On the performance of a smart hybrid damper consisting of shape memory alloy and steel rings

Abstract

This study investigated the performance of hybrid rings used as a smart damper made by shape memory alloy (SMA) as well as steel rings. The aim of the SMA ring was to provide recentering capacity, while the steel ring may provide sufficient damping capacity for fabricated hybrid rings. To this end, two types of hybrid rings were studied: 1) An SMA ring with an outer steel ring and 2) an SMA ring with an inner steel ring. The experimental data during cyclic loading tests were compared to those of pure SMA rings. The results indicated that pure SMA rings showed an almost perfect recentering capacity, and hybrid cases with an outside steel ring increased the energy dissipation when there was a small reduction in the recentering capacity. However, in the case of hybrid dampers with an inner steel ring, the recentering capacity was almost lost, and the damping capacity had a large increase. From finite element (FE) models, it was found that the connection between the two rings was so strong that the hybrid ring became similar to a damping device, regardless of the location of the steel ring. Therefore, the loose connection between the SMA and steel rings is critical to maintain the recentering capacity of SMA rings.