Multilayer shells: Geometrically-exact formulation of equations of motion

We present here a formulation for geometrically-exact multilayer shells, wh ere the number of layers is completely arbitrary and not necessarily restri cted to three as in the case of sandwich shells. Based entirely in terms of stress resultants, the formulation accommodates finite deformation in memb rane, bending, and shear deformation. Typical of geometrically-exact formul ation, the kinematics of the shell is referred directly to an inertial fram e, and not by means of a floating frame. The motion of a transverse fiber o f 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 deformatio n in each layer is expressed in terms of the deformation of an arbitrary la yer chosen as a reference layer. The thickness and side dimensions of each layer are also arbitrary. These features allow a convenient modeling of mul tilayer shells with ply drop-offs. We also show that the present formulatio n reduces exactly to the case of multilayer beams. (C) 2000 Elsevier Scienc e Ltd. All rights reserved.