Damping in civil engineering using SMA Part 2 – particular properties of NiTi for damping of stayed cables in bridges

Abstract

Shape memory alloys (SMAs) show particular properties associated to their martensitic transformation between metastable phases. Their use requires a deep knowledge of the SMA behaviour according to the requirements of the application. In this paper, the following are studied: the required fatigue life of the NiTi SMA that easily overcomes 1 million of oscillations for a complete storm; the suitable thermomechanical treatment to minimise or stabilise the SMA creep; and the temperature effects on the damper and the dynamic phenomena effects modifying the hysteretic energy via the self-heating associated to the release and the absorption of the latent heat were studied. The study includes the effects on SMA of the external summer–winter temperatures.