An Explicit Time Domain Spectral Finite Element for Guided Wave SHM in Composite Plate Strips with Physically Modelled Active Piezoelectric Sensors

摘要

A novel explicit time domain spectral finite element is developed which enhances the simulation accuracy and efficiency of active guided wave based SHM systems for laminated composite strips, in three distinct ways. A new generalized theoretical framework is formulated for piezolaminates which captures symmetric and antisymmetric Lamb waves by employing third-order Hermite polynomials in the approximation of displacements and electric potential through the thickness. The physical presence of piezoelectric actuators and sensors is encompassed in the governing equations. Stiffness, mass, piezoelectric and electric permittivity matrices are assembled, and the coupled transient electromechanical response is predicted by a properly formulated explicit time integration scheme. The excellent accuracy and computational efficiency of the developed FE is first validated against reported numerical results. Additional correlations are presented with measured Lamb wave responses generated by PZT active sensor pairs on carbon/epoxy plate strips.