Experimental and numerical thermo-mechanical analysis of shape memory alloy subjected to tension with various stress and strain rates

Abstract

TiNi shape memory alloy (SMA) is experimentally and numerically investigated in tension tests under different loading rates. The thermomechanical behaviour of the SMA, related to the stress-induced martensitic transformation (SIMT) noticed during the experimental tests, is analysed and the observations are considered for numerical analysis. Initiation, development and saturation of the SIMT are monitored by a fast and sensitive infrared camera. The estimated temperature changes of the SMA sample, related to the exothermic martensitic forward and endothermic reverse transformation, have been analysed with the focus on the rate-dependent response and on the influence of the heat transfer on the mechanical behaviour. The effectively modified constitutive model, proposed by Lagoudas, is implemented in structural PAK finite element method (FEM) software and is thermomechanically coupled with the heat transfer FEM software in a partitioned approach. The experimental results are quantitatively and qualitatively reproduced by the numerical FEM model, which verifies the efficiency and accuracy of the proposed investigation method. © 2014 IOP Publishing Ltd.