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Research and Study of Mechanical Properties and Corrosion Behavior of Welded Joint of Ductile Cast Iron to AISI 304 Austenitic Stainless Steel with Buttering of Nickel on Cast Iron Side
, M.Sc. Thesis Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor)
Abstract
The current work is carried out to characterize welding of AISI 304 Austenitic Stainless Steel to Ductile Cast Iron. The welding method was SMAW and the welds were produced using a Nickel-Buttering by a pure Nickel electrode(ENi1) on Cast Iron side, then by 4 types of filler materials the joints were produced; Ni-base electrode(Ni1), E308 and E309 Austenitic stainless steel electrodes and E7018 electrode. The preheat temperature of Cast Iron has been selected to be 250○ and 500 ○C to avoid crack of weldments. The comparative evaluation was based on metallography, chemical composition, hardness and corrosion behavior on two different preheat temperatures. According to metallography, the best...
Harness Aquatic Clean Energy from Vortex Induced Vibration
, M.Sc. Thesis Sharif University of Technology ; Abbaspour, Madjid (Supervisor) ; Afshin, Hossein (Co-Advisor)
Abstract
Transverse Vortex-Induced Vibration(VIV) and Flow-Induced Vibration(FIV) of a rigid, circular, elastically mounted single degree of freedom cylinder is scrutinized in range 3×104≤ Re ≤12×104 by means of Computational Fluid Dynamics(CFD). ANSYS CFX, based on FV, is employed to simulate VIV and FIV in different system parameters such as stiffness and mass ratio. Firstly, the minimum structured, hexahedron computational cell required to simulate VIV and FIV by means of Finite Volume (FV) method is provided. Then, the appropriate size for computational domain to simulate VIV and FIV accurately is discussed concisely. Approximated amplitude and frequency ratio are compared to experimental data...
Design of a Robust Active Controller to Suppress the Undesirable Vibration of Power Transmission Lines by Using the Intermediate Actuators and Optimization of Their Locations
, M.Sc. Thesis Sharif University of Technology ; Moradi, Hamed (Supervisor)
Abstract
Power transmission lines, which are responsible for the distribution and transmission of electrical energy from the power plant to the consumer areas, due to their characteristics such as long length and flexibility with low structural damping, face environmental irritations, especially the galloping phenomenon, causing many damages annually. In this study, it has been attempted to reduce the vibrations of power transmission lines by designing a robust active control and by using intermediate actuators in such a way that the failures of these lines can be prevented. For this purpose, linear modeling of the system and designing the controller using the pole replacement method have been done....
Design and Construction of a Test Stand for Studying Experimentally Energy Harvesting from Galloping Effect
, M.Sc. Thesis Sharif University of Technology ; Ebrahimi, Abbas (Supervisor)
Abstract
In the last decade, harvesting energy from renewable phenomena in nature has attracted the attention of many researchers and turned it into a hot research focus. Wind flow around the world is an endless, repeatable and available source of energy. Therefore, harvesting wind energy disrupts the damaging cycle of fossil fuels to nature and fades over time. Therefore, in order to convert the mechanical green energy in the wind into electricity, mechanisms based on aeroelastic instabilities have attracted the attention of researchers. In this research, it is intended to design and build a test platform that is a suitable platform for research and testing on the aeroelastic instability of...