The term 'auxetic' is used to describe materials which have a negative Poisson's ratio [1]. Such materials increase in lateral dimension on application of a longitudinal tensile load [2]. Unlike most common materials which disperse when struck auxetic materials have been shown to densify under the point of impact [3]. Composite laminates can be designed to have negative in-plane or through-the-thickness Poisson's ratio [4]. The requirement for an auxetic composite laminate is that the individual ply material be highly anisotropic [5]. In this way a carbon epoxy composite represents the most suitable material system. Previous work has shown that the fracture toughness and hardness of such laminates is enhanced over that of laminates with conventional values of Poisson's ratio [6].
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