CAREER: Dynamic Contact Modeling and Experiments on Miniature Systems

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

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