CAREER: Dynamic Contact Modeling and Experiments on Miniature Systems

滑动接触微器件的性能和耐用性很大程度上依赖于界面现象，如粘着、摩擦、磨损和摩擦/振动相互作用。人们越来越认识到，在时变的载荷和运动存在的情况下，粘着、粘着和其他关键现象，如反弹振动，都是动态发生的。由于高速接触在更具挑战性的条件下运行，原则上接触或粘连可能随时发生。智能优点：在这项研究中，将基于与系统无关的界面模型执行系统方法来研究微系统的动态接触，这些模型与界面的系统相关动力学相耦合。该方法的一个独特特点是将基于连续介质力学的分子间(粘着)力和动摩擦力模型直接结合到动态移动的接触界面中。这将使触点长度范围从微米到毫米范围以及更远的范围被覆盖。此外，还将建造两个独特的微型摩擦计，以测量现实微型系统的关键动态特性，并进行动态接触和摩擦实验，以进行模型验证和研究HDI和MEMS中的此类现象。本研究的成果是：(A)建立了一个严格的微器件动力学摩擦模型；(B)利用该模型来预测界面作用力、阻尼力和动摩擦力，从而为控制微系统中的粘着、摩擦和磨损提供了一个强有力的工具；(C)根据设计参数，如粗糙度、材料特性和系统动力学特性，预测接触和伪接触HDI和MEMS的运动，从而避免大的振动和冲击力以及相关的灾难性后果。广泛的影响：研究计划将促进摩擦学和微摩擦学的知识，而本研究的教育计划将在研究组和大学之外传播。提高对微米/纳米摩擦学和工程学一般认识的教育目标将通过以下方式实现：(A)建立一个针对1至5年级学生(童子军)和高中生的K-12外展方案，(B)利用现代教学技术加强一门摩擦学基础课程，并招募代表不足的学生参与项目并向公众传播信息；(C)开发一个新的微型系统摩擦/振动(微摩擦动力学)研究生班，其中将包括当前的研究成果，以及(D)积极参与地方和专业学会，促进工程学和摩擦学。拟议的综合研究和教育计划将进一步推动微型机械的发展，通过广泛的技术改造，对社会产生重大潜在影响，同时提高对摩擦和摩擦学的认识和意义

The performance and durability of microdevices in sliding contact is strongly dependent on interfacial phenomena like adhesion, friction, wear, and friction/vibration interaction. It is becoming increasingly recognized that problems of stiction, adhesion and other critical phenomena such as bouncing vibrations occur dynamically in the presence of time-varying loads and motions. As high-speed contacts operate under ever more challenging conditions, contact or sticking can, in principle, occur at any time.Intellectual Merit: In this research, a systematic approach to dynamic contact studies of microsystems will be performed based on system independent interfacial models that are coupled to the system dependent dynamics of the interface. A unique feature of the proposed approach is the direct incorporation of the intermolecular (adhesion) forces and kinetic friction models based on continuum mechanics into a dynamically moving contact interface. This will enable contact length scales from micrometer to millimeter range and beyond to be covered. Also, two unique microtribometers will be built to measure key dynamic properties of realistic miniature systems, and to conduct dynamic contact and friction experiments for model verification and for studying such phenomena in HDI's, and MEMS. The outcome of this research is to: (a) Develop a rigorous kinetic friction model for microdevices; (b) Use the model to predict interfacial forces, damping and kinetic friction, thus providing a powerful tool for controlling adhesion, friction and wear in microsystems; (c) Predict the motions of contacting and pseudo-contacting HDI's and MEMS as a function of design parameters like roughness, material properties, and system dynamic properties, thus avoiding large vibrations and impact forces and the associated catastrophic consequences.Broader Impacts: The research plan will advance the knowledge of tribology and microtribolgy, while the education plan of this research will disseminate it outside the research group and beyond the University. The educational goals of increasing the awareness of micro/nanotribology and engineering in general, will be accomplished by: (a) establishing an outreach K-12 program targeting students grades 1 through 5 (cub-scouts) and high school students, (b) enhancing a basic tribology course using modern teaching techniques and also recruiting underrepresented students to work on projects and disseminate the information to the public, (c) developing a new graduate class in friction/vibration for miniature systems (microtribodynamics) that will include current research findings, and (d) actively participating in local and professional societies to promote engineering and tribology.The proposed integrated research and education plan will advance further the development of micromachines, which has a major potential impact on society through transformation of a wide range of technologies, and at the same time increase the awareness and significance of friction and tribology