Calculation of composite structures subjected to follower loads by using a geometrically exact shell element

Based on a 7-parameter shell model, a numerical algorithm has been developed for solving the geometrically nonlinear problem of a multilayer composite shell subjected to a follower pressure and undergoing large displacements and rotations. As unknowns, six displacements of the outer surfaces and addition ally the transverse displacement of midsurface of the shell are chosen. This allows one to use the Green–Lagrange strain tensor, introduced earlier by the authors, which exactly represents arbitrarily large rigid-body displacements of the shell in curvilinear coordinates of a reference surface. A geometrically exact solid shell element is formulated, which permits one to solve the nonlinear deformation problem for thin-walled composite structures subjected to a follower pressure by using a very small number of load steps.