Microbeams under Mechanical Shock and Electrostatic Actuation Accounting for the Effects of Circuit Board and Package Motion

提出的研究目的是通过探索MEMS器件中机械冲击，非线性静电力以及封装和印刷电路板（PCB）运动之间鲜为人知的复杂相互作用，推动微机电系统（MEMS）发展的前沿。由于其小尺寸和高功能，MEMS器件可以提供成本，可制造性和可靠性优于传统的传感器和执行器系统。然而，限制MEMS商业化的一个关键问题是它们在遭受机械冲击时的性能。此外，MEMS成长的一个关键标准是它们在坚硬表面上掉落时的性能和生存能力；对于便携式和手持设备来说尤其如此。这样的冲击会在承载MEMS器件的PCB中引起弯曲运动。这种运动可以传递到微观结构，导致其崩溃或错误的功能，例如在MEMS传感器的情况下给出错误的测量。此外，MEMS中的冲击载荷可能会引起伸缩和相关的短路问题。该项目将模拟、表征和测试在冲击/跌落载荷和非线性静电力联合作用下的微光束，并考虑PCB和封装运动。将重点介绍两种常用的MEMS微光束配置：夹紧和无夹紧微光束。基于非线性欧拉-伯努利梁模型的降阶模型将用于理论研究。我们的理论结果将通过在不同水平的静电驱动和机械冲击载荷下对微加工硅梁进行表征和测试来验证。这项研究将有助于解释文献中报道的许多故障，并将允许设计人员避免它们并设计改进和更可靠的MEMS器件。这项工作将揭示机械冲击对常见但很少被理解的动态拉入现象的影响的重要信息。此外，这项研究的结果将提高许多基于微束的MEMS传感器和执行器的可靠性和商业可行性，这些传感器和执行器在我们的日常生活中广泛使用，例如在汽车中。研究结果还将用于研究由加速触发的智能可调谐微动开关新技术的可行性。这些开关的可调谐特性允许根据各种触发需求定制设备，并可能导致未来的应用和目前无法预见的产品。本研究将训练两名研究生在MEMS微结构的建模、仿真、表征和测试方面。从这项研究中获得的知识将支持MEMS动力学新课程的发展。此外，该项目将在项目期间培训本科少数民族学生，使他们接触这一新的研究领域，并鼓励他们参加研究生院。

The aim of the proposed research is to push the frontiers of micro-electro-mechanical systems (MEMS) development by exploring the little understood complex interaction between mechanical shock, nonlinear electrostatic forces, and the motion of the package and printed circuit board (PCB) in MEMS devices. Because of their small size and high functionality, MEMS devices can offer cost, manufacturability, and reliability advantages over traditional sensors and actuators systems. However, a critical issue limiting the commercialization of MEMS is their performance when subjected to mechanical shock. In addition, a crucial criterion for the growth of MEMS is their performance and survivability when dropped on hard surfaces; this is especially true for portable and handheld devices. Such an impact can induce bending motion in the PCB carrying the MEMS device. This motion can be transmitted to a microstructure leading to either its collapse or to a false function, such as by giving wrong measurements in the case of MEMS sensors. Also, shock loads in MEMS can induce stiction and related short circuit problems. This project will model, characterize, and test microbeams under combined shock/drop loads and nonlinear electrostatic forces and accounting for the PCB and packaging motion. Two commonly used MEMS microbeam configurations will be focused on: clamped-clamped and clamped-free microbeams.Reduced-order models based on the nonlinear Euler-Bernoulli beam model will be used for the theoretical investigation. Our theoretical results will be verified by characterizing and testing micromachined silicon beams under various levels of electrostatic actuation and mechanical shock loads.This research will help explain many of the failures reported in the literature, and will allow designers to avoid them and design improved and more reliable MEMS devices. This effort will reveal significant information about the effect of mechanical shock on the common, but rarely understood, dynamic pull-in phenomenon. In addition, the results of this research will improve the reliability and commercial viability of many microbeam-based MEMS sensors and actuators, which are used in a wide spectrum of applications in our everyday life, such as in automobiles. The results will also be used to investigate the feasibility of a new technology of smart tunable microswitches triggered by acceleration. The tunable nature of these switches allows for tailoring of the device for various triggering needs and may lead to future applications and products currently unforeseen. This research will train two graduate students on the modeling, simulation, characterization, and testing of MEMS microstructures. Knowledge from this research will support the development of a new course on the Dynamics of MEMS. Also, this project will train undergraduate minority students over the duration of the project to expose them to this new area of research and encourage them to attend graduate school.