Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Stiffnes Requirements of Shear Diaphragms Used To Brace Steel I-Beams(Izmir Institute of Technology, 2017) Akbaba, Andaç; Dönmez, Cemalettin; Eğilmez, Oğuz ÖzgürThe buckling capacity of steel I-beams can be increased by providing lateral bracing along the length of the beams by either cross-frames or diaphragms. Metal sheeting that is often used in steel building and bridge constructions to support the fresh concrete, acts like a shear diaphragm and provides continuous bracing to steel beams. In building industry, metal deck forms are considered as a lateral support to the beams. However, due to their flexible connection detail between the girder and shear diaphragm, metal deck forms are not considered as a brace source for bridge construction industry. But with the recent studies, by improvements of the flexible connection details, metal decking can be used as a bracing system. An adequate bracing system must possess sufficient stiffness and strength. A computational study was conducted to investigate stiffness requirements of shear diaphragms used to brace stocky and slender steel I-beams. Both doubly and singly symmetric sections were studied. The computational study consists of eigenvalue buckling analyses on perfectly straight twin-girder system braced by shear diaphragms and large deformation analyses with imperfect girders with different configurations of girder sections and spans. A three dimensional computer programme was utilized to perform analytical studies. Analytical model is verified by a full-scale twin-girder system laboratory test that is carried out on a previous study. Stiffness requirements have been proposed for shear diaphragms used to brace stocky and slender steel I-beams.Master Thesis Development and Experimental Verification of the Stiffness Matrix of the Hiphad Haptic Device(Izmir Institute of Technology, 2015) Taner, Barış; Dede, Mehmet İsmet CanIn this work the evaluation of stiffness performance of HIPHAD haptic device has been studied with 2 semi-analytical and an experimental method in order to obtain the stiffness characteristics of the haptic device for precise motion tracking performance. Since the compliance of a robot depends highly on robot configuration and force is variable in the haptic applications, stiffness properties of main robot elements and methods of evaluating stiffness of a robot manipulator is investigated considering the computational costs. Virtual Joint Method (VJM) and Structural Matrix Analysis (SMA) method is applied to the case study. Although, structural matrix analysis reduces the computational time dramatically by reducing the node elements it is not accurate as Finite Element Analysis (FEA) method. Comparing the VJM to the SMA, it is applicable to online application due to its simplicity and flexibility. In addition, with FEA based link modelling VJM is as accurate as FEA method in finding stiffness of the manipulator. While both methods can include flexible joints FEA based link stiffness parameters computational costs for these methods is the performance criteria for choosing one. For the case study HIPHAD, the VJM method provides better result in terms of flexibility and computation cost with 0.035 seconds finding the resultant force while SMA method calculates result in 0.074 seconds.