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Öğe Elastic-plastic and residual stresses in clamped thermoplastic composite laminates loaded transversely(Mathematical and Computational Applications, 2011) Benli, Semih; Karamolla, Mustafa; Okumuş, Fuat; Sayman, OnurIn this study, an elastic-plastic stress analysis was carried out in woven steel fibers- thermoplastic clamped composite laminates. The stacking sequences were chosen as [0/0]2, [15/-15]2, [30/-30]2 and [45/-45]2 for woven steel fibers – thermoplastic composites plates. The layers were chosen for symmetric and antisymmetric cases. The finite element solution was performed by using the ANSYS software. Solid 186 element was utilized in the solution. Normal stress components at the clamped edges were found to be higher than that at the mid point of the laminated plates. Normal stresses are tensile at the mid point of the clamped edges and compressive at the mid point of the laminated plates. Then, the residual stress components were calculated in the critical points of the composite laminates.Öğe Experimental failure analysis of glass-epoxy laminated composite bolted-joints with clearance under preload(Sage Publications Ltd, 2011) Şen, Faruk; Pakdil, Murat; Sayman, Onur; Benli, SemihIn this study, a failure analysis of glass-epoxy laminated composite bolted-joints with bolt/hole clearance under various torques was carried out. To estimate the effects of joint geometry and fiber orientation on the failure strength and failure mode, parametric studies were conducted experimentally. The two different geometrical parameters were the edge distance-to-hole diameter ratio (E/D) and plate width-to-hole diameter ratio (W/D), E/D ratio was selected from 1 to 5, and W/D ratio was chosen from 2 to 5. The bolt preload torque was also carried out as 0, 3, and 6 Nm. To investigate the material parameters effect, laminated plates were oriented as three different stacking sequences [90(o)](8), [45(o)](8), and [0(o)](8). The experiments were carried out with a clearance between the diameters of the bolt and the circular hole of 5 and 6 mm, respectively. According to experimental results, failure mode and bearing strength are strongly influenced by both material parameters and geometrical parameters. Additionally, when a torque is applied to the bolted-joints, the failure mechanism is affected by its increasing values.Öğe Experimental failure analysis of two-serial-bolted composite plates(John Wiley and Sons Limited, 2009) Şen, Faruk; Sayman, OnurIn this study, a failure analysis of two-serial-bolted glass-fiber-reinforced epoxy composite plates was performed. To determine the influences of the joint geometry and stacking sequences on the bearing strength and failure mode, parametric studies were carried out experimentally. Three different geometrical parameters-the ratio of the edge distance to the hole diameter (E/D), the ratio of the plate width to the hole diameter (W/D), and the ratio of the distance between two holes to the hole diameter (K/D)-were considered. For this reason, the E/D, W/D, and K/D ratios were designed to range from 1 to 5, from 2 to 5, and from 3 to 5, respectively. Furthermore, the tests were performed with various preload moments (2, 3, 4, and 5 Nm) and without any preload moments (0 Nm). Because of the observed effect of the material parameters on the failure behavior, composite laminated plates were stacked in two different stacking sequences: [0 degrees/0 degrees/30 degrees/30 degrees](s) and [0 degrees/0 degrees/45 degrees/45 degrees](s). The experimental results indicated that the failure response of the two-serial-bolted joints were strictly affected by the material parameters, geometrical parameters, and values of the applied preload moments. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 502-515, 2009Öğe Failure response of single bolted composite joints under various preload(2010) Şen, Faruk; Sayman, Onur; Özcan, Reşat; Siyahkoç, RamazanIn this study, an experimental failure analysis is performed to calculate bearing strength of single bolted joints in laminated composites reinforced unidirectional glass fibers. The main goal of this study is to determine the failure behaviour of bolted composite joints under various preload moments as 0, 2.5 and 5 Nm. Furthermore, two different geometrical parameters that are the edge distance-to-hole diameter ratio (E/D) and plate width-to-hole diameter ratio (W/D) are investigated. For that reason, E/D and W/D ratios are selected from 1 to 5 and from 2 to 5, respectively. Besides, the effect of orientation angle of laminated plates is considered. Therefore, four different ply orientations are selected as [30°]4, [45°]4, [60°]4 and [90°]4. The experimental results show that the magnitudes of bearing strengths in single bolted composite joints are strictly influenced from increasing value of applied preload moments, changing of W/D and E/D ratios and also ply orientations.