Advances in the development of pseudo-negative-stiffness dampers for seismic response control

Pseudo-negative-stiffness dampers or PNS dampers are controlled variable dampers that produce negative-stiffness hysteretic loops. Negative-stiffness hysteretic loops are advantageous since dampers are usually set parallel to structure's members, which have stiffness. By adding negative-stiffness hysteretic loops, artificial nonlinearity is obtained but the total force would not be larger than the member's stiffness force. Common passive dampers set parallel to structure's members will have the total force larger than the member's stiffness force. Moreover, applications of the PNS damping to the benchmark control problems for seismic response reduction are also reported. The benchmark structures, consisting of cable-stayed bridges, buildings, and highway bridges, are excited by various types of recorded ground motions. The application of PNS dampers to those benchmark structures shows that this strategy is effective in reducing seismic responses. Recently, the new negative-stiffness damper was innovated and its effectiveness was experimentally proven. Copyright © 2009 John Wiley & Sons, Ltd.