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Delamination characteristics of multi‐directional carbon fiber/epoxy composites under high pressure
Author(s) -
Rhee Kyong Yop,
Oh Hwan Sup,
Jang Seung Ho,
Park SooJin
Publication year - 2001
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.10581
Subject(s) - materials science , composite material , hydrostatic pressure , epoxy , delamination (geology) , fracture toughness , graphite , hydrostatic equilibrium , toughness , paleontology , physics , tectonics , quantum mechanics , biology , subduction , thermodynamics
It was shown in a previous study that for unidirectional (0‐deg) graphite/epoxy composites, the fracture toughness under hydrostatic pressure increased 38% as hydrostatic pressure increased from 0.1 MPa to 200 MPa. This work investigates the compressive delamination behavior of multi‐directional graphite/epoxy laminated composites subjected to various hydrostatic pressures. Compressive delamination tests were performed under four hydrostatic pressure levels: 0.1, 100, 200, and 300 MPa Eighty‐eight‐ply dog‐bone type specimens with a single delamination at the center of the specimen were used. The stacking sequence applied was [0°/±45°/90°] lls . The compliance and fracture load were determined from load‐displacement curves as a function of hydrostatic pressure. The results show that the compliance decreases with increasing pressure while fracture load increases with increasing pressure. The compressive delamination toughness, G c , was determined from the compliance method as a function of applied hydrostatic pressure. The results also show that G c is significantly affected by hydrostatic pressure and increases from 2.11 kJ/m 2 to 3.04 kJ/m2 (44% increase) as hydrostatic pressure increased from 0.1 MPa to 300 MPa. Visual examination of the fractured surface revealed that the increase of G c is due to the suppression of micro‐cracks With increasing pressure. It was also found from SEM examination of delaminated surface that the G c increase is due to more epoxy adhering to the fibers and more plastic deformation of epoxy material as applied hydrostatic pressure increases.