Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Author: search.filters.author.Yardımoğlu, BülentSubject: search.filters.subject.Finite element method

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Now showing 1 - 7 of 7
  • Master Thesis
    Out-Of Plane Displacements of Curved Beams With Variable Curvature
    (Izmir Institute of Technology, 2016) Uyar, Ahmet Serhend; Yardımoğlu, Bülent
    The differential equations of out-of-plane displacements of curved beams with variable curvature have variable coefficients. Selection of the solution method is based on the curvature function of the curved beam. In this study, Differential Quadrature Method (DQM) and Finite Element Method (FEM) are used to find the out-of-plane displacements of curved beams with variable radius of curvature. Since the parabola is very famous and known curve, it is selected as the form of curved beam. To test and validate the computer codes developed based on DQM in Matlab and based on FEM by APDL (ANSYS Parametric Design Language) in ANSYS, some typical examples are considered. As first step, convergence studies are performed to determine the number of sampling points in DQM and number of elements in FEM. After having information about aforementioned modeling parameters, comparisons between DQM and FEM results are given. The effects of variable curvature parameter of the curved beam on out-of-plane displacements are obtained. The practical application of the present model is discussed.
  • Master Thesis
    In Plane Vibrations of Curved Timoshenko Beams With Variable Curvature
    (Izmir Institute of Technology, 2016) Cin, Uğur; Yardımoğlu, Bülent
    In this study, in-plane vibrations of curved Timoshenko beams with variable curvature is studied by Finite Element Method. In the selected method, it is known that generalized differential eigenvalue problem are solved by reducing the equations from continuous to discrete domain. Catenary form is used as the axis of curved beam. An APDL (ANSYS Parametric Design Language) code is developed for the geometric and finite element models of the curved beam. The computer code is validated by the data available in the literature. After validation of developed computer code, the effects of parameters, which are related to shape of the curved beam, on the natural frequencies and mode shapes are studied.
  • Master Thesis
    Displacement Analysis of Non-Circular Planar Curved Beams Under In-Plane Impulsive Load
    (Izmir Institute of Technology, 2015) Çelik, Ahmet; Yardımoğlu, Bülent
    In this study, time response of a planar curved beam with variable curvatures under in-plane impact load is analyzed by two numerical methods which are Finite Difference and Finite Element Methods. The solution procedures in both methods are based on solution of eigenvalue and time response problems. Catenary form is selected as the axis of curved beam. A computer program is developed in Mathematica for the solution with Finite Difference Method. Moreover, a computer code is written for the geometric and finite element models of curved beam with variable curvature in ANSYS by using APDL (ANSYS Parametric Design Language). Solutions of the two methods are compared in each other and then good agreement is observed. The effects of impuls and damping properties on the time response are investigated.
  • Master Thesis
    Modelling and Simulation of Metal Cutting by Finite Element Method
    (Izmir Institute of Technology, 2009) Kılıçaslan, Cenk; Yardımoğlu, Bülent
    Metal cutting is one of the most widely used manufacturing techniques in the industry and there are lots of studies to investigate this complex process in both academic and industrial world. Predictions of important process variables such as temperature, cutting forces and stress distributions play significant role on designing tool geometries and optimising cutting conditions. Researchers find these variables by using experimental techniques which makes the investigation very time consuming and expensive. At this point, finite element modelling and simulation becomes main tool. These important cutting variables can be predicted without doing any experiment with finite element method. This thesis covers a study on modelling and simulation of orthogonal metal cutting by finite element method. For this purpose, orthogonal cutting simulations of AISI 1045 steel are performed and model used in simulations is validated. At first step, effects of work piece flow stress and friction models on cutting variables such as cutting forces, chip geometry and temperature are investigated by comparing simulation results with experimental results available in the literature. Then, mechanical and thermal analyses are performed. Lastly, effects of rake angle and tool tip radius on strain, temperature and stress distributions are investigated.
  • Master Thesis
    Vibration Analysis of Pre-Twisted Rotating Beams
    (Izmir Institute of Technology, 2003) Yıldırım, Tolga; Yardımoğlu, Bülent
    A new linearly pretwisted rotating Timoshenko beam element, which has two nodes and four degrees of freedom per node, is developed and subsequently used for vibration analysis of pretwisted beams with uniform rectangular cross-section. First, displacement functions based on two coupled displacement fields (the polynomial coefficients are coupled through consideration of the differential equations of equilibrium) are derived for pretwisted beams. Next, the stiffness and mass matrices of the finite element model are obtained by using the energy expressions. Finally, the natural frequencies of pretwisted rotating Timoshenko beams are obtained and compared with previously published both theoretical and experimental results to confirm the accuracy and efficiency of the present model. The new pretwisted Timoshenko beam element has good convergence characteristics and excellent agreement is found with the previous studies.
  • Master Thesis
    Vibration Characteristics of Portal Frames
    (Izmir Institute of Technology, 2013) Tatar, İlhan; Yardımoğlu, Bülent
    This research study deals with the defining of dynamic behaviors of a portal frame structure with tapered members by using Finite Element Method (F.E.M.) and experimental modal analysis. Portal frame with three beam members is used in this study. Frame structure is composed by two tapered and one uniform cross sectioned beams. The first part of thesis is about the finite element modelling of the model which is developed in ANSYS. Theoretical modal analysis to find the natural frequencies and mode shapes of the frame is performed by using the finite element model. The second part of thesis is experimental modal analysis of the frame under study. For this purpose, the experimental modal test setup has been established. The modal parameters found from both numerical and experimental methods are compared and good agreement is found.
  • Master Thesis
    Dynamic Analysis of Flexible Mechanisms by Finite Element Method
    (Izmir Institute of Technology, 2010) Ülker, Hakan; Yardımoğlu, Bülent
    In this study, vibration characteristics of flexible four-bar mechanisms are investigated by using the procedure developed in ANSYS. Kinematics and kinetics of the four-bar mechanism having rigid and flexible links are presented for finite element modelling of the flexible mechanism. Equations of motion for rigid and flexible four-bar mechanisms are derived by using Lagrangian dynamics to show the theoretical approach. In order to find the natural frequencies of the flexible four-bar mechanism for different configurations, eigenanalysis of the mechanism is carried out by considering the discrete crank positions. Dynamic natural frequencies based on the motion induced axial loads are found by using the discrete inertia forces acting on the nodes of the finite element model. The mode shapes of the flexible four-bar mechanism are also found and plotted with undeformed configurations.