Composites, especially reinforced with carbon fiber, are light, strong and stiff. They enable aircraft to be lighter and more fuel efficient, which benefits the environment. Carbon fiber reinforced composites have already replaced aluminum as the main material in the fuselages of state-of-the-art airliners like the Airbus A350 XWB and Boeing 787 Dreamliner. But these composites do have an Achilles heel: they are brittle, which can be a problem in a crash. As research into how these materials will perform in an airplane crash is ramping up, we talk to one of the researchers investigating it.

In switching from metal to carbon composite fuselages, research has long been mainly on saving weight and making sure the structure is strong enough to cope with normal flight conditions. Now that more and more carbon fiber bodied airliners are successfully in service (541 in the case of the Boeing 787 Dreamliner, and 81 in the case of the Airbus A350 XWB as of April 2017), it is becoming increasingly important to investigate how they will perform under abnormal circumstances.

Carbon fiber composites pose a distinct challenge here. Not only are they more brittle than metals, they are also more complicated to analyze. And we have much more experience with metals than with high performance composites.

The fact that carbon fiber composite fuselages are more brittle than aluminum ones is probably not very relevant in a catastrophic accident like an aircraft at cruising speed flying into the side of a mountain. But it may make an important difference in survivable incidents, like aborted landings, hard landings and field landings.

This article appeared in the March–April 2018 issue of Reinforced Plastics. Log in to your free materialstoday.com profile to access the article.

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