Sensitivity analysis of dry friction damper position in stay cables

Resumo

The aim of this study is to perform a comparative analysis regarding position influence of a damper
with the dry friction mechanism to control the cable vibrations in cable-stayed bridges. The finite element method
is used to implement the cable model and its validation by analytical theory. Lumped mass matrix and stiffness
matrix considering the applied stress were generated considering the cable discretization in one hundred elements.
The proportional damping matrix is obtained by the Rayleigh method with a damping rate of 0.13%. Damping rate
evaluation take into account the damper position varying unitarily in the first 10% of the cable total length. The
excitation force simulates the cable shape in its first mode of the vibration. To numerically solve the second-order
nonlinear ordinary differential equation, Newmark’s method with average acceleration is used. The damping
factors obtained made it possible to compare with other studies for viscous dampers. Time domain was used to
analysis the amplitude variation in the middle of the cable and at damper position, where it was possible to assess
mobility limitations and the feasibility of choosing the position. It can be concluded that changing the damper
position towards the cable center caused a total damping increase.