Thermomechanically Coupled Micromechanical Analysis of Shape Memory Alloy Composites Undergoing Transformation Induced Plasticity

In this investigation, fully thermomechanically coupled constitutive and energy equations for shape memory alloys (SMAs) that include the effect of transformation induced plasticity are presented. This is followed by a micromechanical analysis for the establishment of the fully coupled thermomechanical constitutive equations that model the overall behavior of SMA composites undergoing transformation induced plasticity. The effects of the thermomechanical coupling and permanent inelasticity which arise by the phase transformation were examined. It was found that the response of the monolithic SMA depends upon the thermomechanical coupling. The permanent inelasticity and the resulting induced temperature become significant especially in the case of several repeating cycles. In addition, the induced average temperature caused by the thermomechanical coupling as well as the stress—strain behavior of SMA/epoxy and SMA/aluminum composite materials were determined. A significant thermomechanical coupling, which corresponds to an appreciable temperature increase, was observed for the SMA/aluminum metal matrix composite material. For the case of SMA/epoxy polymeric matrix composite material the thermomechanical coupling was found to be negligible. This results from the absence of inelastic strains in the polymeric matrix in spite of the existence of rate of dilatation effect in the epoxy phase.