Design of multi-state and smart-bias components using Shape Memory Alloy and Shape Memory Polymer composites

A Multifunctional Smart Material System (MSMS) consists of two or more different smart material phases in the form of a hybrid system, in which every phase performs a different but necessary function. In this work, thermally responsive Shape Memory Alloys (SMAs) and Shape Memory Polymers (SMPs) are combined to form a MSMS. The transformation temperatures martensitic start (Ms), martensitic finish (Mf), austenitic start (As) and austenitic finish (Af) of SMA and the glass transition (Tg) for the SMP play a critical role in designing such a MSMS. Multi-state smart bias systems with varying stiffnesses can be obtained by varying the Tg of SMP between the transformation temperatures Mf and Af of SMA. Guidelines to form such MSMS have been established by estimating the volume fractions of the individual constituents. Various ideas for “smart-bias” tools/devices have been proposed, such that they can operate under three different temperature regimes, with one material constituent being passive and the other active at a given temperature.