The manufacture and characterisation of a novel, low modulus, negative Poisson’s ratio composite

Abstract

Abstract.Relatively few negative Poisson's ratio (auxetic) composites have been manufactured and characterised and none with inherently auxetic phases. This paper presents the use of a novel double helix yarn that is shown to be auxetic, and an auxetic composite made from this yarn in a woven textile structure. This is the first reported composite to exhibit auxetic behaviour using inherently auxetic yarns. Importantly, both the yarn and the composite are produced using standard manufacturing techniques and are therefore potentially useful in a wide range of engineering applications.

Parametric sensitivity analysis to maximise auxetic effect of polymeric fibre based helical yarn

“…The tensile testing method is the only procedure to date, that has been used to determine the NPR of a HAY [11][12][13][14][15][16][17][18][19]. The load was applied until a maximum deformation of 1 mm per cycle of HAY had been reached [17], and the model does not consider contact friction between the core and the wrap.…”

“…The helical auxetic yarn (HAY) presented itself as the most fitting structure to be chosen for the study; as well as having the greatest potential to maximise the auxetic effect 3 [11][12][13][14][15][16][17][18][19]. The HAY has been shown to be capable of achieving a NPR of -6.8 [17], which is the highest published value of any auxetic material to date.…”

“…The material properties that affect a HAY's performance are: Young's modulus of both core and wrap; and Poisson's ratio of core and wrap. Various studies of HAYs [11][12]15] showed that the wrap angle has a profound effect on the NPR value. For example, different values for 4 NPR obtained by Miller et al [11] based on three different HAY designs.…”

“…Various studies of HAYs [11][12]15] showed that the wrap angle has a profound effect on the NPR value. For example, different values for 4 NPR obtained by Miller et al [11] based on three different HAY designs. The lowest wrap angle of 10° resulted in the largest NPR value of -5.8, indicating that a low starting wrap angle is desired for maximising the auxetic behaviour of the HAY.…”

A composite material with Poisson’s ratio tunable from positive to negative values: an experimental and numerical study

“…The current state of research for most NPR materials is still limited to a theoretical stage. Besides cellular solids and some fiber-reinforced composites, there are a few successful NPR materials that can be easily manufactured and employed in a real engineering environment [14,[27][28][29]. It is because most NPR materials usually have some embedded structures with intricate geometries.…”