Multilayer shells: Geometrically-exact formulation of equations of motion

arbitrary and not necessarily restricted to three as in the case of sandwich shells. Based entirely in terms of stress resultants, the formulation accommodates ®nite 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 ¯oating frame. The motion of a transverse ®ber 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-o€s. We also show that the present formulation reduces exactly to the case of multilayer beam