MULTISCALE MODELLING OF POROUS SHAPE MEMORY ALLOY

Abstract

Shape Memory Alloy (SMA) is a novel material due to its unique property of `shape memory e ect' and `pseudo-elastic behavior' arising from reversible phase transformation. Porous SMA, a new generation SMA materials, is a suitable choice in many engineering applications due to its light-weight, low density with good mechanical properties. Therefore, it's important to understand structure-property-function relationship for porous SMA for future applications. However, mechanical properties arising from varying porosities remains less understood till now. Due to the presence of pores, possible local plastic deformation can arise. To investigate reversible austenite to martensitic transformation and plastic deformation, a computational framework is developed to simulate porous SMA structures. Finite element procedure has been adopted to solve governing equations. The evolution equation for inelastic deformation associated with austenite to martensitic transformation is solved using an explicit integration scheme. While plastic deformation is obtained using adaptive integration scheme incorporating both forward and backward Euler integration algorithms. Using the developed framework, we systematically investigate the e ects of shape, size, orientation and distribution of pores on energy dissipation characteristics of the material by employing appropriate boundary conditions. Our ndings will assist in designing and developing porous SMA material with desired speci c strength and energy dissipation.