Combining non-linearities to affect the damping behaviour of fibre-reinforced polymer composites

In several state-of-the-art applications, shape memory alloy (SMA) wires have been successfully added to polymer composite materials in order to improve the damping response, impact resistance and crack closure [1,2]. The tuneable non-linear, pseudoelastic behaviour of the alloy is often exploited for these aims, yet the use of non-linear geometries of the wires remains unexplored. A number of examples in literature present fibres with non-linear geometries used in composites such as Variable Stiffness laminates to optimise material properties like stress distribution, buckling and frequency response [3]. In this work, we present a multimaterial construct, fabricated with non-linear wires of pseudoelastc NiTi embedded in an epoxy matrix. This construct combines material and geometrical non-linearities in order to affect its viscoelastic behavior (Fig. 1). In particular, we discuss how to tune the damping response of SMA wire [4], and characterise the effects that non-linear geometries, combined with this tuning, have on the overall damping factor of the multimaterial.