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Öğe BEHAVIOUR OF BI-ADHESIVE IN DOUBLE-STRAP JOINT WITH EMBEDDED PATCH SUBJECTED TO BENDING(Sciendo, 2015) Temiz, Semsettin; Adin, Hamit; Sulu, Ismail YasinIn this study, behaviour of hi-adhesive used in the repair of damaged parts was analyzed, using the finite element method. In a double-strap joint with an embedded patch, patch is embedded into the adherents for structural requirements. In addition, to increase the strength of the joint, two adhesives are used to bond the adherents. This approach reduces stress concentration at the overlap ends, ad capacity and delays the failure. These effects give rise to strength. For this purpose, a stiff adhesive, FM73 produced by Cytec Fiberite. was applied in the middle portion of the overlap, while a softer adhesive, SBT9211 from 3M, was applied towards the edges, prone to stress concentrations. Non-linear finite element analyses were carried out to predict the failure loads, to assist with the geometric design and to identify effective ratios of sizes to maximize joint strength.Öğe Comparison of mechanical properties of tensile test specimens produced with ABS and PLA material at different printing speeds in 3D printer(Gazi Univ, Fac Engineering Architecture, 2022) Kamer, Muhammed Safa; Temiz, Semsettin; Yaykasli, Hakan; Kaya, Ahmet; Akay, Orhan ErdalIn this study, tensile test specimens have been produced using ABS (acrylonitrile butadiene styrene) and PLA (poly-lactic acid) material at different printing speeds (20-40-60-80-100-120-140mm/s) with Ultimaker 2 Extended 3D printer. The effect of printing speed on mechanical properties has been investigated. Masses, hardness and surface roughness of the produced samples have been measured, porosity values have been calculated and tensile test has been performed on the produced samples. After the tensile test, images have been taken by scanning electron microscopy (SEM) from the breaking regions of the broken samples. The mechanical properties of the samples produced with the same parameters with both materials have been compared. As a result; it has been determined that the tensile strength of the samples produced with PLA material are higher than the samples produced with ABS material, and the elongation at break values of the samples produced with ABS material are higher than the samples produced with PLA material.Öğe Effect of graphene nanoplatelet filling on mechanical properties of natural fiber reinforced polymer composites(Walter De Gruyter Gmbh, 2021) Erdogdu, Yusuf Eren; Korkmaz, Engin Eren; Temiz, SemsettinIn this study, the mechanical properties of plain woven jute-epoxy composite materials were investigated after filling graphene nanoplatelets (GNPs) in different proportions. The time dependent changes in the viscosity and temperature of unfilled epoxy resin, with 0.5, 1 and 2 wt.-% graphene nanoplatelets filled epoxy resins were observed. Woven jute reinforced unfilled, 0.5 wt.-% GNPs filled and 1 wt.-% GNPs filled epoxy composite plates were produced by using vacuum assisted resin transfer molding (VARTM) at the same waiting and processing times. Specimens were prepared and subjected to tensile and flexural tests according to ASTM D 3039 and ASTM D 790 standards, respectively. Images were taken and evaluated with a scanning electron microscope (SEM) in areas where tensile damage occurred. It was observed that the gap amount between the fiber and the matrix increased and the interface adhesion decreased as the fill amount increased in the composites produced. The testing results indicated that the tensile and flexural properties of composites decreased at 0.5 wt.-% and 1 wt.-% during the GNPs loading as compared to unfilled composites.Öğe Effect of protrusion at the ends of bondline in single lap joints under tension and bending(Taylor & Francis Ltd, 2012) Akpinar, Salih; Temiz, Semsettin; Aydin, Murat Demir; Ozel, AdnanIn this work, elasto-plastic stress analysis of single lap joints with and without protrusion in adhesive bondline subjected to tension and bending was carried out using 2D non-linear finite element analysis and confirmed experimentally. AA 2024-T3 aluminum adherends were bonded with SBT 9244 film adhesive. The protrusion was obtained by extending the adhesive film by 2 mm from the overlap length at both overlap ends. Three different adherend thicknesses and overlap lengths for each loading and bondline type were used. The joints with and without protrusion, for comparison, were loaded with the same load for each adherend thickness and overlap length. Finally, it was observed that the protrusion reduces the strength in the joint under tension, while the protrusion increases the strength in the joint under bending.