skip to main content

Title: Evaluation of filament-wound Kevlar-49/epoxy fatigue properties. Final report

This study was conducted by AiResearch Manufacturing of California for LLL to investigate the long-term properties of Kevlar-49/epoxy composite in a fatigue and elevated temperature environment to provide additional information on the material properties of Kevlar-49/epoxy for use in the design of composite flywheel energy storage units. Testing showed that Kevlar-49 has the unusual property of increasing tensile modulus of elasticity under fatigue loading conditions. The change in modulus was shown to be a function of temperature, induced stress level, and number of fatigue cycles. The average modulus before cycling was 13.28 x 10/sup 6/ psi at ambient temperature versus 11.96 x 10/sup 6/ psi at 150/sup 0/F. Creep or residual strain after 100,000 cycles was 4.1 x 10/sup -4/ in/in (ambient) and 11.7 x 10/sup -4/ in/in (150/sup 0/F) at 140 ksi maximum stress level. At 190 ksi temperature did not show any effects on creep, which was measured to be approximately 28 x 10/sup -4/ in/in. The ultimate strength of 150/sup 0/F rings was 249,000 psi compared to 262,000 psi for ambient temperature.
Publication Date:
OSTI Identifier:
5220686
Report Number(s):
UCRL-15264
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Technical Report
Research Org:
AiResearch Mfg. Co., Torrance, CA (USA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 33 ADVANCED PROPULSION SYSTEMS; ARAMIDS; TENSILE PROPERTIES; EPOXIDES; CREEP; ELASTICITY; FATIGUE; FLYWHEEL ENERGY STORAGE; RESIDUAL STRESSES; THERMAL STRESSES; ENERGY STORAGE; MECHANICAL PROPERTIES; ORGANIC COMPOUNDS; ORGANIC OXYGEN COMPOUNDS; PETROCHEMICALS; PETROLEUM PRODUCTS; PLASTICS; STORAGE; STRESSES 360303* -- Composite Materials-- Mechanical Properties-- (-1987); 330500 -- Advanced Propulsion Systems-- Flywheel Propulsion