SYMPOSIA PAPER Published: 26 February 2022

Considerations for Use of Published AM Data for Aircraft Certification


This paper compares and contrasts how design values required by federal aviation regulations have been developed and used for both metallic and composite structure, and it discusses how those methods may be applied to additively manufactured materials. Traditional metallic aircraft structures have a long history of standardization where metallic alloys have public databases of properties that are independent of the metallic material producer. These materials may, by and large, be considered homogeneous and isotropic, leading to simplified theoretical solutions for strength and stiffness that have been further matured over the years into solutions for common aircraft design elements. By contrast, composite materials have published databases of properties for lamina or laminates that are tied to a single proprietary material formulation consolidated and cured/solidified under a single specific procedure. The database is therefore limited to those material and process details, and it is not universally applicable to other materials or similar processes. Due to the complexity of the structures, there are no fundamental solutions that can apply these simple properties to predict the strength and damage tolerance of full‐scale structures without additional levels of empiricism. To address that, composite designers develop unique semiempirical databases at more complex scales of the building block that, again, are only applicable to their specific design details. This paper discusses considerations to help designers determine if the method used for traditional metallic materials, the method used for composites, or a hybrid thereof, is appropriate for their additively manufactured (AM) application.

Author Information

Ashforth, Cindy
Federal Aviation Administration, Des Moines, WA, US
Ilcewicz, Larry
Federal Aviation Administration, Des Moines, WA, US
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Pages: 352–363
DOI: 10.1520/STP163720200129
ISBN-EB: 978-0-8031-7722-2
ISBN-13: 978-0-8031-7721-5