Composite beams with weak shear connection

In the past, the theories of composite beams with weak shear connection only dealt with the problem of bending on a symmetry plane. In this paper a beam model that also takes into account the other state of stress due to torsion and bending on a plane parallel to the connection is presented, in order to analyze the consequence of a flexible connection in these usual states of deformation. In kinematics it is assumed that each component of the cross-section is rigid in its own plane and only a relative slip can occur at the interface while the contact is preserved. The system of balance equations and relevant boundary conditions is established by the virtual work principle. Such a model is used for analyzing the torsion problem of a closed box section and some numerical results referring to a rectangular box section are presented.