Nonlinear Finite-Element Analysis of Stranded Conductors With Variable Bending Stiffness Using the Tangent Stiffness Method

Stranded conductors are widely used structural components. Owing to their construction in layers, their bending stiffness may vary according to their tension, curvature and deformation history. Recently, a sound and practical model of variable bending stiffness using the secant stiffness method became available. Based on the same physical assumptions, this paper presents the development of a variable bending stiffness model using the tangent stiffness method and its implementation in a classical finite- element formulation adapted for nonlinear analysis under arbitrary loading. This extends its use to a general finite-element program. Comparisons with static and dynamic tests on short-span substation conductors show that the model computes a representative bending stiffness for such cases and yields adequate predictions of tractions generated at their ends, in both static and dynamic regimes.