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、空间和海洋车辆尽可能轻。这些结构通常具有轻度阻尼和柔性，并且由于外部干扰的变化（可能与设计阶段考虑的干扰不同），在其较低的自然频率附近很容易受到激励。这可能导致过度振动，这不仅会影响结构系统的性能，而且可能导致子系统或组件失效，随后导致整个系统的灾难性故障。传统被动结构的这种性能限制最近激发了人们对开发一类称为智能或自适应结构的新结构的极大兴趣。智能结构是一种自适应结构，它由一个集成了传感器和执行器的主结构组成，并由一个控制器控制，该控制器能够在时变的环境和操作条件下修改结构的动态响应。 基于智能磁流变液的自适应结构是实现半主动振动控制的有效途径。这些结构可以有效地利用结构的运动，以使用自适应可调MR器件来产生控制力，并提供无源系统的可靠性，同时保持完全有源系统的多功能性和适应性，而不需要大的电源和昂贵的硬件。 该研究将探索智能MR流体和阻尼器的独特功能，并将增强嵌入MR流体或与MR阻尼器集成的自适应结构系统在不可预测的环境激励下的性能。将制定基于数学基础的高效和创新的分析和设计优化技术，以找到所需的配置并抑制各种激励下的振动。还将进行基础实验研究，其中将制造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.