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The final assembly line for the 787 in the Boeing Everett, WA, facility. There are two versions of the aircraft, the 787-8 and the 787-9. The 787-9 is the longer of the two, at 206 ft compared with 186 ft for the 787-8. Both aircraft have a 197-ft wing span and are 56 ft high.
One of the necessities of working with a new material for particular applications is to have high levels of confidence in the performance of that material. Shown here is the “after” of a destructive test on a full-scale composite wing box for the 787. The wing box is the first all-composite one for Boeing. To meet certification, the wing box must withstand loads 1.5 times greater than those that the aircraft would ever be expected to endure.
Within Boeing, technologies are organized into “domains.” There are eight. These range from self-explanatory named ones, like “Systems Engineering and Analysis,” to those with insider-only meaning, like Platform Performance, which encompasses such things as concept and configuration development for commercial, military and space systems and vehicles.
Dr. Andrew Bicos is director of two Boeing domains: Structures, under which there is the development of things like cross-functional architectural systems to new materials, and Manu-facturing. About that, Bicos says, “The manufacturing area basically has two major sub-divisions: the manufacturing processes—how we go from raw materials to fabricate them into pieces that will go into an assembly—and the production system processes—how we assemble the pieces or subassemblies that we get from suppliers.”
One of the interesting aspects of Boeing’s development work on production systems—one predicated, in part, on the fact that the company has backlogged orders for aircraft—is that they are looking to the utilization of robots and other automated systems for builds. “We are all looking at how to increase rate.” This is complicated somewhat by the fact that there is a considerable shift from metal aircraft structures to composites and new aerodynamic designs, driven by the need to achieve greater product performance and efficiency. “Whenever you introduce a new or innovative design,” he points out, “you have to be aware of the impact on building it. If it impacts your rate adversely, then you have to figure out how to minimize that.” He says the Manufacturing domain has a focus on answering the question for its aircraft: “How do you assemble it in a high-quality, low-cost, high-rate fashion?”
The build rate of 787s is presently at 3.5 units per month. The plan is to build 10 a month by the end of 2013.
Bicos says that they’ve been keeping an eye on how the auto industry has implemented automated systems. But historically, there has been a gap between what is done in auto and what can be done in aircraft. For example, he points out that whereas there is a preponderance of robotic spot welding in auto, “The tolerance for a spot weld has a lot more leeway than we have for where we need to put a hole. We’ve been following automotive automation, but it’s only been during the past few years that would allow us to look at this quite seriously.” That’s because, he notes, there have been controllers developed that offer the processing power and precision motors developed that provide the means to drive robotic arms to the required locations. “As your rates increase, you need to get more out and to increase quality. So if you can have a robot that can precisely locate time after time—drill a hole perfectly and put in a rivet perfectly—that allows you to achieve the rates and quality you need.
“If you do it faster and your quality suffers, you’ve got to repair it and then your rate is no good. Quality is important for the rate you need.”
Hearing that, it isn’t surprising to learn that Bicos says Boeing has been working on implementing aspects of the Toyota Production System for more than a decade now.
Boeing itself doesn’t produce materials, but it works with suppliers—closely, he says—in the development of materials. And while he acknowledges that for Boeing, “lightweight is always important,” that’s not the entirety of consideration. “If you’re talking about a military airplane, strength and stiffness are very important. But if you’re talking about a commercial airplane, because you have a lot more cycles—takeoffs and landings—durability is important, as well. Depending on the product, there is an emphasis on different properties.”
Which has led to the deployment of a considerable amount of composites in the build of aircraft, the 787 in particular, which is 50% composite by weight; the majority of its primary structure (e.g., fuselage) is produced with composite materials. Bicos says of composites, “It allows us the flexibility of tailoring the material to the specific properties we need in different parts of the airplane. You could see this to a limited extent with metallics, such as where we use different aluminum alloys in different parts of the airplane. But with a metallic material, there are many more limitations.
“With composites you open up the design space to allow a lot more innovation and to achieve strength, stiffness and durability where you need it and to downplay them where you don’t. You are able to tailor components so that you’re able to get much greater weight efficiencies while getting the performance you want.”
