Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Vibration Analysis of Pre-Twisted Rotating Beams(Izmir Institute of Technology, 2003) Yıldırım, Tolga; Yardımoğlu, Bülent; Yardımoğlu, Bülent; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyA 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 Free Vibration Analysis of Curved Beams With Variable Cross-Sections on Elastic Foundations(Izmir Institute of Technology, 2013) Yazıcı, Ümit Okan; Yardımoğlu, Bülent; Yardımoğlu, Bülent; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyFree out of plane vibration characteristics of curved beams with variable cross-sections on elastic foundations are studied by TMM (Transfer Matrix Method) since the mathematical model of the present system based on the coupled differential eigenvalue problem with variable coefficients which can not be solved easily by exact methods. Vibrations of beams on different elastic foundations are reviewed. Out of plane vibration of curved beams on different elastic foundations are investigated. TMM is detailed with its applications to vibration problems. To solve the vibration problems, TMM is examined with several computer programs developed in Mathematica. The accuracy of the TMM results obtained from the developed program is evaluated by comparing with FEM results found from model created in ANSYS. Finally, the effects of the variation of cross-section of the curved beams and elastic foundation parameters on natural frequencies are investigated.Master Thesis Free Vibration Analysis of Curved Beams With Variable Radii of Curvature on Elastic Foundations(Izmir Institute of Technology, 2013) Çelebi, Sanal; Yardımoğlu, Bülent; Yardımoğlu, Bülent; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyFree out of plane vibration characteristics of curved beams with variable curvature on elastic foundation are studied by Finite Difference Method (FDM) since the mathematical model of the present system based on the coupled differential eigenvalue problem with variable coefficients. Firstly, vibrations of beams on different elastic foundations are reviewed. Then, out of plane vibrations of curved beams on different elastic foundations are investigated. FDM is detailed for this study. To solve the coupled differential eigenvalue problem, FDM is examined with several computer programs developed in Mathematica. The effects of curvature of the curved beams and elastic foundation parameters on natural frequencies are investigated. The accuracy of the present results obtained from the developed program is evaluated by comparing with FEM results found from model created in ANSYS.Master Thesis Out-Of Vibrations of Planar Curved Beams Having Variable Curvature and Cross-Section(Izmir Institute of Technology, 2012) Kaygısız, Kaan; Yardımoğlu, Bülent; Yardımoğlu, Bülent; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, out of plane vibration characteristics of curved beams having variable curvatures and cross-sections are studied by FDM (Finite Difference Method). The effects of curvature and cross-section of the curved beam on natural frequencies are investigated for the curved beams having; variable curvature & constant cross-section and variable curvature & variable cross-section. Mathematical model of the present problem is based on the coupled differential eigenvalue problem with variable coefficients. Numerical solutions of the problem in this study are obtained by the computer program developed in Mathematica. The accuracy of the present results obtained from the developed program is evaluated by comparing with FEM (Finite Element Method) results found from solid model created in ANSYS. Good agreement is obtained in the comparisons of the present results with other results. All results are presented in tabular and graphical forms.