WIAS Preprint No. 1931, (2014)

``Entropic'' solutions to a thermodynamically consistent PDE system for phase transitions and damage



Authors

  • Rocca, Elisabetta
  • Rossi, Riccarda

2010 Mathematics Subject Classification

  • 35D30 74G25 93C55 82B26 74A45

Keywords

  • damage, phase transitions, thermoviscoelasticity, global-in-time weak solutions, time discretization

Abstract

In this paper we analyze a PDE system modelling (non-isothermal) phase transitions and dam- age phenomena in thermoviscoelastic materials. The model is thermodynamically consistent: in particular, no small perturbation assumption is adopted, which results in the presence of quadratic terms on the right-hand side of the temperature equation, only estimated in L^1. The whole system has a highly nonlinear character. We address the existence of a weak notion of solution, referred to as ``entropic'', where the temperature equation is formulated with the aid of an entropy inequality, and of a total energy inequality. This solvability concept reflects the basic principles of thermomechanics as well as the thermodynamical consistency of the model. It allows us to obtain global-in-time existence theorems without imposing any restriction on the size of the initial data. We prove our results by passing to the limit in a time discretization scheme, carefully tailored to the nonlinear features of the PDE system (with its ``entropic'' formulation), and of the a priori estimates performed on it. Our time-discrete analysis could be useful towards the numerical study of this model.

Appeared in

  • SIAM J. Math. Anal., 74 (2015) pp. 2519--2586.

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