A unified coupled efficient layerwise theory is presented for the dynamics of smart
laminated beams with surface-mounted and embedded piezoelectric actuators and
sensors with arbitrary poling directions, acting in extension or shear mode. The
theory considers a global third-order variation across the thickness combined with a
layerwise linear variation for the axial displacement, expressed in terms of only three
primary variables, and accounts for the transverse normal strain due to the electric
field in the approximation for the transverse displacement. The electric potential is
approximated as piecewise quadratic across sublayers. A finite element is developed
which has two physical nodes with mechanical and some electric potential degrees
of freedom (DOF), and an
electric node for the electric potentials of the
electroded surfaces of the piezoelectric patches. The
electric nodes eliminate
the need for imposition of equality constraints of the electric DOF on the
equipotential electroded surfaces of the segmented piezoelectric elements and result
in significant reduction in the number of electric DOF. The electric DOF
associated with the physical nodes allow for the inplane electric field that is
induced via a direct piezoelectric effect. The accuracy of the formulation is
established by comparing the results with those available in literature and the 2D
piezoelasticity solutions for extension and shear mode actuators, sensors and adaptive
beams. The effect of segmentation of the electroded surface on the deflection,
sensory potential and natural frequencies is illustrated for both extension and
shear mode cases. The influence of the location of extension and shear mode
actuators and sensors on the response is investigated for a hybrid mode
composite beam. The effect of actuator thickness on the actuation authority is
studied.