Feasibility of Cu-Al-Mn superelastic alloy bar as a self-sensor material

This article examines the feasibility of Cu-Al-Mn superelastic alloy bars as possible self-sensor components, taking electrical resistance measurement as a feedback. Superelastic alloy bars change their crystallographic structure with phase transformation, as well as electrical resistance during loading–unloading process at ambient temperature. This work studies the relationship between strain and electrical resistance measurements of superelastic alloys at room temperature. Such relationship can be used in determining the state of a shape memory alloy–based structure effectively, without separate sensors, by appropriately measuring the changes in electrical resistance during and after structure’s loading history. Quasi-static cyclic tensile tests are conducted in this article to investigate the relationship between electrical resistance and strain for a 4-mm-diameter Cu-Al-Mn superelastic alloy bar. It was demonstrated that linear relationship with little hysteresis can be achieved up to 10% strain. The test observations support the feasibility of newly developed Cu-Al-Mn superelastic alloy bars, characterized by low material cost and high machinability, as a multifunctional material for both structural and sensing elements.