Boeing is still struggling with Carbon fibre technology. Like I had once said in one post, carbon fibre is too difficult to manufacture inspite of its obvious advantage as a material.
At Boeing, Dreamliner Fix Reveals New Wrinkle - WSJ.com
At Boeing, Dreamliner Fix Turns Up New Glitch
By PETER SANDERS
Boeing Co. said Thursday it had finished fixing the problem that had forced it to postpone the maiden flight of its long-delayed 787 Dreamliner. But in making the repair, the aerospace giant got a fresh reminder of the complexities involved in working with the high-tech materials used to build the aircraft.
Damage to the area where the wings join the plane's body emerged during stress testing earlier this year. That prompted Boeing to delay flight testing of the aircraft and urgently search for a repair.
See production delays in the long-awaited 787 Dreamliner, plus stock price and key events for Boeing.
As Boeing raced to find a remedy this summer, it discovered another issue with the composite material in the plane's wings, according to internal company documents and a person familiar with the matter. Metal bolts inside the wings of one of the six test airplanes were found to have slightly damaged the surrounding material—causing so-called delamination, or cracking—the documents show.
The damage, which Boeing engineers cited as an additional reason to keep the plane grounded, was discovered as the original problem was being fixed. It isn't known whether the five other test-flight aircraft showed similar damage.
The aerospace giant faces challenges in its commercial business, but its defense side is also feeling revenue pressure. MarketWatch's Christopher Hinton reports on the company's latest results.
The damage created by the metal bolts, called freeze plugs, was confined to a relatively small area. However, according to an internal Boeing document from October, it raised red flags among engineers, who decided the plane couldn't fly until the problem was corrected.
A work order written by one of the company's engineers, and reviewed by The Wall Street Journal, says, "Noted conditions are structurally and functionally acceptable to Engineering for GROUND TESTING ONLY," and adds, "NO FLIGHT TEST IS ALLOWED."
The company acknowledged Thursday that delamination occurred in the composite material surrounding bolt holes, but said it won't affect the plane's first flight or require a repair. It said it routinely uses metal freeze plugs, which are installed after being frozen in liquid nitrogen and expand as they thaw.
"The freeze plug process is a standard repair we perform on both metallic and composite structure. We have extensive experience using these techniques. We have not seen any issues with these repairs that are inconsistent with our experience or the capability of these repair techniques," a Boeing official said.
In developing a new airplane as complex as the Dreamliner, problems large and small are inevitable. Boeing's European rival, Airbus, encountered significant problems and delays in developing its giant A380 jetliner, though those delays involved wiring and interior-customization issues.
Composite materials, essentially sandwiched layers of carbon fiber and epoxy, can make planes lighter and more fuel efficient than conventional materials like aluminum. Airbus, a unit of European Aerospace & Defence Co., uses composites widely in its planes, but it has adopted them much more gradually over successive aircraft models than Boeing's big leap with the 787. Boeing's use of composites throughout the Dreamliner is the most extensive use of these materials ever attempted in a large commercial jetliner.
Journal Communitydiscuss“ As energy prices rise, this doesn't seem to bode well for Boeing and Airbus getting a new generation of more efficient planes to market quickly. ”
—Thomas Broen Boeing remains convinced that "composites are the right material choice for the 787 Dreamliner. We are progressing well toward first flight and are on track to fly by the end of the year," said Scott Fancher, vice president and general manager of the 787 program.
Though composite materials are both strong and lightweight when intact, cracks or bubbling in the materials can potentially undermine their integrity, experts say. Much remains unknown about their behavior. Boeing has only computer models to predict how they will react to the stresses of flight, especially under long-term use.
"Delamination is a very, very challenging problem to model analytically," says Andy Hansen, professor of mechanical engineering at the University of Wyoming and an expert in composite analysis. "If you're talking about building an airplane you want to fly for 30 years, it's an issue."
When composites are damaged, or delaminate, Prof. Hansen says, "you had better be concerned about them propagating over time."
The discovery of the damage comes at a very late stage in the Dreamliner's development and production process. The company is preparing to ramp up production once its aircraft clear the rigorous test-flight phase. Crafting engineering solutions for problems such as these at this stage of production can be exceedingly complicated and expensive.
According to a person familiar with the details, Boeing is still aiming to get the first Dreamliner airborne on Dec. 22. Workers at Boeing's massive factory in Everett, Wash., are on duty around the clock preparing the first batch of Dreamliners for test flights
Boeing executives are under intense pressure to get the Dreamliner aloft. The plane is now more than two years behind schedule, and Boeing last quarter took a $2.5 billion charge related to development costs associated with the program. These delays have cost the company hundreds of millions of dollars in concessions and penalties to its customers, though the company still has orders for 840 Dreamliners.
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Any chance you could jsut paste the complete artcle here ( and incur the wrath of WSJ lawyers no doubt 
)
Originally Posted by henk4
