uslu, Merve; Kaman, Mete Onur; Yanen, Cenk; Albayrak, Mustafa; Dağ, Serkan; Erdem, Serkan; Turan, Kadir
    In aircraft design, factors such as fuel efficiency, lightness and durability are critical due to the effect of various loads. Therefore, the use of "U" profile beams, which are stronger in terms of strength, provides versatile advantages. In this study, a reinforced composite panel was designed and fabricated by adding support beams to the "U" profiles to maintain the safety and integrity of aircraft structures. Glass fiber and epoxy resin were employed in the composite production process. The vacuum infusion method was employed for composite production, with molds specifically designed for the "U" profile and "I" support beams. Following production, the compatibility of the "U" profile, "I" support beam and sub-composite base forming the composite panel was evaluated. It was determined that the produced "I" support beam constituted only 18.8% by weight of the composite panel.
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    Effect of Curing Conditions on the Interface Strength of Single-Fibre Composite Specimens
    (Carl Hanser Verlag, 2012) Solmaz, Murat Yavuz; Kaman, Mete Onur; Turan, Kadir
    The purpose of this paper is to examine the effect of curing conditions on interface strength in single-fibre composites. Test specimens produced by using polyester resin and single glass fibre were cured under four different temperatures, which were room temperature, 40 degrees C, 55 degrees C and 70 degrees C for three different curing periods, which were 1 hour, 4 hours and 8 hours. Afterwards they were subjected to tensile test. As a result of the examination under optic microscope, it has been observed that the major damage formations are in the form of matrix cracks and fibre fragments. Young modulus and therefore mechanical properties of single-fibre composite specimens improved after a treatment above 40 degrees C.
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    Effect of Fiber Orientation Angle on the Failure Mode of Pin Jointed Laminated Composite Plates
    (Pamukkale Univ, 2010) Turan, Kadir; Kaman, Mete Onur; Gur, Mustafa
    In this study, the major aim is to investigate change effects of fiber orientation angles on the failure loads and failure modes for the pin jointed laminated composite plates. In the analysis, laminated composite plates with epoxy matrix resin reinforced unidirectional carbon fibers are used. The ply arrangements are chosen [theta degrees](4) and theta; fiber reinforced angle changes from 0 degrees to 90 degrees with 15 degrees increments. The failure load and failure mode are analyzed experimentally and numerically. In the numerical analysis Ansys program is used. In the program, material properties are degraded using APDL code which is written for progressive failure analysis and contains Hashin failure criteria for laminated composite plates. In the experimental study, the maximum failure load for [15 degrees](4) laminae cofiguration, 749.917 N and minimum failure load for [60 degrees](4), 467.483 N laminae configuration are obtained. A good agreement between experimental and numerical solution is obtained.
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    Effects of Ductile Fiber Size on the Fracture Toughness of Copper/Polyester Composites
    (Sage Publications Ltd, 2010) Kaman, Mete Onur; Solmaz, Murat Yavuz; Turan, Kadir
    The objective of this study is to examine the effect of fiber size on the fracture toughness of ductile fiber reinforced composite materials. For this purpose, pull-out tests of copper fiber embedded in polyester matrix have been conducted, as a result of which load-displacement graphics for different fiber diameters and embedded lengths have been obtained. Using the derived load-displacement graphics, debonding load of each specimen has been found, and sliding shear stress, bond shear stress, and pull-out work have been calculated. Then, fracture energy increments per unit cross-sectional area have been determined. In the numeric part of the study, pull-out test was modeled using finite element package program ANSYS (11.0). With the help of this model, load-displacement graphic obtained in the test has been repeated in numeric terms. Obtained results have been presented in the form of tables and graphs and interpreted. It has been observed that the fracture energy increment increases with increase in the diameter of the copper fiber.
