An auxetic web structure or field structure useful for a medical implant, combining the advantageous mechanical properties of auxetic structures and stretchable interconnects in such a way as to provide an auxetic structure which is particularly stretchable, while at the same time providing sufficiently large areas which are subjected at most to only minor stresses. This structure takes advantage of the superior mechanical properties offered by auxetic metamechanical materials (hereafter referred to as auxetic) and improves their stretchability and compressibility by incorporating interconnects into the auxetic framework.

A method of sub-ambient pressure processing of blow-molded polymer foams and skin-over-foam sandwich panel configurations for lightweight components having improved structural properties. The method can create either skinned or un-skinned foams that offer smooth interior and exterior surfaces, zero or controlled surface porosity, skins of pre-defined thickness, and foam cells that are expanded and oriented normal to the material plane, effectively spherical or polyhedral in nature, and offering improved bending and compressive strength.

An article of footwear has an upper and a sole structure. The upper includes a base layer and one or more tensile strands. The sole structure includes an auxetic element operable to expand in two orthogonal horizontal directions in response to a tension applied in one of the directions. Each tensile strand has at least one end secured in fixed position relative to a peripheral region of the sole structure.

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.

In methods and apparatuses for producing auxetic foam from conventional foam, conventional foam is compressed into a mold before thermal, chemical or thermo-chemical treatment processes are performed. A segmented mold is accommodated in a compressing apparatus. After compressing the foam between the mold segments, the mold is fastened shut and removed from the compressing apparatus. The forces applied to any given volume of foam and the amounts by which the foam is compressed while being processed are controlled to impart desired mechanical properties to the produced foam. Poisson's ratio and density of discrete portions of finished foam shapes are reliably predicted and controlled to achieve uniform and non-uniform mechanical properties within a single continuous quantity of foam.

In some aspects, an auxetic structure includes a first sheet and a second sheet, the first sheet defining therein a plurality of first openings in a first pattern, the plurality of first openings providing a first porosity and the second sheet defining therein a plurality of second openings in a second pattern to provide a second porosity. The second sheet is positioned to overlay the first sheet so that the plurality of second openings at least partially occlude the plurality of first openings to define a plurality of third openings in a third pattern, the plurality of third openings defining a third porosity less than that of the first porosity or the second porosity. The second sheet is connected to the first sheet by a plurality of distinct connection elements.

A door includes a rectangular panel having a first face, a second face, and two pairs of opposing edges, in which the edges of each pair of edges are parallel and in which a first pair of edges is longer than a second pair of edges. The rectangular panel includes a layered composite material, in which a first layer of the composite material has a positive Poisson's ratio (PPR) and a second layer of the composite material is disposed in contact with the first layer and that includes a material having a negative Poisson's ratio (NPR). The door includes a hinge including plates joined together by a joint, in which a first one of the plates is attached to a first one of the edges of the first pair of edges and in which a second one of the plates extends beyond the first one of the edges. The door also includes a handle opening defined through a thickness of the rectangular panel.

A method of sub-ambient pressure processing of blow-molded polymer foams and skin-over-foam sandwich panel configurations for lightweight components having improved structural properties. The method can create either skinned or un-skinned foams that offer smooth interior and exterior surfaces, zero or controlled surface porosity, skins of pre-defined thickness, and foam cells that are expanded and oriented normal to the material plane, effectively spherical or polyhedral in nature, and offering improved bending and compressive strength.

An article of footwear has an upper and a sole structure. The upper includes a base layer and one or more tensile strands. The sole structure includes an auxetic element operable to expand in two orthogonal horizontal directions in response to a tension applied in one of the directions. Each tensile strand has at least one end secured in fixed position relative to a peripheral region of the sole structure.

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.