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Öğe Comparison of Hashin and Puck criterions for failure behavior of pin loaded composite plates(John Wiley and Sons Inc, 2024) Doğan, Caner; Kaman, Mete Onur; Erdem, Serkan; Albayrak, MustafaIn this study, the failure behavior of carbon fiber-reinforced pin-jointed composite plates were analyzed for different criteria. For this purpose, composite plates with a single and double pin joints were prepared from four layers carbon fiber composites. The effect of pin number, pin position on plate damage load and type was investigated experimentally and numerically under the tensile test. Numerically, progressive damage analysis was performed using Hashin and Puck failure criteria, and the approach rates to the experimental results were determined. It was observed that the experimental results obtained for single pin joint composites and the numerical data obtained using the Puck damage criterion were at least 87 % compatible, and this rate was determined as 85 % for the Hashin failure criterion. For the double pin jointed composites, it was seen that the experimental results and the results of the Puck damage criterion were compatible with at least 90 %, and this rate was obtained as 84 % for the Hashin failure criterion. The dominant damage type seen in the specimen is matrix shear and fiber compression according to the Hashin damage criterion, inter fiber failure in transverse tension for Puck. © 2024 Wiley-VCH GmbH.Öğe 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, KadirIn 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.Öğe Effect of Curing Conditions on the Interface Strength of Single-Fibre Composite Specimens(Carl Hanser Verlag, 2012) Solmaz, Murat Yavuz; Kaman, Mete Onur; Turan, KadirThe 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.Öğe Effect of Fiber Orientation Angle on the Failure Mode of Pin Jointed Laminated Composite Plates(Pamukkale Univ, 2010) Turan, Kadir; Kaman, Mete Onur; Gur, MustafaIn 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.Öğe Effects of Ductile Fiber Size on the Fracture Toughness of Copper/Polyester Composites(Sage Publications Ltd, 2010) Kaman, Mete Onur; Solmaz, Murat Yavuz; Turan, KadirThe 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.Öğe 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, KadirIn 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 %.Öğe Experimental and Numerical Analysis of Critical Buckling Load of Honeycomb Sandwich Panels(Sage Publications Ltd, 2010) Kaman, Mete Onur; Solmaz, Murat Yavuz; Turan, KadirThe 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.Öğe 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, KadirIn 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.Öğe Investigation of pin joint performances of damaged composites repaired with adhesively patches(Springer Heidelberg, 2019) Kaman, Mete Onur; Parlamis, Abdulkerim; Turan, Kadir; Gur, MustafaIn 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%.Öğe 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, KadirTo 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%.Öğe Kompozit malzemeler için ilerlemeli hasar analizinde çözümü etkileyen faktörler(Dicle Üniversitesi Mühendislik Fakültesi, 2019) Kaman, Mete Onur; Turan, KadirFiber 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.Öğe Pim Bağlantılı Tabakalı Kompozit Levhalarda Fiber Takviye Açısının Hasar Tipine Etkisi(2010) Turan, Kadir; Kaman, Mete Onur; Gür, MustafaBu 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 edilmiştirÖğe Progressive Failure Analysis of Laminated Composite Plates With Two Serial Pinned Joints(Taylor & Francis Inc, 2015) Turan, Kadir; Kaman, Mete Onur; Gur, MustafaThis study presents experimental and numerical failure analyses for two serial pin loaded holes in unidirectional carbon fiber/epoxy resin composite laminates. The failure loads and failure modes of composite laminates are determined for different geometrical parameters and different stacking sequences. Three-dimensional ANSYS Parametric Design Language codes are developed in the ANSYS (R) finite element software. Hashin Failure Criteria and material degradation rules are used to determine failure loads and failure modes in the numerical analysis. Experimental and numerical results show that failure loads and failure modes were affected with geometrical parameters.Öğe Progressive Failure Analysis of Pin-Loaded Unidirectional Carbon-Epoxy Laminated Composites(Taylor & Francis Inc, 2014) Turan, Kadir; Gur, Mustafa; Kaman, Mete OnurIn this study, a research was carried out to determine the failure modes and failure loads at pinned joint unidirectional laminated carbon/epoxy composite plates. To evaluate the effects of joint geometry and fiber orientation on the failure loads and failure modes, parametric studies were performed experimentally and numerically. A numerical study was performed by using 3D APDL codes with ANSYS fem software and Hashin Failure Criteria was used for predicted failure mode and failure load. The experimental and numerical results showed that the failure loads of composite plates were increased with increasing E/D and W/D ratios.Öğe Progressive Failure Analysis on the Single Lap Bonded Joints(Pamukkale Univ, 2010) Turan, Kadir; Kaman, Mete OnurIn this study, the failure analysis on the single lap bonded joint, which is used for joined two composite plates each other with adhesive, is investigated experimentally and numerically. In the joint, the epoxy resin is used for adhesive and the four layered carbon fiber reinforced epoxy matrix resin composite plates are used for adherent. Numerical study is performed in the ANSYS software which is used finite element method for solution. For obtained numerical failure loads, the progressive failure analysis is used with material property degradation rules. In the failure analysis the Hashin Failure Criterion is used for composite plates and the Maximum Principal Stress failure criterion is used for adhesive. The effects of the adhesive thickness overlap lengths and plate weight on the joint strength is investigated with numerically. As a result it is seen that the failure loads is affected the bond face area. The results are presented with graphs and tables.Öğe Tek Tesirli Yapıştırma Bağlantılarında İlerlemeli Hasar Analizi(2010) Turan, Kadir; Kaman, Mete OnurBu çalışmada, iki kompozit levhayı birleştirmek için yapıştırıcı kullanılarak elde edilmiş olan tek tesirli yapıştırma bağlantısının hasar analizi deneysel ve sayısal metotlar kullanılarak araştırılmıştır. Bağlantı yapılırken yapıştırıcı olarak epoksi reçine ve yapışan olarak ta karbon fiber takviyeli epoksi reçine matriksli dört tabakadan oluşan kompozit levhalar kullanılmıştır. Sayısal çalışma sonlu elemanlar metodunu kullanarak çözüm yapan ANSYS programında yapılmıştır. Sayısal hasar yüklerini elde etmek için ilerlemeli hasar analizi metodu malzeme indirgeme kuralları ile birlikte kullanılmıştır. Hasar analizinde kompozit levhalar için Hashin Hasar Teorisi kullanılırken yapıştırıcı için Maksimum Asal Gerilme Hasar Teorisi kullanılmıştır. Bağlantı mukavemeti üzerine yapıştırıcı kalınlığı, bindirme uzunluğu ve plaka genişliğinin etkisi sayısal olarak araştırılmıştır. Sonuç olarak yapışma yüzey alanının değişiminin hasar yükleri üzerinde etkili olduğu görülmüştür. Elde edilen sonuçlar tablolar ve grafikler halinde sunulmuştur.
