A computational evaluation of material characteristics of porous shape memory alloys

Abstract

The structural characteristics of porous shape memory alloys (SMAs) are determined through use of computational techniques. Mesoscale analyses techniques are used examine the behavior of porous materials through evaluation of a volume containing multiple pores. Finite element modeling of a representative volume element is performed to determine pore interactions, pore spacing and pore size effects. Porosity volume fractions ranging from 0.2 to 0.4 are examined. Results are compared with prior computational work in which micromechanical approaches based on unit cell analyses and averaging techniques were used to determine the macroscopic response of porous SMAs. Good agreement is seen in calculated elastic material properties for low to moderate (0.3) levels of pore volume fractions. Mesh refinement is examined as a possible cause of differences in results at higher pore volume fractions. Results of mesh refinement evaluation indicate that variations at higher pore volume fraction are results of pore spacing and interaction phenomena not captured by unit cell analyses rather than mesh refinement issues.