CMU Campus
Center for                           Nonlinear Analysis
CNA Home People Seminars Publications Workshops and Conferences CNA Working Groups CNA Comments Form Summer Schools Summer Undergraduate Institute PIRE Cooperation Graduate Topics Courses SIAM Chapter Seminar Positions Contact
Seminar Abstracts

Gianni Dal Maso

Quasistatic evolution for Cam-Clay plasticity


Cam-Clay nonassociative plasticity exhibits both hardening and softening behavior, depending on the loading. For many initial data the classical formulation of the quasistatic evolution problem has no smooth solution. We propose here a notion of generalized solution, based on a viscoplastic approximation. To study the limit of the viscoplastic evolutions we rescale time, in such a way that the plastic strain is uniformly Lipschitz with respect to the rescaled time. The limit of these rescaled solutions, as the viscosity parameter tends to zero, is characterized through an energy-dissipation balance, that can be written in a natural way using the rescaled time. It turns out that the proposed solution may be discontinuous with respect to the original time, and our formulation allows to compute the amouunt of viscous dissipation occurring instantaneously at each discontinuity time.

TUESDAY, September 22, 2009
Time: 1:30 P.M.
Location: PPB 300