Seyed Mohammad Navid Ghoreishi; Mohammad Aminjafari; Amir Sedaghati; Ehsan Zabihian
Abstract
The structure of a satellite, during its operational life, must be tolerated all applied mechanical loads which the most important of them is vibration loads during the launch. To ensure the verification of design of the satellite structure, finite element analysis and vibration tests should be performed ...
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The structure of a satellite, during its operational life, must be tolerated all applied mechanical loads which the most important of them is vibration loads during the launch. To ensure the verification of design of the satellite structure, finite element analysis and vibration tests should be performed on the structure of satellite according to the ECSS standard. In this paper, while simultaneously examining the optimal design process for a satellite structure with an increase in the strength to mass ratio, the required finite element analyzes along with the mechanical tests of the structure of a telecommunication satellite, including random vibrations, sinusoidal vibrations, shock and quasi-static, are fully presented. The results showed that by employing the cross section design for the satellite structure, the natural frequency of the satellite in the longitudinal direction have increased appreciably, which increases the strength of the satellite in the longitudinal direction. Also, the results of the conducted tests proved that the designed structure meets the frequency requirements of the launcher while tolerate the mechanical loads during launch. The results of the tests were in good agreement with the finite element analysis, including the modal analysis, random and sine vibrations and indicate the verification of the design of the satellite structure
Control dynamics
Ehsan Maani miandoab; Ehsan Zabihian; Hossein Najafi
Abstract
In all types of satellites, communication systems are utilized for data transmission between satellite and ground stations. pointing the communication antennas to the ground is necessary for the correct mission transmission information. The vibration of the satellite antenna leads to deforming antenna ...
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In all types of satellites, communication systems are utilized for data transmission between satellite and ground stations. pointing the communication antennas to the ground is necessary for the correct mission transmission information. The vibration of the satellite antenna leads to deforming antenna pattern, creating noise and reducing connection quality. Moreover, working the attitude control actuators near the antenna's natural frequency leads to its resonance and large amplitude vibration in the antenna and satellite structure. Thus it is necessary to identify the satellite antenna dynamic behavior as natural frequency and damping ratio. In this paper, the satellite antenna is intended as a smart beam, based on the free vibration of clamped-free beam shape of satellite antenna and sensing its vibration by the piezoelectric sensor, its dynamic characteristic as damping and frequency is identified and verified by comparing the results with experimental ones. The considered mathematical model is very accurate and this model can be used to determine the dynamic behavior of the antenna in different satellite secondary structures.