Öğe Effect of welding parameters on microstructure and mechanical properties of AA7075/AA5182 alloys joined by TIG and MIG welding methods(Springer Heidelberg, 2020) Cetkin, Edip; Celik, Yahya Hisman; Temiz, SemsettinIn this study, V and X welding grooves were opened to the forehead positions of the AA5182 and AA7075 aluminum alloy pairs and these alloy pairs were joined with tungsten inert gas ( TIG) and metal inert gas (MIG) methods. Three different welding currents were used in joints. Gas flow rates of 12 and 17 l/min at the TIG welding and wire feed rates of 38 and 45 cm/min at MIG welding were selected. The effect of the welding grooves, welding current, gas flow rate and wire feed rate on microstructure and mechanical properties were investigated. Microstructures of welding zones were analyzed by an optical microscope and a scanning electron microscope (SEM). Vickers hardness of these zones was also measured. In addition, tensile and fatigue tests were carried out. Fracture mechanisms of failed specimens were conducted after the tensile tests were examined by using SEM. The highest hardness, tensile and fatigue strengths were obtained from the alloy pairs joined by opening X welding groove with TIG welding method. These values were 89 HV, 262.87 MPa, and 131.5 MPa, respectively. Similarly, the lowest tensile and fatigue strengths were obtained from the alloy pairs joined by opening V welding groove in the TIG welding method. These values were, respectively, 94.48 MPa and 19.1 MPa. However, the minimum hardness value was measured as 58 HV from the alloy pairs joined by opening V welding groove with MIG welding methods. In addition, it was observed on the fracture surfaces that the grain distributions and mechanisms differed depending on the welding methods, welding groove, and welding parameters.Öğe Experimental and FEM investigation of bending behaviors of S-core sandwich panel composites(Pergamon-Elsevier Science Ltd, 2024) Oztemiz, Hasan Murat; Temiz, SemsettinSandwich panel composites have numerous applications in material technology. The sandwich panel composite structure's mechanical behavior and performance are determined by the material properties and geometry of the relevant components. The top and bottom sheets of the designed sandwich panel composite material are made of stainless steel-316, the core material is aluminum 1050A-0, and the binding element is DP-8405 acrylic adhesive. Three-point bending tests and finite element models were utilized to investigate the bending behavior of S-core composite sandwich panels. Finite element models have been developed to characterize the effect of composite element bending behavior on variations. The specific flexural modulus and strength of composite S-core sand-wich structures can be compared to core structures in the literature in general. As a consequence, the minimum weight design was used as a guideline to produce weight and density-efficient hybrid composite sandwich panels. The load-carrying capacity of the composite panel increased as the wall thickness of the S-shaped core increased when the damage loads were examined in the variations. It has been ascertained that as the core height increases, the load-carrying capacity of the composite panel decreases.Öğe An experimental and finite element analysis of 3D printed honeycomb structures under axial compression(Sage Publications Ltd, 2022) Kaveloglu, Serdar; Temiz, SemsettinThe present study focuses on maximum compressive force of honeycomb structures produced from polylactic acid (PLA) and acrylonitrile butadiene styrene filament using an Ultimaker hot plate 3D printer. A honeycomb structure with an equal surface area and three different cell sizes and wall thickness was designed. The samples were produced with a cell width (d) of 6 mm, 9 mm, 12 mm, a cell wall thickness (t) of 0.8 mm, 1.2 mm, 1.6 mm and a cell height (h) of 10 mm, 20 mm and 30 mm for each cell width, respectively. The produced samples were weighed in order to calculate their porosity percentages. During the compression test, the highest compressive force was obtained from the samples produced from PLA filament with a cell height of 10 mm, a width of 12 mm and a wall thickness of 1.6 mm. Similarly, a detailed finite elements analysis of three structures with different cell widths and thicknesses using ANSYS (R) software yielded results similar to the experimental study. ANSYS (R) results were reliable in the range of approximately 81-98%. Thus, although the cell width in honeycomb structures with an equal surface area was increased using both experimental and finite elements method, it was observed that the wall thickness was directly proportional to a higher maximum compressive force.