Master Degree / Yüksek Lisans Tezleri

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

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Subject: search.filters.subject.Materials--Dynamic testing

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  • Master Thesis
    Static and Dynamic Deformation Behavior of Combined Geometry Aisi 304l Stainless Stell Shells
    (Izmir Institute of Technology, 2015) Şahin, Selim; Taşdemirci, Alper; Güden, Mustafa; Taşdemirci, Alper; Güden, Mustafa; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, the static and dynamic crushing behavior of combined geometry shells consisting of hemi-spherical and cylindrical segments were studied both experimentally and numerically. The proposed geometries were manufactured by deep drawing. Due to the nature of the deep drawing process, specimens inherited significant amount of residual stress/strain and thickness variation along the cross-section was observed. Thus, the manufacturing process was also numerically modeled explicitly. Quasi-static compression and dynamic drop weight tests were conducted both experimentally and numerically. The plastic deformation of the combined geometry shells started with the inward dimpling of the hemi-spherical segment and progressively continued deforming with the asymmetric or axisymmetric folding in cylindrical segment depending on the radius to thickness ratios and strain rates. The failure/fracture was observed in the thicker specimens at dynamic strain rates and that caused decreases in specific absorbing energy (SAE) levels. In addition, the energy partitions between the hemi-spherical segments increased at higher loading rates. Furthermore, the inertia and rate sensitivity influenced the crushing response of cylindrical segment more than that of hemi-spherical segment and inertia effect was more pronounced than the rate sensitivity at higher loading rates. Considering the thermal effects in the crushing behavior of the combined geometry shells, it was shown that the mean crushing load lowered as the temperature increased. Additionally, the percentages of increase in the crushing load were limited at lower temperatures for varying loading rates. It was shown that as the absolute temperature increased the percentage of increase in crushing load was significantly increased due to the change in deformation mode.
  • Master Thesis
    Dynamic Behavior of Reinfor Ced Concrete Frames With Infill Walls
    (Izmir Institute of Technology, 2011) Çankaya, Mehmet Alper; Dönmez, Cemalettin; Dönmez, Cemalettin; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Current practices utilize infill walls as insulation or partition material but not as a structural material. The main reason for this choice is the complexity of the partition wall-frame interaction behavior. Therefore infill walls typically ignored in the structural designs. However, existence of partition walls heavily effect stiffness, strength and behavior of structures. The main purpose of the presented study is the investigation of the dynamic parameters of reinforced concrete frames with and without infill walls. Moreover, lateral strength, stiffness and energy dissipation properties of the frames are also studied. In order to achieve the purpose four planar, one-bay, four story RC frames with 1/5 scale are designed, constructed and tested. In the frames main parameters are selected as presence of partition walls and ductile/non-ductile reinforcement detailing. Experiments are consisted of static and dynamic tests. In static tests each frame subjected to lateral loads that were applied at the each story level to provide a lateral loading increasing with height. Lateral load levels were controlled by the drift levels in the first story. Dynamic tests were performed at the end of each deformation level and modal analysis methods are utilized. Analyses have shown that existence of partition walls in the frame increased the natural frequencies of the frames. However, reinforcement detailing did not have a significant effect on natural frequencies. It is also observed that the natural frequencies of the frames decreased with increasing damage level. On the other hand, presence of partition walls effected the damaged behavior of the frames and drift is observed to concentrate to the first story with the increasing level of damage. And finally stiffness, strength and energy dissipation properties of frames with partition walls are observed to be dramatically higher than the frames without partition walls.