A Phenomenological Multiaxial Constitutive Model for Shape Memory Alloys and Its Application : 1st Report, Comparison Between Multiaxial Formulations and an Extension to TiNi-SMA Model

Abstract

A multiaxial constitutive model to describe the pseudoelastic and shape-memory behavior for TiNi shape memory alloys has been developed from a phenomenological point of view. The rhombohedral and martensitic phase transformations of TiNi shape memory alloys have been taken into account. A generalized expression for the transformation strain range which depends on applied stress and current phase volume fraction has been proposed to obtain closed hysteresis loops for closed cyclic loading paths. The predictive capability of the present model for the hysteretic behavior of TiNi shape memory alloys has been demonstrated through simulations of the stress-strain curves under isothermal uniaxial and multiaxial loading-unloading cycles. A comparison between existing constitutive models for shape memory alloys has been also presented.