While it might seem that there has been a phenomenal shift from metallic structures to the composite-intensive 787, a shift that has occurred in a comparatively short period of time, Bicos says that the deployment “has been a long time in happening.” Back in the 1970s they started using composites for secondary and tertiary structures, “not flight-critical primary structures.” Through the ‘80s, the number of composite components continued to increase. Then in the ‘90s, the empennage—or tail assembly—for the 777 had many composite parts. Additionally, they were doing development for military aircraft, so the amount of understanding was growing. “By the time we had to decide on the next airplane, the 787, it was a big jump, but not as dramatic a change as it might look.”
Realize that one of the elements of deploying a new material on an aircraft is undergoing an intensive FAA certification process. “That takes a long time and is cost-intensive, so when you go to a new material, you don’t do so willy-nilly—there has to be a heck of a business case for doing it,” Bicos says.
Although they have garnered extensive experience with composites, Bicos believes there remains plenty of work to be done, especially with regard to coming up with more innovative designs that will help increase throughput and reduce costs while maintaining the highest levels of quality. “It is an important fact of life that when you introduce something like composites, you are high on the learning curve. But every time you build a new product, the learning and the process improvements you get drive you down the curve.”
And he thinks there is a big upside coming regarding composite development vis-à-vis the learning curve: “You’re going to see dramatic improvements over the next 10 to 20 years on the aircraft side.”
He adds, “That’s part of what my job entails: what’s the strategy and investment we need to implement so we can go down the learning curve?”
One of the reasons that the cost of composite materials has been high is because demand has been comparatively low. And one of the reasons the demand for composite materials has been comparatively low is because the price of the materials has been high.
So more demand should drive down prices, right?
Boeing and its primary competitor, Airbus, have become significant users of composite materials. And Dr. Andrew Bicos, director of Boeing’s Structures and Manufacturing Technology Domains, says that there are a number of companies around the world—e.g., Cytec, Hexcel, Toray—that have capacity to provide for the existing demands.
But here comes the auto industry. While its use of composites has been not much more than a rounding error in global shipments, as things like increased miles per gallon or reduced carbon dioxide per kilometer come to the fore, there could be more composite demand in the not-too-distant future.
And Bicos says that there is the real possibility that this demand is going to drive material prices up, given that there may not be sufficient capacity to deal with the increased number of aircraft and automobiles that use the strong, light material.
Eventually, of course, supply and demand will become more aligned. But in the meantime . . .
This is the left-hand upper wing cover being lifted into the first main assembly jig for the production of the Airbus A350XWB at a plant in Broughton, UK. Airbus, like Boeing, is using carbon fiber composites extensively.
Just as the aircraft industry is making the transition to using composites, the auto racing industry, as exemplified by F1 racing, is an area where composite materials are being used to the utmost.
Case in point is the Lotus F1 Team E20. The car is based on a molded carbon fiber and aluminum honeycomb composite monocoque that’s manufactured by the team at its plant in Enstone, in Oxfordshire. The 2.4-liter Renault RS27-2012 V8 engine is integrated as a fully stressed member.
The front and rear suspension wishbones use carbon fiber. The suspension uprights are aluminum. The wheels are machined magnesium. The driver’s seat is carbon fiber, as well.
The E20 is 198.3-in. long, 70.87-in. wide, and 37.4-in. high. With the drivers, cameras, and ballast, it weighs just 1,411 lb.
Last year Lotus F1 Team brought a 60% wind tunnel
into its product development capabilities. But what they’re finding to be of the utmost importance to aerodynamic developments is the use of computational fluid dynamics (CFD); CFD supplier CD-adapco (cd-adapco.com) is one of the team’s partners (as is Boeing Research & Technology).
Validation of the importance of CFD was realized through a case study performed at Enstone for Nissan. Nissan provided a digital model of an existing car. It was run through the Lotus F1 Team CFD program, and they were able to optimize the external shape of the vehicle so as to realize a drag reduction of some 4%. To check the findings, Nissan ran this through a different CFD program and validated the results.
Like the Boeing fuel cell aircraft, a Lotus F1 Team E20 will be at the Advanced Manufacturing Center exhibit (W-160) at the International Manufacturing Technology Show in Chicago, September 10-15 (imts.com).
The Lotus E20 F1 car. Made aero through the use of computational fluid dynamics. Made light through the use of advanced composites.
Working on a composite part for the Lotus E20 at the team’s Enstone facility in the UK.