Simultaneous Multi-Objective Optimal Sizing of Energy Dissipative Steel Cushions for Transversal Loading

Current practice in structural engineering requires dissipating some part of seismic energy by sacrificial elements rather than structural members and/or joints. As an easy-to-produce and plug-and-play damper with stable hysteretic loops and large displacement capacity, steel cushion (SC) is a significant device to improve the seismic performance of the structures. It was stated in the previous studies that SC is less effective in the transversal direction. Hence, the efficiency of the damper is improved by optimal sizing through intelligent optimization techniques in this study. The complex optimization problem could be converted to a relatively simple mathematical problem since closed-form equations of the damper are exist in the literature. The optimal sizing problem was solved using two distinct methods namely the ∈-constraint method and the elitist non-dominated sorting genetic algorithm (NSGA-II). The employed optimization methods were verified by each other as almost similar geometric ratios were obtained. The efficiency of the optimization is evaluated through finite element analysis (FEA). It is shown that the optimally sized SC is superior in terms of energy dissipation.