Vibrations of Nonlinear Systems in Aerospace Structures

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It is important to study nonlinear dynamic behaviors of light-weigted of thin-walled structures, such as very flexible large space structures under a micro-gravity condition and high-speed aeroplanes subjected to high temperature and dynamic pressure. First, we examinated the nonlinear oscillation of a curved beam which modelled buckling of a plate due to aerodynamic heating in supersonic/hypersonic flight ranges, predicted that chaotic motions would appear on certain conditions of the forced intensity and the curvature of the beam because of the appearance of the horseshoe in Poin-care's map, and showed actually the occurrence of the chaotic motion using a numerical analysis. As for laminated composite plates as important elements of the light-weighted structures, a higher-order displacement field theory in which the continuity of transverse shear stresses is satisfied at interfaces ha s next been proposed to compare with existing exact and approximate analysis. Flutter and divergence of laminated composite plate wings in a supersonic flow were also studied to clarify the effect of ratios of bending/torsional rigidity of the laminae of the critical speed. Finally, the nonlinear oscillation of a cantilever beam representing an antenna during deployment from a satellite was also studied analytically and experimentally. The FEM was applied using elongating elements, and a good agreement between the analysis and the experiment was obtained. In addition to the finite element numerical analysis, the motion of a deploying beam having both ends supported was analytically examined using a green function approach.