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Öğe Bilateral Tubal Faktör Nedenli Yardımla Üreme Tedavisi Uygulanan İki Kadında Endometriyum Tüberkülozu Tanısı: Olgu Sunumu(İnönü Üniversitesi Tıp Fakültesi Dergisi, 2012) Şahin, Levent; Albayrak, Mustafa; Çelik, Ebru; Özkan, Zehra Sema; Artaş, Gökhan; Aygün, Banu KumbakGenital tüberküloz (tbc) kadın infertilitesinin önemli bir nedeni olup son yıllarda primer ve sekonder infertilite bulunan olgularda daha sık tanınmaya başlamıştır. Bu yazıda tubal faktör infertilitesi olan ve daha önce birçok kez yardımla üreme tedavisi uygulanan iki hastada saptanan endometriyal tbc olgusu bildirilmiştir. Tubal faktör infertilitesi nedeniyle yardımcı üreme tedavileri uygulanmasına rağmen gebelik elde edilemeyen iki olgu implantasyon başarısızlığınının araştırılması için laparoskopi ve histeroskopi ile değerlendirilmiştir. Yardımla üreme tedavilerinde tekrarlayan başarısızlık görülen iki hastaya ofis histeroskopi uygulanmış ve işlem esnasında alınan endometrial örneklerin histopatolojik incelemesi granulomatöz endometrit olarak sonuçlanmıştır. Olguların birinde endometrial doku kültüründe Mycobacterium tuberculosis üremesi gözlenmiştir.Her iki olguya da tüberküloza yönelik tedavi başlanmıştır. : Bilateral tubal faktörü olan olgularda genital tbc ayırıcı tanıda düşünülebilir. Böylesi olgularda endometrial kavite değerlendirilmeli ve histopatolojik inceleme için endometrial örnek alınmalıdır.Öğe Bilateral Tubal Faktör Nedenli Yardımla Üreme Tedavisi Uygulanan İki Kadında Endometriyum Tüberkülozu Tanısı: Olgu Sunumu(2012) Şahin, Levent; Albayrak, Mustafa; Çelik, Ebru; Özkan, Zehra Sema; Artaş, Gökhan; Aygün, Banu KumbakGenital tüberküloz (tbc) kadın infertilitesinin önemli bir nedeni olup son yıllarda primer ve sekonder infertilite bulunan olgularda daha sık tanınmaya başlamıştır. Bu yazıda tubal faktör infertilitesi olan ve daha önce birçok kez yardımla üreme tedavisi uygulanan iki hastada saptanan endometriyal tbc olgusu bildirilmiştir. Tubal faktör infertilitesi nedeniyle yardımcı üreme tedavileri uygulanmasına rağmen gebelik elde edilemeyen iki olgu implantasyon başarısızlığınının araştırılması için laparoskopi ve histeroskopi ile değerlendirilmiştir. Yardımla üreme tedavilerinde tekrarlayan başarısızlık görülen iki hastaya ofis histeroskopi uygulanmış ve işlem esnasında alınan endometrial örneklerin histopatolojik incelemesi granulomatöz endometrit olarak sonuçlanmıştır. Olguların birinde endometrial doku kültüründe Mycobacterium tuberculosis üremesi gözlenmiştir. Her iki olguya da tüberküloza yönelik tedavi başlanmıştır. :Bilateral tubal faktörü olan olgularda genital tbc ayırıcı tanıda düşünülebilir. Böylesi olgularda endometrial kavite değerlendirilmeli ve histopatolojik inceleme için endometrial örnek alınmalıdır.Öğe Charpy darbe testinin deneysel ve sayısal analizi(2019) Albayrak, Mustafa; Kaman, Mete OnurÖz: Bu çalışmada, St37 çelik ve AA7075-T651 alüminyum numunesi üzerine Charpy darbe testi uygulayarak malzemelerin darbe absorbe enerjileri incelenmiştir. Deliksiz ve ortasında farklı delik geometrilerine sahip delikli numune modelleri kullanılmıştır. Deneysel prosedürde, numuneler 50x20x2 mm boyutlarında hazırlandıktan sonra dairesel delik etkisini inceleyebilmek için numune merkezine 9 mm çapında dairesel delik açılmıştır. Deneyler üniversal Charpy darbe test cihazında, dairesel delikli ve deliksiz St37 çelik numuneler için üçer kez tekrar edilmiştir. Test cihazının vurucu kütlesi 6.784 kg olup kapasitesi 49.05 J dür. Sayısal çalışmada, ANSYS yazılımı ön işlemci olarak, LS-DYNA ise çözücü olarak kullanılmıştır. St37 çelik ve AA7075-T651 alüminyum malzeme numunesi için, çözücüde Mat 15(Johson-Cook) malzeme modeli tercih edilmiştir. Vurucu ve mesnet modeli için Mat 20 (Rigid) malzeme modeli seçilmiştir. Enerji sönümleme mekanizması hem deneysel hem de sayısal yöntemlerle analiz edilerek, delikli ve deliksiz numuneler için karşılaştırılmıştır. Elde edilen verilere göre St37 çelik numuneler için deliksiz numunelerin darbe dirençleri, merkezinde 9 mm çapında dairesel delik bulunan numunelerle kıyaslandığında önemli bir üstünlüğe sahip olduğu gözlemlenmiştir. Numune kesitinde sürekliliğin bozulmasıyla birlikte darbe sönümleme enerjisinin deneysel olarak % 46.53 oranında düştüğü tespit edilmiştir. Numunelerin deneysel çalışmalar sonrasında ölçülen darbe absorbe enerjileri ile sonlu elemanlar metodu kullanılarak elde edilen sayısal analiz sonuçları karşılaştırılarak grafikler halinde sunulmuştur. Çalışma sonucunda, sayısal ve deneysel yöntemlerle elde edilen sonuçlar arasındaki maksimum fark tüm numuneler için %4.62 olarak elde edilmiştir. Kullanılan sayısal darbe test metodunun deneylere gerek kalmadan karmaşık ve farklı geometrilere sahip numuneler için uygulanabilirliği ortaya çıkmıştır.