Hexachiral truss-core with twisted hemp yarns: Out-of-plane shear properties

This work describes a truss-core structure made of hemp/epoxy biocomposite based on a topology with auxetic (negative Poisson's ratio) characteristics. Epoxy-based composites with 25. wt.% of hemp yarns have been manufactured and characterized with tensile and flexural tests. Truss-core hexagonal chiral panels with the biocomposite core have been produced using a Resin Transfer Molding technique. The panels have been subjected to standard transverse shear tests, and their properties predicted with a Finite Element nonlinear modeling. The results show that the hexachiral biocomposite truss core exhibits specific shear modulus and strength significantly higher compared to the ones observed in previous demonstrators made of polymeric core. © 2012.