Öğe Failure response of two serial bolted aluminum sandwich composite plates(Sage Publications LTD, 2010) Şen, Faruk; Sayman, OnurThe scope of this study is to examine the failure response in an aluminum-glass-epoxy sandwich composite plate with two serial circular holes, which is subjected to a traction force by two serial bolts. To determine the effects of joint geometry and applied/without preload moments on the bearing strength and failure mode, parametric studies were carried out experimentally. The end distance to diameter (E/D) and width to diameter (W/D) ratios in the specimens were designed from 1-5 to 2-5, respectively, whereas the distance between two serial holes and diameter ratio were fixed as 4. Besides, each type of specimen were tested under various applied preload moments as 2, 3, 4, 5 Nm and without preload moments (0 Nm). According to the experimental results, the bearing strength and maximum failure load generally increase by increasing E/D and W/D ratios and of applied preload moments. Besides, failure modes strictly affected these parameters.Öğe Prediction of bearing strength of two serial pinned/bolted composite joints using artificial neural networks(Sage Publications LTD, 2010) Şen, Faruk; Kömür, M. Aydın; Sayman, OnurThe aim of this study is to investigate the improvement of an artificial neural network (ANN) method for the prediction of bearing strength of two serial pinned/bolted E-glass reinforced epoxy composite joints. The experimental data from the previous study with different geometrical parameters without torque and various applied torque were used for developing the ANN model. Comparisons of ANN results with desired values showed that there is a good agreement between input and output variables of the experimental data. Therefore, ANN was illustrated to be a valid powerful tool for the prediction of bearing strength of two serial pinned/bolted composite joints.Öğe Sea water effect on failure behaviour of mechanically fastened composites(Carl Hanser Verlag, 2013) Sayman, Onur; Özen, Mustafa; Şen, Faruk; Benli, SemihIn this study, sea water effect on failure behaviour was investigated for mechanically fastened composites that are oriented as [0/90/45/-60](s). The laminated composite specimens were fastened with two serial fasteners and were tested under non-immersed and immersed conditions, i. e. in sea water for 200 days. The experiments were carried out according to D 5229/D 5229M standard test method for evaluation of moisture absorption properties and equilibrium conditioning of polymer matrix composite materials. The results point out that the immersion into sea water of the composite specimens can cause a decrease in failure loads of both, pinned and bolted joints, particularly.Öğe The prediction of maximum failure loads of two serial pinned/bolted composite joints with ANN(2011) Kömür, Mehmet Aydın; Şen, Faruk; Sayman, OnurThe scope of this study is to examine the development of an artificial neural network (ANN) method for the prediction of maximum failure loads of two serial pinned/bolted E-glass reinforced epoxy composite joints. The experimental data provided from the previous study with different geometrical parameters without preload moments and various applied preload moments were used for developing the ANN model. Comparisons of ANN results with desired values pointed out that there is an excellent agreement between input and output variables of the experimental data. Consequently, ANN was showed to be a suitable powerful tool for the prediction of maximum failure loads of two serial pinned/bolted composite joints.Öğe Thermal stress analysis of Wc-Co/Cr-Ni multilayer coatings on 316L steel substrate during cooling process(ELSEVIER SCI, 2009) Sayman, Onur; Şen, Faruk; Çelik, Erdal; Arman, YusufIn this study, a thermal stress analysis was performed in WC-Co/Cr-Ni multilayer coatings deposited on 316L steel substrate during the cooling process from 1273 K to room temperature. Firstly, the cooling curve of this coating system was measured by a thermocouple, experimentally. Then, this curve was considered for numerical analysis. With this regard, a transient thermal analysis was carried out using finite element method (FEM) utilizing ANSYS software. Thermal residual stresses were calculated for all system and were compared for different nodes selected in terms of concentrated stress areas on the model. The compressive and tensile stresses occurred in WC-Co/Cr-Ni coatings and 316L substrate owing to the different thermal expansion coefficients in each material, respectively. Additionally, the cooling curves determined from experimental and numerical studies are very similar to each other and the differences between them can be neglected. Crown Copyright