Öğe The effect of lamina configuration on low-velocity impact behaviour for glass fiber/rubber curved composites(Sage Publications Ltd, 2023) Albayrak, Mustafa; Kaman, Mete Onur; Bozkurt, IlyasThe aim of this study is to produce curved sandwich composites with different arrays by adding Ethylene Propylene Diene Monomer (EPDM) rubber interlayers between glass fiber woven fabrics and to investigate their behaviours under low-velocity impact. For this purpose, sandwich plates were produced through the vacuum infusion method by using glass fiber and rubber layers on the steel mold manufactured in curved form. Impact tests were applied on the plates and the effect of the stacking sequence for glass fibers/rubber layer on the impact energy absorption was examined. The energy absorption property of the composites was improved by a maximum of 45% with a layer epdm used in the midplane of the composite. Also, when rubber layers were used on the outermost surface of the composites, the damage area reduced by 14%. In the numerical part, the tests were modelled using LS-DYNA finite element packaged programme and the Hashin failure criterion-based material model was used in order to view any damages on the composite structure after the tests. The agreement between numerical and experimental results was obtained with a maximum error of 19%Öğe Effect of nonlinear material behavior on progressive failure analysis of pin-joint composites(Taylor & Francis Inc, 2024) Cayir, Sibel; Kaman, Mete Onur; Albayrak, MustafaIn this study, the mechanical performances of glass fiber-reinforced notched and pin-connected composite plates were investigated experimentally and numerically. For this purpose, composite plates with a circular hole, semicircular double-edge notched, U-edge notched, and single and double pin joints were prepared from [0 degrees]8 layer glass fiber composites. Tensile tests were carried out on the obtained specimens. The effect of notch type, number of pins, and position of pins on plate damage load and type was investigated for linear and non-linear material behavior. Progressive failure analysis was performed using the Hashin damage criteria. Subprogram codes were written in the Ansys program using the finite element method. According to the obtained data, it was determined that the type of notch and the number of pins have a significant effect on the damage loads of the plates and the behavior of the material is important in terms of convergence to the experimental results in numerical solutions. In single-pin composites, the type of damage changed from net-tension to shear out as the pin approached the free edge of the plate. It was observed that the distance between the pins did not have any effect on the damage type of the composites in the double-pin joint structure. Compared to single-pin joint composites, double-pin joint composites were found to carry a maximum of 34% more damage load. The convergence rate of experimental and numerical data was obtained as a minimum of 92.1% for nonlinear material behavior and a minimum of 73.4% for linear material behaviorÖğe Effect of repair parameters on composite plates under low velocity impact(2022) Albayrak, Mustafa; Gür, Mustafa; Kaman, Mete OnurIn this study, the impact behavior of patch-repaired layered composite plates under low velocity impact loads was numerically investigated. For this purpose, layered composite plates with holes with different geometries in the middle were repaired with patches using various adhesives. Impact behavior of the composite material was investigated by dropping the strikers with different speeds on the repaired composite plate. Layered composite plate was used as the sheet and patch material, and the orientation angles are [0 ° / 45 ° / 45 ° / 0 °] for the plate and [0 ° / 45 °] for the patch. ANSYS Ls-Dyna finite element package program was used for three dimensional modelling and solution. Therefore, the effects of variables such as striker, adhesive, plate and patch on the impact behavior of layered composite material were investigated for different boundary conditions. It has been determined that the hexagonal patch type performs better than other patch geometries.