Tuesday, January 29, 2013
4:00 PM - 5:00 PM
Where: Technological Institute, L211, 2145 Sheridan Road, Evanston, IL 60208 map it
Audience: Faculty/Staff - Student - Public
Category: Lectures & Meetings
The Department of Materials Science and Engineering welcomes you to its 2013 Winter Colloquium series.
Kevin J. Hemker
Professor and Chair
Department of Mechanical Engineering
Johns Hopkins University
Tuesday, January 29, 2013
Tech L211, 4:00pm
“Micro-scale Characterization and Multi-scale Failure Modeling of Layered Thermal Protection Systems”
Modern thermal and environmental protection systems have multiple layers and functionalities, and important phenomena governing the life of these systems occur in each layer and especially at the interfaces between layers. Mechanical characterization of the various layers is complicated by their reduced dimensionality and the need to measure small-scale and scale-specific properties at elevated temperatures. This talk will highlight recent micro-scale experiments that have been developed to characterize constituent properties and summarize the incorporation of these experimental findings into two salient TBC failure models. The first employs a special purpose multilayer code, developed by Balint and Hutchinson and applicable to TGO rumpling and ratcheting. The second describes a collaborative experimental and multi-scale modeling effort to develop a design code for systems that fail by abrupt delamination along the TGO-bond coat interface. A new experimental technique for measuring mode II delamination toughness, the compression edge delamination test, will also be presented, and insight gained from this work will be interpreted in context of the need for hierarchical models of layered material systems.
Biography: Kevin J. Hemker is the Alonzo G. Decker Chair of Mechanical Engineering and is currently Professor and Chair of the Department of Mechanical Engineering at Johns Hopkins University, and holds joint appointments in the Departments of Materials Science & Engineering and Earth & Planetary Sciences. He holds a BS in metallurgy from the University of Cincinnati (1985), MS and PhD degrees in materials science and engineering from Stanford University (1990), and completed a postdoctoral fellowship in physics at the Ecole Polytechnique Federale de Lausanne. He is a former editor of Scripta Materialia, is on the board of directors of The Minerals, Metals, Materials Society (TMS), a fellow of the American Society of Mechanical Engineers (ASME), a Fellow of the American Society of Metals (ASM International), and a member of the DARPA Defense Sciences Research Council (DSRC).