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Öğe An approach for calculation of press loads in closed - die upsetting of gear blanks of gear pumps(Elsevier Sci Ltd, 2007) Altinbalik, Tahir; Akata, H. Erol; Can, YilmazSome results of an industrial research and development project aimed to develop the manufacturing technologies of gear pumps were presented. Gear blanks of gear pumps that have traditionally been produced by machining from round bars in an industrial company were closed-die forged as an alternative. A comparison method of mechanical properties of the manufacturing methods was published formerly. A classical method was applied to calculation of press loads in closed-die upsetting of gear blanks of gear pumps and results were compared with those of measured in the experimental part of the work. Commercially pure lead was used as test material. In addition to comparison of calculated and measured loads, contributions of the method applied on the manufacturing costs of gear blanks were also discussed in the study. (c) 2005 Elsevier Ltd. All rights reserved.Öğe Effect of die inlet geometry on extrusion of clover sections through curved dies: Upper bound analysis and experimental verification(Elsevier Science Bv, 2013) Altinbalik, Tahir; Ayer, OnderThe effect of die inlet and transition geometry on the extrusion loads and material flow for extrusion of clover sections were investigated and presented both theoretically and experimentally. For this purpose, four different die geometries including straight tapered and cosine transition profile and each of them having round and clover inlet geometries were chosen. In the experimental study, commercially pure lead was used because of its hot forming characteristic at room temperature. A newly kinematical admissible velocity field to analyze different profiles of extrusion dies of clover section from round bars was proposed by upper bound analysis. It is clear that the extrusion loads obtained from the theoretical analysis for various die inlet-die transition geometry combinations are in good agreement with the experimental results. Axis deviations of the parts which define the dimensional quality of the products were also investigated.Öğe An experimental study of lateral extrusion of splines(Elsevier Sci Ltd, 2006) Altinbalik, Tahir; Can, YilmazThe aim of this study is to investigate the lateral extrusion of splines in terms Of load requirement and die filling. The prediction of forming load and pressure is an important task in metal forming. The upper bound method has been employed to investigate the load requirement for different process parameters, to this effect, kinematically admissible velocity fields have been developed. A series of experiment has been carried out using solid lead billets with two different diameters. The theoretical prediction of forming load is compared with experimental results. The predicted load values are higher than the experimental values during the tooth formation period but lower than the experimental values during the corner filling stage. Metal flow in the tooth region is not uniform and barreling occurs due to frictional resistance between the workpiece and the die gap surface. The barrel profile is assumed as a second order polynomial and a simple empirical relationship between the tooth dimensions and the barrel profile has been given using experimental data. (c) 2005 Elsevier Ltd. All rights reserved.Öğe Extrusion load prediction of gear-like profile for different die geometries using ANN and FEM with experimental verification(Springer London Ltd, 2015) Bingol, Sedat; Ayer, Onder; Altinbalik, TahirThis paper deals with the extrusion of gear-like profiles and uses of finite element method (FEM) and artificial neural network (ANN) to predict the extrusion load. In the study, gear-like components has been manufactured by forward extrusion for the AA1070 aluminum alloy and the process was simulated by using a DEFORM-3D software package to establish a database in order to provide the data for ANN modeling. Serious experiments were performed for only one die set and four teeth gear profile to obtain data for comparing with DEFORM-3D results. After verifying a highly appropriate FEM simulation with the experiment at the same conditions, Results were enhanced for different die lengths, extrusion ratios, and two extra teeth number as three and six using FEM simulations. Subsequently, the data from the performed FEM simulations were submitted for the best obtained ANN model. Finally, a good agreement between FE-simulated and ANN-predicted results was obtained. The proposed ANN model is found to be useful in predicting the forming load of the different die set variations based on the reliable test data.Öğe Fatigue life modeling of gear like products using ANN(Natl Inst Science Communication-Niscair, 2016) Ayer, Onder; Bingol, Sedat; Altinbalik, Tahir; Kilicgedik, Hidir YankiThe expected life of a gear is important parameter especially for the gears to secure of the mechanics of it. Related to this importance, fatigue failure is one of the most seen failures occurred on gears working under cyclic loads. It is not possible to eliminate fatigue failure effects but it is possible to reduce by appropriate materials selection and design criteria. Due to demand for gears with higher load-carrying capacity and increased fatigue life, it is important to determine the fatigue strengths of the gears. hi this study, forward extrusion method with cosine and tapered profile dies is carried out to obtain gear-like products. The products are then tested under cyclic loads to determine the fatigue life. The results obtained from the experiments are used as inputs in developing the ANN models. Different ANN models are developed for cosine curved and straight tapered profiles to obtain the best models. A comparative analysis is performed in order to evaluate the accuracy of the developed models, in terms of statistical measurements (R-2, MSE, MAE). Results revealed that proposed ANN models for both cosine curved and tapered profiles are able to predict the fatigue life of the gear-like profiles.