Öğe Experimental and numerical determination of interlayer shear strength of glass fiber-reinforced epoxy composites(2022) Albayrak, Mustafa; Aşan, Ahmet Murat; Kaman, Mete Onur; Bozkurt, İlyasThis study aims to produce glass fiber composite plates by vacuum infusion method and to determine the interlaminar shear strength (ILSS) under the short beam test. For this purpose, composite plates were produced under the effect of vacuum and temperature by adding glass fiber layers on a flat vacuum table. Short beam tests were carried out on the obtained laminated composite plates and the interlayer shear strength, which is generally characterized by delamination damage, was investigated. In the numerical part, the tests were modeled using the LS-DYNA finite element package program, and the Hashin damage criterion-based material model was used to see the damages that occurred in the composite structure after the tests.Öğe Experimental and numerical impact behavior of fully carbon fiber sandwiches for different core types(Springer Heidelberg, 2024) Bozkurt, Ilyas; Kaman, Mete Onur; Albayrak, MustafaThe aim of this study is to experimentally and numerically examine the impact strength and damage mechanisms of sandwich composites consisting entirely of fiber-reinforced composites for different core geometries. For this purpose, firstly, composite sandwich plates with egg box, lattice and square plate core structures were produced. Low-velocity impact tests were carried out by dropping impactors with hemispherical geometry onto the resulting sandwich structure with three different core geometries, and the effect of the core shape on impact strength was determined. For comparison, the cell width and height of these three different types of core were chosen to be similar. In addition, progressive damage analysis with the finite element method was applied. For this purpose, the MAT-162 material model, which provides three-dimensional progressive damage analysis in composite materials and applies the Hashin damage criterion, was preferred to be used in the LS-DYNA (R) program. When specific loads are compared using a square core specimen under the same conditions, it can be said that the contact force of the egg box structure is higher. While the striker rebounded from the square core at the same impact energy, it perforated the sandwich structure in the egg box and completely damaged the lattice core structure.Öğe Experimental and numerical investigation of patch effect on the bending behavior for hat-shaped carbon fiber composite beams(Walter De Gruyter Gmbh, 2024) Albayrak, MustafaIn this study, reinforced composite panels with hat-shaped profile were produced from woven carbon fiber fabrics by vacuum infusion method. Holes were drilled on the crown surface of these panels and repaired with composite patches. The mechanical behavior was examined by performing a three-point bending test on the obtained patched and unpatched specimens. The contribution of the repair to the failure load of the damaged specimens under bending load has been clearly determined. In the numerical part, Hashin damage criterion was used for the beginning of damage. For damage progression, both Continuum Damage Mechanics and Material Property Degradation methods were preferred and compared. In the analysis carried out using the finite element package program Workbench, the cohesive zone model (CZM) was added to the model and its effect on the damage behavior and load of the composite structure was determined. As a result of the experiments and analyses, it was seen that the maximum contact force of the specimens under the bending load decreased by 29.8 % by increasing the number of holes on the specimen surface from 1 to 3. The maximum contact force was determined to increase by 18.52 % due to repairing the three-hole specimens with a patch.