Öğe Experimental and numerical investigation of flexural behavior of balsa core sandwich composite structures(Walter De Gruyter Gmbh, 2023) Onal, Tugberk; Temiz, SemsettinThe mechanical properties of bio-core sandwich composite structures fabricated in different configurations were investigated experimentally and numerically in this study. Balsa woods with thicknesses of 4, 6, 8, and 10mm were used in the core element. Glass fiber/epoxy composites with 8 and 12 layers at [0 degrees](2s), [0/90 degrees](s), and [+/- 45 degrees] (s) fiber orientation zones were used on the bottom and top surfaces of the sandwich structure. The effects of external surface fiber arrangement variation, the number of layers, and core thickness increase on the flexural damage load of sandwich structures produced by the vacuum infusion method were investigated. For this purpose, a three-point bending test was applied to the sandwich specimens. Maximum damage load values were determined using the three-point bending test performed in accordance with ASTM C-393 standard. Experimental and numerical data were compared with the finite element model created in the ANSYS package program. As a result of the tests, the damaged specimens were visualized and the types of damage to the balsa wood and composite element were determined.Öğe Experimental determination of the static and fatigue strength of the adhesive joints bonded by epoxy adhesive including different particles(Elsevier Sci Ltd, 2018) Sarac, Ismail; Adin, Hamit; Temiz, SemsettinBecause of their many advantages, adhesively bonded joints are intensively used in many engineering fields. So, the mechanical research of the adhesively bonded joints is very important to use these joints safely. There are many studies performed by researchers to investigate the mechanical properties of the adhesive joints. There has been a considerable interest in nanoparticles added to structural adhesives recently because nanoparticles improve the mechanical properties of adhesives and joints. In this paper, different nanoparticles reinforced by epoxy adhesive, and neat adhesive were used to produce single lap joints. The static and fatigue strengths of single lap joints incorporating nanoparticles were compared to those without nanoparticles. Experiments were performed at 20 mm overlap length. DP460 epoxy was used as the adhesive material, and nano-Al2O3, nano-TiO2 and nano-SiO2 were used as the nanoparticles; and AISI 304 stainless steel plates were used as the adherents. The results of the experimental research revealed that average failure load increased significantly in nanoparticle-reinforced adhesive joints. The highest average failure load was obtained with 4 wt% nano-Al2O3 in epoxy adhesive. Fatigue tests were performed at 10 Hz frequency, and 0.1 loading ratio (R). When the fatigue test results were examined, it was observed that the addition of the nano-Al2O3 and nano-SiO2 to the adhesive increased fatigue strength of the adhesive joints, on the other hand, the addition of the nano-TiO2 to the adhesive reduced fatigue strength of the adhesive joints.Öğe Failure analysis of an adhesively joined composite pipe system under internal pressure(Carl Hanser Verlag, 2018) Sulu, Ismail Yasin; Temiz, SemsettinFailure and stress analyses of adhesively joined composite pipe systems of varied orientation angles under internal pressure have been carried out using the 3-D finite element method (FEM) and experimentally. Composite pipes adhesively joined without sleeves were examined. The composite pipes were produced from E-glass fiber and adhesively joined using the adhesive types DP410 and DP490. The numerical model was created using ANSYS software and the efficiency of the model was verified by the experimental results. The finite element analyses (FEA) and experimental tests were carried out to predict the failure internal pressure. The internal failure pressures were obtained from experimental tests and compared with the numerical results. Radial, tangential, axial and shear stress values were obtained via numerical analyses in composite pipes and in the adhesive layers. In addition, the von Mises stress distributions in the adhesive were obtained. The effects of the orientation angles were investigated in the interface region between the pipes and the adhesive. The most effect parameters were determined for the composite pipe system joined at various pipe radii. It was found that the composite pipes could be used under high internal pressure, a fact that is important for industrial applications.