Analytical, numerical and experimentalstudieson the Semi-Active Friction TendonHernan

For controllingvibrations, a Semi-Active Friction Tendon (SAFT), which consists of a semi-active friction damper and an auxiliary spring that are linked to the structure by a cable, is studied experimentally, numerically and analytically. Two semiactive control laws are implemented, one is based on velocity feedback (denoted as SQDCL) and the other is based on force feedback (denoted as SPCL); the passive control case is also studied for comparison. Based on the structural displacement reduction and the hysteretic behavior assessment, it is clearly demonstrated that (for SAFTs with a given pre-tension force): (1) the effectiveness of the optimized passive-control case can always be improved by using semi-active control with any of thetwocontrol laws; and (2) the SPCL is more effective for large displacements, while the SQDCL is more advantageous for very smalldisplacements. Moreover, closed-form expressions for the dissipated energy are presentedfor the three cases under consideration, which can be used in preliminary design of SAFTs to decide between passive and semi-active control and to choose the more suitable control law. (C) 2017 The Authors. Published by Elsevier Ltd.