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Nonlinear Dynamics and Control of Flexible Structures
Final rept. Oct 1986-Jun 1990
CORNELL UNIV ITHACA NY
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The goals of these research projects were to examine the nonlinear dynamics and control of flexible structures, some of which might be used for space applications. This project was a collaborative one involving structural, electrical and mechanical engineers. A major part of the research was on trussesframes structures. Five different truss structures from three to ten meters in size were constructed, two with active controls. However, nonlinear dynamics of continuous beam type structures were also investigated. One of the principal themes was to explore what types of nonlinearities would result in chaotic and unpredictable vibrations. Loose joints in truss structures, friction, buckling and geometric nonlinearities were all found to lead to chaotic motions under certain periodic forcing conditions. Actuators and sensors for space truss active vibration suppression was investigated. New methods were developed for structural control using techniques for simulated annealing for actuator placement, nonlinear random vibrations of pin-jointed trusses, vibration analysis and new models to analyze chaotic dynamics in nonlinear structures with large deformations and friction forces. Finally, a major numerical effort resulted in new codes to predict large motions of structures under active control using parallel processing algorithms.
APPROVED FOR PUBLIC RELEASE