Fabrication of three-dimensional kirigami structures with tunable properties

Patent metadata

Field	Value
Publication number	US-11433633-B2
Application number	US-201615391745-A
Country	US
Kind code	B2
Filing date	Dec 27, 2016
Priority date	Dec 27, 2015
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A method of forming a structural honeycomb includes cutting and folding a substrate sheet according to predetermined cutting and folding patterns and fold angles that cause the sheet to form a honeycomb having cells that each have at least one face abutting, or nearly abutting, the face of another cell. The honeycomb is then stabilized by joining abutting, or nearly abutting, faces to hold the honeycomb together. The honeycomb may have a prespecified three-dimensional shape. The folding pattern may include corrugation, canted corrugation, or zig-zag folds. Joining may employ fixed and/or reversible joinery, including slotted cross section, tabbed strip, angled strip, integral skin, sewn, or laced. At least some folds may be partially-closed to create bends and twists in the honeycomb structure. Some surfaces of the honeycomb may be covered with a skin or face sheet. The substrate sheet may have flexible electronic traces.

First claim

What is claimed is:

1. A method of forming a structural honeycomb, comprising:
cutting a substrate sheet according to a predetermined cutting pattern, the predetermined cutting pattern being formulated according to parameters derived for creation of a three-dimensional honeycomb having specific properties;
after the step of cutting, folding the cut substrate sheet according to a predetermined folding pattern and at least one predetermined fold angle, wherein folding comprises at least contacting at least a first part of the substrate sheet against at least a second part of the substrate sheet that the first part of the substrate sheet did not abut before folding, the predetermined folding pattern being formulated according to parameters derived for creation of a three-dimensional honeycomb having specific properties, and the at least one predetermined fold angle being sufficient to cause the cut and folded substrate sheet to form a structural honeycomb having a plurality of cells, each cell having at least one face abutting, or nearly abutting, at least one face of another cell, wherein the predetermined cutting pattern and the predetermined folding pattern together comprise cut-and-fold instructions for the structural honeycomb, wherein parameters used in creating the cut-and-fold instructions for the structural honeycomb are calculated by:
establishing functions t(x,y) and u(x,y), giving the height of the top and bottom, respectively, of the desired honeycomb shape for each x and y value; and
calculating the parameters in terms of the values of functions t(x,y) and u(x,y) at the honeycomb coordinates t(i,j) and u(i,j); and

stabilizing the structural honeycomb by joining one or more abutting, or nearly abutting, honeycomb faces in a manner that holds the structural honeycomb together.

2. The method of claim 1 , wherein the cut-and-fold instructions include instructions to include or exclude cells in order that the structural honeycomb will have a prespecified outline.

3. The method of claim 1 , wherein the cut-and-fold instructions include instructions to create a honeycomb wherein at least one of the top or bottom of the honeycomb forms an arbitrary shape along its length.

4. The method of claim 1 , wherein the folding pattern specifies zig-zag corrugation folds in at least one direction.

5. The method of claim 1 , wherein the folding pattern specifies canted corrugation folds in at least one direction.

6. The method of claim 1 , further comprising the step of tuning the three-dimensional shape and material properties of the structural honeycomb by adjusting the parameters of the cut-and-fold instructions.

7. The method of claim 6 , wherein the step of tuning includes adjusting an angle formed by the sides of each honeycomb cell by holding the cell width constant and changing the length of at least one cell side.

8. The method of claim 1 , wherein the structural honeycomb is a volume-filling honeycomb.

9. The method of claim 1 , wherein the step of stabilizing by joining employs reversible joinery.

10. The method of claim 9 , wherein the reversible joinery employs at least one of slotted cross sections, tabbed strip joinery, angled strip joinery, an integral skin, sewn joinery, or laced joinery.

11. The method of claim 1 , wherein the step of stabilizing by joining further comprises the step of constraining the width of the honeycomb cells by modifying features of a selected joining method.

12. The method of claim 1 , wherein the step of stabilizing by joining further comprises the step of modifying features of a selected joining method to specify at least some partially-closed cross-sectional folds in order to create bends and twists in the honeycomb overall structure.

13. The method of claim 1 , further comprising the step of at least partially covering at least one surface of the honeycomb with a skin or face sheet.

14. The method of claim 1 , wherein the substrate sheet has at least one set of flexible electronic traces applied before at least one of the steps of cutting or folding.

15. A method of forming a structural honeycomb, comprising the steps of:
cutting a substrate sheet according to a predetermined cutting pattern, the predetermined cutting pattern being formulated according to parameters derived for creation of a three-dimensional honeycomb having specific properties;
folding the cut substrate sheet according to a predetermined folding pattern and at least one predetermined fold angle, the predetermined folding pattern being formulated according to parameters derived for creation of a three-dimensional honeycomb having specific properties, and the at least one predetermined fold angle being sufficient to cause the cut and folded substrate sheet to form a structural honeycomb having a plurality of cells, each cell having at least one face abutting, or nearly abutting, at least one face of another cell, wherein the predetermined cutting pattern and the predetermined folding pattern together comprise cut-and-fold instructions for the structural honeycomb,
wherein parameters used in creating the cut-and-fold instructions for the structural honeycomb are calculated according to the following steps:
establishing functions t(x,y) and u(x,y), giving the height of the top and bottom, respectively, of the desired honeycomb shape for each x and y value; and
calculating the parameters in terms of the values of functions t(x,y) and u(x,y) at the honeycomb coordinates t(i,j) and u(i,j), according to the steps of:
calculating unshifted parameters A′(i,j), B′(i,j), C′(i,j), and D′(i,j), providing the cut-and-fold instructions parameters through the column shifts, according to the formulas
A i,j =A′ i,j +W i
B i,j =B′ i,j +W i
C i,j =C′ i,j +V i
D i,j =D′ i,j +V i

calculating:

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j

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Assignees

• Massachusetts Inst Technology

Inventors

• Calisch Samuel Eli
• Gershenfeld Neil A

Classifications

• B29C53/285

  using rolls or endless bands · CPC title

• B29C53/36

  Bending and joining, e.g. for making hollow articles (B29C53/56 takes precedence) · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title

• H05K2201/055

  Folded back on itself · CPC title

• F21Y2109/00

  Light sources with light-generating elements disposed on transparent or translucent supports or substrates · CPC title