Analysis of energy absorption for NiTi wires under different diameters and loop types

Abstract

This paper presents the research undertaken at the University of Minho aiming to study the behaviour of 3D weft-knitted structures using Shape Memory Alloy (SMA) wires and elastomeric yarns, in order to produce dynamic structures as a support to answer specific situations and applications. Several samples were produced using Nitinol® wires in different diameters and loop types. The Tensile tests were carried out being based to NP EN ISO 2062:1993 standards, using a H100KS Hounsfield Universal Testing Instrument. The results showed that The 50 μm wire showed to be too thin to this propose; moreover, The 210 μm NiTi wire showed to be hard to process on the knitting machine due to its high stiffness; The 127 μm NiTi wire showed to be the best among them, due to the process and energy absorption ratio. Finally, for both NiTi wires in different diameters studied, tuck loop showed to have the highest energy absorption capacity.