Determination of a shape and size independent material modulus for honeycomb structures in additive manufacturing

Most prior work on modeling cellular structures either assumes a continuum model or homogenizes “effective” cell behavior. The challenge with the former is that bulk properties do not always represent behavior at the scale of the cellular member, while homogenization results in models that are shape specific and offer little insight into practical design matters like transitions between shapes, partial cells or skin junction effects. This paper demonstrates the strong dependence of measured properties on the size of the honeycomb specimen used for experimental purposes and develops a methodology to extract a material modulus in the presence of this dependence for three different honeycomb shapes. The results in this paper show that the extracted modulus for each shape converges as the number of cells in the specimen increases and further, that the converging values of the material moduli derived from the three shapes are within 10% of each other.