Effects of curved cell edges on the stiffness and strength of two-dimensional cellular solids

The Young's modulus, Poisson's ratio, plastic collapse strength and brittle crushing strength of hexagonal honeycombs with non-straight cell edges are derived theoretically from a curved cell edge model. In the model, the geometry of curved cell edges is taken to be either circular or sinusoidal. Theoretical results indicate that the elastic moduli and strengths of hexagonal honeycombs are significantly affected by curved cell edges. To evaluate the effect of non-straight cell edges, the elastic moduli and strengths of regular hexagonal honeycombs with curved cell edges are normalized by those of same relative-density hexagonal honeycombs with straight cell edges. It is found that the normalized elastic moduli and strengths of regular hexagonal honeycombs decrease with increasing cell curvature and waviness. Meanwhile, the decreases of the normalized elastic moduli and strengths of regular hexagonal honeycombs with either circular or sinusoidal cell edges are found to be only dependent on cell curvature and waviness, regardless of their relative density.