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Towards a damage tolerance philosophy for composite materials and structuresA damage-threshold/fail-safe approach is proposed to ensure that composite structures are both sufficiently durable for economy of operation, as well as adequately fail-safe or damage tolerant for flight safety. Matrix cracks are assumed to exist throughout the off-axis plies. Delamination onset is predicted using a strain energy release rate characterization. Delamination growth is accounted for in one of three ways: either analytically, using delamination growth laws in conjunction with strain energy release rate analyses incorporating delamination resistance curves; experimentally, using measured stiffness loss; or conservatively, assuming delamination onset corresponds to catastrophic delamination growth. Fail-safety is assessed by accounting for the accumulation of delaminations through the thickness. A tension fatigue life prediction for composite laminates is presented as a case study to illustrate how this approach may be implemented. Suggestions are made for applying the damage-threshold/fail-safe approach to compression fatigue, tension/compression fatigue, and compression strength following low velocity impact.
Document ID
19900053072
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
O'Brien, T. Kevin
(NASA Langley Research Center; U.S. Army, Aerostructures Directorate, Hampton VA, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Subject Category
Composite Materials
Meeting Information
Meeting: Symposium on Composite Materials: Testing and Design
Location: Sparks, NV
Country: United States
Start Date: April 27, 1988
End Date: April 29, 1988
Sponsors: ASTM
Accession Number
90A40127
Distribution Limits
Public
Copyright
Other

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