College of Engineering

Augmenting Automated Material Placement via Material Characterization
Sayata Ghose, Associate Technical Fellow, Composites Fabrication, The Boeing Company

The lay-up performance during automated material placement (AMP) is significantly affected by the quality of adhesion (tack) at three interfaces: 1) between the material and the tool, 2) between neighboring material layers, and 3) between the material and rollers on the deposition head. There is currently no means of defining the ideal processing parameters for automated processes.

To optimize AMP process parameters, tack on different surfaces was characterized for multiple aerospace grade unidirectional tapes. A peel test fixture, developed jointly with the University of Nottingham and currently residing at multiple Boeing locations, was used to measure tack between a prepreg and a steel substrate. Modifications of the test methodology enabled the measurement of prepreg-to-prepreg tack and prepreg-to-fluorinated ethylene propylene (FEP) tack. In general, the test parameters, feed rate, and temperature affect the balance between cohesion within the resin and adhesion between resin and substrate. Exploring a range of parameters is required to understand the effect of viscoelastic resin properties on tack. Changes in molecular mobility in the resin related to specimen conditioning (i.e., aging or moisture uptake) result in maximum tack to occur at lower or higher feed rates, respectively. The test method is currently being developed as an ASTM standard (D30) and will assist in achieving maximum production rates and product quality by appropriately tailoring AMP process conditions.

Bio: Dr. Sayata Ghose attained her Ph.D. in Polymer Engineering from The University of Akron following a B.S. in Chemistry and B.Tech in Polymer Engineering. She then worked at NASA Langley Research Center for 7.5 years before joining The Boeing Company in 2011 where she has been working on materials producibility and composites fabrication. Ghose has 18+ years of experience processing and characterizing elastomers, nanocomposites, aerospace prepregs and high temperature resins. Her academic work includes 26 peer-reviewed journal publications, ~60 conference proceedings,15 poster presentations, 2 book chapters, >1000 citations, 10 U.S. patents, 1 patent application publication as well as multiple invited talks and funded proposals.