TY - GEN
T1 - Environmental Effects on High Strain Rate Properties of Graphite/Epoxy Composite
AU - Yaniv, Gershon
AU - Peimanidis, Gus
AU - Daniel, Isaac M.
N1 - Publisher Copyright:
© 1989 ASTM International. All rights reserved.
PY - 1989
Y1 - 1989
N2 - A unidirectional graphite/epoxy material was characterized at strain rates ranging from 5 * 10-6 to 5 s-1 under various hygrothermal conditions. New techniques were successfully employed for measuring hygrothermal properties and for strain monitoring of "wet" specimens at high strain rates. A time-temperature-moisture equivalence principle was applied to obtain master curves for the longitudinal, transverse, and in-plane shear moduli and corresponding strengths and ultimate strains of the unidirectional graphite/epoxy. It was found that, except for the longitudinal modulus, which shows a slight increase with strain rate, temperature, and moisture, all other longitudinal properties in general remain unchanged. The transverse modulus increases with strain rate but decreases with increasing temperature and moisture content. All transverse and intralaminar shear properties decrease with increasing temperature and moisture content for a fixed strain rate. Transverse ultimate properties as a function of strain rate show a trend reversal with a local maximum. The in-plane shear strength increases noticeably with strain rate, whereas the ultimate shear strain decreases slightly. The time-temperature-moisture shift function is expressed as a function of two variables, allowing interchangeability of the three parameters, time, temperature, and moisture content.
AB - A unidirectional graphite/epoxy material was characterized at strain rates ranging from 5 * 10-6 to 5 s-1 under various hygrothermal conditions. New techniques were successfully employed for measuring hygrothermal properties and for strain monitoring of "wet" specimens at high strain rates. A time-temperature-moisture equivalence principle was applied to obtain master curves for the longitudinal, transverse, and in-plane shear moduli and corresponding strengths and ultimate strains of the unidirectional graphite/epoxy. It was found that, except for the longitudinal modulus, which shows a slight increase with strain rate, temperature, and moisture, all other longitudinal properties in general remain unchanged. The transverse modulus increases with strain rate but decreases with increasing temperature and moisture content. All transverse and intralaminar shear properties decrease with increasing temperature and moisture content for a fixed strain rate. Transverse ultimate properties as a function of strain rate show a trend reversal with a local maximum. The in-plane shear strength increases noticeably with strain rate, whereas the ultimate shear strain decreases slightly. The time-temperature-moisture shift function is expressed as a function of two variables, allowing interchangeability of the three parameters, time, temperature, and moisture content.
KW - environmental effects
KW - graphite/epoxy composites
KW - hygrothermal characterization
KW - strain-rate effects
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U2 - 10.1520/STP10017S
DO - 10.1520/STP10017S
M3 - Conference contribution
AN - SCOPUS:85165726721
T3 - ASTM Special Technical Publication
SP - 16
EP - 30
BT - Test Methods and Design Allowables for Fibrous Composites
A2 - Chamis, Christos C.
PB - ASTM International
T2 - 2nd Symposium on Test Methods and Design Allowables for Fibrous Composites
Y2 - 3 November 1986 through 4 November 1986
ER -