Geometric Nonlinearity for the Shell, Plate, Membrane, Beam, and Truss Interfaces

For the Shell, Plate, Membrane, and Truss interfaces, geometrically nonlinear analysis is handled in the same way described above. For the Membrane and Truss interfaces, geometric nonlinearity must almost always be used, because nonlinear effects supply stiffness in the transverse direction. The geometric nonlinearity in the Beam interface is limited to large rotations and displacements, but small strains. It is possible to force a geometrically linear formulation in the beam interface.