Woodruff School of Mechanical Engineering
COE/Structural Mechanics Seminar
Building from the Bottom Up: Simulation-Based Design of Bioinspired Materials
Prof. Sinan Keten
Assistant Professor, Northwestern University, Evanston, IL
Monday, October 20, 2014 at 3:00:00 PM
MRDC Building, Room 4211
A grand challenge in materials design is to blend disparate properties in a single system just like nature does, such as strength and toughness in structural materials inspired from nacre. While biological principles and building blocks provide inspiration for synthetic materials, finding optimal solutions by trial-and-error is slow and expensive. In this talk, we will discuss how we can speed up this process with computer simulations and by taking lessons from nature. In pursuit of stronger, lighter, tougher materials, new coarse-grained molecular simulation techniques that provide insight into the structure-property relationships in polymer nanocomposites will be presented. The applications covered will involve functionalized graphene-polymer nanocomposites and nanocellulose neat films and nanocomposites. Simulations will first delineate the conditions under which dramatic changes in the polymer layer 3D constitutive behavior emerges due to nanoconfinement. In analogy with nacre, the discussion will draw similarities to recent experimental findings on the role of the organic nanolayers, identifying how interphases contribute to the impressive mechanical properties of biological and bioinspired composites. Findings on the localization and failure behavior of the multi-layer graphitic phase will be presented to emphasize differences between biological systems and engineering counterparts. Multi-scale studies on nanocellulose will be presented to discuss challenges and opportunities for using the natureís most common structural building block to achieve desired material properties. Key importance of nanoscale interfaces and moisture effects on macroscopic mechanical response will be illustrated. I will conclude with a discussion of the strengths and the shortcomings of continuum theories in describing nanostructured materials. Finally, prioritizing the bottom up self-assembly paradigm in soft matter, I will conclude with a question: Are nanoscale features such as confinement and chemical interactions important for biomimicry, or focusing on structure alone through top-down additive manufacturing is our best solution?
Sinan Keten is an Assistant Professor of Civil & Environmental Engineering and Mechanical Engineering at Northwestern University. He joined Northwestern University faculty in 2010 after obtaining his Ph.D. in Civil & Environmental Engineering from MIT. His research expertise is on computational materials science and mechanics with an emphasis on biological and bioinspired systems such as spiderís silk, nanocellulose and novel nanocomposites. His most notable contributions have involved theoretical calculations and multi-scale simulations that have explained how biological nanostructured materials achieve strength and toughness through important molecular level size and geometric effects. He has published 40 articles in journals such as Nature Materials, PNAS, and Nano Letters and highlighted in mainstream media, Science, and Nature Physics. Dr. Keten currently serves as the principal investigator for federally funded research projects by the National Science Foundation (The Materials Genome Initiative), Office of Naval Research, and Army Research Office. He has given numerous invited lectures and keynotes around the world and has received awards from the Materials Research Society and the American Society of Mechanical Engineers. Dr. Keten is also actively involved in creating new web-based educational tools that facilitate training of students and researchers in mechanics, materials and computational engineering around the world.
Refreshments will be served.