Effects of cell irregularity on the elastic properties of 2D Voronoi honeycombs

Foams are more and more widely used in different areas. Most available mechanical models are usually based on idealised unit cell structures, and are not able to account for the natural variations in microstructure which are typical for most foam structures. The objective of this work has been to investigate how the cell irregularity affects the elastic properties of 2D random foams. We have constructed periodical random structures with different degrees of irregularity, and applied finite element analysis (FEA) to determine their effective elastic properties. The results indicate that, the more irregular the 2D random foams, the larger will be their effective Young's modulus and shear modulus, and the smaller will be their bulk modulus at a constant overall relative density. However, for varying degrees of irregularity, the foams remain isotropic and the Poisson's ratios are very close to 1. Both Young's modulus and Poisson's ratio of random Voronoi honeycombs having different degrees of regularity ?, decrease gradually with increasing relative density ?