Öğe Experimental and Numerical Investigation of the Geometrical Effect on Low Velocity Impact Behavior for Curved Composites with a Rubber Interlayer(Springer, 2023) Albayrak, Mustafa; Kaman, Mete Onur; Bozkurt, IlyasThe present study aims to produce sandwich composites with curved surfaces with different surface geometries by adding rubber (EPDM) between glass fiber woven fabrics and to examine their behavior under the influence of low-velocity impact numerically and experimentally. For this purpose, glass fiber and rubber layers were added to steel molds manufactured in curved forms and sandwich plates were produced through the vacuum infusion method. Low-velocity impact tests were performed by lowering strikers with a hemispherical tip on the produced curved-surface plates, and the effect of the surface geometry on the impact energy absorption was determined. By using rubber intermediate layers, the energy absorption ability can be increased by a maximum of 21%. The curved surface geometry affects the absorbed energy. If the height of the curved surface composites is kept constant and the width is increased to 1.5 times, the impact energy absorption increases by 16 percent. If the width is kept constant and the height is increased to 2.3 times, the impact energy absorption has decreased by 13 percent. When the impact resistance of composites with triangular rectangular, R125 circular arc and flat geometries with the same height and width are compared, it is observed that the lowest impact absorption ability occurs in the plates with triangular geometry, while the impact damping feature increases as the surface geometry becomes flatter and accordingly the contact surface increases. The impact absorption energies of the specimens were determined to be 82% compared to the flat plates. When the impact absorption energies of the upper side lengths of the outer tangent quadrilaterals to the R125 circle arc are compared, a significant increase in the impact absorption capabilities was observed as the side lengths increased. In the numerical part, the tests performed were modeled using the LS-DYNA finite element package program and the Hashin damage criterion-based MAT162 material model was used in order to see the damage caused to the composite structure in three dimensions after the tests. The numerical results obtained were a minimum of 84% compatible to the experimental results.Öğe Investigation of the mechanical response of laminated composites reinforced with different type wire mesh(Springer Heidelberg, 2023) Alev, Kubranur Isgor; Kaman, Mete Onur; Albayrak, Mustafa; Yanen, CenkIn this study, the mechanical behavior of laminated glass fiber composite plates reinforced with wire meshes under in-plane and out-of-plane loads was investigated. For this purpose, composite plates were produced by vacuum infusion method by placing aluminum and glass fiber wire layers with different mesh numbers between woven glass fiber fabrics. Afterward, impact and tensile tests were applied to the obtained specimens, respectively. The effect of the added reinforcement wires meshes on the impact resistance and tensile strength of the composites was determined. According to the data obtained; When glass wire with the same mesh number is used, 19.2% more reaction force was obtained than aluminum wire. The results of the double cantilever beam (DCB) and end notched flexure (ENF) test results confirmed that glass wire meshes had a better adhesion surface compared to aluminum. In addition, critical energy release rates were obtained with the help of the ANSYS & REG; finite element program and the data were compared with the experimental results. In the case of increasing the mesh number, it was observed that the reaction force of the glass wire mesh reinforced composite decreased by 17.54% under the impact. It was determined by scanning electron microscope (SEM) images that this decrease in the reaction force occurred due to the matrix material contacting the interlayer adhesion surfaces to a lesser extent. One layer of wire mesh reinforcement had no significant effect on the tensile strength of the glass fiber composite.