Öğe Failure and stress analysis of internal pressurized composite pipes joined with sleeves(Taylor & Francis Ltd, 2018) Sulu, Ismail Yasin; Temiz, SemsettinFailure and stress analyses were carried out for composite pipes adhesively joined with sleeves subjected to internal pressure. In the study, the composite pipes and sleeves were E glass fiber/epoxy with different fiber orientation angles. Circular pieces cut from four layered composite pipes with different orientation angle were used as sleeves. Composite pipes with different orientation angle were bonded using DP410 and DP490 type adhesives. The codes of a numerical model were generated via ANSYS software package for the numerical analyses, and the numerical results were verified using experimental results. The problems were analyzed by using a calculation method based on finite elements method (FEM). The finite element analyses (FEA) were carried out to predict the failure internal pressure. Radial, tangential, axial and shear stress values were obtained via numerical analyses for composite pipes and adhesive layers in the thickness direction. In addition, Von-Mises stress distributions that develop on the adhesive were obtained as well. The effects of orientation angle, sleeve length and adhesive type on strength of composite pipe and bonded zone were examined. The results showed that the adhesive type has higher effect on the strength of bonded composite pipes when compared with orientation angle and sleeve length. In addition, increase in sleeve length increased the failure internal pressure.Öğe Investigation of low-velocity impact performances of sandwich composites manufactured using 3d printer(Gazi Univ, Fac Engineering Architecture, 2024) Kaveloglu, Serdar; Temiz, SemsettinIn this study, the low-velocity impact performances of sandwich composites in honeycomb geometry with three different cell widths and cell wall thicknesses but close surface areas were investigated. Three different cell width and cell wall thickness sizes of the core produced in the 3D printer and the cross-sectional views of the samples after the impact test are shown in Figure A.Purpose:The main aim of this study is to reveal the effects of different cell widths with similar surface areas on the low-velocity impact behavior of 3D printed sandwich composite test specimens.Theory and Methods:The cores of the sandwich composites were produced using a 3D printer using the additive manufacturing method. The tests of the samples were carried out according to the ASTM D7766 impact test standard by bonding the cores with CFRP plates. Impact behavior of samples with different cell widths at impact energies of 30J, 40J, 60J, 80J and 100J were presented with graphics and figures.Results:In the impact tests, as the impact energy increased, the damage height in the samples increased. While the striker perforated the top surface at 60J impact energy and damaged the core, it only damaged the bottom surface at 80J impact energy. At 100J impact energy, it completely perforated the sample.Conclusion:The behavior of the test samples produced in the 3D printer against five different impacts was determined.Öğe Investigation of the effect of use of Nano-Al2O3, Nano-TiO2 and Nano-SiO2 powders on strength of single lap joints bonded with epoxy adhesive(Elsevier Sci Ltd, 2019) Sarac, Ismail; Adin, Hamit; Temiz, SemsettinIn this study, single lap joints were formed by adding nano-Al2O3, nano-TiO2 and nano-Al2O3 powders in various proportions to the epoxy adhesive and using the additive-free epoxy adhesive; and also the mechanical properties of the connections were experimentally investigated at 20, 25, 30, 50 and 70 mm overlap lengths under shear load. In the experimental work, DP460 epoxy adhesive was used as adhesive and AISI 304 stainless steel plate as adherent material. When the results obtained from the experiments were examined, it was revealed that the average damage load in connection with the use of nanoparticle-added adhesives increased considerably in general. As a result of the experiments, the most effective nanoparticle in increasing the failure strength of the adhesive joints with nano-Al2O3 particles and the maximum failure strength increase rate was 20 mm in overlap length and 97% in 4 wt% nano-Al2O3 reinforced specimens. It was also found that the nanoparticle strain was an important parameter in the tensile strength of the adhesive joints. In addition, it has been found that the addition of nanoparticles into the adhesive increases the elongation of the joints. When the adhesion surfaces of the samples were examined as in the case of plain adhesives, damage was observed as adhesion separation while nanoparticle reinforcement was observed as a mixture of adhesion and cohesion.