CAREER: Dynamic Contact Modeling and Experiments on Miniature Systems

滑动接触中微器件的性能和耐久性强烈依赖于界面现象，如粘附、摩擦、磨损和摩擦/振动相互作用。 人们越来越认识到，在存在时变载荷和运动的情况下，会动态地出现静摩擦、粘附和其他关键现象，如弹跳振动。 由于高速接触下操作更具挑战性的条件下，接触或粘附，原则上，可以发生在任何时间。智力优点：在这项研究中，一个系统的方法来动态接触研究的微系统将进行基于系统独立的界面模型，耦合到系统相关的动态接口。 该方法的一个独特之处是将基于连续介质力学的分子间（粘附）力和动摩擦模型直接纳入动态移动接触界面中。 这将使接触长度尺度从微米到毫米的范围和超越被覆盖。 此外，将建立两个独特的微型摩擦计来测量实际微型系统的关键动态特性，并进行动态接触和摩擦实验，用于模型验证和研究HDI和MEMS中的此类现象。 （B）利用该模型预测界面力、阻尼和动摩擦力，为微系统的粘附、摩擦和磨损控制提供了有力的工具;（c）预测接触和伪接触HDI和MEMS的运动作为设计参数的函数，如粗糙度、材料特性，更广泛的影响：研究计划将促进摩擦学和微摩擦学的知识，而这项研究的教育计划将在研究小组和大学之外传播它。 提高对微/纳米摩擦学和工程学的认识的教育目标将通过以下方式实现：（a）针对一至五年级的学生，制定一项K-12外展计划（B）利用现代教学技术加强基础摩擦学课程，并招募代表性不足的学生从事项目工作并向公众传播信息，（c）开设一个新的微型系统摩擦/振动研究生班（微观摩擦动力学），包括最新的研究成果，以及（d）积极参与当地和专业协会，以促进工程和摩擦学。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，通过广泛的技术变革对社会产生重大的潜在影响，同时提高人们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