Design, Characterization and Sensitivity Analysis of a Piezoelectric Ceramic/Metal Composite Transducer

This article presents experimental characterization and numerical simulation techniques used to create large amplitude and high frequency surface waves with the help of a metal/ceramic composite transducer array. Four piezoelectric bimorph transducers are cascaded and operated in a nonlinear regime, creating broad band resonant vibrations. The used metallic plate itself resembles a movable wall which can align perfectly with an airfoil surface. A phase-shifted operation of the actuators results in local displacements that generate a surface wave in the boundary layer for an active turbulence control application. The primary focus of this article is actuator design and a systematic parameter variation experiment which helped optimize its nonlinear dynamics. Finite Element Model (FEM) simulations were performed for different design variants, with a primary focus in particular on the minimization of bending stress seen directly on the piezo elements while achieving the highest possible deflection of the vibrating metallic plate. Large output force and a small yield stress (leading to a relatively small output stoke) are characteristics intrinsic to the stiff piezo-ceramics. Optimized piezo thickness and its spatial distribution on the bending surface resulted in an efficient stress management within the bimorph design. Thus, our proposed resonant transduction array achieved surface vibrations with a maximum peak-to-peak amplitude of 500 μ m in a frequency range around 1200 Hz.