Öğe Low-speed impact behavior of fiber-reinforced polymer-based glass, carbon, and glass/carbon hybrid composites(Walter De Gruyter Gmbh, 2022) Saylik, Ahmet; Temiz, SemsettinImpact is defined as an instantaneous external force applied to a material or structure at low, medium, and high speeds over a very short period of time. In this study, we investigate the impact behavior of glass-epoxy composite (GFRP), carbon-epoxy composite (CFRP), and glass/carbon-epoxy hybrid composite (GCFRP) samples subjected to low-velocity impact testing with varying impact energy levels. Composite plates of 330 x 330 mm(2) consisting of eight layers were prepared using the VARTM method for impact experiments. Each composite type was tested with impact energy values of 10, 20, 30, and 40 J and their impact behaviors were examined. It was observed that as impact energy increased, the maximum force and the collapse values increased as well. The GFRP composite samples had the highest impact strength, while the GCFRP hybrid composite samples had poorer impact resistance compared to the GFRP composites and better impact resistance compared to the CFRP composites.Öğe Manufacturing and FSW of hybrid functionally graded metal matrix composite(Walter De Gruyter Gmbh, 2022) Avci, Ugur; Temiz, SemsettinThis study focuses on the manufacturing of hybrid functionally graded metal matrix composite (HFGMMC) using Al7039 alloy matrix phase which is used as armor material in today's world. In this context, manufacturing stages of matrix material were analyzed, and necessary parameters were determined for remanufacturing using casting method. With the determined parameters, the matrix material was reinforced by SiC, Al2O3, and B4C particles in different volume rates at an average size of 3-10 mu m using stir casting method. Three metal matrix composite (MMC) plates which were manufactured using different reinforcement particles in different volume rates were joined as semi-solid with the effect of temperature and pressure in a specially designed mold. In order to complete the manufacturing process, hot forging, and heat treatment were applied to the manufactured composite plate in accordance with the parameters determined in the manufacturing of the matrix. The manufactured MMC and HFGMMC plates were compared in terms of their micro structure, micro hardness, tensile strength, and wear behavior. Finally, HFGMMC plates were joined together by friction stir welding (FSW) in order to analyze their micro structures and mechanical properties after welding.Öğe Mechanical behavior of composite parts joined through different processes(Walter De Gruyter Gmbh, 2021) Sulu, Ismail Yasin; Temiz, SemsettinIn this research, composite parts joined according to different joining methods such as single-lap and double-lap embedded adhesive subjected to tensile load were analyzed via the 3-D finite element method (FEM). The study differed from other studies in terms of joining techniques used and the specified parameter and model design. This study aims to emphasize the advantages of joining techniques in terms of aesthetically and joining methods over each other. In the analysis, composite parts carbon/epoxy (T 700) at varied fiber orientation angles and adhesive DP 410 were used. The models for numerical analyses were created in an ANSYS 14.5 software package. Finite element analysis (FEA) was successful in predicting failure loads. Stress in the x, y, z directions, shear stress and von-Mises stress on the adhesive were obtained at the time of failure for predetermined parameters. As a result, the effects of orientation angles, overlap lengths, adhesive layer and bonding methods were investigated. The maximum effect parameter and joining technique was determined for the composite parts joined through varied joining methods.