Actuation and sensing of piezolaminated sandwich type structures

A new piezolaminated sandwich type structure to be eventually used as a smart wall for active control of sound radiated by harmonically excited thin walled structures is proposed. The present study presents the equations of motion of the new adaptive sandwich structures in a sufficiently accurate model in a form readily for solution either in closed-form or by approximate methods. The theoretical natural frequencies are compared with an approximate evaluation and test results yielding a good correlation. It also yields the axial strains and the curvature of the composite beam leading to the calculation of equivalent mechanical loads produced by the piezoceramic actuator for inclusion in a finite element code. The numerical results are compared with experimental ones obtained during a test series on a cantilever sandwich beam equipped with piezoceramic sensors and actuators and constructed according to the new proposed concept. The influence of the input voltage on the performance of the new sandwich structure is investigated. The beam tip deflection induced by the piezoceramic actuators is measured and compared with numerical and finite element predictions to yield a very good match. Both the numerical and the experimental results show the applicability of the new proposed concept.