Investigation on Deflection Characteristics of Auxetic Beam Structures Using FEM

Auxetics structures, otherwise known as Negative Poisson’s Ratio structures, respond to a tensile load by expanding laterally and to a compressive load by contracting laterally. A prominent structure of this kind is the re-entrant hexagonal honeycomb. Over the years, studies have been carried out in an attempt to understand the behaviour of such structures in terms of properties like Poisson’s ratio and Young’s modulus, circumventing studies over its load-bearing capacities and potential applications. This paper deals with the latter of the two. Re-entrant structured beams are designed and tested numerically using FE models. Inferior deflection characteristics of the conventional re-entrant beams indicate scope for improvement in the design. An additional design factor of the introduction of filler materials into the voids of cells and its influence is also analysed. Multiple foreign filler materials are introduced in the design to understand the effect of filler materials in deflection characteristics of auxetic beams. Influence of these filler materials, expressed through the ranges of their modulus of elasticity, is recorded and shown. Results obtained from the analysis of beams with filler materials indicate a profitable design with enhancement in deflection characteristics compared to that of the conventional auxetic re-entrant beam.