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    Effects of translaminar edge crack and fiber angle on fracture toughness and crack propagation behaviors of laminated carbon fiber composites
    (Walter De Gruyter Gmbh, 2024) Asan, Ahmet Murat; Kaman, Mete Onur; Dag, Serkan; Erdem, Serkan; Turan, Kadir
    In this study, the translaminar fracture toughness of carbon fiber laminated composites with different layer sequences was investigated experimentally and numerically for different crack directions. In the numerical study, first of all, the critical stress intensity factor was determined by using the M-integral method. Three-dimensional model and M-integral analysis were achieved in the ANSYS finite element package program. The non-local stress fracture criterion was used to in order to find failure curves of the materials. Then, in order to find the crack propagation directions numerically, the solid model was transferred to the LS-DYNA program and progressive failure analysis was performed. Fracture toughness decreased by 9.92 % with the change of crack angle from 15 degrees to 90 degrees. As the fiber angle changed from 0 degrees to 45 degrees, it decreased by 9.17 %. The biggest error between the experimental and numerical study results was found at alpha = 45 degrees, with a rate of 12.3 %.
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    Experimental and Numerical Analysis of Critical Buckling Load of Honeycomb Sandwich Panels
    (Sage Publications Ltd, 2010) Kaman, Mete Onur; Solmaz, Murat Yavuz; Turan, Kadir
    The critical buckling loads for various core densities and materials of honeycomb composite panels are experimentally and numerically investigated in this study. The surface plates of honeycomb composite panels are of polyester/glass fiber composite. Polyester resin-impregnated paper or aluminum is used as the honeycomb core material. Honeycomb panels with different cell sizes, but approximately the same volume, are produced and the effect of the honeycomb core density on the critical buckling load is investigated by compression tests. The critical buckling load of paper core panels is determined to be higher than that of aluminum core panels. It is seen that the buckling strength of the specimens increases by the increase of core density. As the critical buckling load exceeds a certain limit, regional core cell buckling and core crushing are seen in aluminum core panels. In paper core panels, regional cracks are seen, in addition to these failures. The study also calculates the numeric buckling loads of the panels using the ANSYS finite element analysis program. The achieved experimental and numerical results are compared with each other and the results are provided in tables.
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    Failure analysis of adhesive-patch-repaired edge-notched composite plates
    (Taylor & Francis Ltd, 2017) Turan, Kadir; Orcen, Gurbet
    In this study, failure behaviors of edge-notched composite plates which were repaired with using patch and adhesive were investigated experimentally and numerically. The composite plates had a (0 degrees/90 degrees)(3) anti-symmetric stacking sequence; the patches were obtained from the same plates and were bonded using an epoxy-based adhesive. The effects of the geometry of the notch were investigated using U-, V-, and square-shaped notches. We varied the notch geometry, investigated single-lap and double-lap repairs, and varied the patch fiber-stacking sequence. Simulations were carried out to analyze the three-dimensional failure progression using ANSYS. The failure loads of the repaired plates increased by 170-304% for single-lap repairs and 240-476% for double-lap repairs compared with the notched plates. The simulated and measured failure loads were in agreement within 0.2-23.6%.
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    Investigation failure behaviours of notched composite plates repaired with using adhesive and patch
    (Taylor & Francis Inc, 2024) Çelik, Abdullah; Turan, Kadir; Arman, Yusuf
    In this study, the damage behaviors of different type-notched composite plates repaired with composite patches were investigated experimentally and numerically. Eight-layer woven glass fiber reinforced epoxy resin matrix composite plates and epoxy-based adhesive were used as materials. Notch type's variations, adhesive thickness, patch length; double-side repair and single-side repair were used as parameter. Although the same size patch was used, the load values varied due to the different positions of the notches. Notched composite samples with the same area dimensions but different locations have different tensile strength values. Patching and bonding processes have different effects on notched samples with different tensile strength values. A feature of this study is that many parameters were compared for many samples under the same experimental conditions in order to improve repair quality and durability in an understandable way. As a result of the repair process, the failure loads were increased from 47% to 307% ratios according to parameters.
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    Investigation of mechanical and tribological properties of boric acid reinforced composite plates
    (INESEG Yayıncılık, 2021) Aydın, Taner; Turan, Kadir; Sarı, Nejat Yıldırım
    In this study, the mechanical and tribological properties of unidirectional glass fiber/polyester resin and unidirectional carbon fiber / polyester resin composite materials reinforced with boron particles have been investigated by experimental methods. Composite plates were produced by hand lay-up method using polyester resin mixed with boric acid particles (H3BO3) with a specific gravity of 1.51 g/cm3 and a molecular weight of 61.83 g/mol, which were utilized as boron particles. As particle reinforcement, 1%, 5% and 10% boron oxide polyester resin mixture was obtained. The effects of particle reinforcement on mechanical and tribological properties were investigated. As a result of the experimental studies, it was determined that, due to the increase in the particle ratio, the wear resistance increased by between the ratios 5% and 50% in some samples compared to the samples not reinforced with boric acid particles and the tensile strength improved up to 32% in some samples.
