Optimum design and vibration suppression of flexible adaptive structures

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The increase demand for high speed and less energy consumption requires that the land, space and marine vehicles to be as light as possible. These structures are typically lightly damped and flexible and can be easily excited near their lower natural frequencies due to varying external disturbances which may be different than those considered in the design stage. This may lead to excessive vibration which not only can influence the performance of the structural system but also may cause subsystems or components to fail, subsequently causing the catastrophic failure of the whole system. Such a performance limitation of the traditional passive structures has recently motivated considerable interests in developing a new class of structures called smart or adaptive structures. A smart structure is a self-adaptive structure made up of a host structure which is integrated with sensors and actuators and directed by a controller capable of modifying the dynamic response of the structure in the presence of time-varying environmental and operational conditions. Adaptive structures using smart Magnetorheological (MR) fluid have been shown to be a feasible and effective way to semi-actively control vibration under different environmental excitations. These structures can effectively utilize the motion of the structure to develop the control forces using adaptive tunable MR devices and offer the reliability of passive systems, yet maintaining the versatility and adaptability of fully active systems, without requiring large power sources and expensive hardware. The proposed research, with its many fundamental and applied research oriented components, will explore the unique feature of smart MR fluid and dampers and will enhance the performance of adaptive structural systems embedded with MR fluids or integrated with MR damper under unpredictable environmental excitations. Efficient and innovative analysis and design optimization techniques based on the mathematical foundation will be formulated to find a desired configuration and suppress the vibration under a wide range of excitations. Fundamental experimental studies will also be conducted where the proof of-concept test adaptive structures will be fabricated and their performance will be evaluated.