Method and System For Forming Composite Geometric Support Structures

• US 20100065192A1
• Filed: 08/17/2009
• Published: 03/18/2010
• Est. Priority Date: 08/15/2008
• Status: Active Grant

• Current Assignee: SigmaTel Incorporated (NXP Semiconductors NV)
• Original Assignee: SigmaTel Incorporated (NXP Semiconductors NV)
• Inventors: Kipp, Michael D., Wilson, Erich A., Ridges, Michael D.
• Granted Patent: US 8,313,600 B2
• Time in Patent Office: Days
• US Class Current: 156/180
• CPC Class Codes: B29C 70/46 using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386

Abstract

A method and system for fabricating a geometrically versatile composite lattice support structure having a seamless three-dimensional configuration. The lattice support structure is created by forming two or more cross supports, such as helical, longitudinal, circumferential and/or lateral cross supports, which intersect to form a plurality of multi-layered nodes. The lattice support structure may be designed without any protrusions extending outward from the overall geometry, thus enabling efficient tooling, and thus enabling ease of mass production. The lattice support structure may comprise a completely circumferentially closed geometry, such as a cylinder, ellipse, airfoil, etc. The method for fabricating the lattice support structure comprises laying up a fiber material, in the presence of resin, within rigid channels of a rigid mold, thus creating a green, uncured three-dimensional geometry of unconsolidated cross supports and multi-layered nodes where these intersect. Subjecting these to a curing system functions to consolidate the cross supports and multi-layered nodes to produce the composite lattice support structure.

Claims

1. A method for forming a composite lattice support structure having a plurality of cross supports intersecting one another to form a plurality of nodes, said method comprising:

providing a rigid mold having a working surface with rigid boundaries that define a plurality of channels;

depositing, systematically, a fiber material within said channels, wherein at least one layer of fiber material within a first channel is situated between at least two layers of fiber material within a second channel at an intersection of said first and second channels to form a multi-layered node; and

consolidating said fiber material within said channels in the presence of resin, heat and pressure,

wherein said pressure is caused to be concentrated about said channels to enhance compaction of said fiber material within said channels.

8. The method of claim 1, wherein said forming a vacuum enclosure about said rigid mold and said fiber material comprises:

applying a flexible, gas impervious vacuum bag about said pressure transfer layer and said rigid mold; and

sealing said vacuum bag to said rigid mold.

2. A method for forming a composite lattice support structure having a plurality of cross supports intersecting one another to form a plurality of multi-layered nodes, said method comprising:

obtaining a rigid mold having a working surface with a network of channels intersecting at strategic locations, said channels cooperatively establishing a substantially continuous interconnected lattice corresponding to a three dimensional geometric configuration to be imparted to a composite lattice support structure;

depositing a fiber material, in the presence of a resin, within said channels to provide a fiber material lay-up systematically arranged to contribute to the makeup of a plurality of composite cross supports that intersect to form a plurality of nodes;

applying a dynamic pressure transfer layer about said rigid mold and said fiber material lay-up, said pressure transfer layer being resilient and adapted to displace about said working surface and concentrate an applied pressure about said channels and onto said fiber material lay-up to compact said fiber material within said channels;

forming a vacuum enclosure about said fiber material lay-up and said rigid mold to facilitate drawing of a vacuum;

subjecting said fiber material lay-up to a curing cycle to consolidate said fiber material to form said lattice support structure having said cross supports and said nodes; and

releasing said lattice support structure from said rigid mold.

3. The method of claim 2, wherein said subjecting said lay-up to elevated temperature and pressure comprises placing said lay-up, in an uncured state, within a pre-heated, elevated temperature environment to rapidly increase a rate of temperature increase of said lay-up.

4. The method of claim 3, further comprising immediately removing said formed lattice support structure, at said elevated temperature, from said elevated temperature environment and placing it into an ambient temperature environment to instantly remove exposure to said elevated temperatures.

5. The method of claim 4, further comprising actively cooling said formed lattice support structure upon removal from said elevated temperature environment.

6. The method of claim 2, wherein said pressure transfer layer comprises a silicone material.

7. The method of claim 2, wherein said pressure transfer layer comprises a liquid material curable under ambient conditions adapted to be applied to and seal said rigid mold and to comprise and function as said vacuum enclosure.

