  Describing and measuring the elastic properties of cellular materials such as
honeycombs and foams can be a difficult problem when the cell structure is
disordered. This paper suggests that tracking the flow of forces through the
material can help in visualizing and understanding how the geometry of the cell
structure affects the elastic behaviour. The mean strain tensor for a sample of
material can be calculated by summing over the force paths, weighted by the
strengths of the paths. This method emphasizes the paths with the greatest
stress, which can have the most dynamic effect. The path averaging technique
reproduces previous expressions for the Poisson's ratio of regular honeycombs,
but easily extends to disordered honeycombs and foams.
