|When:||Monday, October 7, 2013|
3:00 PM - 4:00 PM
Technological Institute, L211 |
2145 Sheridan Road
Evanston, IL 60208 map it
|Audience:||- Faculty/Staff - Student - Public|
|Contact:||Cara Elizabeth Lapinski
|Group:||McCormick - Mechanical Engineering|
Mechanical Engineering 512 Seminar Series presents Kyung-Suk Kim, Professor of Engineering at Brown University and Simpson Memorial Visiting Faculty Fellow, Northwestern University.
ABSTRACT: In recent years nano science and technology has enabled us to explore new functional properties of hierarchical ruga structured materials through folding or wrapping thin surface layer structures with nanometer scale features. The Latin word ruga means a state of a “large-amplitude” wrinkle, crease, fold or ridge to form various 1-D or 2-D patterns. As multi-scale surface morphologies of rugae determine effective properties such as wetting, adhesion, friction and optoelectronic properties, ruga state control is considered as a viable method for real-time regulation of effective surface properties. It is found that graded or layered elastic properties of the substrate can provide diverse bifurcation paths of surface deformation under lateral compression, producing various surface ruga states. In the first half of the talk I will introduce mathematical analysis of sequential bifurcation processes in surface deformation of a neo-Hookean substrate with its elastic modulus exponentially decaying along the depth from its free surface. In turn, iso-periodic-compression Ruga Phase Diagram of neo-Hookean solids with their moduli exponentially decaying with depth has been constructed, and its implications on engineering multi-scale ruga structures are presented. In the second half of the talk, a new invention of dual-tip AFM interferometer (DT-AFMI) will be introduced. Then, it will be shown how the DT-AFMI is used to discover a static shock (strain discontinuity) in graphene, i.e. a crinkle ridge (a nano-ruga !). The static shock has its transition thickness of only 2.7nm. The crinkle ridge networks on graphite surfaces exhibit high protein adsorptivity; implications of the high protein adsorptivity on the function of an artificial graphite heart valve will be discussed as an application example.
BIO: Kyung-Suk Kim received his B.S. (1974) and M.S. (1976) degrees in Mechanical Engineering from Seoul National University in South Korea. He received his Ph.D. in Solid Mechanics from Brown University in Providence, Rhode Island in 1980. He served on the faculty of University of Illinois at Urbana-Champaign from 1980-1989, where he was promoted from Assistant Professor to Associate Professor. After his time at UIUC, he became a Full Professor of Engineering at Brown University, where he presently teaches.
Professor Kim has been working as an engineering scientist, as an inventor, and as an educator to contribute to the rapidly evolving society. His research interest is in an interdisciplinary area, solid mechanics of small scale material structures; nano and micromechanics of solids in both experiment and theoretical modeling. For his research he has invented numerous new scientific instruments and analytical methods, and he has recently initiated “ruga mechanics” as a new thrust in applied mechanics research. For teaching, he has developed a number of innovative laboratory course materials, including “Bow and arrow dynamics”, “Wheel and suspension dynamics” and “Violin and bell dynamics” laboratory course materials. So far, he has advised 26 PhD students and Post Docs who are currently in academia or industries. For public service, he is currently a board member and the secretary of the Society of Engineering Science.