Design of Honeycomb Meta-Materials for High Shear Flexure

Abstract

A numerical study for a functional design of honeycomb meta-materials targeting flexible shear properties (about 6.5MPa effective shear modulus and 15% maximum effective shear strain) is conducted with two material selections — polycarbonate (PC) and mild-steel (MS), and five honeycomb configurations. Cell wall thicknesses are found for each material to reach the target shear modulus for available cell heights with five honeycomb configurations. PC honeycomb structures can be tailored with 0.4 to 1.3mm cell wall thicknesses to attain the 6.5MPa shear modulus. MS honeycombs can be built with 0.2mm or lower wall thicknesses to reach the target shear modulus. Sensitivity of wall thickness on effective properties may be a hurdle to overcome when designing metallic honeycombs. The sensitivity appears to be more significant with an increased number of unit cells in the vertical direction. PC auxetic honeycombs having 0.4 to 1.9 mm cell wall thicknesses show 15% maximum effective shear strain without local cell damage. Auxetic honeycombs having negative Poisson’s ratio show lower effective shear moduli and higher maximum effective shear strains than the regular counterparts, implying that auxetic honeycombs are candidate geometries for a shear flexure design.