Öğe Low-velocity impact behaviours of sandwiches manufactured from fully carbon fiber composite for different cell types and compression behaviours for different core types(Walter De Gruyter Gmbh, 2023) Bozkurt, Ilyas; Kaman, Mete Onur; Albayrak, MustafaThis study aims to manufacture sandwich composite structures consisting of fully fiber-reinforced composites and then to investigate experimentally and numerically the impact and compressive strength and damage mechanisms of these structures for different cell and core types. To achieve this, firstly, composite sandwich plates with triangular, square and rectangular cell structures were manufactured. Low-velocity impact tests were run on sandwich structures with these three different cell geometries and the effect of cell shape on impact strength was determined. Although the maximum contact force of the square structure under impact load was smaller than the maximum contact force of the triangular and rectangular specimens, the specific contact force was 15.52 % greater than the triangular specimen and 16.29 % greater than the rectangular specimen. Then, the specimens with square, egg box and lattice core types were manufactured and compression tests were performed. The specific peak load value for square specimens was 33.2 % greater than that of egg box specimens and 78.1 % greater than that of lattice specimens. In the numerical study, the experimental results were confirmed by applying the progressive failure analysis with the LS-DYNA finite element program.Öğe Numerical Investigation of the Effect of Deltoid Radius on Tensile Load in T-joints(2024) Albayrak, MustafaIn this study, T-shaped joints were designed from composites with different deltoid radius. For this purpose, carbon fiber woven fabrics were preferred as reinforcement elements. Then, tensile analyzes were performed on these composite T-joints. The effect of the deltoid radius on the maximum tensile load and damage behavior of the structure was examined. As a result of the analyses, fiber tensile-compression damage images occurring in the structure for each deltoid radius were obtained along with the load-displacement graph. The Hashin damage criterion was preferred for damage onset. Material Property Degradation (MPDG) method was used for damage progression in progressive damage analysis. By increasing the deltoid radius from 6 mm to 12 mm, the maximum contact load increased by approximately 10%, and by increasing it to 18 mm, the maximum contact load increased by approximately 20.11%. Fiber compression damage, spread over a wide area on the lower surface of the flange where it does not come into contact with the web, was determined to be the dominant damage type, and it was determined that this damage decreased with the increase of the deltoid radius. it was observed that as the deltoid radius increases, the T-jointed composite structure exhibits more rigid material behavior.Öğe Production of Curved Surface Composites Reinforced with Rubber Layer(2021) Albayrak, Mustafa; Kaman, Mete OnurAbstract: In this study, laminated composites reinforced with rubber layers were produced under vacuum infusion method for different curved surface geometries. For this purpose, EPDM rubber interlayers, known for their impact-absorbing feature, were laid on curved-surface metal molds processed on computer numerical control (CNC) benches together with woven glass fiber woven fabrics. Thus, sandwich plates with an array of [0 °] 6 glass fiber / EPDM rubber / [0 °] 6 glass fiber were obtained. It has been evaluated how the interface adhesion pr operties of the structure, which is formed by combining different types of materials under vacuum, depending on the temperature curing. For this reason, composites were produced by curing under high temperature and room temperature. As a result, it was determined that in composites produced by curing at room temperature, separation occurred between layers and the desired interface toughness could not be achieved. However, no delamination defects were observed in the structure of sandwich plates obtained for 100 ° C curing, and it was observed that the adhesion tendency of rubbers with hyper-elastic material structure increased with temperature. A good harmony was achieved between fabrics and rubbers with the effect of temperature together with vacuum and very smooth geometries were obtained.
