Analysis, Design Optimization and Control of Flexible Adaptive Structures to Attenuate Noise and Vibration

在航空航天、地面和海上交通工具中，对更高速度、更低燃料消耗和更高有效载荷能力的需求增加，这要求在这些交通工具中使用的承载结构尽可能轻。然而，柔性轻质结构通常是轻微阻尼的，因此在变化的外部干扰下，在其较低的固有频率附近可以容易地被激励。这可能导致过度振动，这可能导致结构部件的疲劳失效或整个系统的灾难性失效。低频振动还可能导致严重的结构噪声，为乘客和机组人员创造恶劣的环境，这可能导致长期反复暴露的严重健康问题。由于传统被动结构的性能限制以及全主动系统的复杂硬件和大功率要求，包括半主动可控电流变（ER）和磁流变（MR）流体和弹性体的自适应结构作为设计满足可靠性、性能和人体舒适性标准的下一代低成本轻质结构的可行技术已经受到越来越多的关注。MR和ER材料是一类智能多功能材料，其流变性能可以分别通过改变外部电场和磁场来快速、连续和可逆地控制。与ER材料相比，MR材料可以提供显著更高的可控场依赖屈服强度和模量，因此一直是最近研究的焦点。将分布式MR材料直接集成到柔性结构中，以及开发基于MR的自适应调谐减振器，可以提供独特的机会来提供可变刚度和阻尼特性，从而大大增强这些独特智能材料在宽频率范围内的控制权威。拟议的研究旨在为具有MR材料的柔性自适应结构开发分析、设计优化和控制策略，以在宽频率范围内衰减噪声和振动。

The increased demand for higher speed, lower fuel consumption and higher payload capacity in aerospace, ground and marine vehicles requires the load carrying structures used in these vehicles to be as light as possible. However, flexible lightweight structures are typically lightly damped and thus can be easily excited near their lower natural frequencies under varying external disturbances. This may lead to excessive vibration, which may cause fatigue failure of structural components or catastrophic failure of whole systems. Vibrating at low frequencies can also cause severe structure-born-noise creating a harsh environment for passengers and crews, which may lead to severe health issues under repeated long-term exposure. Due to the performance limitation of traditional passive structures and also the complex hardware and large power requirements of fully active systems, adaptive structures comprising semi-active controllable Electrorheological (ER) and Magnetorhelogical (MR) fluids and elastomers have received growing interest as a viable technology to design the next generation of cost-effective lightweight structures which meet standards for reliability, performance and human comfort. MR and ER materials are types of smart multifunctional materials whose rheological properties can be controlled rapidly, continually and reversibly through variation of an external electric and magnetic field, respectively. MR materials can provide significantly higher controllable field-dependent yield strength and moduli compared with their ER counterparts and thus have been the focus of recent studies. Integration of distributed MR materials directly into flexible structures and the development of MR-based adaptive tuned vibration absorbers can offer unique opportunities to provide variable stiffness and damping properties which greatly enhance the control authority of these unique smart materials over a broad range of frequencies. The proposed research aims to develop analysis, design optimization and control strategies for flexible adaptive structures featuring MR materials to attenuate noise and vibration in a broad frequency range.