Space subsystems design: (navigation, control, structure and…)
Milad َAzimi; Samad Moradi
Volume 16, Issue 3 , September 2023, , Pages 15-26
Abstract
This paper deals with form-finding and free vibration analysis of a pre-stressed class-one triplex tensegrity structure. The form-finding is performed via a two-step procedure, the nodal coordinates connectivity matrix, and structural element force density determination. Accordingly, the possible states ...
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This paper deals with form-finding and free vibration analysis of a pre-stressed class-one triplex tensegrity structure. The form-finding is performed via a two-step procedure, the nodal coordinates connectivity matrix, and structural element force density determination. Accordingly, the possible states for the nodal coordinates and the structural force density of the triplex prism have been determined by trial and error (based on topology and member type knowledge) to satisfy the force density, and equilibrium matrices rank requirements. Based on different structural topologies, the equation of the motion in the frequency domain for free vibration analysis of the system is derived using the spectral element approach and dynamic shape functions. Simulations are provided for different system heights and the top-bottom aria ratios and compared with the FEM. The numerical simulations in the form of a comparative study of the natural frequencies of triplex tensegrity prism with different heights and cross-sections represent the system’s robustness with different topologies for single or multi-stage applications.
Space systems design (spacecraft, satellites, space stations and their equipment)
Mona Habibi; Mahdi Fakoor; Hadi Parviz Nowruzani
Volume 14, Issue 1 , March 2021, , Pages 65-75
Abstract
In this research, to investigate the effects of uncertainties on the natural frequency of satellite system attributed to the variation of layout components, the optimal layout of the satellite is performed utilizing particle swarm optimization (PSO) algorithm, considering stability and geometrical constraints. ...
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In this research, to investigate the effects of uncertainties on the natural frequency of satellite system attributed to the variation of layout components, the optimal layout of the satellite is performed utilizing particle swarm optimization (PSO) algorithm, considering stability and geometrical constraints. In order to produce random samples, enough number of results will be extracted, which are mass center of components, and based on the outputs, the finite element modeling of different samples by considering mass point is carried out. After modal analysis, mass and stiffness matrices are extracted, the simulation of Monte - Carlo runs based on Wishart random matrix theory and the eigenvalues of the matrix, i.e. natural frequencies, are obtained. Probabilistic distribution of natural frequencies is shown that in the proposed layout, the distribution of samples is very low and the variation of natural frequency is robust to the proposed optimal location.
