The excitation of waves by piezoelectric patch actuators arranged symmetrically on both surfaces of an elastic layer

An electromechanical system consisting of an elastic waveguide and flexible symmetrically arranged piezoelectric patch actuators attached to both of its surfaces is considered. In the mathematical model employed, which takes into account both the dynamic contact interaction of the patch with the waveguide and the presence of higher modes of oscillation of the layer, the effect of the geometrical and physical parameters of the system on the amount of energy delivered by the piezoelectric actuators in the substrate and its distribution between the excited Lamb waves is investigated. The analysis is carried out using the solution of a system of integro-differential equations, to which the boundary-value problem considered is reduced. In particular, it is shown that the maximum radiation of energy, transferred by antisymmetric and symmetric normal modes, is reached when the width of the patch is equal to a half-integer number of wavelengths of one of the normal modes of the patch-layer-patch triple-layer structure.