An Impedance Study of Curved Sandwich Trim Panels Driven by Piezoelectric Patch Actuators

Recent research in the area of structural acoustic control for aircraft interior noise suppression has been focused on developing active trim panels. Active trim panels being part of non-critical structures offer many advantages over active controls applied to load critical structures such as aircraft frames and skins. Because there are many flanking paths for the noise to get into the cabin, and because it is not realistic to apply active controls to the entire interior trim panel, the part of the trim that is instrumented with structural controls will inevitably be driven hard enough to cancel the cabin noise. This probably entails high power requirements for active trim panels. The present paper presents an analytical study of cylindrically curved sandwich composite trim and aluminum panels driven by piezoelectric path actuators. An impedance formulation is taken in the study. This paper studies the effect of curvature on the dynamics of the trim panel and the uniform aluminum panel, and has found that the curvature has an opposite effect on the variation of deflection resonance of the composite trim to that of the aluminum panel. Numerical results of mechanical power transfer between the actuator and the host panel are also presented in the paper. This quantity can be used to assess the control authority of the composite trim panels as compared to that of uniform aluminum panels.