Öğe Mechanical behavior of composite pipes joined with non-embedded and embedded adhesive layers(Carl Hanser Verlag, 2020) Sulu, Ismail Yasin; Temiz, SemsettinIn this study, the mechanical behavior of composite pipes joined with embedded and non-embedded adhesive layers is investigated. Due to their high resistance, corrosion resistance, repair and lightness, composite materials have been used in industry increasingly. In general, composite pipes are used for the transport of pressurized liquids and gases. Joining processes are performed using many different methods. This study is intended to facilitate the joining process of composite pipes and to increase their applicability. In this study, the development of various bonding methods were investigated using composite pipes and double reinforced structural adhesives. Likewise stress behavior was analyzed. Generally, models with patch and patch quality are found in the literature.In this study by contrast, joining operations will be made easier by means of composite pipe joining models designed using glue without a patch. As a result, time and extra cost savings can be achieved.Öğe Mechanical behavior of pressurized composite pipes made of various materials(Carl Hanser Verlag, 2020) Sulu, Ismail Yasin; Temiz, SemsettinIn this study, multi-layered composite pipes with varied orientation angles and subjected to internal pressure were investigated by using the 3-D finite element method (FEM) and through experimental tests. The composite pipes were made of E-glass and T300/934 carbon fiber. The studies were carried out experimentally, analytically and numerically. The T300/934 carbon fiber reinforced composite pipes and E-glass reinforced composite pipes were given numerical model codes via ANSYS 14.5 software. These models were then compared with analytical results in the literature and with the experimental results. Finite element analyses (FEA) were carried out to predict failure loads. Each layer of the composite pipes was numerically examined from various orientation angles. Hoop and shear stress wereobtained numerically for each layer. Radial strain and radial stress were achieved in the radial direction of the composite pipes. Shear extension coupling was considered because the layup angles with + theta and - theta layers were in varied radii. Subsequently, the effects of the orientation angles were examined for all models. Moreover, it was found that an embedded adhesive joint is important for industrial applications.Öğe Mechanical characterization of composite pipe systems joined using different radii pipes subject to internal pressure(Taylor & Francis Inc, 2023) Sulu, Ismail Yasin; Temiz, SemsettinFailure tests for internal pressurized composite pipe system joined by using different radii pipes were carried out by the finite element method and experimental tests. The composite pipes were produced from E glass fiber/epoxy. DP410 and DP490 type adhesives were used to join the composite pipes. The numerical results and experimental results were compared. It was shown that the numerical analyzes results were close to experimental results. Tangential, radial, axial, and shear stress values on composite pipes and adhesive layers were obtained via numerical analyses in the radial direction. Additionally, the von Mises stress distributions were obtained on the adhesive. The effects of adhesive layer lengths, adhesives types, and orientation angle on the effect of the joint zone were investigated.Öğe Microstructure and mechanical properties of AA7075/AA5182 jointed by FSW(Elsevier Science Sa, 2019) Cetkin, Edip; Celik, Y. H.; Temiz, SemsettinIn this study, AA7075 and AA5182 aluminium alloys were joined using different rotation speeds (980, 1325 and 1800 rpm), feed rates (108 and 233 mm/min) and stirred pins having two different geometries (conical helical and triangular). Microstructures of welding joints were examined by an optical microscope and a scanning electron microscope (SEM). Vickers hardness measurements were performed in the welding zone of samples removed from each welded plate. Tensile and fatigue tests were also applied to the test specimens taken from the welded plates. After the tensile tests, the surface fractures and possible welding defects were scanned via SEM. The best mechanical properties were obtained when conical helical shape stirrer pins were used. The values were 265 MPa for tensile test and 159 MPa for fatigue test. The hardness value was very close to each other and varied depending on the rotation speed. The highest hardness value was determined as 87 HV in the weld center at 1325-rpm rotation speed.
