Hysteretic behaviours of a novel lead-viscoelastic coupling beam damper: Numerical analysis and Bouc-Wen based model

Abstract

The replaceable coupling beam damper (RCBD) is widely recognized as an effective device to improve the seismic performances of shear wall structures. However, the extensively studied metallic-type RCBD has poor fatigue performance, while the viscoelastic-type RCBD is sensitive to the loading frequency. To overcome the drawbacks of the RCBDs mentioned above, the novel lead-viscoelastic coupling beam damper (LVCBD), which is mainly composed of lead rods, composite viscoelastic layers and steel plates, was proposed by the authors recently. Cyclic loading tests revealed that the lead rods of the LVCBD can overcome the drawback of frequency dependency of the conventional viscoelastic damper, making this innovative damper frequency-independent, fatigue resistant and stable in energy dissipation. In order to clarify the influence of the lead rod on the LVCBD, this paper performs numerical studies to investigate the effects of the lead rod number and lead rod diameter on the hysteretic behaviours of the LVCBD. Theoretical formulae are derived to calculate the shear-bearing force and stiffness of the damper and validated by the test and numerical results. Finally, by using the genetic algorithm (GA), a Bouc-Wen based hysteretic model is developed to depict the hysteretic behaviours of the LVCBD. Results show that the properly designed LVCBD with four lead rods exhibits a favorable shear-bearing capacity with uniform stress distribution. Increasing the lead rod diameter can effectively enhance the shear-bearing capacity of the damper. The developed formulae and hysteretic model yield good predictions of the hysteretic behaviours of the LVCBD, which can be used in the design and analysis of the LVCBD.