JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 59

Effects of ageing on the mechanical and structural properties of glass/epoxy composite pipes in seawater

Table 1: Concentration of salt components in seawater [45]

Element

Parts per million

Cl (chloride)

21,700

Na (sodium)

19,497

SO4 (sulphate)

2880

Mg (magnesium)

1838

K (potassium)

743

Ca (calcium)

602

HCO3 (bicarbonate)

200

Fig. 4: Effect of water molecules on the fibre/matrix
interface (redrawn from Anshu Anjali Singh et al. [47])

caused in multi-directional piles by the absorption of moisture. The absorption of moisture degrades the mechanical properties and shortens
fatigue life at extreme temperatures.
Salt concentration analysis
The diffusion of moisture in the fibre and matrix boundary causes leakage of the alkali metal oxides present in E-glass fabric, then intensifying
the concentration gradient and the concentration of salt solutions.
Table 1 shows the major salt components liquefied in seawater, as determined in previous literature [45].
Immersion temperature analysis
The absorption of water molecules into the pipe covering greatly depends on the ageing temperature. As time increases, the water molecules diffuse into the film and are absorbed by the fibre and matrix
interface, causing debonding, micro-cracks and delamination in the
layered pipeline. The kinetics of water absorption in materials at various
temperatures is determined by plotting curves of the type [46]:
ΔM (%) =f (√t) (1)
Amplifying the ageing temperature first influences the growth of the
pipe weight and the equilibrium phase reduces the weight of the sample.
Gap analysis
As stated in the preceding section, various studies were performed to
describe the mechanical operation of glass/epoxy fibre-reinforced
pipes from various shown points. Certain other significant and determining features are yet in need of greater discussion and understanding.
In earlier studies, a lot of work concentrated on pipe ageing failure but
the failure should be considered from the point of the manufacturing
process itself. In the case of moisture absorption, researchers stated and
investigated that the failure is due to water molecules found between
the fibre and the matrix, but this should be considered during the manufacturing process itself, where the formation of air bubbles between
the matrix and fibre should be avoided. The fibre and matrix orientation should be defined carefully to stop water molecules from forming
between the layers.
Another cause found out during the study was that the modulus and
tensile strength properties of fibre/epoxy reinforced pipes change
when the immersion time in seawater increases.
Another important factor is the interlaminar shear strength of the
pipeline, which is a significant design constraint and has not attracted

Fig. 5: Interlaminar shear failure in a composite pile
(redrawn from Prajer et al. [48])

considerable attention. After immersion at different temperatures, the
interlaminar shear strength of composites was not predicted accurately
by various researchers.
The figure below shows the interlaminar shear failure using the short
beam shear test method.
Finally, the researcher has to calculate the endurance statistics during
the seawater ageing period for sustained intervals of diffusion that can
be acceptable to exactly choose the usage and time period of pipelines
placed in seawater.
Conclusion
A comprehensive work was conducted to predict the mechanical and
structural damage caused by the ageing of specimens in seawater. The
following factors are also corroborated by other research:
1.	
Moisture absorption depends on the temperature of the
immersion medium. At high temperatures, more moisture can be absorbed by the pipeline than at low temperature.
2.	
The diffusion factor and the utmost moisture absorbed depend on the ageing temperature of the medium in which the samples
are immersed. As this temperature rises, the effect on the sample's
properties become increasingly significant and important.
3.	
The structural and mechanical properties of glass/epoxy
composite pipes change with increasing ageing temperatures and periods of immersion, and finally the existence of salts interacting with the
pipeline structure. This initiates ductility and strength damage.
4.	
A disadvantage of operating composites in seawater is that
the fibre/matrix combination can be damaged by the hydrolysis of unsaturated groups inside the resin.

N°129 July - August 2019

More information:
www.upm.edu.my

/ jec composites magazine

59


http://www.upm.edu.my

JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019

Cover
Edito
Moving composites forward: on the shoulders of giant
Contents
NEWS
In brief
Successful partners
Agenda
BUSINESS
Matrix - CFRP composite manufacturing trends
Cost - A brand-new approach for economically competitive composites
MANUFACTURING
Fibre placement - Replacing individual unit tests by integrated process control
NDT - Optical metrology improves the production of composite products at every step
Initiative - Spotlights from the world of lightweighting
FEATURE SPORTS & LEISURE - The largest testing ground
Success story - DPS designs the world’s most advanced skis
Carbon - New type of unidirectional prepreg for sport applications with complex shapes
Additive manufacturing - lnnovative composite bicycle frame
Textile - Porcher lndustries: excellence in sports and leisure
Innovations - Sports on the scene at JEC World 2019
Carbon - The next generation of high-performance rigging
Standardisation - Research, innovation and development for composite marine and offshore applications
SOLUTIONS
Infrastructure - Can carbon-reinforced concrete replace steel in the long run?
Art - “Train your brain, think disruptive, outside the box and follow your visions!”
Music - Music instruments from carbon, glass or flax fibres
Watch - A watch ahead of its time
In the world - Composites visit the doctor
TECHNOLOGY
Ageing - Effects of ageing on the mechanical and structural properties of glass/epoxy composite pipes in seawater
Inside the lab - Advanced Composites Research Group – Queen’s University Belfast
Index
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JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 68
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Cover
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 2
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Edito
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Moving composites forward: on the shoulders of giant
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 5
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Contents
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 7
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - In brief
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 9
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Successful partners
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Agenda
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Matrix - CFRP composite manufacturing trends
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 13
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 14
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Cost - A brand-new approach for economically competitive composites
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 16
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 17
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 18
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Fibre placement - Replacing individual unit tests by integrated process control
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 20
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - NDT - Optical metrology improves the production of composite products at every step
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 22
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 23
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Initiative - Spotlights from the world of lightweighting
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 25
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 26
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Success story - DPS designs the world’s most advanced skis
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 28
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Carbon - New type of unidirectional prepreg for sport applications with complex shapes
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 30
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Additive manufacturing - lnnovative composite bicycle frame
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 32
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Textile - Porcher lndustries: excellence in sports and leisure
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 34
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 35
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Innovations - Sports on the scene at JEC World 2019
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 37
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Carbon - The next generation of high-performance rigging
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 39
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Standardisation - Research, innovation and development for composite marine and offshore applications
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 41
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 42
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Infrastructure - Can carbon-reinforced concrete replace steel in the long run?
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 44
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 45
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 46
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Art - “Train your brain, think disruptive, outside the box and follow your visions!”
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 48
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Music - Music instruments from carbon, glass or flax fibres
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 50
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 51
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Watch - A watch ahead of its time
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 53
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - In the world - Composites visit the doctor
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 55
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Ageing - Effects of ageing on the mechanical and structural properties of glass/epoxy composite pipes in seawater
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 57
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 58
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 59
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 60
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 61
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Inside the lab - Advanced Composites Research Group – Queen’s University Belfast
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 63
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 64
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 65
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - Advertisers
JEC COMPOSITES MAGAZINE - Issue #129 - July/August 2019 - 67
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