An improved efficient zigzag theory (IZIGT) and an improved third-order theory
(ITOT) are presented for hybrid piezoelectric angle-ply composite circular cylindrical
shells under electrothermomechanical loading. In both theories, the potential and
thermal fields are approximated as piecewise linear across a number of sublayers so
that the nonlinear potential field and actual temperature profile across the
laminate thickness can be captured to any desired degree of accuracy. The
transverse displacement is approximated to explicitly account for the transverse
normal strain resulting from thermal and electric fields without introducing
additional unknowns. The shear traction free conditions on the top and bottom
surfaces in both theories and the continuity of transverse shear stresses at layer
interfaces in the IZIGT are satisfied exactly considering coupled constitutive
equations. The theories are assessed in comparison with the available exact 3D
piezothermoelasticity solution for simply supported angle-ply hybrid cylindrical
panels under electrothermomechanical loads. The comparisons for a hybrid test
panel, a composite panel, and a sandwich panel establish that the IZIGT is very
accurate and the ITOT is an improvement over the conventional third-order theory
for thermal loads, which assumes uniform deflection across the laminate
thickness.
