CompositesWorld

FEB 2016

CompositesWorld

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FEBRUARY 2016 8 CompositesWorld PERSPECTIVES & PROVOCATIONS » Although we're still awaiting the mass production of fying cars and miniature fusion reactors, some predictions in the 1985 flm Back to the Future for 2015 have, indeed, come true. Among them are in-home videoconferencing and voice and fngerprint recogni- tion for personal devices. On the 30 th anniversary of the movie, the US Defense Advanced Research Projects Agency (DARPA) issued some predictions about the world in 2045 (www.darpa.mil/news-events/2015-10-21). Some of them seem pretty far-fetched, but given the pace of technological devel- opment, they might be realized much sooner. So, what would an idealized future for the advanced composites industry look like? And rather than looking out 30 years, how about the next 10 to 20? Here are some of my thoughts: "Make it and break it" is a thing of the past. Today's "building block" approach to composites, from coupon level to full struc- tures, is both time-consuming and expensive. As computing power evolves, the necessity to fabricate and test thousands of coupons to derive design allowables goes away. Instead, we manufacture a modest set of critical panels and measure a handful of mechanical properties, and use proven and reliable mathematical models to accurately predict the remaining design properties, called "virtual allowables." Most important, we believe in them. From these, we are able to predict behavior of as-manufactured components and assemblies in impact, crash, fatigue and other potential failure modes, leading us to design parts at minimum weight and cost. We also characterize the rheology of the various polymers in compos- ites, as well as forming behavior of fbers and textile forms to conf- dently simulate composite manufacturing processes. Nondestructive evaluation (NDE) is no longer about "pass/fail." In fact, NDE is only about making sure things are made correctly, so we no longer wait to sort out the good parts from the bad after all costs have been incurred. We've moved diagnostics further upstream into all the manufacturing processes that can impact fnal part quality, including base fber and resin production. NDE now provides immediate, automated validation of ply sequences and fber orientations during part layup or forming, as well as state of cure, resin fow, fber wash and other parameters during the molding or curing stages. Validated, end-to-end simulation tools take information gathered by a variety of sensors and actually control manufacturing processes, predicting when a process is headed out of specifcation and then making automated, intelli- gent decisions: Tis might lead the machine to increase or reduce mold temperature or resin fow-rate setpoints upon sensing that a particular batch of resin is more or less reactive than the previous one. And this occurs without human intervention. Eforts to minimize energy use, cycle time and process cost bear fruit. Te manufacture of advanced composites structures, previ- ously energy intensive, particularly for carbon fber, which had very high embodied energy in solution spinning and oxidation of PAN polymers, is no longer. Te vision's a bit hazy here: Perhaps these are still PAN variants, or maybe they are modifed polyolefns, or other polymers altogether, including bio-based. But we've designed precursor molecules that yield the strength and stifness needed, yet can be melt spun and oxidized/carbonized at much greater energy efciency. Termoset curing and thermoplastic crystallization times have come down, enabling less than one-minute part cycle times with continuous fber orientations. An increasing number of production parts are 3D printed, and this process has found wide use in the manufacture of rate tooling for all molding processes. In addition to polymer-based tooling, large-area additive manu- facturing of metals and metal-matrix composites enables rapid, low-cost fabrication of high-temperature, high-strength molds. Nearly 100% use and re-use of materials. Watching high levels of cutting scrap go into landflls is a thing of the past. "Buy/fy" ratios (applicable to aircraft structures, and per some colleagues, wind turbines) and "buy/drive" ratios (now a real term for vehicles) for materials procurement have moved close to 1:1, from historical 1.5:1 and higher levels. Large structures in aircraft have closed the gap via automated tape laying and fber placement, and multiple technologies have done the same for parts with complex geom- etries, such as those in the auto industry. What in-plant ofal we do generate (we no longer produce scrap parts — see NDE above) is immediately recycled into value-added components, perhaps as molding compounds. And at the end of life, we have cost-efective methods to recover and recycle the fbers and, hopefully, the resin as well, and to do so proftably. All of the above areas are intertwined and all must move in parallel for this idealized future to occur. For that to happen, the best technologies will have to proliferate globally, and do so quickly. I believe it can be realized. Who's with me? Advanced composites — An idealized future Dale Brosius is the chief commercialization ofcer for the Institute for Advanced Composites Manufacturing Innovation (IACMI, Knoxville, TN, US), a US Department of Energy (DoE)- sponsored public/private partnership targeting high-volume applications of composites in energy-related industries. He is also head of his own consulting company and his career has included positions at US-based frms Dow Chemical Co. (Midland, MI), Fiberite (Tempe, AZ) and successor Cytec Industries Inc. (Woodland Park, NJ), and Bankstown Airport, NSW, Australia-based Quickstep Holdings. He served as chair of the Society of Plastics Engineers Composites and Thermoset Divisions. Brosius has a BS in chemical engineering from Texas A&M; University and an MBA. I believe our industry's "idealized" future can be realized. Who's with me?

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