Dynamics and Control of Micropolar Material Structures with Embedded Angular Momentum

30年前，有人提出将包含大量陀螺仪的结构系统建模为嵌入角动量连续分布的弹性连续体。这个想法来自航天界，在那里非常大的空间平台(卫星)的概念很受欢迎，控制它们的形状和方向的方法很感兴趣。最初的工作确立了结构形状控制这一想法的优点，但人们的兴趣减弱了，因为这些系统因其成本而无法实现。在尺度光谱的另一端，存在着应用这一想法的新机会。微电子机械系统(MEMS)设备为构建“智能”材料系统提供了前所未有的机会，这种系统将在宏观上显示常规材料无法实现的行为。随着微纳器件制造的不断发展，如果有令人信服的理由，可以创造出一种包含嵌入的、独立的和可控的角动量分布的材料。具有这些属性的材料，以前被称为回转材料，很少受到关注，但先前的工作已经确定了它们在结构形状控制方面的潜力。这种能力可以有益地结合在光学设备中以调谐反射镜，在航空应用中主动控制边界层行为，或者可能在非常小的形状变化可能是有利的外科器械中结合。它有很多潜在的应用。这些材料模型需要一个不对称的应力张量，并且已经证明，假定应变和应力张量不对称的材料模型在微米尺度上是有效的和适用的。因此，建议用微极弹性理论研究由分布的惯性、弹性、耗散和陀螺影响引起的基本贡献材料和结构系统的动力学和控制。

Thirty years ago it was proposed to model structural systems that contained a very large number of gyroscopes as an elastic continuum with an embedded continuous distribution of angular momentum. The idea came from the astronautics community where the notion of very large space platforms (satellites) was popular and means of controlling their shape and orientation were of interest. Initial work established the merits of the idea for structural shape control but interest waned because these systems would not be realized owing to their cost. A new opportunity for application of this idea lies at the opposite end of the scale spectrum. Micro-Electro-Mechanical-Systems (MEMS) devices offer an unprecedented opportunity to build "smart" material systems that will macroscopically display behaviours not possible with conventional materials. With the ongoing developments in micro and nano device fabrication a material that contains an embedded, independent, and controllable distribution of angular momentum could be created, should there be compelling reasons to do so. Materials with these attributes, previously referred to as gyric materials, have received scant attention but prior work has established their potential for structural shape control. This ability could be beneficially incorporated in optical devices to tune mirrors, in the active control of boundary layer behaviour in aeronautic applications, or possibly in surgical instruments where very small shape changes may be advantageous. There are many potential applications. These material models require an asymmetric stress tensor and it has been shown that material models that assume asymmetric strain and stress tensors are effective and applicable at the micron scale. Hence it is proposed that an investigation into the dynamics and control of material and structural systems with fundamental contributions from distributed inertial, elastic, dissipative, and gyroscopic influences be undertaken using a micropolar theory of elasticity.