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Material Issues in Space Shuttle Composite Overwrapped Pressure VesselsComposite Overwrapped Pressure Vessels (COPV) store gases used in four subsystems for NASA's Space Shuttle Fleet. While there are 24 COPV on each Orbiter ranging in size from 19-40", stress rupture failure of a pressurized Orbiter COPV on the ground or in flight is a catastrophic hazard and would likely lead to significant damage/loss of vehicle and/or life and is categorized as a Crit 1 failure. These vessels were manufactured during the late 1970's and into the early 1980's using Titanium liners, Kevlar 49 fiber, epoxy matrix resin, and polyurethane coating. The COPVs are pressurized periodically to 3-5ksi and therefore experience significant strain in the composite overwrap. Similar composite vessels were developed in a variety of DOE Programs (primarily at Lawrence Livermore National Laboratories or LLNL), as well as for NASA Space Shuttle Fleet Leader COPV program. The NASA Engineering Safety Center (NESC) formed an Independent Technical Assessment (ITA) team whose primary focus was to investigate whether or not enough composite life remained in the Shuttle COPV in order to provide a strategic rationale for continued COPV use aboard the Space Shuttle Fleet with the existing 25-year-old vessels. Several material science issues were examined and will be discussed in this presentation including morphological changes to Kevlar 49 fiber under stress, manufacturing changes in Kevlar 49 and their effect on morphology and tensile strength, epoxy resin strain, composite creep, degradation of polyurethane coatings, and Titanium yield characteristics.
Document ID
20060020264
Acquisition Source
Glenn Research Center
Document Type
Other
Authors
Sutter, James K. (NASA Glenn Research Center Cleveland, OH, United States)
Jensen, Brian J. (NASA Langley Research Center Hampton, VA, United States)
Gates, Thomas S. (NASA Langley Research Center Hampton, VA, United States)
Morgan, Roger J. (Texas A&M Univ. TX, United States)
Thesken, John C. (Ohio Aerospace Inst. OH, United States)
Phoenix, S. Leigh (Cornell Univ. NY, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2006
Subject Category
Composite Materials
Meeting Information
Meeting: 9th Conference on Aging Aircraft
Location: Atlanta, GA
Country: United States
Start Date: March 6, 2006
End Date: March 9, 2006
Sponsors: Federal Aviation Administration, Department of Defense, NASA Headquarters
Funding Number(s)
OTHER: 515-02-01-03-03-01-07
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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