Control of thermoelastic deformation in a smart composite disk by a stepwise applied electric potential distribution

Abstract

This paper deals with a smart composite disk for control of a thermoelastic deformation resulting from an unknown thermal load. The disk consists of a structural layer onto which piezoelectric sensor and actuator layers are bonded. First, an unknown heating temperature distribution is inferred from a sensor output. The thermoelastic displacement on the bottom free surface is then controlled by applying electric potentials to electrodes on the actuator layers. For a composite disk with one actuator layer, applied electric potentials are determined by solving a direct optimization problem with and without stress constraints, respectively. The introduction of the stress constraints leads to a deterioration in the effectiveness of the displacement control. In order to resolve this issue, an approximate optimum design problem of a composite disk with two actuator layers is solved under stress constraints. As a result, the thermoelastic displacement is satisfactorily controlled to the desired distribution.