A New Discrete-Layer Finite Element for Electromechanically Coupled Analyses of Piezoelectric Adaptive Composite Structures
M. Al-Ajmi; A. Benjeddou

doi:10.3970/cmc.2011.023.265
Source CMC: Computers, Materials & Continua, Vol. 23, No. 3, pp. 265-286, 2011
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Keywords Discrete layer, finite element, piezoelectric, composite, plate, free-vibration, short-circuit, open-circuit, effective electromechanical coupling coefficient, sensing.
Abstract A new discrete layer finite element (DLFE) is presented for electro-mechanically coupled analyses of moderately thick piezoelectric adaptive composite plates. The retained kinematics is based on layer-wise first-order shear deformation theory, and considers the plies top and bottom surfaces in-plane displacements and the plate transverse deflection as mechanical unknowns. The former are assumed in-plane Lagrange linear, while the latter is assumed in-plane full (Lagrange) quadratic; this results in a nine nodes quadrangular (Q9) DLFE. The latter is validated in free-vibrations, first numerically against ANSYS three-dimensional piezoelectric finite elements for a cantilever moderately thick aluminum plate with two co-localized piezoceramic patches, and then experimentally against a free quasi-isotropic transverse composite thin plate with four piezoceramic patches. The obtained short-circuit and open-circuit (OC) frequencies were satisfactory for both benchmarks, while the post-treated modal effective electromechanical coupling coefficients agreed well with ANSYS results (first benchmark) but only fairly with the experimental ones (second benchmark). Once validated, the Q9-DLFE was used to assess numerically the equipotential (EP) physical condition influence on the OC sensed electric potential; for this purpose, the above first benchmark, but with the top piezoceramic patch only, was finally analyzed. It was found that the EP condition homogenizes and lowers the sensed potential on the OC electrode.
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