Frequency-amplitude response of individual polyvinylidene fluoride piezoelectric C-block actuators

There is an increasing need in the field of smart materials and structures for high-force, high-displacement actuators. C- blocks, created to meet this need, are curved piezoelectric laminated beams poled in the radial direction which flex when voltage is applied. C-blocks can be made from a number of different materials with any number of layers, both active and inactive. An important portion of the characterization of an individual C-block actuator is the identification of natural frequencies and the description of the amplitude response across the frequency spectrum. This paper introduces a simple model for the frequency-amplitude behavior of the C-block. The model is derived using Hamilton's principle to formulate the equations of motion for a general composite piezoelectric C- block, and solving the equations using the appropriate boundary conditions and piezoelectric forcing terms. To verify the model, piezoelectric polymeric C-block prototypes were fabricated and displacement amplitudes were experimentally determined across a range of frequencies. The response of the prototypes matched well the behavior predicted by the simple analytical model.