Hysteretic model and experimental validation of a variable damping self-centering brace

The variable damping self-centering brace (VD-SCB), which uses disc springs and magnetorheological fluid to recenter and dissipate energy, is a lateral force-resisting component that reduces residual deformation. This paper presents the hysteretic modeling of the VD-SCB. Full-scale cyclic tests were conducted on the VD-SCB with different pre-pressed forces and stiffness due to sinusoidal excitations with varying frequencies and amplitudes. The results demonstrate that the brace presents a quasi-flag-shaped behavior, which provides reliable energy dissipation and recentering capabilities. A modified model based on the Bouc-Wen system is proposed to predict the hysteretic behaviors of the VD-SCB. The parameters of the modified restoring force model are analyzed to develop a reasonable 7-step selection process. The predictions of the model are sufficiently accurate to portray the test data. Compared with the existing self-centering brace, the VD-SCB has a fuller force-displacement response under a dynamic exd ta t ion, and the brace exhibits a greater energy dissipation, and both a lower activation force and sudden stiffness change. (C) 2020 Elsevier Ltd. All rights reserved.