Vibration and acoustic numerical analysis of gregorian type communication antenna planted on communication satellite

Karaoğlu, Onur Kaan
The acoustic load during lift-off of the spacecraft rockets is one of the most destructive loads especially for the light and large space structures. This thesis mainly focuses on vibro-acoustic behavior of a large composite reflector satellite antenna. The study starts with manufacturing processes, material properties and design criteria of the antenna which is Gregorian type with two reflectors. Then, Finite Element Model (FEM) of the antenna which is prepared in HyperMesh is analyzed structurally with calculation of modal and frequency response in MSC. NASTRAN. The FEM model and results are adjusted by using the sine-sweep test results performed on a modal shaker. After obtaining proper FEM model, vibro-acoustic numerical model is constructed and solved in MSC. ACTRAN. One of the strongest parts of this thesis is presenting acoustic test results performed in a reverberant chamber which provides the diffuse sound field. In summary, this thesis presents manufacturing processes of satellite reflector antenna and examines the vibration and acoustic test responses and FEM results with their comparisons.


A Control moment gyroscope based on rotational vibrations, dynamic model and experimentation
Arberkli, Ferhat; Azgın, Kıvanç; Department of Mechanical Engineering (2018)
Satellite attitude determination and control system is one of the main subsystems of a spacecraft. Within this domain, there are several types of actuators; such as reaction wheels, control moment gyroscopes (CMG), propulsion systems and magnetic torque rods. All of them are common and currently being used on modern satellites and space stations depending on the application. Conventional reaction wheel and CMG operation are based on the continuous rotation of their rotor mass to exchange angular momentum be...
Attitude control of an earth orbiting solar sail satellite to progressively change the selected orbital element
Ataş, Ömer; Tekinalp, Ozan; Department of Aerospace Engineering (2014)
Solar sailing is currently under investigation for space propulsion. Radiation pressure from the Sun is utilized to propel the spacecraft. This thesis examines locally optimal steering law to progressively change the selected orbital elements, without considering others, of an Earth centered Keplerian orbit of a cube satellite with solar sail. The proper attitude maneuver mechanization is proposed to harvest highest solar radiation force in the desired direction for such Earth orbiting satellites. The satel...
Acoustic Fatigue and Dynamic Behavior of Composite Panels Under Acoustic Excitation
Uz, Canan; Ata, Tamer T. (2016-01-28)
Composite panels in aircraft structures are exposed to fluctuating sound pressure originating mostly from engine noise and air flow. In this paper, acoustic fatigue and dynamic response of composite panels under acoustic excitation are investigated numerically. Composite panel is simulated with finite element analysis. The panel is considered clamped at one edge, whereas the opposite edge is assumed to be free. The panel is subjected to random repeated loading generated by sound waves. The analysis estimate...
Kahraman, Ozgur; Tekinalp, Ozan (2009-02-12)
Low Earth orbit satellites are usually equipped with magnetic torquers for momentum dumping and reaction wheels to carry out three axis attitude stabilization and control. These two different types of actuators mixed and used together to carry out slew maneuvers. The problem of allocating the control to these different types of actuators is realized using a recently developed algorithm called blended inverse. The algorithm is compared with the Moore-Penrose pseudo inverse demonstrating its success in realiz...
Development of structural optimization and neural network design tool for buckling behaviour of skin stringer structures under combined compression and shear loading
Okul, Aydın; Gürses, Ercan; Department of Aerospace Engineering (2019)
Stiffened panels are commonly used in aircraft structures in order to resist high compression and shear forces with minimum total weight. Minimization of the weight is obtained by combining the optimum design parameters. The skin panel dimensions, the stringer spacing and the stringer dimensions are some of the critical parameters which affect the global buckling behaviour of the stiffened panel. The aim of this thesis is to develop a neural network design tool and to carry out a geometric optimization for ...
Citation Formats
O. K. Karaoğlu, “Vibration and acoustic numerical analysis of gregorian type communication antenna planted on communication satellite,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Mechanical Engineering., Middle East Technical University, 2020.