Tech

June 12, 2013

Army researchers chase helicopter performance gains

Army photograph by Capt. Jesse Paulsboe

A new study by Army researchers looks at inserting carbon nanotubes into the structural design of helicopter rotor blades to improve performance. Pictured here, an AH-64 Apache rises from behind a hill during a training exercise at Yakima Training Center, Wash. The AH-64E Guardian replaces the AH-64D “Longbow” and integrates more powerful engines, improved rotor blade technology and advanced electronics.

A new study by Army researchers looks at inserting carbon nanotubes into the structural design of helicopter rotor blades to improve performance.

The U.S. Army Research, Development and Engineering Command’s research laboratory hopes this approach could lead to the design and fabrication of the next generation of rotor blades and fixed wings.

Bryan Glaz, Ph.D., Jaret Riddick, Ph.D., and Ed Habtour, research engineers from the U.S. Army Research Laboratory Vehicle Technology Directorate, lead this effort.

Glaz and a team of structural, mechanical and aerospace engineers are embedding carbon nanotubes inside the composite matrix, resin material throughout the blade, and in specific locations like near the hub, which he said “gives more bang for the buck.”

“Especially in conflicts like Afghanistan, it really highlighted the deficiencies of the DOD current fleet in terms of payload capacity, speeds in supporting the warfighter and a big thing for the Department of Defense was the maintenance and cost,” Glaz said. “They can’t be sitting in a maintenance bay because if they’re in a maintenance bay, they’re not out there supporting the warfighter.”

Rotor structural dynamics can be inherently unstable. Structural design and the aeromechanics of rotorcraft flight can limit forward flight and maneuver capabilities and potentially lead to catastrophic structural failures in takeoff and landing conditions.

There is a tradeoff between rotor blades designed to transmit low vibrations to the aircraft and blades designed for stability, Glaz said. Blades with good stability characteristics tend to transmit high vibratory loads to the aircraft, and the high vibratory loads of rotorcraft are a major source of maintenance, repair and logistics burden associated with the DOD vertical-lift fleet.

The reverse is also true – blade designs with to low vibration tend to have structural dynamic stability issues that tend to limit the performance of the aircraft. This trade-off prevents the development of next-generation radical design concepts with substantially improved payload, speed, range and cost.

“Our goal is to eliminate the trade-off,” Glaz said. “We would like to be able to design blades that transmit low loads yet still have good stability characteristics.”

With the carbon nanotubes inside and inherent to that structure, researchers expect to enhance energy dissipation through friction at the nanotube-matrix interface and improve damping.

“We believe this improvement in damping can be exploited to so drastically improve stability without adding weight or mechanical complexity that rotorcraft designs never considered possible may become reality,” Glaz said.

Army researchers turned to recent scientific publications that indicate that carbon nanotubes can effectively dissipate energy for small scale samples. They’re venturing into uncharted research territory by investigating how much of the energy dissipation mechanism can be achieved when the carbon nanotubes are used to damp dynamic modes of actual structures as opposed to small laboratory samples.

These components would be similar to existing structures in the sense that the composite structures would still consist of a matrix with fiber reinforcement.

“In our case though, the matrix would be completely different since it would have carbon nanotubes inserted throughout,” Glaz said. “The nanotube enhanced matrix would provide the damping while fibers would still be used for strength and stiffness of the structure.”

In the future, the next-generation fleet will carry greater payloads and fly unimagined speeds with very low maintenance considerations, researchers said.

 




All of this week's top headlines to your email every Friday.


 
 

 
University of Rhode Island photograph by Tom Glennon

NASA kicks off field campaign to probe ocean ecology, carbon cycle

University of Rhode Island photograph by Tom Glennon The Research Vessel Endeavor is the floating laboratory that scientists will use for the ocean-going portion of the SABOR field campaign this summer. NASA embarks this week o...
 
 
NASA photograph by Carla Thomas

NASA’s high-flying laser altimeter to check out summer sea ice, more

NASA photograph by Carla Thomas This summer, the Multiple Altimeter Beam Experimental Lidar, or MABEL, will fly above Alaska and the Arctic Ocean on one of NASA’s ER-2 high-altitude aircraft. Sea ice in summer looks dramatica...
 
 
SOFIA

Outer space to inner space: SOFIA inside Lufthansa Technik hangar

NASA photograph by Jeff Doughty NASA’s Stratospheric Observatory for Infrared Astronomy is shown inside the Lufthansa Technik hangar in Hamburg, Germany where it is beginning its decadal inspection. Flight, aircraft maint...
 

 
NASA photograph by Tony Landis

New life for an old bird: NASA’s F-15B test bed gets new engines

NASA photograph NASA’s F-15B flight research test bed carries shuttle thermal insulation panels on its underbelly during a research flight in 2005. NASA Armstrong’s F-15B aeronautics research test bed, a workhorse at th...
 
 
NASA photograph by Tom Tschida

Towed glider benefits from center’s new 3-D printer capability

NASA photograph by Tom Tschida The major components of NASA Armstrong’s new high-resolution 3-D additive manufacturing printer occupy a shelf in the center’s subscale aircraft research lab. Robert “Red” ...
 
 
NASA photograph by Emmett Given

NASA completes testing on 3-D printer

NASA photograph by Emmett Given United Space Alliance engineer Cynthia Azzarita, left, and Boeing Company engineer Chen Deng, members of the Human Factors Integration Team at NASA’s Johnson Space Center, conduct a “...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>