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US 12,473,950 B2Granted
Axial auxetic structures
AssigneeUniversity of Washington
InventorJeffrey Lipton
Life of this patent
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Abstract
A novel range of non-shearing axial auxetic structures are disclosed having useful functions and properties. The novel non-shearing axial auxetic structures have applications including compliant universal joints, structures with switchable Poisson ratios, nd multiple discrete dimensional configurations. Further, combination structures of multiple individual non-shearing axial auxetic structures having useful functions and properties are also disclosed.
Claims13
An apparatus comprising:
- a non-shearing axial auxetic structure including a spheroid surface having a pattern of repeating unit cells, each unit cell formed by four elements in a closed shape, each of the plurality of elements having two ends, where each of the two ends of each of the plurality of elements is coupled to one or more adjacent elements by a pivot joint, where a first pivot joint between two of the four elements couples to at least one first adjacent cell;
- wherein the pattern of repeating unit cells has a contracted configuration and an expanded configuration, wherein a second pivot joint between the remaining two of the four elements couples to at least one second adjacent cell opposite the first adjacent cell and wherein the spheroid surface comprises an n* orbifold and the pattern of repeating unit cells comprises unit cells each formed of the four elements form a closed equatorial ring around the spheroid surface.
An apparatus comprising:
- a non-shearing axial auxetic structure including a spheroid surface having a pattern of repeating unit cells, each unit cell defined by a plurality of elements in a closed shape, each of the plurality of elements having two ends, where each of the two ends of the plurality of elements is coupled to one or more adjacent elements by a pivot joint, where the pattern of repeating unit cells has a contracted configuration and an expanded configuration;
- wherein the non-shearing axial auxetic structure further comprises a pair of opposing crown elements each having a common number of extensions from a central hub, each of the pair of opposing crown elements having the central hub disposed at opposite poles of the spheroid surface such that ends of the extensions interlace and the end of each extension comprises an extension pivot joint coupled to adjacent extension links between both adjacent extensions of the opposing crown element.
An apparatus comprising:
- a non-shearing axial auxetic structure including a spheroid surface having a pattern of repeating unit cells, each unit cell formed by four elements in a closed shape, each of the plurality of elements having two ends, where each of the two ends of each of the plurality of elements is coupled to one or more adjacent elements by a pivot joint, where a first pivot joint between two of the four elements couples to at least one first adjacent cell and a second pivot joint between the remaining two of the four elements couples to at least one second adjacent cell opposite the first adjacent cell;
- wherein the pattern of repeating unit cells has a contracted configuration and an expanded configuration and the pattern of repeating unit cells comprises unit cells each formed of the four elements where the first pivot joint of each unit cell is disposed at a pole of the spheroid surface and the second pivot joint between the remaining two of the four elements moves toward an equator of the spheroid surface in the expanded configuration and the non-shearing auxetic axial structure comprises a universal joint across poles of the spheroid surface.
An apparatus comprising:
- a non-shearing axial auxetic structure including a spheroid surface having a pattern of repeating unit cells, each unit cell formed by four elements in a closed shape, each of the plurality of elements having two ends, where each of the two ends of each of the plurality of elements is coupled to one or more adjacent elements by a pivot joint, where a first pivot joint between two of the four elements couples to at least one first adjacent cell;
- wherein the pattern of repeating unit cells has a contracted configuration and an expanded configuration, wherein a second pivot joint between the remaining two of the four elements couples to at least one second adjacent cell opposite the first adjacent cell, and wherein the spheroid surface comprises an 2*n orbifold and the pattern of repeating unit cells comprises unit cells each formed of the four elements where the first pivot joint of each unit cell is disposed at a pole of the spheroid surface and the second pivot joint between the remaining two of the four elements moves toward an equator of the spheroid surface in the expanded configuration.
Dependencies are inferred from the claim text.