JEC COMPOSITES MAGAZINE - Issue #90 - June/July 2014 - 42

infusion
IMO/HSC Code (Code of Safety for High Speed Craft of
the International Maritime Organisation).
The VI process is proposed as the manufacturing method
in the project due to its advantages, such as widespread
availability, cost-effectiveness, scalability to large structures
and high fibre content.
The role of FSI is to explore i) the processability of the
UP/phenolic blends in the VI process to manufacture good
quality composites, and ii) the fire mechanics of the glassfibre-reinforced UP/phenolic composites. This article
focuses on the resin processing part in the VI process and
presents the research methodology in the context of:
i) Flow and cure monitoring in the VI process using a
purpose-built rig,
ii) Preform characterisation (permeability and compressibility measurements) by means of a purpose-built rig
installed on an Instron test machine,
iii) Resin characterisation (viscosity and cure),
iv) VI process simulation (flow and cure) using the PAMRTM software.

Process monitoring
Flow and cure monitoring during the infusion process is
important for the manufacture of high-quality composites.
Flow front monitoring is necessary for the evaluation of
resin processability. Cure monitoring is required to detect
the uncured parts or to know when to remove the final part
from the mould. For this purpose, a VI process monitoring
setup (Figure 1) is utilised. The set-up enables the acquisition of process variables and consists of i) a VI setup using
a metal mould, ii) a high-resolution camera to monitor the
flow front progression on the upper surface, iii) K-type
thermocouples to monitor the flow front advancements
inside the preform for the purpose of three-dimensional (3D) flow monitoring and measure the temperatures

Fig. 1: Illustration of the VI process monitoring rig

42 jec composites magazine / No90 June - July 2014

Fig. 2: Examples of flow front monitoring results a) A fast curing resin
system b) A slow curing resin system

a)

b)

c)

Fig. 3: UP resin flow front advancement (without an infusion mesh)
a) 1150 seconds b) 3600 seconds c) 8820 seconds

at various locations for cure monitoring, iv) four flush
diaphragm pressure transducers to monitor the compaction
pressures, v) a liquid pressure sensor at the inlet to measure
the resin pressure, vi) linear variable differential transducers (LVDTs) to measure the thickness variation from the
inlet to the vent for the calculation of the fibre volume fractions, vii) a weighing scale to monitor the mass flow rate of
resin, viii) a vacuum pump, ix) fibre Bragg gratings (FBG)
and an interrogator for cure monitoring and residual strain
measurements, and x) a National Instruments Compact-Rio
kit as the data acquisition system and associated Labview
software to record the data.
An important purpose of this setup is to determine an
appropriate vacuum pressure (from 0 to 1 bar) that allows
complete infusion before the gelling time of the resins.
The vacuum pressure plays an important role in the fibre/
resin content of the final part, the compaction/resin pressure during infusion and the total filling time. During the
experiments, it is noted that thermocouples embedded in
different parts of the preform are able to provide flow front
advancement information. The important difference of
the present research from other thermocouple flow front
monitoring studies is that no temperature difference is
provided between the reinforcement, the infusion liquid
and the mould, and the experiments take place at room
temperature. The arrival of the resin causes changes in
the temperature versus time data (Figure 2) acquired by
the thermocouples, and this is recorded as the flow front
arrival times.
JEC COMPOSITES MAGAZINE - Issue #90 - June/July 2014

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