A Poromechanics-Based Phenomenological Model for Porous Shape Memory Alloys

Experimental studies show that shape memory alloys exhibit pressure-dependent deformation in the presence of porosity. In this context, a macro-scale phenomenological model is proposed for the mechanical behavior of porous SMAs using a poromechanics approach. The new phenomenological model considers the porous medium as a skeleton consisting of a solid matrix and connected porous space. The new model is built starting from a model for dense SMAs in which the porosity is included as an internal state variable. Both the pseudoelastic and plastic deformations of the skeleton are considered. The model is implemented into Abaqus through a user defined material subroutine and is validated using experimental results from the literature. The numerical results obtained by unit-cell (UC) technique are also used. The uni-axial stress–strain response is captured in a great extent with significant reduction in terms of the numerical cost when compared to the UC approach. It is shown that the proposed model can be used to study the mechanical behavior of porous SMAs. The poromechanics approach allows tracking the overall deformation of the RVE, and the porosity simultaneously.