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Current Active Rubber Research Projects at QMUL
(25 researchers):
Abrasion of Elastomer Materials (Cabot
sponsored)
For tyres the
rate of abrasion is clearly important when determining the product life.
Abrasion tests are being done in parallel with a coupled finite element /
fracture mechanics approach. For typical SBR tyre tread compounds the
principal abrasion rate determining mechanisms for the loss of rubber
results from tearing phenomena occurring at the root of individual
asperities in the contact patch and this has allowed the complex abrasion
processes to be understood. This has shown that the rate of abrasion
under a wide range of friction conditions can be predicted from
measurements made on independent fatigue test pieces. This project is
designed to see how nano-particulate reinforced
materials can be optimised to improve abrasion resistance of tyre
formulations.
Development of new applications for
dielectric polymer composites (ARTIS sponsored)
This
programme seeks to develop new materials and applications for dielectric
polymer composite structures which will become “smart” materials in
themselves. The development of new materials with an increased response
to an applied voltage will allow new applications to be developed.
Dynamic Behaviour of Rubber Materials (EPSRC
/ Sibelco sponsored)
This
project is examining how the visco-elastic
properties of different filled elastomer materials are affected by
compounding and test temperature. Building on a relatively simple testing
and modelling approach developed by a previous researcher in the group (Suphadon), this programme examines how the visco-elastic behaviour of a filled compound can be
understood from a measure of the damping at small strains coupled with
model creep experiments. The aim is to deduce the fundamental reinforcing
mechanisms of filled elastomer materials.
Electric Breakdown of Dielectric Elastomer
Actuator Materials (NPL sponsored)
Dielectric
elastomers are a class of Electroactive Polymer
developed for high strain actuators. To achieve a strain of over 100%,
high electric fields approaching the dielectric breakdown strength of the
material are applied. Improvements in the performance and reliability of
these materials will be made by understanding the mechanisms that lead to
breakdown in these materials. This will be underpinned by development of
robust techniques to characterise the failure strength under the
influence of sample geometry, frequency, time, environment etc and analysis of experimental data in the
framework of theories and models of dielectric breakdown in polymer
insulators, as well as of electromechanical instability in dielectric
elastomer actuators.
Fatigue Failure in Aircraft Tyre (EPSRC /
Dunlop Aircraft Tyres Sponsored)
This
project builds upon the earlier work done in the group (Ratsmiba, Tsunoda, Ng,
Liang, Asare) which
measures the cyclic fatigue crack growth for specific tearing energies in
a variety of elastomer compounds using simple test pieces. Then finite
element techniques are applied to calculate the tearing energy
relationships for cracks of different sizes located in real components.
From this it is possible to calculate the fatigue life of the component.
The main aim of this current investigation is to model inter layer
fatigue peeling failure in aircraft tyres.
Friction behaviour of rubber
This
project builds upon the earlier work done in the group (Gabriel) to
investigate the fundamental frictional properties between rubber
materials and rigid surfaces. The project examines how friction behaviour
depends upon compounding with nanoparticles, surface roughness, sliding
speed, temperature and surface preparation. The project uses a range of
finite element analysis modelling techniques and other experimental
methods to observe how phemomenon such as the microvibrations at the surface and the Schallamach waves are formed during sliding.
Modelling of filler reinforcement in elastomers
(TARRC, Bridgestone and Sibleco sponsored)
Materials
such as carbon black, clays and silica significantly improve the
mechanical properties measured in terms of strength and fatigue
resistance when compounded into elastomers. In addition, these fillers
typically impart an increase in the stiffness of the material. This work
uses different models over a wide range of length scales to understand
polymer filler interactions at the atomic scale to micro-structural
finite element models at the nanoscale.
Modelling of Foamed Rubbers (DSTL sponsored)
A hollow
filler material can be used to create a closed cell foam structure. The
full behaviour of this type of foamed elastomer is not well understood.
This project examines these novel materials. The behaviour is observed in
transparent elastomer materials using microscopy techniques to observe
the process of bending, buckling and collapsing as well as to investigate
any de-wetting at the rubber filler interface.
Modelling the Behaviour of Liquid Crystal
Elastomers (SEPNET sponsored)
Models of smectic-C liquid-crystal elastomers predict that they
can display soft elasticity, in which the shape of the elastomer changes
at no energy cost. This research programme aims to model and understand
this phenomenon with a view to developing a good enough understanding so
that the behaviour can be exploited in engineering applications. The work
involves developing constitutive models that can be incorporated into
finite element packages to understand the behaviour.
Smart Rubber Sensor Devices (Bridgestone
sponsored)
This work
extends earlier work in the group (Yamaguchi, Jha)
into how changes in the DC electrical properties (resistivity) change
with strain for elastomers filled with conducting fillers such as carbon
black. This programme is concerned with AC type measurements of the
dielectric behaviour to see if more robust sensor type materials can be
developed.
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