FLEXURAL RECOVERY BEHAVIOUR OF A NiTi STRIP IN PARTIALLY CONSTRAINED CONDITIONS

This paper presents the development of an active structure obtained by embedding a single NiTi shape memory alloy strip in a glass reinforced polyamide plate. In order to evaluate the bending ability in free recovery condition, the strip was thermally trained to memorise a bent shape and experimentally tested. The martensitic and reverse martensitic transformations were thermally activated, by means of cold and hot Propylene Glycol-based water solution in contact with the strip. Partially recovery constrained conditions tests were performed through the insertion of the SMA into a polymeric prototype specifically realised. The maximum bending values of the structure due to the phase transformations were studied. To describe the behaviour of the NiTi strip in free recovery conditions and to compare the numerical prediction with the experimental data, a phenomenological model is proposed.