Inflatable composite structures enable lightweight transportable buildings

Inflatable structures (aka airbeams) have developed rapidly in recent times, finding application in a variety of new engineering projects ranging from military tents in Iraq and Afghanistan to antennas in outer space. With necessity as the driving force, a team of engineers at the U.S. Army Soldier Systems Center in Natick forms the backbone of research into the technology. And the results have been spectacular - the technology has reduced the transportable weight of a tent by 66%, the transportable volume by 75% and the setup time by 50%.

Founded in 2002, the Center of Excellence for Inflatable Composite Structures headquartered at the Natick Soldier Center’s Collective Protection Directorate has managed a textile technology process to create airbeams that are lightweight and compact.

Army shelters were the first beneficiaries of airbeam technology, but the technology has transferred to the Air Force, Marine Corps, Navy and NASA with the assistance of industry partners Vertigo Inc. and Federal Fabrics-Fibers Inc.

“The technology was around, and people were working on inflatables, but there was no standard in the industry in design or performance, so we wanted all the expertise in one place to design (a customer’s) particular composite for different applications,” said Amy Soo Leighton, a chemical engineer on the Fabric Structures Team.

Leighton along with engineers Jean Hampel, Claudia Quigley and Karen Santee contribute to the design, testing and evaluation of airbeam products for the Center of Excellence, using modeling and analysis to find the optimal design.

Interest has grown in inflatable structures as they spread the word at conferences and in publications.

“We can think of a lot of applications at Natick, but others think of areas that we never expected,” Leighton said, recalling one inquiry on an airbeam design to quickly move a generator off a vehicle. “We know the technology well enough to meet their standards and have the capability in-house to design (the structures) taking into consideration safety and failure methods.”

Airbeams are manufactured by continuous braiding or weaving of a high-strength 3-D fabric sleeve to provide structural strength over an air-holding bladder. What results is a smooth, durable and seamless tube anywhere from 2-40 inches in diameter set at different pressures, depending on the support needed. Each collapsible tube has a built-in valve for a fill-up from a commercial air compressor modified with an automatic shut-off.

By changing design parameters, the airbeam shape can be modified for different products. The team guided and matured two weaving and braiding capabilities into a reliable technology with unlimited potential, according to Leighton, and in the process created an economical manufacturing base.

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