Stability and instability results of the Kirchhoff plate equation with delay terms on boundary or dynamical boundary controls
In this paper, we consider two models of the Kirchhoff plate equation, the first one with delay terms on the dynamical boundary controls (see system (1.1) below), and the second one where delay terms on the boundary control are added (see system (1.2) below). For the first system, we prove its well-posedness, strong stability, non-exponential stability, and polynomial stability under a multiplier geometric control condition. For the second one, we prove its well-posedness, strong stability, and exponential stability under the same multiplier geometric control condition. Finally, we give some instability examples of system (1.2) for some choices of delays.