Modelling rotational friction damping devices using the Non-Smooth Dynamics method

Abstract

The dynamic response of frames equipped with an anti-seismic rotational friction damper is studied. The algorithm of the Non-Smooth Dynamics method (NSD), specifically designed for the numerical simulation of non-smooth dynamical systems, was programmed to efficiently deal with the non-smooth character of the friction law. An extensive campaign of numerical computations was carried out to study different frames, either submitted to a harmonic excitation force or to the ground acceleration history of the El Centro earthquake. Each friction damper has two prestressed bracing bars; the cases of axially rigid and axially compliant bracing bars were considered. Performance criteria enabled to conclude on the optimal range for the maximum moment at the frictional hinge of the damper. For the analyzed frames of one, three and five floors and for both rigid and deformable bracing bars, under the action of the El Centro earthquake, it was concluded that the optimal range for the frictional moment is wide and approximately independent of the number of floors. An important reduction of the relative displacements and absolute accelerations of the floors of the frames with friction dampers was observed with respect to the situation of absent frictional damping.