Finite Element Method for the Calculation of Nonlinear Buckling of Shell Structures.

The geometrically nonlinear theory of finite displacements is formulated in terms of finite elements in a mixed representation. The problem is linearized by the method of linear increments. The method is specialized for thin shell structures and is applied in a study on the pre- and postbuckling behavior of plates and circular cylindrical shells. The effect of different boundary conditions and imperfections on the buckling behavior is made clear by a number of examples.