US Patent 10986894 Auxetic structures and footwear with soles having auxetic structures

A material that includes at least one layer made of an auxetic structure and articles of footwear having soles comprising the materials. When the material is under tension, it expands in both the direction under tension and in the direction orthogonal to the direction under tension. The articles of footwear have soles that have at least one layer made of a material that has a pattern of apertures to provide the auxetic structure. The apertures are surrounded by sole portions that can rotate or pivot to change the size of the apertures. An outer covering can be mated with an outsole structure formed by the auxetic structure. The outer covering includes features that mate with the apertures in the outsole structure. The outer covering is elastic and can stretch to accommodate expansion of the auxetic structure.