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    Investigation of mechanical behavior of reinforced u-profile composites under low velocity impact
    (Ahmet ÇALIK, 2024) Uslu, Merve; Kaman, Mete Onur; Albayrak, Mustafa; Yanen, Cenk; Dağ, Serkan; Erdem, Serkan; Turan, Kadir
    In this study, the impact resistance of reinforced composite panels with unsupported, and U profile supported by I profile was numerically examined. For this purpose, firstly, unsupported glass fiber/epoxy composite panels were designed, and then I-profile composite supports were added to these panels. The impact strength, and damage behavior of supported, and unsupported specimens under low-velocity impact were compared numerically. In the analysis, the MAT22 material card, also known as the Chang-Chang damage model for composite material, was used in the LS-DYNA program. As a result of the analysis, maximum damage load of the unsupported specimen is determined to be approximately 294 N. It was determined that by adding an I profile to the structure, the maximum damage load increased to 543 N. It was seen that the added I profile supports increased the maximum contact force of the composite structure by approximately 85%. Fiber breakage damages were observed in both supported, and unsupported specimens. However, with the use of I profile support, the damaged area was further reduced. It has been determined that under low-velocity impact, supported specimens exhibit more rigid material behavior than unsupported specimens.
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    Investigation of patch application failure behaviors according to fiber orientation difference at notched composite plates
    (Taylor & Francis Inc, 2024) Celik, Abdullah; Turan, Kadir; Arman, Yusuf
    In this study, the damage behaviors of different type notched composite plates bonded with external composite patches were investigated experimentally under static tensile test. Eight-layer woven glass fiber reinforced epoxy resin matrix composite plates and epoxy based adhesive were used as materials. Notch type, fiber orientation angle, double side repair and single side repair were used as parameter. Effects of fiber orientation angle was investigated for 0 degrees,15 degrees,30 degrees and 45 degrees. Radial notch in the center (Type I), semicircular notch on the plate edge (Type II), a circular hole in the plate center (Type III) and U notch at the edges (Type IV) have been examined for 4 different notch types. The outstanding feature of this study is that many parameters were compared for many samples under the same experimental conditions. The composite plates and patches were used from same materials. Reducing of the damage loads has been observed for all notch types depending upon the increasing of fiber orientation angle significantly. In addition, that patch application to different fiber orientation plates is quite effective on damage loads. The extension was changed depending on the notch geometry at unrepaired composite. The load increasing rate is between +%24 and +%189 for one-sided bonded repair; +%60 and +%349 for two-sided bonded repair compared to the unrepaired samples. The results of this work can serve as a guide for workers to improve repair quality and durability in an understandable way.
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    Investigation of pin joint performances of damaged composites repaired with adhesively patches
    (Springer Heidelberg, 2019) Kaman, Mete Onur; Parlamis, Abdulkerim; Turan, Kadir; Gur, Mustafa
    In this study, the failure analysis of composite plates repaired with adhesive patch was investigated experimentally and numerically. The failure analysis consisted of two steps: In the first step, the damaged composite plates used in previous studies were repaired with epoxy-based adhesive and patch. In the second step, the repaired composite plates were loaded with pin and the failure analysis was realized. The four-layered unidirectional carbon/epoxy composite plates were used as composite and patch materials. The layer configuration of the composites was selected as [0 degrees/theta degrees](s) and [0 degrees/theta degrees](2). The numerical study was carried out in ANSYS by using three-dimensional progressive failure codes. As a result of the studies, the failure loads of repaired composite plates were compared with the un-damaged plates. It was determined that the failure loads of adhesively repaired composite plates increased between 238% and 514%.
