Porous Shape Memory Alloys. Part 2. Modeling of the Thermomechanical Response.

摘要

Shape memory alloys (SMAs) have emerged as a class of materials with unique thermal and mechanical properties that have found numerous applications in various engineering areas. There have been a variety of applications that perform in a quasi-static manner. Recent work has proposed the use of porous SMAs as an energy absorbing material under dynamic loading conditions. Porous SMAs hold the promise of making high-efficiency damping devices that are superior to those made of conventional materials. The focus of this work is on establishing the quasi-static properties of porous SMA material. To accomplish this, a micromechanics-based analysis of the overall behavior of porous SMA is carried out. The porous SMA is modeled as a composite with SMA matrix, which is modeled using an incremental formulation, and pores as inhomogeneities of zero stiffness. The macroscopic constitutive behavior of the effective medium is established using the incremental Mori-Tanaka averaging method for a random distribution of pores, and a FEM analysis of a unit cell for a periodic arrangement of pores. In addition, a mesoscale level analysis allowing for the examination of pore size and shape variation effects is performed.