US-12623397-B2 - Techniques for generating composite structures that combine metal and polymer compositions

Abstract

A multi-material structure includes: a structural member that includes an isotropic material and at least one open-cell void formed in the isotropic material; and a skin that includes a polymetric material and is disposed on a surface of the structural member and within the at least one open-cell void.

Inventors

• Massimiliano Moruzzi
• Francesco Iorio

Assignees

• Augmenta Inc.

Dates

Publication Date

20260512

Application Date

20230105

Claims (20)

1. 1 . A multi-material structure, comprising: a structural member that includes an isotropic material and at least one open-cell void formed in the isotropic material; and a skin that includes a polymeric material, is disposed on a surface of the structural member and within the at least one open-cell void, and has at least one closed-cell void that is disposed on the surface of the structural member.
2. 2 . The multi-material structure of claim 1 , wherein the at least one closed-cell void contains an adhesive material.
3. 3 . The multi-material structure of claim 1 , wherein the at least one closed-cell void is initially formed with no opening.
4. 4 . The multi-material structure of claim 1 , wherein the at least one closed-cell void is disposed between the surface of the structural member and the skin.
5. 5 . The multi-material structure of claim 1 , further comprising at least one injection hole formed between an outer surface of the skin and the at least one closed-cell void.
6. 6 . The multi-material structure of claim 1 , further comprising two or more injection holes formed between an outer surface of the skin and the at least one closed-cell void.
7. 7 . The multi-material structure of claim 1 , wherein a first portion of the polymeric material is disposed on the surface of the structural member, a second portion of the polymeric material is disposed within the at least one open-cell void, and a third portion of the polymeric material is disposed in an opening of the at least one open-cell void and joins the first portion and the second portion.
8. 8 . The multi-material structure of claim 1 , wherein an infiltration process has been performed on an outer surface of the polymeric material.
9. 9 . The multi-material structure of claim 1 , wherein the polymeric material comprises an anisotropic material.
10. 10 . The multi-material structure of claim 1 , wherein the polymeric material comprises a fiber-reinforced thermoplastic.
11. 11 . The multi-material structure of claim 10 , wherein fibers in the fiber-reinforced thermoplastic in a portion of the skin are aligned with a predicted stress-strain line associated with the portion of the skin.
12. 12 . The multi-material structure of claim 1 , wherein the at least one open-cell void is initially formed with an opening.
13. 13 . The multi-material structure of claim 1 , wherein a portion of the skin that is disposed within the at least one open-cell void contacts all interior surfaces of the at least one open-cell void.
14. 14 . The multi-material structure of claim 1 , wherein the structural member includes a central cavity that contains a stochastic material.
15. 15 . The multi-material structure of claim 1 , wherein a surface of the at least one open-cell void has a roughened surface.
16. 16 . A multi-material structure, comprising: a structural member that includes an isotropic material; and a skin that includes a polymeric material, is disposed on a surface of the structural member, and has at least one closed-cell void that is disposed on the surface of the structural member and contains an adhesive material.
17. 17 . The multi-material structure of claim 16 , wherein the at least one closed-cell void is initially formed with no opening.
18. 18 . The multi-material structure of claim 16 , wherein the at least one closed-cell void is disposed between the surface of the structural member and the skin.
19. 19 . The multi-material structure of claim 16 , wherein the polymeric material comprises a fiber-reinforced thermoplastic.
20. 20 . The multi-material structure of claim 19 , wherein fibers in the fiber- reinforced thermoplastic in a portion of the skin are aligned with a predicted stress-strain line associated with the portion of the skin.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority benefit of the United States Provisional patent application titled, “TECHNIQUES FOR COMPOSITE STRUCTURES THAT COMBINE METAL AND POLYMER COMPOSITIONS” filed on Jan. 6, 2022 and having Ser. No. 63/297,022. The subject matter of this related application is hereby incorporated herein by reference. BACKGROUND Field of the Various Embodiments The various embodiments relate generally to additive manufacturing and, more specifically, to techniques for generating composite structures that combine metal and polymer compositions. Description of the Related Art Additive manufacturing, also known as three-dimensional (3D) printing, is the construction of a three-dimensional object by sequentially depositing one material layer at a time via a special printing machine to build out the three-dimensional object or by adding material to build out the three-dimensional object via some other technique. In many additive manufacturing processes, the material layers can be deposited, joined, or solidified under computer control that is based on a computer-aided design (CAD) or other a digital 3D model to form a multi-material structure. Because multi-material structures can have superior physical properties, they are tremendously important in applications where strong, lightweight mechanical systems are needed, such as automotive, aerospace, and construction applications. Further, multi-material structures frequently fulfill multiple functions, such as when a given structure serves as a structural component that also is corrosion- and environmental agent-resistant. One drawback to additive manufacturing is that there is generally poor mechanical coupling between the different materials that are included in a multi-material component. For example, 3D-printed polymers that are formed on the surfaces of dissimilar substrates (such as a metals or ceramics) are known to have poor adhesion to those surfaces. Consequently, the different materials making up a multi-material component behave as separate structural elements as opposed to contributing collectively to the mechanical properties of the overall component. As a result, the multi-material component cannot act as a monolithic structure in response to stresses, impacts, and the like. For example, a polymeric skin that is 3D printed onto a surface of a metallic structural member may closely conform to the surface of the structural member, but may not contribute to the rigidity of the metallic structural member due to poor or nonexistent mechanical coupling between the polymeric skin and the surface of the metallic structural member. In such a situation, the polymeric skins may add little or no structural strength or rigidity to the metallic structural member. Another drawback to additive manufacturing is that the polymeric materials typically employed in 3D-printing can be highly sensitive to the way in which those materials are deposited. For example, 3D-printer nozzle velocity, deposition temperature, deposition rate, and direction of deposition can all significantly affect the physical properties of a 3D-printed polymer. As a result, the physical properties of 3D-printed polymers can be undesirably variable and difficult to predict, which can be problematic when such polymers are included in components that are load-bearing and/or receive impacts. These issues can be particularly prevalent for fiber-reinforced polymers, which can be highly anisotropic. As the foregoing illustrates, what is needed in the art are more effective additive manufacturing techniques that involve polymers and metallic substrates. SUMMARY A multi-material structure includes: a structural member that includes an isotropic material and at least one open-cell void formed in the isotropic material; and a skin that includes a polymetric material and is disposed on a surface of the structural member and within the at least one open-cell void. A multi-material structure includes: a structural member that includes an isotropic material; and a skin that includes a polymetric material, is disposed on a surface of the structural member, and has at least one closed-cell void that is disposed on the surface of the structural member and contains an adhesive material. A method for fabricating a multi-material structure, the method comprising: forming a structural member with at least one open-cell void that is formed on a surface of the structural member; depositing a first portion of a polymeric skin on the surface; and depositing a second portion of the polymeric skin within the at least one open-cell void. A method for fabricating a multi-material structure, the method comprising: forming a structural member with a surface; forming a polymeric skin on the surface by depositing a first portion of a polymeric material on a first portion of the surface; forming at least one open-cell void on the surface by depositing a second portion of a polymeric