Speaker : Prof. K.T. Ramesh, Decker Professor of Science & Engineering, The Johns Hopkins University, USA
Abstract: Extreme conditions arise in a variety of situations, some obvious (such as asteroid impacts, nuclear blasts, and major earthquakes) and some surprising but just as important (such as the leading edge of a wing, the white matter in the brain during a concussion, and when the tip of your pen hits the glass surface of your cell phone). Our interest is in the responseof materials to such extreme environments, and then in the design of new materials for those environments. How can we design materials to survive – or protect you from – an extreme environment? Our traditional approaches to design will not work here, because we do not have the information about the material behavior that we need for empirical design.
Materials in extreme environments fail in many different ways (we call these mechanisms) simultaneously. To design the material, therefore, we must try to control multiple failure mechanisms. Some of these mechanisms are not apparent under common environments, such as the phenomenon of spall (dynamic tensile failure). Many of these mechanisms involve high energy densities (e.g., a highly precompressed state) that are suddenly released, so that failure occurs at many levels.
Materials design in this context is thus a “multiscale” problem – that is, it involves a wide range of lengthscales and timescales. We demonstrate here an integrated multiscale approach to materials design that brings together mechanics, materials science, physics, chemistry, and computational science within a big data framework. As an example, we consider the design of materials to survive impacts (like a micrometeorite striking a spacecraft).
About the speaker: K. T. Ramesh is the Alonzo G. Decker Jr. Professor of Science & Engineering at Johns Hopkins University and the Director of the Hopkins Extreme Materials Institute. He is a Professor in the Departments of Mechanical Engineering, Materials Science and Engineering, and Earth & Planetary Sciences. Professor Ramesh received his doctorate from Brown University in 1987. He joined the Department of Mechanical Engineering at Johns Hopkins in 1988, becoming Department Chair from 1999-2002 and the founding director of the Hopkins Extreme Materials Institute (HEMI) in 2012. From an applications perspective, he studies integrated multiscale materials design for extreme environments, the disruption of incoming asteroids, and the mechanics of traumatic brain injuries such as concussions. Finally, he has a particular interest in the ways in which creativity is integrated into the sciences, arts and engineering.