Fatigue Behaviour Of Oil Palm Fruit Bunch Fibre/Epoxy And Carbon Fibre/Epoxy Composites
Tensile test on unidirectional Oil Palm Fruit Bunch (OPFB) fibre/epoxy composite and unidirectional Carbon Fibre (CF)/epoxy composite were conducted to determine their ultimate tensile stress, the Young's modulus and elongation at fracture Two different fibre volume fractions of 35'1&qu...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2003
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/12144/1/FK_2003_3.pdf |
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| Summary: | Tensile test on unidirectional Oil Palm Fruit Bunch (OPFB) fibre/epoxy composite
and unidirectional Carbon Fibre (CF)/epoxy composite were conducted to determine
their ultimate tensile stress, the Young's modulus and elongation at fracture Two
different fibre volume fractions of 35'1"0 and 55% were studied in OPFB fibre/epoxy
composite. The fibre volume fraction of CF/epoxy composite studied was 42%.
The ultimate tensile stress determined from the tensile tests were then used to
determine the maximum stress levels, Smax of fatigue tests for CF and OPFB
fibre/epoxy composites.
Two parameters were studied in fatigue test, which were stress ratio, R (0.1 and 0.5)
and fibre volume fraction, Vr (35% and 55%). All Fatigue tests were performed at
constant stress amplitude, at an air-conditioned room temperature of 20°C and at a
frequency of 20 Hz. Observation on fractured surface of tensile and fatigue tested
specimens were also done.The ultimate tensile stress of CF/epoxy composite is 247.0 MPa. OPFB fibre/epoxy
composite with fibre volume fraction of 35% and 55% have ultimate tensile stress of
47.8 MPa and 46.1 Mpa, respectively.
The observation on fractured surface of tensile tested specimens showed that CF and
OPFB fibre/epoxy composites failed in a brittle manner. Fatigue behaviour of
CF/epoxy composite shows a reduction in fatigue resistance with decreasing stress
ratio. Three specimens survived 1 million cycles, which were cycled at stress ratio
of 0.1 and maximum stress leveL Smax of 0.65. There was no indication of fatigue
limit shown by S-N curves for OPFB fibre/epoxy composite for both fibre volume
fractions. However the S-N curves of OPFB fibre/epoxy composite showed a
decrease of fatigue resistance with the increase of fibre volume fraction from 35% to
55%.
Two types of fractured surface were observed on the CF/epoxy composite failed in
fatigue test, which were brittle and delamination. Meanwhile the fractured surface
of OPFB fibre/epoxy composite showed brittle, delamination and fibre pull-out. |
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