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    Investigation of the translaminar fracture behavior of the fiber-reinforced composites stitched perpendicular to their plane
    (Springer Heidelberg, 2024) Asan, Ahmet Murat; Kaman, Mete Onur; Dag, Serkan; Erdem, Serkan; Turan, Kadir
    To increase the fracture toughness, the two-dimensional laminated textiles can be stitched with fibers throughout their thickness. But the stitch properties effect the mechanical behavior of the composite plates. Because of this reason, in this study, translaminar toughness of carbon fiber composites stitched with different densities and angles is investigated for the first time, experimentally and numerically. In the experimental study, fracture tests are performed according to ASTM E1922 standard and critical load; crack tip opening displacements and fracture toughness values are determined. In the numerical study, the critical stress intensity factor is determined using the M-integral method and the displacement correlation method. Modeling and fracture toughness analyses are performed in ANSYS finite element package. In order to find the crack propagation directions numerically, the model prepared in ANSYS is transferred to the LS-DYNA program and progressive failure analysis is performed. Stitching the layered composites perpendicular to the plane has increased the fracture toughness by 23.5-80.6% for plain-woven composites and 1.41-9.38% for UD composites. Fracture toughness values have increased with increasing stitch density. This increase is highest in the specimen stitched in the longitudinal direction where the toughness increased by similar to 15.4% with 100% increase in stitch density. The highest fracture toughness is obtained with double-directional stitching with a stitch density of 1.25 mm. It is determined that the designed heterogeneous model gives more accurate results than the homogeneous model by similar to 1-6%.
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    Joint angle effect on the failure behavior of pinned joint composite plates
    (Sage Publications Ltd, 2013) Turan, Kadir
    In this study, the failure behaviors of composite plates with double-pin joints were investigated with experimental and numerical methods. The effects of joint angle, fiber orientation angle, and numerical modeling techniques on failure behavior were examined for composite plates consisting of epoxy matrix resin reinforced with woven glass fiber in four layers. The numerical study was performed in ANSYS 11.0 using two- and three-dimensional modeling techniques. Progressive failure analysis was performed by means of a subprogram. Tsai-Wu and Hashin failure criterion were used for two- and three-dimensional solutions, respectively. Material properties degradation rules were adopted for modeling the failure progress. As a result studies, a convergence ranging between 1% and 6% was obtained between the predicted and experimented failure loads. At the end of the study, it has been discovered that the failure loads, due to increment of the joint angle, cause decrease ranging between 16% and 43%.
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    Kompozit malzemeler için ilerlemeli hasar analizinde çözümü etkileyen faktörler
    (Dicle Üniversitesi Mühendislik Fakültesi, 2019) Kaman, Mete Onur; Turan, Kadir
    Fiber takviyeli kompozit malzemelerin hasarları anizotropik yapıları gereği geleneksel malzemelere göre daha karmaşık ve ayrıntılıdır. Matris ve fiberin ayrı ayrı çekme, basma ve kayma hasarlarının belirlenmesine olanak sağlayan Hashin hasar kriteri, ilerlemeli hasar analizi için kullanılır. İlerlemeli hasar analizinde; her bir elemandaki yükleme sonrası elde edilen gerilme değerleri, ilgili malzeme dayanım değerlerine göre hasar formülünde kullanılarak hasar kontrolü yapılır. Eğer elemanda hasar elde edilirse o elemana ait mekanik özellikler sıfıra yakın değerler ile çarpılarak, malzeme özellikleri indirgenir. Devamında indirgenmiş elemanlar içeren model tekrar yüklenerek hasarın ilerlemesi sağlanır. Hasar analizinde uygulanacak yüklemenin veya yer değiştirmenin belirli bir oranda artırılması gereklidir. Sonlu eleman modelindeki eleman sayısının da ayrıca optimizasyonu yapılmalıdır. Her iki durum da hasar ilerlemesini etkileyebilen faktörlerdir. Bu çalışmada çekme yükü etkisinde, ortasında dairesel delik bulunan fiber takviyeli kompozit levhalarda hasar ilerlemesini etkileyen faktörler incelenmiştir. Hashin hasar kriteri kullanılarak yapılan çalışmada levha kenarına üniform yer değiştirme uygulanarak levhada oluşan reaksiyon kuvvetleri hesaplanmıştır. Kompozit levhanın sonlu eleman sıklığı ve ilerleme adımına karşılık levhada oluşan reaksiyon kuvvetleri yer değiştirme değerleri ile birlikte grafikler halinde sunulmuştur. Uzama artışı miktarının artırılması levhada meydana gelen maksimum reaksiyon kuvvetini artırmıştır. Delik çevresinde eleman boyutunun artırılması da reaksiyon kuvvetini artırmıştır. Ancak bu artış uzama adımı sayısının artışı kadar etkili değildir.
