Ultra-strong 2-manifold panels based on biomimetic inspired, algorithmically optimized structures

Patent metadata

Field	Value
Publication number	US-2019232563-A1
Application number	US-201815882436-A
Country	US
Kind code	A1
Filing date	Jan 29, 2018
Priority date	Jan 29, 2018
Publication date	Aug 1, 2019
Grant date	—

Abstract

2-manifold structures are structures having continuously curvilinear surfaces, with no kinks or sharp angles. Methods for building strong, lightweight 2-manifold structures include a computer implemented strength optimization process. The computer implemented process includes a structure optimization sub-routine in which a plurality of rod-like members, constituting an irregular scaffold, is constrained into a volume corresponding to the 2-manifold structure. The strength of the irregular scaffold is then optimized by application of an algorithm that maximizes strength as a function of variations in the ratio of the largest macroscopic dimension of the panel to the average length of the members; the aspect ratio of the members (diameter divided by length); the average or maximum number of times a member can contact another member; and the distribution of member lengths. Strength maximization can be simultaneous to minimization of total length of the members. The process can includes additional compositional and structural optimizations, prior to fabrication of the irregular scaffold, and encasing of the scaffold in a shell, or infiltration of the scaffold with a matrix material.

First claim

What is claimed is:

1 . A method for building a structure having a high specific strength, the method comprising:
performing a computer implemented process for optimizing strength of the structure, the process comprising:
defining a 2-manifold surface that is continuously curvilinear, the 2-manifold surface enclosing a containment volume;
constraining an irregular scaffold, formed of a plurality of rod-like members, into the containment volume;
applying a structure optimization algorithm to the irregular scaffold, the algorithm having a variable-structure strength maximization objective function, subject to the following variable structural parameters:
γ: a ratio of a largest macroscopic dimension of the structure to an average length of the members;
ρ: an average aspect ratio of the members;
χ: a value selected from the group comprising:
an average number of times a member can contact another member; and
a maximum number of times a member can contact another member; and

a distribution of member lengths,

wherein the applying step produces structure-optimized values for the structural parameters;
fabricating the irregular scaffold based on the structure-optimized values for the structural parameters; and encasing the irregular scaffold in an encapsulating shell.

2 . The method as recited in claim 1 , wherein the structure optimization algorithm is a multi-objective algorithm comprising an objective function to minimize total length of the plurality of rod-like members.

3 . The method as recited in claim 1 , wherein the strength maximization objective function is further subject to at least one compositional parameter having a fixed value, the at least one compositional parameter selected from the group consisting of: Young's modulus; shear modulus; bulk modulus; friction coefficient; strain hardening exponent; yield strength; and density.

4 . The method as recited in claim 3 , wherein the computer implemented process for optimizing strength of the structure further includes a composition optimization sub-routine comprising:
applying a composition optimization algorithm to the irregular scaffold, the algorithm having a variable-composition strength maximization objective function, subject to the structural parameters held constant at the optimized values, and subject to the at least one compositional parameter as a variable, wherein applying the composition optimization algorithm produces composition-optimized values for the at least one compositional parameter.

5 . The method as recited in claim 4 , wherein the computer implemented process for optimizing strength of the structure further comprises:
re-applying the structure optimization algorithm to the irregular scaffold, the structure-optimization algorithm subject to the at least one compositional parameter held constant at the respective composition-optimized value.

6 . The method as recited in claim 1 , wherein the step of fabricating the irregular scaffold is performed by 3D printing.

7 . The method as recited in claim 1 , wherein encasing comprises wrapping one or more preformed sheets around the irregular scaffold.

8 . A method for building a structure formed of a composite material, the method comprising:
performing a computer implemented process for optimizing strength of the structure, the process including a structure optimization sub-routine comprising:
fitting an irregular scaffold, formed of a plurality of rod-like members, to a 2-manifold structure having a continuously curvilinear surface;
applying a structure optimization algorithm to the irregular scaffold, the algorithm having a variable-structure strength maximization objective function, subject to the following variable structural parameters:
γ: a ratio of a largest macroscopic dimension of the structure to an average length of the members;
ρ: an average aspect ratio of the members;
χ: a value selected from the group comprising:
an average number of times a member can contact another member; and
a maximum number of times a member can contact another member; and

a distribution of member lengths,

wherein the applying step produces structure-optimized values for the structural parameters;
fabricating the irregular scaffold based on the structure-optimized values for the structural parameters; and infiltrating the irregular scaffold with a matrix material.

9 . The method as recited in claim 8 , wherein the structure optimization algorithm is a multi-objective algorithm comprising an objective function to minimize total length of the plurality of rod-like members.

10 . The method as recited in claim 8 , wherein the strength maximization objective function is further subject to at least one compositional parameter having a fixed value, the at least one compositional parameter selected from the group consisting of: Young's modulus; shear modulus; bulk modulus; friction coefficient; strain hardening exponent; yield strength; and density.

11 . The method as recited in claim 10 , wherein the computer implemented process for optimizing strength of the structure further includes a composition optimization sub-routine comprising:
applying a composition optimization algorithm to the irregular scaffold, the algorithm having a variable-composition strength maximization objective function, subject to the structural parameters held constant at the optimized values, and subject to the at least one compositional parameter as a variable, wherein applying the composition optimization algorithm produces composition-optimized values for the at least one compositional parameter.

12 . The method as recited in claim 11 , wherein the computer implemented process for optimizing strength of the structure further comprises:
re-applying the structure optimization algorithm to the irregular scaffold, the structure-optimization algorithm subject to the at least one compositional parameter held constant at the respective composition-optimized value.

13 . The method as recited in claim 8 , wherein the step of fabricating the irregular scaffold is performed by 3D printing.

14 . The method as recited in claim 8 , wherein the step of fabricating the irregular scaffold comprises fabricating the irregular scaffold from a material selected from the group consisting of: carbon fiber, fiberglass, an aramid fiber, and basalt.

15 . The method as recited in claim 8 , wherein the step of infiltrating the irregular scaffold with a matrix material comprises infiltrating the irregular scaffold with a matrix material selected from the group consisting of: an epoxy, a vinyl ester, a polyester thermosetting plastic, and a phenol formaldehyde resin.

Assignees

• Toyota Res Inst Inc

Inventors

• Anapolsky Abraham S

Classifications

• B29C64/393 Primary

  for controlling or regulating additive manufacturing processes · CPC title

• B29C70/688

  the inserts being meshes or lattices (B29C70/82, B29C70/683 take precedence) · CPC title

• B33Y50/02

  for controlling or regulating additive manufacturing processes · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B29C64/10

  Processes of additive manufacturing · CPC title