Piezoelectric T-Beam Actuators

This paper develops models, fabricates, experimentally tests, and optimizes a novel piezoelectric T-beam actuator. With a T-shaped cross-section, and bottom and top flanges and web electrodes, a cantilevered beam can bend in both in-plane and out-of-plane directions upon actuation. Analytical models predict the tip displacement and blocking force in both directions. Six mesoscale T-beam prototypes are monolithically fabricated by machining and microfabrication techniques and experimentally tested for in-plane and out-of-plane displacements and out-of-plane blocking force. The analytical models closely predict the T-beam displacement and blocking force performance. A nondimensional analytical model predicts that all T-beam designs for both in-plane and out-of-plane actuations, regardless of scale, have nondimensional displacement and blocking force equal to nondimensional voltage. Another form of nondimensional model optimizes the T-beam cross-section for maximum performance. Optimization study shows that a cross-section with width ratio, b*, and thickness ratio, t*, approaching zero produces maximum displacement, b*=t*=0.381 produces maximum blocking force, and b*≈0.25, t*≈0.33 produces maximum mechanical energy.