Title:

Multiscale Experimental Studies of Material Deformation and Failure

Speaker:

Dr. John Lambros

Affiliation:

University of Illinois at Urbana-Champaign,Aerospace Engineering

When:

Tuesday, May 18, 2010 at 11:00:00 AM   Add to Calendar

Where:

Guggenheim Building, Room 442

Host:

Bethany L. Smith
bethany.smith@aerospace.gatech.edu
404-894-3251

Abstract

As materials and structures are increasingly being used in extreme loading situations, highly accurate multiscale physics-based models are necessary that are able to describe material/structural response under a host of such extreme, and often coupled, loading. Such models would possess the potential to enable better performance and lifetime prediction over a wider range of complex loading conditions than is currently possible. However, an accurate description of material response is a prerequisite for developing such models. Even though large scale simulation efforts are underway to fulfill such an understanding, companion full field and real time experimental information is also needed to better develop, and fully validate, these models. In our work, the optical techniques of digital image correlation (DIC) in 2D, and digital volume correlation (DVC) in 3D, are employed to study material response over a range of length scales, ranging from the macroscale (2 microns/pixel) to the sub-grain level (300 nm/pixel). DIC differs form many light based interferometric techniques in that it does not possess an inherent length scale that limits resolution. This make DIC highly suitable for use across multiple length scales to provide datasets that can be easily integrated into a multiscale analysis and simulation framework. Several different case studies will be discussed that involve thermomechanical fatigue of a nickel based superalloy (Hastelloy X), dynamic loading of highly textured Zr, extreme dynamic loading response of Microelectormechanical (MEMS) systems and thin films, and granular materials for stress wave mitigation. The major challenges associated with each experimental methodology, as well as the major results in each case, will be presented.

Biography

In 1988 Dr. Lambros received a B.Eng. degree from the Aeronautics department of the Imperial College of Science and Technology of the University of London. He then spent approximately 7 years at Caltech first obtaining an M.S. degree in 1988, then a Ph.D. degree in 1994 and finally spending a year as a postdoctoral research fellow, all with the Graduate Aeronautical Laboratories (GALCIT) at Caltech. In August of 1995 he joined the Mechanical Engineering department of the University of Delaware as an Assistant Professor. He moved to the Aerospace Engineering department of the University of Illinois at Urbana-Champaign in 2000 as an Associate Professor, and became a full professor in this department in 2007. In 1999 he received an NSF CAREER award. Between 1999-2005 Dr. Lambros was Associate Editor for Experimental Mechanics. In 2007 he received the UIUC Xerox Award for excellence in faculty research, and starting in July 2008 has served as a board member of the Executive Board of the Society for Experimental Mechanics.