Simulation, Reliability and Optimal Design of Micro-Electro-Mechanical (MEM) Structures

9321508 MACDONALD微机电（MEM）器件由集成的可移动微结构和电子器件组成。 对于具有高纵横比且尺寸范围为0.1 - 100{SYMBOL 109 \f“Symbol”}m的结构元件，可以通过施加低电压（{SYMBOL 187 \f“Symbol”} 10伏）获得显著的力和/或变形。 这里的指导原则是制造用于精确运动和致动的集成可移动微结构。 MEM结构的制造技术与超大规模集成电路（VLSI）技术密切相关。 主要应用领域是微传感器和微执行器。 这项技术的可能应用非常广泛。 据信，可以用MEMS技术制造全新类别的机械、光学、流体、热和化学机器。 研究重点是发展微机电（MEM）结构的更好的理解，并涉及仿真，可靠性分析和优化设计。 该研究小组是跨学科的，包括一名具有纳米结构领域实验研究主要专业知识的电气工程师，两名具有应用力学计算机模拟主要专业知识的机械工程师，包括优化问题，以及断裂力学领域的专家。 研究团队还包括学术界和工业界之间的合作。 预计研究团队的多样性将导致思想的交叉施肥，从而在这一具有挑战性的研究领域的知识基础上取得重大进展。 此外，工业研究人员常驻大学校园，将大大促进向工业界“转让技术”的进程。 该项目有三个主要重点领域。 第一个是有效和准确地模拟MEM结构的静态和动态行为，受到电场，因此静电力。 非线性行为-几何，以及相关的材料，将包括在模拟中。 一个状态的耦合的外部边界元法（BEM）的电气分析和内部有限元法（FEM）的机械分析，将用于此目的。 第二个任务是可靠性分析的MEM结构进行循环，动态加载。 在这里，一个有代表性的问题要研究的是随时间变化的裂纹扩展的振动梁和梁的固有频率和振型的影响。 最后，第三个任务是MEM结构的优化形状设计。这里，可变截面振动梁的形状将被设计为具有期望的固有频率特性。 研究的每一个方面都将有实验和分析的平衡。 因此，例如，测量的频率与时间曲线上逐渐开裂的梁将被用来解决裂纹识别的逆问题，和优化设计的MEM梁将被制造和他们的性能测试对其他形状的梁。 ***

9321508 MACDONALD Micro-electro-mechanical (MEM) devices consist of integrated movable micro-structures with electronics. With structural elements having high aspect ratios and being in the size range of 0.1 - 100{SYMBOL 109 \f "Symbol"}m , significant forces and/or deformations can be obtained with the application of low voltages ({SYMBOL 187 \f "Symbol"} 10 volts). The guiding principle here is to fabricate integrated, movable microstructures for precision motion and actuation. Fabrication techniques for MEM structures are closely related to very large scale integration (VLSI) technology. Primary application areas are in micro-sensors and micro-actuators. Possible applications of this technology are very diverse. It is believed that entire new classes of mechanical , optical, fluid, thermal and chemical machines can be fabricated with MEMS technology. The research focus is development of a better understanding of micro-electro-mechanical (MEM) structures and involves simulation, reliability analysis and optimal design. The research team is interdisciplinary, involving an electrical engineer with primary expertise in experimental research in the area of nanostructures, two mechanical engineers with primary expertise in computer simulation in applied mechanics, including optimization problems, and an expert in the area of fracture mechanics. The research team also includes a collaboration between academia and industry. It is expected that the diversity of the research team will lead to a cross-fertilization of ideas leading to significant advances in the knowledge base in this challenging research area. In addition, the presence of an industrial researcher, who is resident at a university campus, will greatly facilitate the process of "technology transfer" to industry. The project has three primary focus areas. The first is the efficient and accurate simulation of static as well as dynamic behavior of MEM structures, subjected to electric fields, and hence electrostatic forces . Nonlinear behavior-geometric, as well as, where relevant, material, will be included in the simulation. A state of the are coupling of an exterior boundary element method (BEM) for electrical analysis and interior finite element method (FEM) for mechanical analysis, will be employed for this purpose. A second task is reliability analysis of MEM structures subjected to cyclic, dynamic loading. Here, a representative problem to be studied is time-dependent crack growth in a vibrating beam and its effect on the natural frequencies and mode shapes of the beam. Finally, the third task is optimal shape design of MEM structures. Here, the shapes of variable cross-section vibrating beams will be designed to have desired natural frequency characteristics. Every aspect of the research will have a balance of experiment and analysis. Thus, for example, measured frequency versus time curves on a progressively cracking beam will be used to solve the inverse problem of crack identification, and optimally designed MEM beams will be fabricated and their performance tested against beams of other shapes. ***