Shape memory alloy (SMA)-based dampers have the capability to dissipate seismic input energy and restore structural integrity upon unloading. One approach to enhance the capacity of SMA-based dampers is to incorporate steel plates to create a hybrid damper that can absorb more energy during an earthquake. The optimum design of such nonlinear structural systems under dynamic loads can be overly complex.
A low-computational-costs algorithm based on the concept of uniform damage distribution (UDD) is developed for the optimal seismic design of hybrid dampers in steel structures. In this method, the distribution of structural material is iteratively updated until it is fully exploited. The efficiency of the method is demonstrated for optimum design of 4-, 8- and 12-story steel frames equipped with hybrid dampers.
The results indicate that the proposed method can significantly reduce the required number of hybrid dampers by up to 12% for SMA and 18% for steel dampers, compared with a uniform damper layout, while all the design objectives remain fully satisfied.
For the first time, the concept of UDD is applied to simultaneously reduce the maximum interstory drift ratios and residual drift to their permissible levels with a reduced number of steps. The outcomes of this study should prove useful for the more efficient design of hybrid yielding dampers with shape-memory alloy in practical applications.
