Behavior of Piezoelectric Friction Dampers under Dynamic Loading

Piezoelectric materials are stressed when exposed to electric field and subjected to a restraint in their motion due to the electromechanical coupling effect. Use can be made of this property to control the motion of civil engineering structures. This paper is focused on the conceptual design of a piezoelectric friction damper and the analytical study on its behavior under harmonic loads. The friction damper takes advantage of the slip mode at the friction surface to endure the large deformation in structures and uses the piezoelectric actuators to regulate the clamped force on the damper. A new algorithm is introduced to determine the friction force for increased energy dissipation capacity. It combines the hysteretic and viscous damping mechanisms. Analytical results have shown, the superiority of the proposed algorithm over others in terms of energy dissipation. The damper is then used to mitigate the dynamic responses of a single-story frame structure subjected to harmonic loads. The structural responses controlled with a friction damper are determined numerically. However, it is found that the structure with the damper can be approximately analyzed with an equivalent linear system. This approximation greatly simplifies the design of friction dampers for practical applications.