Effect of double-edge semi-circular notches on the mechanical response of superelastic NiTi shape memory alloy: Experimental observations

Abstract

In this article, the effect of notches on the mechanical response of superelastic NiTi shape memory alloy is studied experimentally. Due to the complexity and feasibility in designing and manufacturing, double-edge semi-circular notches were chosen as the investigating features, and a dimensionless parameter was introduced to ease the discussion. With the help of in situ digital image correlation, both local and global mechanical responses were analyzed in the study. From the local mechanical response of notched specimens, the λ-shaped intersection of the transformation bands and the V-shaped transformation fronts were observed; from the global mechanical response of notched specimens, the intermediate stage prior to the upper stress plateau was identified. These observations shed light on the ongoing relevant study on the mechanical characteristics of NiTi shape memory alloy with complex geometry.