Dampers in engineering via SMAs

Abstract. The particular properties of shape memory alloys (SMAs) are related to a martensitic transformation between metastable phases. Their applicability to dampers in civil engineering requires a fully guaranteed behaviour of the SMAs both on mesoscopic and atomic levels. The first one relates the thermomechanical properties (fracture, number of working cycles, summer–winter temperature effects and, for instance, self-heating associated with latent heat and the frictional work converted on heat) and the second one, the actions on the phase transition of the thermodynamic forces (temperature and stress). The properties of the CuAlBe alloy are explained and the characteristics of the NiTi alloy are outlined. By establishing an appropriate model the SMA dampers are introduced inside a structure and, via the ANSYS software, the dynamic response of the free and of the damped structure are obtained by simulation under the action of acceleration from the earthquakes available in the literature. As a conclusion, the conditions for the appropriateness of the dampers are given