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    Kompozit malzemelerde yapışma bağlantılarının mukavemeti üzerine yama fiber takviye açısı etkisi
    (Dicle Üniversitesi Mühendislik Fakültesi, 2016) Turan, Kadir
    Bu çalışmada; kompozit levhalarda yapışma bağlantılarının mukavemeti üzerine yama fiber takviye açısının etkileri deneysel yöntemlerle araştırılmıştır. [θo ]8 tabakalı örgülü cam elyaf takviyeli epoksi matriks reçineli kompozit levhalar epoksi bazlı yapıştırıcı kullanılarak birleştirilmiştir. Statik çekme deneyi ile yapılan deneysel çalışmada yama takviye açısının, yama uzunluğunun ve yapıştırıcı kalınlığının etkileri araştırılmıştır. Kompozit levhanın fiber takviye açısı olarak 0o ve yamanın fiber takviye açısı 0o , 15o , 30o ve 45o olarak seçilmiştir. Yama uzunluğu olarak 25.4, 38.1 ve 50.8 mm ve yapıştırıcı kalınlığı 0.2, 0.6 ve 1.0 mm olarak seçilmiştir. Bağlantı mukavemetinin yama fiber takviye açısı ile önemli oranda değiştiği belirlenmiştir. Yama uzunluğu artışının bağlantı mukavemetini % 10 ile % 45 arasında değişen oranlarda arttırdığı tespit edilmiştir. Çift yüzünden yapışmanın tek yüzünden yapışmaya oranla hasar yüklerini %73 ile % 160 arası değişen oranlarda arttığı belirlenmiştir. Yapıştırıcı kalınlığının artmasına bağlı olarak ta hasar yüklerinin %11 ile % 30 arasında değişen oranda azaldığı görülmüştür.
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    Mechanical properties of composite plates at different conditions
    (INESEG Yayıncılık, 2020) Örçen, Gurbet; Turan, Kadir; Bingöl, Sedat
    In this study; the effects of thermal aging on the mechanical properties of composite materials were investigated. In study, eight layered woven glass fiber reinforced epoxy composite plates were used. Thermal aging was performed in an electric furnace using time and temperature change parameters. The time changes were 1, 3 and 5 hours, and 50 0C, 100 0C, and 150 0C were used for temperature changes. Thermally aged composite plates, at specified time and temperature values; modulus of elasticity, poisson ratio, tensile strength, compression strength, shear modulus and shear strength were determined in fiber reinforcement direction. The results obtained were compared with the results obtained from the specimens waited at room temperature. At the end of the study, it was determined that the mechanical properties of the composite plates changed when the thermal aging temperature and temperature increased.
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    Pim Bağlantılı Tabakalı Kompozit Levhalarda Fiber Takviye Açısının Hasar Tipine Etkisi
    (2010) Turan, Kadir; Kaman, Mete Onur; Gür, Mustafa
    Bu çalışmada, pim bağlantılı tabakalı kompozit levhalarda fiber takviye açısının değişiminin hasar yükleri ve hasar tipleri üzerindeki etkileri araştırılmıştır. Analizlerde tek yönlü karbon fiberlerle takviye edilmiş epoksi reçine matriksli tabakalı kompozit levhalar kullanılmıştır. Tabaka dizilimleri [?0] olmak üzere, ?; fiber takviye açısı 00 'den 900'ye kadar 150'lik artımlarla seçilmiştir. Levhaların farklı fiber takviye açılarındaki hasar yükü ve hasar tipleri deneysel ve sayısal olarak bulunmuştur. Sayısal çalışmada Ansys programı kullanılmıştır. Tabakalı kompozit levhaların ilerlemeli hasar analizi için Hashin hasar kriteri kullanan APDL kodları yazılarak malzeme indirgemeleri yapılmıştır. Deneysel çalışmada en büyük hasar yükü 749.917 N ile [150] tabaka dizilimi için ve en düşük hasar yükü ise 467.483 N ile [600] tabaka dizilimi için elde edilmiştir. Sayısal ve deneysel çalışma sonuçlarının uyumlu olduğu tespit edilmiştir