Dynamics of Cable Structures: Modeling and Applications

Keywords: Earthquake engineering, cable dynamics; nonlinear dynamics; flexible bus conductors; earthquake excitation; tensegrity; complementarity

Abstract: The use of cables may be seen in different engineering applications such as suspension and cable-stayed bridges, tensegrity systems, power transmission lines and moorings in ocean engineering. During extreme excitations, cables can undergo large displacements and be subjected to complex three-dimensional motion. Besides tension, cables can be subjected to shear, bending and torsion. In electrical substations, cable configurations can be seen that cannot be explained by simple tension. In the first part of this report, a 3-D finite deformation beam formulation is presented and applied to the analysis of the complex nonlinear dynamic behavior of flexible bus conductors used in electrical substations. Comparison of the finite element analyses with experiments clearly shows that stiffness and damping in these conductors are dependent on the amplitude of motion. The second part of the work is focused on tensegrity structures, a particular type of prestressed cable structure. An approach is presented for the dynamic analysis of these structures based on casting the computation in each time increment as a complementarity problem.