Theoretical derivation and experimental validation of a restoring force model for a self-centering rotational friction damper with variable friction device

A rotational friction damper is proposed for the mortise-tenon joints of wooden beams and columns. The proposed damper features variable friction characteristics and a degree of self-centering capability, attributed to its unique design features, including sliding teeth, a circular slope friction surface within the sliding groove, and a dish-shaped spring. This paper provides a comprehensive analysis of the damper's fundamental structure and operational mechanism, delineating the working process into five distinct stages. The output equations for each stage are derived, and a restoring force model for the damper is formulated. Subsequently, performance testing of the rotational friction damper is conducted under reciprocating force to validate the reliability of the established restoring force model. The findings indicate that the hysteretic curve of the damper exhibits a pronounced "flag-shaped" shape, with notable asymmetry between the positive and negative directions. Moreover, the damper demonstrates stable mechanical properties and effective energy dissipation capabilities. Furthermore, these results align closely with the experimental data, accurately reflecting the operational characteristics of the damper.