In theory a material with a negative Poisson's ratio (i.e. an auxetic material) has improved hardness, impact resistance, fracture toughness, and shear modulus over one with a positive Poisson's ratio and the same Young's modulus. Experimental evidence of auxetic behavior in random fibrous architectures has been reported, but this class of auxetic materials remains largely under explored. Here an alternate route to the design and development of auxetic fiber reinforced composites will be investigated using numerical and experimental methods. The central hypothesis is that an auxetic composite can be manufactured by embedding an auxetic fibrous network within a conventional matrix material. The validity of this hypothesis will be investigated in the experimental component of the project through the fabrication and mechanical testing of composite samples. The primary modeling objective is the development of a numerical network model whereby the auxetic behavior of random fibrous network materials can be thoroughly investigated. The intellectual merits lie in the benefits to be gained by exploring alternate routes to the design of auxetic materials. The numerical model will be a valuable tool in the field of auxetics and will be critical to the design and development of new composite materials which are optimized for both Young's modulus and Poisson ratio. The outreach activities to K-12 students from underrepresented groups will serve to provide a broader impact of the project through increased awareness and interest in engineering and give students the opportunity to learn about the research activities through campus visits, presentations and mentoring activities.
