Jeffrey W. Kysar is a professor of mechanical engineering at Columbia University. His current research interests include understanding the fracture process from the atomic length scale to the macroscopic length scale, especially in materials that exhibit an elastic-plastic constitutive behavior such as ductile metals.
About
The past 15 years have seen an intense effort to try to understand and numerically simulate the physical and chemical phenomena within the region close to the tip of a crack, where large deformations and fracture mechanisms render the constitutive and geometric assumptions of continuum fracture mechanics theories invalid. This task is made very difficult because this so-called fracture process zone spans many different length scales. At its most basic level, fracture involves the separation of atoms so that simulations are performed at the sub-atomic length scale (10-11 to 10-10 m) to determine the interatomic forces and potentials using quantum mechanics calculations. Once the potentials are known, fracture simulations at the atomic length scale (10-10 to 10-7 m) are performed in which the individual atoms around a crack tip are treated discretely in order to investigate the interactions between dislocation structures and the crack tip.
However, only a very small volume of atoms can be directly simulated, so at some length scale, it becomes desirable to treat the underlying atomic structure as a continuum and to keep track only of the dislocations and dislocation structures at the microscopic length scale (10-7 to 10-5 m) using so-called discrete dislocation plasticity analyses. Eventually, the number and complexity of the dislocation structures becomes overwhelming and it is necessary to resort to a continuum-based description of elastic-plastic deformation using physics-based constitutive relationships at the mesoscopic length scale (10-5 to 10-3 m). Above this length scale, at the macroscopic length scale, conventional engineering techniques can be used to design the systems and structures that we encounter in our daily lives. In this way, a hierarchy of simulations is performed, with information passed successively from simulations at smaller length scales to simulations at larger length scales to eventually provide a coherent material description across all length scales. These efforts have been termed multiscale simulations.
Education:
Kansas State University
B.S. and M.S., Mechanical Engineering
Harvard University
S.M. and Ph.D., Engineering Sciences
Professional Experience:
Chair of Mechanical Engineering
Columbia University
07/14 to present
Professor of Mechanical Engineering
Columbia University
07/11 to present
Associate Professor
Columbia University
01/06 to 06/11
Assistant Professor
Columbia University
07/01 to 12/05
Research Associate
Brown University
09/98 to 08/01
Awards and Honors:
International Journal of Plasticity Young Research Award, 2012
Presidential Early Career Award for Scientists and Engineers, 2006
Department of Energy Early Career Scientist and Engineer Award, 2006
Frontiers of Engineering Program at National Academy of Engineering, 2003
National Science Foundation Faculty Early Career Development (CAREER) Award, 2001
Bok Center Certificate of Distinction in Teaching, Harvard University, 1995
Courtlandt S. Gross Fellowship, Harvard University, 1994|
NASA-USRA Summer Fellowship, Marshall Space Flight Center,1989
Rotary Foundation Ambassadorial Scholar, University of Canterbury, Christchurch, New Zealand, 1988