Composite tubes subjected to four point bending
The objective of this study is to identify the how pure bending will affect different materials in the view of assessing the spoolability of these materials. Experiments using four point bending were conducted on multilayered com posite tubular pipes. The multilayered pipes have an external hard...
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Format: | Theses and Dissertations |
Language: | English |
Published: |
2016
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Subjects: | |
Online Access: | http://hdl.handle.net/10356/68670 |
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Institution: | Nanyang Technological University |
Language: | English |
Summary: | The objective of this study is to identify the how pure bending will affect different
materials in the view of assessing the spoolability of these materials. Experiments
using four point bending were conducted on multilayered com posite tubular pipes.
The multilayered pipes have an external hard layer with a softer inner layer made of
high density polyethylene (HDPE) thermoplastic. The external hard layer is made
from either polyvinyl chloride (PVC) and glass/epoxy. The interface conditions
between the hard and soft layers are either bonded or unbonded.
From the experimental results, the deflection and loading versus deflections and
loading versus strains graphs show glass/epoxy has a much higher stiffness and larger
deflections as compared to PVC. The experimental results also indicated that bonded
and unbonded soft layer of HDPE does not affect the stiffness significantly. The
minimum spool radius for PVC is 2.5 m while adding a soft layer of H D P E reduces it
to 2.08 m for both bonded or unbonded cases. The corresponding increase in moment
is 13.65%. For glass/epoxy fibre, the spool radius is about 2.08 m with or without the
HDPE layer. There was also a large increase in the loading moment between using
glass/epoxy and PVC pipes, a massive 627%. It is conclusive that spoolability
performance o f glass/epoxy is much lesser than that o f PVC. While adding a soft
inner layer for PVC leads to some increase in spoolability, it does not have any
significant impact for the harder pipes such as glass/epoxy.
The study also consider the differences between measurements taken on loading
movements from the bottom rollers or the top rollers. The results corroborated that
the displacement from bottom rollers are more coherent and accurate to the actual
displacements. Hence, measurements from loading movements of the bottom rollers
should be used in 4 point bending experiments. |
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