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Title: Statistical analysis of Kevlar 49/epoxy composite stress-rupture data

Abstract

Statistical analyses are presented for LLNL stress-rupture data sets involving kevlar 49/epoxy strands and NASA Kevlar 49/epoxy spherical pressure vessels subjected to sustained loading. Raw data, summarized inferences, and figures are included.

Authors:
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (USA)
OSTI Identifier:
5835477
Report Number(s):
UCID-19849
ON: DE84000516
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COMPOSITE MATERIALS; RUPTURES; FIBERS; PRESSURE VESSELS; ARAMIDS; DATA ANALYSIS; EPOXIDES; EXPERIMENTAL DATA; FAILURES; STRESSES; CONTAINERS; DATA; INFORMATION; MATERIALS; NUMERICAL DATA; ORGANIC COMPOUNDS; ORGANIC OXYGEN COMPOUNDS; PETROCHEMICALS; PETROLEUM PRODUCTS; PLASTICS; SYNTHETIC MATERIALS; 360303* - Composite Materials- Mechanical Properties- (-1987)

Citation Formats

Glaser, R.E. Statistical analysis of Kevlar 49/epoxy composite stress-rupture data. United States: N. p., 1983. Web.
Glaser, R.E. Statistical analysis of Kevlar 49/epoxy composite stress-rupture data. United States.
Glaser, R.E. 1983. "Statistical analysis of Kevlar 49/epoxy composite stress-rupture data". United States. doi:.
@article{osti_5835477,
title = {Statistical analysis of Kevlar 49/epoxy composite stress-rupture data},
author = {Glaser, R.E.},
abstractNote = {Statistical analyses are presented for LLNL stress-rupture data sets involving kevlar 49/epoxy strands and NASA Kevlar 49/epoxy spherical pressure vessels subjected to sustained loading. Raw data, summarized inferences, and figures are included.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1983,
month = 9
}

Technical Report:
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  • In this report, the raw data obtained from accelerated stress-rupture studies of Kevlar 49/epoxy strand specimens is presented.
  • Raw data obtained from a study of the stress-rupture behavior of filament-wound organic fiber/epoxy strand specimens is tabulated.
  • A study is in progress to determine the life of Kevlar/epoxy spherical pressure vessels subjected to a constant, sustained pressure until vessel failure, i.e., stress-rupture. This study has two objectives: to generate baseline data on the stress-rupture life of Kevlar/epoxy pressure vessel and to apply statistical reliability theory to vessel and strand data to define vessel life statistics and reliability at given pressure (stress) levels. This report, the second of three, is a compilation of the current pressure vessel data to-date and all strand stress-rupture data generated at Lawrence Livermore Laboratory on several composite materials.
  • This study of stress rupture has two objectives: to generate baseline data on vessel life under pressure and to apply statistical reliability theory to vessel and strand data in order to predict reliability at given stress levels. The improved life prediction methods useful in the analysis of life data are described. These methods are applied to two sets of data, i.e., the extensive Kevlar/epoxy strand data and the current Kevlar/epoxy spherical pressure vessel data. Of principal importance is the observation that the hazard rates for both data sets are time-dependent at low stress levels; as a result, the exponential lifetimemore » distribution is not valid. Plans are discussed for accelerated life-tests of pre-production units, methods for choosing sample sizes, and in-service replacement policies.« less
  • An experimental study supporting the Composite Bombcase Program is described. The purpose of the study was to generate mechanical properties and structural response data on composite plates and cylinders. This data base is now available to assist in the evaluation of composite materials for bombcase applications. Two composites, Kevlar 49/epoxy and IM6 graphite/epoxy, were chosen for testing. The mechanical properties from flat unidirectional specimens were used to predict the elastic response of thick quasi-isotropic laminates in four-point bending and the elastic response of 18.0 inch diameter quasi-isotropic rings to diametral compressive loading. Good agreement between theoretical and experimental values ofmore » elastic response was obtained for both geometries. Load-deflection and load-strain curves in the elastic, post-yield, and failure regions were obtained for composite and aluminum rings. Delamination between plies was the principal failure mode in the QI composite plate and ring specimens. Even with many delaminations at large deflections, composite rings continued to carry load and retain some structural integrity.« less