Stelios Kyriakides, Research
Abstract
The evolution of inhomogeneous deformation in a NiTi shape memory alloy under uniaxial tension is studied both experimentally and analytically. Interesting features of stress-induced phase transformation fronts are observed in experiments of NiTi strips. The nucleation of a new phase occurs as a sharp band of localized strain inclined at 55deg; to the axis of loading. Under prescribed end displacement the new phase then spreads either by steady-state propagation of angled transition fronts or by an alternating pattern of finger-like features. These features are successfully captured by finite element analyses with a special trilinear stress-strain model having an intermediate unstable branch.
Experiment
Simulation
