A refined zigzag theory is presented for laminated-composite and sandwich plates
that includes the kinematics of first-order shear deformation theory as its baseline.
The theory is variationally consistent and is derived from the virtual work
principle. Novel piecewise-linear zigzag functions are used, providing a more
realistic representation of the deformation states of transverse shear-flexible
plates than other similar theories. The formulation does not enforce full
continuity of the transverse shear stresses across the plate’s thickness, yet it is
robust. Transverse shear correction factors are not required to yield accurate
results. The theory avoids the shortcomings of earlier zigzag theories (such as
shear-force inconsistency and difficulties in simulating clamped boundary
conditions) which have limited their accuracy. This new theory requires only
-continuous
kinematic approximations and is perfectly suited for developing computationally
efficient finite elements. It should be useful for obtaining relatively efficient, accurate
estimates of structural response, needed in designing high-performance load-bearing
aerospace structures.