Ten-year Ground Exposure of Composite Materials Used on the Bell Model 206L Helicopter Flight Service Program
Author: Donald J. Baker
Publisher:
Published: 1994
Total Pages: 60
ISBN-13:
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Author: Donald J. Baker
Publisher:
Published: 1994
Total Pages: 60
ISBN-13:
DOWNLOAD EBOOKAuthor: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
Published: 2018-07-16
Total Pages: 56
ISBN-13: 9781722798666
DOWNLOAD EBOOKResidual strength results are presented for four composite material systems that have been exposed for up to 10 years to the environment at five different locations on the North American continent. The exposure locations are near where the Bell Model 206L helicopters, which participated in a flight service program sponsored by NASA Langley Research Center and the U.S. Army, were flying in daily commercial service. The composite material systems are (1) Kevlar-49 fabric/F-185 epoxy; (2) Kevlar-49 fabric/LRF-277 epoxy; (3) Kevlar-49 fabric/CE-306 epoxy; and (4) T-300 graphite/E-788 epoxy. Six replicates of each material were removed and tested after 1, 3, 5, 7, and 10 years of exposure. The average baseline strength was determined from testing six as-fabricated specimens. More than 1700 specimens have been tested. All specimens that were tested to determine their strength were painted with a polyurethane paint. Each set of specimens also included an unpainted panel for observing the weathering effects on the composite materials. A statistically based procedure has been used to determine the strength value above which at least 90 percent of the population is expected to fall with a 95-percent confidence level. The computed compression strengths are 80 to 90 percent of the baseline (no-exposure) strengths. The resulting compression strengths are approximately 8 percent below the population mean strengths. The computed short-beam-shear strengths are 83 to 92 percent of the baseline (no-exposure) strengths. The computed tension strength of all materials is 93 to 97 percent of the baseline (no-exposure) strengths. Baker, Donald J. Langley Research Center...
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
Published: 2018-07-06
Total Pages: 94
ISBN-13: 9781722398552
DOWNLOAD EBOOKPart of the results of a U.S. Army/NASA-Langley sponsored research program to establish the long term-term effects of realistic ground based exposure on advanced composite materials is presented. Residual strengths and moisture absorption as a function of exposure time and exposure location are reported for four different composite material systems that were exposed for five years on the North American Continent. Baker, Donald J. Langley Research Center...
Author:
Publisher:
Published: 1995
Total Pages: 1994
ISBN-13:
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Published:
Total Pages: 1450
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Publisher:
Published: 1995
Total Pages: 704
ISBN-13:
DOWNLOAD EBOOKAuthor: Donald J. Baker
Publisher:
Published: 1989
Total Pages: 96
ISBN-13:
DOWNLOAD EBOOKAuthor: Donald J. Baker
Publisher:
Published: 1983
Total Pages: 20
ISBN-13:
DOWNLOAD EBOOKProgress on two programs to evaluate composite structural components in flight service on commercial helicopters is described. Thirty-six ship sets of composite components that include the litter door, baggage door, forward fairing, and vertical fin have been installed on Bell Model 206L helicopters that are operating in widely different climatic areas. Four horizontal stabilizers and ten tail rotor spars that are production components on the S-76 helicopter will be tested after prescribed periods of service to determine the effects of the operating environment on their performance. Concurrent with the flight evaluation, specimens from materials used to fabricate the components are being exposed in ground racks and tested at specified intervals to determine the effects of outdoor environments. Results achieved from 14,000 hours of accumulated service on the 206L components, tests on a S-76 horizontal stabilizer after 1600 hours of service, tests on a S-76 tail rotor spar after 2300 hours service, and two years of ground based exposure of material coupons are reported. (Author).
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Publisher:
Published: 1990
Total Pages: 496
ISBN-13:
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Publisher:
Published: 1984
Total Pages: 12
ISBN-13:
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