Optimal control problems for 1D parabolic state-systems of KWC types with dynamic boundary conditions

Abstract

In this paper, we consider a class of optimal control problems governed by 1D parabolic state-systems of KWC types with dynamic boundary conditions. The state-systems are based on a phase-field model of grain boundary motion, proposed in [Kobayashi--Warren--Carter, Physica D, 140, 141--150, 2000], and in the context, the dynamic boundary conditions are supposed to reproduce the transmitted heat exchanges between interior and boundary of a polycrystal body. Our optimal control problems are labeled by using a constant $ \varepsilon \geq 0 $, and roughly summarized, the case when $ \varepsilon = 0 $ and the cases when $ \varepsilon > 0 $ correspond to the physically realistic setting, and its regularized approximating ones, respectively. Under suitable assumptions, the mathematical results concerned with: the solvability and continuous dependence for the state-systems; the solvability and $ \varepsilon $-dependence of optimal control problems; and the first order necessary optimality conditions in the problems when $ \varepsilon > 0 $ and the limiting optimality condition as $ \varepsilon \downarrow 0 $; will be obtained in forms of three Main Theorems of this paper.