Modeling and simulation of spring steel damper based on parameter identification with a heuristic optimization approach

In seismic design of building frames, dampers are designed to absorb an earthquake’s energy. Conventional steel tension braces have disadvantages, such as pinching or deterioration of stiffness and strength under cyclic loading. A new type of elasto-plastic damper can potentially avoid such disadvantages at a relatively low cost. Main characteristics of the damper are twofold: i) hardening effect caused by geometric nonlinearity, and ii) asymmetric hysteretic restoring force in tensile and compressive loading conditions. The objective of the study is to present a constitutive model and identify the corresponding parameters. The process of parameter identification of the model is formulated as a non-smooth optimization problem and derivative-free optimization methods are suited for the problem. Through numerical examples, we investigate the seismic response reduction property of the damper. The results demonstrate the effectiveness of the optimization approach.