Experimental investigation and numerical evaluation of an innovative shape memory alloy damper

Abstract

Superelastic shape memory alloy (SMA) is a potential candidate for use in structural damping devices due to its unique mechanical properties. An innovative re-centering SMA damper is presented. Being configurated simply, the device comprises two functional groups of SMA strands, such as the un-pre-tensioned wires and the pre-tensioned wires, resulting in a perfect energy dissipation compatible with a negligible residual displacement. Based on the cyclic loading tests of the superelastic SMA wires, the Lagoudas simplified model is determined. Extensive experiments are carried out to investigate the influence of cycles, frequency and displacement amplitude on the mechanical behaviors of the damper, such as the secant stiffness, the dissipated energy per cycle and the equivalent viscous damping. By analyzing the working mechanism, a model is set up to simulate the hysteretic curve of the damper, its feasible predictions being validated by the experimental results. Furthermore, nonlinear time history analyses of a SDOF system are performed, and the results show that the re-centering damper not only can decrease the vibration of the system under excitations, but also can mitigate residual displacement after excitations.