Optimum design and vibration suppression of flexible adaptive structures

对高速和低能耗的日益增长的需求要求陆地、太空和海上交通工具尽可能轻。这些结构通常具有轻微的阻尼和柔性，并且由于不同的外部干扰（可能与设计阶段考虑的不同），可以很容易地在其较低的固有频率附近被激发。这可能导致过度振动，不仅会影响结构系统的性能，而且可能导致子系统或部件失效，从而导致整个系统的灾难性失效。传统被动结构的这种性能限制最近引起了人们对开发一种称为智能或自适应结构的新型结构的极大兴趣。智能结构是一种自适应结构，由集成了传感器和执行器的主结构组成，并由能够在时变环境和操作条件下修改结构动态响应的控制器控制。采用智能磁流变液的自适应结构是实现不同环境激励下的半主动振动控制的一种可行有效的方法。这些结构可以有效地利用结构的运动来开发使用自适应可调谐磁阻装置的控制力，并提供无源系统的可靠性，同时保持全主动系统的多功能性和适应性，而不需要大型电源和昂贵的硬件。本研究将探索智能磁流变液和阻尼器的独特特性，并将提高嵌入磁流变液或集成磁流变阻尼器的自适应结构系统在不可预测环境激励下的性能。基于数学基础的高效创新的分析和设计优化技术将被制定，以找到理想的配置，并在广泛的激励下抑制振动。还将进行基础实验研究，其中将制作概念验证测试自适应结构并评估其性能。

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.