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Response of automated tow placed laminates to stress concentrationsIn this study, the response of laminates with stress concentrations is explored. Automated Tow Placed (ATP, also known as Fiber Placement) laminates are compared to conventional tape layup manufacturing. Previous tensile fracture tests on fiber placed laminates show an improvement in tensile fracture of large notches over 20 percent compared to tape layup laminates. A hierarchial modeling scheme is presented. In this scheme, a global model is developed for laminates with notches. A local model is developed to study the influence of inhomogeneities at the notch tip, which are a consequence of the fiber placement manufacturing technique. In addition, a stacked membrane model was developed to study delaminations and splitting on a ply-by-ply basis. The results indicate that some benefit with respect to tensile fracture (up to 11 percent) can be gained from inhomogeneity alone, but that the most improvement may be obtained with splitting and delaminations which are more severe in the case of fiber placement compared to tape layup. Improvements up to 36 percent were found from the model for fiber placed laminates with damage at the notch tip compared to conventional tape layup.
Document ID
19950022412
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Cairns, Douglas S. (Hercules Aerospace Co. Magna, UT, United States)
Ilcewicz, Larry B. (Boeing Commercial Airplane Co. Seattle, WA., United States)
Walker, Tom (Boeing Commercial Airplane Co. Seattle, WA., United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1993
Publication Information
Publication: NASA. Langley Research Center, Third NASA Advanced Composites Technology Conference, Volume 1, Part 2
Subject Category
Composite Materials
Accession Number
95N28833
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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