Master Degree / Yüksek Lisans Tezleri

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

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Author: search.filters.author.Aktaş, EnginSubject: search.filters.subject.Finite element model

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  • Master Thesis
    A Practical Finite Element Model of Tsadwa Type Semi-Rigid Connections for Push-Over Analysis of Steel Frames in Sap2000
    (01. Izmir Institute of Technology, 2021) Şeker, Öncel; Aktaş, Engin
    In steel structural analyses, beam to column connections is traditionally fully pinned or fully rigid. In the analysis assumption, moment (rigid) connections are assumed not to undergo rotation, and shear (pinned) connections can't transfer moment. These classifications do not represent actual connection behavior. Moment (rigid) connections have some relative flexibilities to rotate, and shear (pinned) connections have some capacity to transfer moment. In the light of these actual connection capabilities, another type of connection called partially restrained (PR) or semi-rigid connection is introduced. This study focuses on the behavior of bolted top, and seat angle with double web angle (TSADWA) connection using finite element method (FEM) software (ANSYS) to obtain moment-rotation curves, including geometrical and mechanical properties of the connection and adaptation of the PR connection behavior into the planar frame is performed for performance analysis through SAP2000 software by considering current codes and literature. Azizinamini's (Azizinamini, 1985) experimental and Frye and Morris's (Frye & Morris, 1975) mathematical moment-rotation curves are used to compare with the curves produced in the ANSYS to validate the feasibility of the finite element based PR connection models. A portal frame model with an 8S10 PR connection in the SAP2000 for performance analysis is also compared with the ANSYS portal frame model to demonstrate the correlation between the push-over analysesto reduce the margin of error. Although there is a lack of experimental information on the TSADWA connected frame models, results show that semi-rigid connection models and their usage on the steel frames can propose a reliable and practical methodology for the analysis process.
  • Master Thesis
    Reliability Based Seismic Assessment of Unanchored Circular Steel Storage Tanks
    (Izmir Institute of Technology, 2020) Bektaş, Nurullah; Aktaş, Engin
    Since liquid storage tanks are important systems for the safety of industrial facilities, the tightness of these structures and their serviceability are key issues. Therefore, the ability of large liquid storage tanks to withstand damage during earthquakes is of great relevance not only to the engineering profession but also to the safety of society in general. This is because these structures often form an important part of a community's lifeline and therefore should remain in use in emergency situations. In addition, since the content stored in some facilities could be hazardous, in this case, necessary measures must be taken against accidental infiltration. Due to the importance of storage tanks for society, there are many studies and standards in the literature on the behavior of liquid storage tanks. The most detailed method is the incremental dynamic analysis, which considers the time history analysis within a finite element model for the seismic analysis of unanchored circular steel liquid storage tanks to assess performance. In this study, a performance-based study was conducted on the dynamic behavior of an unanchored circular steel liquid storage tank in order to consider possible improvements in the design phase of the model to withstand earthquakes. It is assumed that the tanks stand on a rigid foundation and are exposed to one-way horizontal ground motion. The main purpose of the study is to determine the performance of the structure for certain failure criteria by using the engineering program ABAQUS to perform reliability-based analyzes of the model.