Numerical investigation and optimisation of a combination of a rubber isolator and steel U-shaped dampers

Seismic isolation systems with rubber isolators are effective tools to minimise damage of structures subjected to earthquakes. Large displacements in isolators often can lead to instability of the structure due to initiation of overturning moments, and sometimes these systems suffer from problems corresponding to insufficient dissipated energy. Therefore, additional steel devices may be utilised to improve the seismic behaviour of such isolators. This research aims to study multi-criteria optimisation of a rubber isolator equipped with steel U-shaped dampers. Numerical models are proposed using finite element simulation implemented in ABAQUS software. The effect of changing geometric properties of steel dampers on mechanical properties of a rubber isolator is investigated. Based on obtained hysteretic curves of a combination system: isolator and dampers, a comprehensive parametric study is carried out. The results demonstrated that selecting the maximum length of the dampers led to best improvement in the overall efficiency of the combination system.