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US 10,611,118 B2Granted
Negative poisson's ratio waffle structures
AssigneesPresident and Fellows of Harvard College, Siemens Canada Limited
InventorsKatia Bertoldi, Matthew Christopher Innes, Farhad Javid, Minh Quan Pham, Megan Schaenzer, Ali Shanian
Life of this patent
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Abstract
In at least some aspects, an auxetic structure includes a first sheet defining therein a plurality of a plurality of structural elements projecting from the first sheet, the plurality of structural elements being arranged to provide a negative Poisson's ratio, and a second sheet disposed adjacent the first sheet to define a first internal cavity between the first sheet and the second sheet. In yet other aspects, one or more additional sheets may be advantageously provided to provide a multi-layered structure having auxetic properties.
Claims16
An auxetic structure comprising:
- a first sheet defining therein a first plurality of structural elements and a second plurality of structural elements, the first plurality of structural elements projecting from the first sheet in the form of convex dimples, the second plurality of structural elements projecting from the first sheet in the form of concave dimples, the first plurality of structural elements being disposed in an alternating relationship relative to the second plurality of structural elements, the first plurality of structural elements and the second plurality of structural elements being non-porous with a zero-porosity that prevents fluids from passing through the first plurality of structural elements and the second plurality of structural elements;
- and
- a second sheet disposed adjacent the first sheet to define a first internal cavity between the first sheet and the second sheet,
- wherein the first plurality of structural elements and the second plurality of structural elements provide a Negative Poisson's Ratio (NPR) along a plane of the first sheet,
- wherein the first sheet is a thin-wall or thin-shell structure having a thickness that is about ten times less than lateral dimensions, and
- wherein each structural element of the first plurality of structural elements and the second plurality of structural elements has a cross-sectional radius projecting from the plane of the first sheet and a major axis that is longer than a minor axis along the plane of the first sheet, the cross-sectional radius or half of the minor axis being less than about ten times that of the thickness.
3 more elements
A poly-layer auxetic structure, comprising:
- a first sheet defining therein a first plurality of structural elements and a second plurality of structural elements, the first plurality of structural elements projecting from the first sheet in the form of convex dimples, the second plurality of structural elements projecting from the first sheet in the form of concave dimples, the first plurality of structural elements being disposed in an alternating relationship relative to the second plurality of structural elements, the first plurality of structural elements and the second plurality of structural elements being non-porous with a zero-porosity that prevents fluids from passing through the first plurality of structural elements and the second plurality of structural elements;
- a second sheet;
- and
- a third sheet,
- wherein the second sheet is disposed between the first sheet and the third sheet to define a first internal cavity between the first sheet and the second sheet and to define a second internal cavity between the second sheet and the third sheet, and
- wherein at least one of the second sheet and the third sheet comprises a third plurality of structural elements,
- wherein the first plurality of structural elements and the second plurality of structural elements provide a Negative Poisson's Ratio (NPR) along a plane of the first sheet,
- wherein the first sheet is a thin-wall or thin-shell structure having a thickness that is about ten times less than lateral dimensions, and
- wherein each structural element of the first plurality of structural elements and the second plurality of structural elements has a cross-sectional radius projecting from the plane of the first sheet and a major axis that is longer than a minor axis along the plane of the first sheet, the cross-sectional radius or half of the minor axis being less than about ten times that of the thickness.
6 more elements
A poly-layer auxetic structure, comprising:
- a first sheet defining therein a first plurality of structural elements and a second plurality of structural elements, the first plurality of structural elements projecting from the first sheet in the form of convex dimples, the second plurality of structural elements projecting from the first sheet in the form of concave dimples, the first plurality of structural elements being disposed in an alternating relationship relative to the second plurality of structural elements, the first plurality of structural elements and the second plurality of structural elements being non-porous with a zero-porosity that prevents fluids from passing through the first plurality of structural elements and the second plurality of structural elements;
- a second sheet;
- and
- a third sheet,
- wherein the second sheet is disposed between the first sheet and the third sheet to define a first internal cavity between the first sheet and the second sheet and to define a second internal cavity between the second sheet and the third sheet,
- wherein the first plurality of structural elements and the second plurality of structural elements provide a Negative Poisson's Ratio (NPR) along a plane of the first sheet,
- wherein the first sheet is a thin-wall or thin-shell structure having a thickness that is about ten times less than lateral dimensions, and
- wherein each structural element of the first plurality of structural elements and the second plurality of structural elements has a cross-sectional radius projecting from the plane of the first sheet and a major axis that is longer than a minor axis along the plane of the first sheet, the cross-sectional radius or half of the minor axis being less than about ten times that of the thickness.
5 more elements
Dependencies are inferred from the claim text.