Shape memory alloys in fibre-reinforced polymer composites

This article reviews the current state-of-the-art in the applications of shape memory alloy (SMA) wires into high performance fibre reinforced polymer composite materials (FRPs). SMAs have been investigated to date to address four main areas of properties improvement: (i) damping and vibrational response, where SMAs are integrated into composites either in the plane of the neutral axis, or as transverse stitches; (ii) impact, where SMAs are integrated in the neutral axis or as stitches; (iii) crack closure, where SMAs are integrated transverse to the crack, as stitches and (iv) shape morphing, where SMAs are integrated in plane into the composite, but in the non-neutral axis. The critical parameters for successful integration of SMAs to FRPs are highlighted, mostly from a composite processing angle. Finally, this review evaluates some hurdles remaining in the implementation of SMAs to FRPs to create smart and efficient composite structures without compromising their processing route, structural properties, weight and cost.