Design, fabrication, nonlinear analysis, and experimental validation for an active sandwich beam in strong electric field and thermal environment

Abstract

In the present work, an efficient one-dimensional finite element (1D-FE) framework considering layerwise mechanics with full electro-mechanical coupling has been developed for the laminated smart sandwich beams submitted to active damping. Nonlinear constitutive relations of piezo-thermo-elasticity at large electric field with temperature-dependent material properties have been considered. The efficient layerwise theory (ELWT) considers the normal deformation of the piezoelectric sensing/actuating patches/layers due to the more significant value of piezoelectric strain coefficient d33. The electric potential variation across the thickness of the PZT sensor/actuator has been assumed quadratic. The state space format of the dynamical system has been constructed based on a reduced order model in modal space. The feedback linearization approach has been applied to the nonlinear system of equations to design an equivalent linear optimal control strategy. An experimental facility has been developed to test the accuracy of the present nonlinear FE model. This facility consists of a thermal chamber with a heating system, air gun, actuation & sensing units with band-pass filters, a smart sandwich beam equipped with PZT-SP5H patches, a data acquisition system, and a computer with LabVIEW software. Open- and closed-loop responses from the present 1D-FE model have been compared with those obtained through experimentation at different temperatures. It has been observed that the current nonlinear FE model correctly captures the dynamic behavior of the vibrating smart sandwich beam at different operating temperatures and strong electric field. The study shows a strong dependence of the PZT materials on thermal chamber temperature and actuation field. New results for a smart sandwich beam are also presented to study the performance of PZT-SP5H patches as sensors/actuators for nonlinear active shape and vibration control in a thermal environment. The effect of piezoelectric actuator/sensor thickness, patch size, position, and applied mechanical load on the active shape and vibration control has been discussed.