Experiment investigation and dynamic responses of three-dimensional isolation system with high-static-low-dynamic stiffness

The application of three-dimensional (3D) isolators was limited due to the demands of long isolation period and strong supporting capacity. This paper introduces the configuration and mechanical behavior of 3D isolation system with high-static-low-dynamic stiffness (HSLDS). The proposed 3D isolator consists of the negative stiffness device and pre-deformed inclined rubber bearing. The mechanical model combining negative and positive stiffness is developed. Furthermore, experiments on both the separated and combined negative stiffness device and the pre-deformed rubber bearing are performed to characterize the behavior of HSLDS isolator. Subsequently, a numerical study of different isolated structures is performed and the variations on the structural responses as well as the hysteretic loops are illustrated. By comparing the vertical accelerations and the isolator behavior, the efficiency of HSLDS isolator on mitigating the structural acceleration as well as the vertical static displacement is confirmed.