AFRL research advances 3D printable CF/epoxy composites

The Composites Branch Air Force Research Laboratory (AFRL, Dayton, Ohio, U.S.) has partnered with the University of Arkansas, the University of Miami, Louisiana Tech University and the University of Texas at El Paso to develop additively manufactured epoxy/carbon fiber composites for use in structural parts for air- and spacecraft.

The polymers used for the printed materials are said to be the same materials already being used on Air Force systems, which have been developed for high thermal and environmental durability, high strength and very light weight.

In comparison to traditional composites, AFRL says that it is possible to more easily create complex additively manufactured composite parts and that this process eliminates the need for expensive and long curing processes. Additive manufacturing also is said to simplify the logistics involved with producing, assembling, and repairing parts, since these processes can be done in the field or at the depot.

In addition, AFRL has formed joint projects with international allies, including India, to use the composite 3D printing to make complex core structures which, when combined with top and bottom face sheets, create lightweight sandwich structures with properties tailored to the physical forces that need to be carried.

The manufacturing agility of these additively printed cores is said to enable the easy insertion of other materials like metal fittings and electrical components, easing assembly and creating multifunctional structures with embedded sensing, actuation, computation or electrical power for next-generation multifunctional unmanned aerial vehicles.

Traditional sandwich structures are used on aircraft skins with the same core geometries over the entire area. Additively printing sandwich structures reportedly will enable structures that can withstand heavier forces where needed and to remain lighter weight where they are not.

“The potential to quickly print high-strength composite parts and fixtures for the warfighter could be a tremendous asset both in the field and for accelerating weapon system development,” says Dr. Jeffery Baur, leader of the Composite Performance Research Team.

The results of the team’s work will be published in a special issue of the Journal of Experimental Mechanics dedicated to the Mechanics of Additively Manufactured Materials.