9. The method of claim 2, wherein said forming a vacuum enclosure about said rigid mold and said fiber material comprises:

applying a vacuum bag formed of, at least initially, a prepolymer composition about said rigid mold, said prepolymer composition functioning as said vacuum enclosure and said pressure transfer layer;

sealing said vacuum bag to said rigid mold.

10. The method of claim 9, wherein said prepolymer composition is in liquid form and polymerized after being applied about said rigid mold, and wherein said sealing comprises extending application of said prepolymer composition to a surface of said rigid mold.

11. The method of claim 2, further comprising facilitating an expansion of said fiber material within said channels, without overstressing particles of said fiber material, for the purpose of increasing the pressure curve across said lattice support structure and optimizing said consolidation.

12. The method of claim 2, wherein said obtaining said rigid mold comprises configuring a mandrel to comprise a plurality of rigid grooves formed in a surface thereof, at least some of said plurality of grooves intersecting at strategic locations.

13. The method of claim 12, further comprising configuring said mandrel to be collapsible, with several component parts facilitating selective assembly and disassembly of said mandrel.

14. The method of claim 2, wherein said formed lattice support structure comprises a seamless configuration.

15. The method of claim 2, wherein said depositing a fiber material comprises pre-determining a type of fiber material, a size of fiber material, a fiber count and an index or amount of fiber material to be deposited within said channels, based on one or more desired performance characteristics of said lattice support structure.

16. The method of claim 2, wherein said depositing a fiber material comprises depositing said fiber material in accordance with a pre-determined number of layers to be present within said node, said node comprising a multi-layered node with at least one layer of fiber material within a first channel situated between at least two layers of fiber material within a second channel at an intersection of said first and second channels.

17. The method of claim 2, wherein said depositing a fiber material comprises winding a fiber-based tow onto said rigid mold in accordance with a pre-determined winding process, said channels providing a secure pathway for said tow.

18. The method of claim 17, wherein said fiber-based tow is subjected to a resin component in situ during said winding process and as it is to being deposited within said channels.

19. The method of claim 17, wherein said fiber-based tow comprises a preimpregnated tow or towpreg.

20. The method of claim 2, further comprising applying a release layer about said rigid mold and said fiber material beneath said vacuum enclosure to facilitate release of said lattice structural support from said vacuum enclosure.

21. The method of claim 2, further comprising maintaining a direction and deposited path of said fiber material through an intersection of said channels, such that any formed cross support and multi-layered node comprises unidirectional fiber materials prior to said consolidating.

22. The method of claim 2, further comprising configuring said rigid mold and said channels to form a structural support having a uniform cross-section taken along a longitudinal length of said support structure.

23. The method of claim 2, further comprising configuring said channels to define one or more of a helical channel, a reverse helical channel, a longitudinal channel, a lateral channel, a transverse channel, and any combination of these.

24. The method of claim 2, further comprising configuring said channels to be curved between intersections.

25. The method of claim 2, further comprising containing said cross supports and said multi-layered nodes within a common radial plane, such that said support structure comprises substantially no protruding elements.

26. The method of claim 2, further comprising layering multiple layers of said fiber material within said channels.

27. The method of claim 2, further comprising configuring said support structure to comprise a circumferentially open geometry.

28. A system for forming a composite lattice support structure, said system comprising:

a rigid mold having a working surface with a network of channels intersecting at strategic locations, said channels cooperatively establishing a substantially continuous interconnected lattice corresponding to a three dimensional geometric configuration to be imparted to a composite lattice support structure;

a fiber material deposited, in the presence of a resin, within said channels to provide a fiber material lay-up systematically arranged to contribute to the makeup of a plurality of composite cross supports that intersect to form a plurality of nodes;

a dynamic pressure transfer layer situated about said rigid mold and said fiber material lay-up, said pressure transfer layer being resilient and adapted to displace about said working surface and concentrate an applied pressure about said channels and onto said fiber material lay-up to compact said fiber material within said channels;

a vacuum enclosure situated about said fiber material lay-up and said rigid mold to facilitate drawing of a vacuum; and

a curing system adapted to consolidate said fiber material to form said lattice support structure having said cross supports and said nodes.