M.J Ashrafi - Mechanical Engineering Department, Sharif University of Technology
J Arghavani - Mechanical Engineering Department, Golpayegan University of Technology
S Sohrabpour - Mechanical Engineering Department, Sharif University of Technology

In this study the macro scale pseudoelastic behavior of porous shape memory alloys has been simulated under axial and hydrostatic loadings. A computational method is utilized to estimate the behavior of a porous shape memory alloy. The method is based on a ۳-D finite element model of a representative volume element (RVE) to determine effective material response. The porous shape memory alloy is defined as comprised of two constituents, dense NiTi shape memory alloy (SMA), and pores that are defined as an elastic material with very low modulus which are distributed randomly in the RVE. An existing constitutive model is used to define the dense SMA material behavior. The model is numerically implemented in ABAQUS using user subroutine material (UMAT). After performing convergence study on the mesh size and random pore distribution, the effective material behavior under axial and hydrostatic loadings is calculated for a range of porosity (۰.۱ to ۰.۶), and the effect of pore volume fraction is studied. The Calculated effective material elastic and transformation behavior are in agreement with experimental observations. The results have implications for use of porous SMAs in biomedical and structural applications.

shape memory alloys, porous materials, finite element method, transformation behavior