Multilayer shells: Geometrically-exact formulation of equations of motion

We present here a formulation for geometrically-exact multilayer shells, where the number of layers is completely arbitrary and not necessarily restricted to three as in the case of sandwich shells. Based entirely in terms of stress resultants, the formulation accommodates finite deformation in membrane, bending, and shear deformation. Typical of geometrically-exact formulation, the kinematics of the shell is referred directly to an inertial frame, and not by means of a floating frame. The motion of a transverse fiber of an N-layer shell is exactly that of a chain of N rigid links connected by universal joints, in three-dimensional space. The kinematics of deformation in each layer is expressed in terms of the deformation of an arbitrary layer chosen as a reference layer. The thickness and side dimensions of each layer are also arbitrary. These features allow a convenient modeling of multilayer shells with ply drop-offs. We also show that the present formulation reduces exactly to the case of multilayer beams. (C) 2000 Elsevier Science Ltd. All rights reserved.