Yannis Dafalias
Professor
Civil & Environmental Engineering
2001 Engineering III
(530) 752-3423
Ph.D. 1975 University of California, Berkeley
The main focus of Professor Dafalias' research is the development and implementation of constitutive models for engineering materials such as metals, soils, concretes, polymers, etc. Particular issues and attributes of this research effort are as follows:
(1) Anisotropy of constitutive modeling as a result of texture development at large plastic deformations, and relation between micro and macro mechanical perspectives. The concept and application of constitutive and plastic spins are pursued.
(2) Unified soil constitutive models for monotonic and cyclic loadings. Emphasis is given in obtaining realistic but parsimonious models, which are user-friendly in both calibration and numerical implementation.
(3) Description of localization by enhancing the constitutive models with higher order gradient of state variables. Consideration of large deformation and rotation within the localized zones. Effect in the solution of inhomogenous boundary value problems.
Dr. Dafalias has been the recipient of the Japanese Society of Soil Mechanics and Foundation Engineering Foreign Researcher Shield Plate, and the American Society of Civil Engineers Walter L. Huber Research Prize.
Selected Publications
Dafalias, Y. F. (1993) "Planar double-slip micromechanical model for polycrystal plasticity", J. Eng. Mech., ASCE, 119, 1260-1284.
Cho, H.W. and Dafalias Y. F. (1996) "Distortional and orientational hardening at large viscoplastic deformations", Int. J. Plasticity, 12, 903-925.
Manzari, M. T. and Dafalias Y.F. (1997) "A critical state two-surface plasticity model for sands", Geotechnique, 47, 255-272.
Dafalias, Y. F. (1998) "Plastic spin: necessity or redundancy ?", Int. J. Plasticity, 14, 909-931.
Li, X.-S, Dafalias,Y.F. and Wang, Z.-L. (1999) "State dependent dilatancy in critical state constitutive modelling of sand", Canadian Geotechnical Journal, in press.