Stochastic Response-Based Optimization of a Bilinear ECD Model for Seismic Analysis

The eddy current damper (ECD), as a high-performance seismic protection device, has been increasingly applied in the field of civil engineering. However, most existing finite element software lacks a nonlinear constitutive model for this type of damper, and an equivalent simplified model capable of accurately capturing its real damping characteristics under complex seismic excitations has not yet been established. To address this gap, this paper proposes a stochastic optimization framework for calibrating a bilinear ECD model, using the Wouterse model as a reference. Specifically, the core of this framework employs a Monte Carlo Simulation (MCS) approach, in which a suite of spectrum-compatible seismic excitations is generated and analyzed to evaluate the corresponding stochastic structural responses. The Grey Wolf Optimizer (GWO) is then utilized to minimize the discrepancy between the dynamic responses predicted by the proposed bilinear model and those of the reference model. A key outcome of this study is a practical bilinear model in which these parameters can be treated as constants, enabling designers to focus exclusively on the physical parameters fmax and vcr. This study bridges the gap between high-fidelity simulations and practical engineering design, providing a feasible pathway for integrating ECDs into existing finite element software for dynamic analysis.