A geometric nonlinear model for composite beams with partial interaction

In this paper a kinematical model for planar composite beams including longitudinal partial interaction as well as vertical uplift is developed within the nonlinear finite deformation theory. Afterwards a reduced formulation, useful for solving structural problems, is derived on the basis of the theory of small strain and moderate rotations. This simplification involves some limitations in the magnitude of displacements and strains, and in the geometry, which are compatible with the results commonly observed in civil structures. The resulting nonlinear problem is solved using a displacement-based finite element formulation, and some numerical results are illustrated in order to highlight the capabilities of the presented beam model.