Improved Composite Reinforcement Sheet? "Tailorable Universal Feedstock for Forming("TuFF")

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Vigilant1

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I've read a few write-ups about these products, seems they might be useful in some applications. Apparently, compared to "normal" woven or biax materials they are more conformable, can make compound curves more readily. The targeted use appears to be small parts that are now more economically made using pressed metal.

In a nutshell, the fabric can be composed of many possible fibers (carbon, fiberglass, etc). The fibers are short (aspect ratios between 100 and 1000) but almost all are aligned in one direction. Just like "regular" fabrics, layers/orientations are arranged to get the desired properties. The sheets can be stretched over a mold (dry, for later infusion, or as wet pre-pregs). Strength/weight is about the same as a part made from conventional biax, etc.
In use, they cut the sheet(s) for the desired part, constrain the edges, then force it into a mold, just like forming a metal part.

From this article: Revolutionizing the composites cost paradigm, Part 1: Feedstock
Laminates with <1% voids and up to 63% fiber volume have demonstrated >40% biaxial in-plane strain capability during forming, enabling metals-like molding of complex geometries without darting or complex ply patterns.
This process may be more useful to high-production industrial operations than to a typical homebuilder, but it seemed potentially useful for cowlings, wingtips, wheelpants, etc. Even for larger parts, it might be useful to avoid overlaps, darts, seams, etc.

Nope, I don't know how much it costs or where to get it.

Highlights:
The Tailorable Feedstock and Forming (TFF) program was launched by The Defense Advanced Research Projects Agency (DARPA, Arlington, Va., U.S.) in 2015 to enable rapid, low-cost and agile manufacture of complex geometry composite parts that weigh less than 20 pounds. Composites win against metals for large, stiffened skins made with processes such as automated tape laying and fiber placement (ATL/AFP). However, more than 80% of the parts in a typical tactical military airframe are small with complex geometry. For these, machined aluminum is favored because of the high cost and complexity of composite materials and manufacturing for small parts.
....
To achieve this vision, TFF is divided into two subprograms — the first for materials (feedstock) discussed here in Part 1 and the second for molding (forming) explored in next month’s Part 2:
The TuFF feedstock is a highly aligned, discontinuous fiber preform in thin-ply format, which can be combined with thermoplastic (TP) or thermoset (TS) resins for prepreg, or used in dry form for infusion-based processes. A patent-pending, discontinuous fiber alignment and preforming process has been demonstrated in a 5-ton/year pilot facility at UD-CCM comprising:
  • Short fiber dispersion and alignment
  • Automated layup and stacking
  • Prepregging and tailored blank production
  • TS/TP forming and liquid molding cell, to be added by the third quarter of 2020.
 
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