Jeffrey W. Kysar
244 S. W. Mudd, Mail Code: 4703
Phone: +1 212-854-7432
Fax: +1 212-854-3304
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Jeffrey W. Kysar is an associate 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.
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.
Publications
Mesarovic, S. D., and J. W. Kysar (1996). “Continuum aspects of directionally dependent cracking of an interface between copper and alumina crystals.” Mech. Mater. , 23, 271-286.
Kysar, J. W. (1998). “Effects of strain field on light in crack opening interferometry.” Int. J. Solids Structures, 35, 33-49.
Kysar, J. W. (1999). “Experiments and simulations of directionally dependent fracture along copper/sapphire interfaces.” Materials Research Society Symposium Proceedings, 539, 299-311.
Kysar, J. W. (2000). “Directional dependence of fracture in copper/sapphire bicrystals.” Acta Mater., 48, 3509-3524.
Kysar, J. W. (2000). “Intergranular Fracture: The effect of grain boundary orientation and crack growth directions.” Materials Research Society Symposium Proceedings, 586, 219-230.
Kysar, J. W. (2001). “Crack opening interferometry at the interfaces of a transparent materials and metals.” Experimental Mechanics, 41, 52-57.
Kysar, J. W. (2001). “Path of light in near crack tip region in anisotropic medium and under mixed-mode loading.” Int. J. Solids Structures, 38, 5963-5973.
Kysar, J. W. (2001). “Continuum simulations of directional dependence of crack growth along a copper/sapphire bicrystal interface: Part I, Experiments and crystal plasticity background.” J. Mech. Phys. Solids, 49, 1099-1128.
Kysar, J. W. (2001). “Continuum simulations of directional dependence of crack growth along a copper/sapphire bicrystal interface: Part II, Crack tip stress and deformation analysis.” J. Mech. Phys. Solids, 49, 1129-1153.
Kysar, J. W., and C. L. Briant (2002). "Crack tip fields in ductile single crystals." Acta Mater., 50, 2367-2380.
Kysar, J. W., and C. L. Briant (2002). "Crack tip deformation fields in
ductile single crystals." Acta Mater., 50, 2367-2380 .
Kysar, J. W. (2003). "Energy dissipation mechanisms in ductile fracture." J.
Mech. Phys. Solids, 51, 795-824.
Kysar J. W., and C. L. Briant (2003) "Crack tip deformation fields in
ductile single crystals (vol 50, pg 2367, 2002)" Acta Materialia, 51,
1503-1503.
Kysar, J. W. (2003). "Brittle to Ductile Transition in Intermetallic
Alloys." Materials Research Society Symposium Proceedings, 753, 483-488.
Kysar, J. W. (2004). "Initial Energy Dissipation Mechanism at Crack Tip."
Multiscale Modeling and Characterization of Elastic-Inelastic Behavior of
Engineering Materials, eds: Ahzi S., Cherkaoui, M., Khaleel M., Zbib H.,
Zikry M., and Lamatina, B., Kluwer Publishing, Dordrecht, 199-206.
Chen, H., Yao, Y.L., Kysar, J.W., (2004). "Spatially Resolved
Characterization of Residual Stress Induced by Micro Scale Laser Shock
Peening." Journal of Manufacturing Science and Engineering, 126, 226-236.
Chen, H., Kysar, J.W., Yao, Y.L., (2004). "Characterization of Plastic
Deformation Induced by Micro Scale Laser Shock Peening.", Journal of Applied
Mechanics, 71, 713-723.
Kysar, J. W. (2004). "Dependence of ductile and brittle response on initial
energy dissipation mechanism at crack tip." Mesoscale Dynamics in Fracture
Process and Strength of Materials, eds: H. Kitagawa and Y. Shibutani.,
Kluwer Publishing, Dordrecht, 289-300.
Chen, H., Wang, Y., Kysar, J. W., Yao, Y. L., (2004) "Advances in Microscale
Laser Shock Peening", Tsinghua Science and Technology, 9, 506-518.
Kysar, J. W., Gan, Y.-X., Mendez-Arzuza, G., (2005) "Cylindrical Void in a
Rigid-Ideally Plastic Single Crystal I: Anisotropic Slip Line Theory
Solution for Face-Centered Cubic Crystals", International Journal of
Plasticity, to appear.
Gan, Y.-X., Kysar, J. W., Y.-X., Morse, T. L., (2005) "Cylindrical Void in a
Rigid-Ideally Plastic Single Crystal II: Experiments and Simulations",
International Journal of Plasticity, to appear.
Chen, H., Yao, Y.L., Kysar, J.W., Noyan, I.C., Wang, Y., (2005). "Fourier
Analysis of X-ray Microdiffraction Profiles to Characterize Laser Shock
Peened Metals" International Journal of Solids and Structures, to appear.
Chen, H., Kysar, J.W., Yao, Y.L., (2005). "Experimental Characterization and
Simulation of Three Dimensional Plastic Deformation Induced by Microscale
Laser Shock Peening." Journal of Applied Mechanics, submitted.
Chen, H., Wang, Y., Kysar, J.W., Yao, Y.L., (2005). "Systematical
Characterization of Material Response to Micro Scale Laser Shock Peening."
Journal of Manufacturing Science and Engineering, submitted.
Gan, Y.-X., Kysar, J. W., (2005) "Plastic Deformation around a Cylindrical
Void in a Single Crystal with Regular Hexagonal Yield Surface" Journal of
the Mechanics and Physics of Solids, to be submitted.
Wang, Y., Chen, H., Kysar, J. W., Yao, Y. L. (2005) "Response of Thin Films
and Substrate to Micro Laser Shock Peening", Journal of Manufacturing
Science and Engineering, submitted.
Gan, Y. X., Kysar, J. W., Lee, D. (2005) "Structure and Properties of
Electrocodeposited Cu-Al2O3 Nanocomposite Thin Films", Journal of
Engineering Materials and Technology, submitted.