Replacement of metallic structures for composites in aerospace, and other
market segments, has been a common trend over the last decade and will continue
to occur as a result of the performance benefits composite structures offer
over traditional metallic structures, particularly specific strength and stiffness.
As the industry moves to the use of more composite structures, it is becoming
increasingly difficult to fabricate the desired shapes and sizes due to the
tooling required for complex part geometries. This requirement for complex
tooling geometries is particularly evident in the fabrication of composite
aerospace parts. Currently, to fabricate composite complex parts with trapped
features requires either a silicone bladder tool or a rigid sectional mandrel.
Both approaches, bladder and sectional mandrel, offer drawbacks resulting
in sacrifices in part cost or part performance.
While these tooling approaches allow for the fabrication of complex geometries, they both have serious drawbacks that result in increased manpower and tooling costs that are reflected in the price per unit cost of the final part. These increases in costs have traditionally made complex composite parts less attractive to an end user as compared with their more traditional aluminum competition. In addition to cost increases, part reproducibility and reliability also potentially suffer from these tool shortcomings as a result of the lack of automated processes.
To address these issues, CRG has developed Smart Mandrels™. Smart Mandrels™ are intended to be a direct one-for-one replacement of rigid multi-section mandrels for use as a rigid tool during cure that can be vacuum bagged and cured in an autoclave. Smart Mandrels™ are tools that have the ability to change storage modulus as a function of temperature. The materials that comprise these tools have the ability to change in storage modulus from a high-performance composite to a high-performance elastomer. This change in mechanical performance allows CRG to fabricate tools that can be rigid during the cure temperatures of the composite; however, during post-cure, they can become soft for mandrel extraction.
Bio:
Thomas Margraf received his B.S. in Mechanical Engineering from the University
of Dayton, Ohio where he led a research team investigating the usefulness
of piezoelectric patches in morphing aircraft.
Mr. Margraf joined the CRG professional staff as a Research Engineer and was promoted to Business Development Engineer. His Genesys™ composite technology gives structures the in-service capability to autonomously identify and heal damage. Genesys™ has application in aerospace, automotive, and marine industries. He led CRG’s development of this technology under a NASA SBIR contract and is currently focused on commercializing it. He has published technical papers on Genesys™ for SPIE, AIAA, NSMMS, and JANNAF.
Mr. Margraf
leads multidisciplinary teams developing a commercial application for other
SBIR-originated technologies (morphing aircraft, composite tooling technology
and advancing technology from TRL 6 to TRL 9). He has hands-on expertise in
a wide variety of composite processing techniques (wet lay-up, RTM, VARTM
and filament winding).