Öğe Finite Element Analysis of Gear Like Form by Using Lateral and Forward Extrusion(Assoc Information Communication Technology Education & Science, 2014) Altinbalik, Tahir; Ayer, OnderThe aim of this research is the reduction in deformation load, improvement of the mechanical properties of the product by means of an optimum forming process and die profile. Forward extrusion and lateral extrusion were chosen as two different forming methods to manufacture a spur gear form. Four different die geometries were chosen for the forward extrusion; including straight tapered transition profile and cosine transition profile with having two different die lengths. Al 1070 was used as workpiece material in the experimental study. Experiments using five sets of dies with spur gear form were performed, and the measured forming load results were compared with the predictions of the finite element method for the same deformation situations by using DEFORM-3D. The state of stress and strain was also determined for two forming methods by means of DEFORM-3D. Finally, a series of fatigue tests were carried out for four teeth gear forms produced by both processes to evaluate influence of the forming processes.Öğe Redesigning and Manufacturing of a Land Levelling Shovel by Assembly Structural Stress Analysis(Hindawi Publishing Corporation, 2014) Altinbalik, Tahir; Irsel, GurkanThe aim was to redesign and manufacture of a shovel for a pull-type land levelling machine, which, in its present condition, is used to get easily damaged even under low loads. Firstly, the maximum pulling load affecting the levelling shovel was experimentally determined. Then, stable-shovel system with the bolt connection was replaced with a bearing-shaft connection system. In this way, the new shovel has gained a capability of making oscillation motion so that it can operate on sloped grounds. CATIA program was used in the design studies. The shovel system was investigated by assembly structural stress analyses. This new construction enabled the system to operate 3 times more securely at maximum stress conditions without changing the levelling shovel material. Thus, it is managed to prevent any possible damages that might occur due to maximum loading conditions of the system. Besides, displacements that occur on the shovel decreased at the rate of 90%.Öğe A study of barreling profile and effect of aspect ratio on material flow in lateral extrusion of gear-like forms(Natl Inst Science Communication-Niscair, 2007) Altinbalik, TahirThe aim of this study is to investigate the lateral extrusion of tapered in terms of die filling and barrel formation at the front of tooth. A series of experiments has been carried out using solid lead billets with two different billet diameters and three different billet heights of each diameter. Metal flow in the tooth region is not uniform and barreling Occurs due to frictional resistance between the workpiece and the die gap surface. The barrel profile is assumed as a second order polynomial and a simple empirical relationship between the tooth dimensions and the barrel profile has been given using experimental data. Bulging profile of the tooth was measured and simulated by CAD/CAM software. Load-stroke relations and die filling ratios are obtained. In addition, Microsoft Visual Basic was coded and also magnitude and the position of the maximum stresses ill the die chamber were determined by using CATIA.Öğe A theoretical and experimental study for forward extrusion of clover sections(Elsevier Sci Ltd, 2008) Altinbalik, Tahir; Ayer, OnderForward extrusion of clover section from different billet diameters has been investigated. The die profile is given by radius function to construct the new kinematically admissible velocity fields for three dimensional extrusion and then by using the upper bound method total extrusion loads are obtained. In the experimental studies, lead billets which having same initial heights but three different diameters have been extruded with the same strokes in order to verify the analysis. Die land length/billet diameter ratio was taken equal or greater than 0.6 as recommended in literature. A good agreement was found between the measured and the predicted load and so it is suggested that present analysis could be used the other commercial materials. (C) 2007 Elsevier Ltd. All rights reserved.Öğe A THEORETICAL AND EXPERIMENTAL STUDY FOR THE LOAD OPTIMIZATION OF GEAR-LIKE PROFILES BY USING FORWARD AND LATERAL EXTRUSION(Canadian Science Publishing, 2015) Altinbalik, Tahir; Ayer, OnderThe main purpose of this research is to investigate the minimum deformation load by selecting a suitable forming method for manufacturing of gear-like sections and to compare the load estimation methods between Upper Bound Analysis and DEFORM-3D. Forward and lateral extrusion were chosen as two different forming methods. The effect of die transition geometry on deformation load was also investigated by straight tapered and cosine profiles. A newly kinematical admissible velocity field to analyze different profiles of extrusion dies was proposed by upper bound analysis. Al 1070 was used as working material. Experiments using five sets of dies with gear-like form were performed, and the measured forming load results were compared with the predictions of the theoretical solutions. Experiments were carried out on the 150 metric ton hydraulic press.Öğe An upper bound analysis and determination of the barrelling profile in upsetting(Natl Inst Science Communication-Niscair, 2011) Altinbalik, Tahir; Can, YilmazThe aim of this work is to investigate the barreling of aluminium cylinders having two different aspect ratios in terms of barrel profiles and required loads. A modified upper bound solution including a dimensionless optimizing parameter for uniaxial upsetting has been developed and the loads calculated thereby have been compared with the results of several experiments conducted. Furthennore, the barrel profile is firstly assumed as a second-order polynomial for the upsetting process and an empirical correlation between the billet dimensions and the barrel profile has been established using experimental data. AA6082 is used as test material. The experiments are carried out on a 150 metric ton capacity hydraulic press. Besides, the bulging profile and effective strain distribution of the billets are obtained with a commercially FEM program called DEFORM 3D.
