J. Summerscales | Plymouth University (original) (raw)

Papers by J. Summerscales

The vacuum infusion process has been found to be very versatile for making large composite struct... more The vacuum infusion process has been found to be very versatile for making large composite structures. Despite the cost effectiveness and ability to achieve fibre to resin ratios as high as 70:30 by volume, the process, is susceptible to air bubble formation. In fact, some reinforced fibre and sandwich material combination appear to be almost perfect bubble nucleation agents. As void content affects the performance of a composite structure, it is very important to reduce it as far as possible. The nucleation and formation of air bubbles from dissolved gas in the resin solution signifies the need of a degassing process, prior to infusion. Recent experiments have shown that a degassing process for vacuum infusion, conducted in batches of a small quantity with bubble nucleation agent (Scotch-Brite) and air-sparging method could reduce void formation. However, using this method, only 40% to 50% of dissolved gas can be extracted from the resin. Despite the removing some dissolved gas, so...

Composites Manufacturing, 1992

Composites Manufacturing, 1994

International Journal of Fatigue, 2007

Material and test procedure: Production; tensile tests; investigation of fracture surfaces and ma... more Material and test procedure: Production; tensile tests; investigation of fracture surfaces and material characterization. Results: microstructure, mechanical properties, characterization of fracture behaviour and the failure mechanisms. Discussion. Conclusions and outlook.

SIGLEAvailable from British Library Document Supply Centre- DSC:D49705/84 / BLDSC - British Libra... more SIGLEAvailable from British Library Document Supply Centre- DSC:D49705/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

In the context of a comparative and Quantitative Life Cycle Assessment (QLCA) of natural fibre re... more In the context of a comparative and Quantitative Life Cycle Assessment (QLCA) of natural fibre relative to glass fibre when used as the reinforcement in composites, experiments have been conducted to study the differences in their processability and performance. Composites were manufactured from plain weave reinforcement fabrics by resin infusion under flexible tooling (RIFT). It proved difficult to get truly comparable reinforcement fabrics, but the indications are that mould filling times will be longer for natural fibres at comparable fibre volume fractions. The mechanical properties were measured in flexure and indicate that comparable panel stiffnesses are possible at equal weight.

Journal of Cleaner Production, 2021

The present study reports the development of sandwich panels for building walls having electromag... more The present study reports the development of sandwich panels for building walls having electromagnetic interference (EMI) shielding abilities. Conductive polymer composites (CPCs) have started being employed as EMI shielding materials. In this paper we propose the use of a conductive polymer composite flat sheet made of high-density polyethylene (HDPE) recovered from municipal solid wastes (MSW) used as polymeric matrix, "doped" with dispersed metal fillers recycled from e-wastes. Test results proved that the recycled metal fillers enhance the electrical conductivity and enable EMI shielding. Different sandwich panels were discussed in the context of building applications, using identical HDPE/metal-filler EMI sheets, but different thermal insulation material (polystyrene and glass wool). The life cycle assessment (LCA) methodology was applied to evaluate the environmental impact generated during the following steps: a) recycling of thermoplastic materials from MSW; b) recovering of metallic components from waste PCB; c) re-use of the recovered components into sandwich panels with electromagnetic shielding properties for buildings. The goal of the LCA was to perform a comparative analysis of the composite sandwich structures manufactured to be used as EMI shielding in buildings applications in order to assist the materials selection and eco-design. By means of the LCA results it was possible to manufacture a building component with good EMI shielding properties and reduced environmental impacts.

Applied Composite Materials, Feb 20, 2014

The elastic properties of a composite can be predicted by micromechanical models based on the pro... more The elastic properties of a composite can be predicted by micromechanical models based on the properties of the individual constituent materials of the composite and their geometrical characteristics. This paper presents a novel methodology using image analysis to determine (a) the fibre volume fraction and (b) the fibre orientation distribution factor of quasi-unidirectional jute fibre reinforced epoxy resin composites. For fibre volume fraction, digital micrographs were smoothed to reduce noise in the image, an intensity histogram informed selection of the threshold intensity for conversion to a binary image, the image was morphologically closed and opened to remove internal voids and small features respectively and the fibre volume fraction was calculated as the ratio of the detected fibre area to the total image area. For fibre orientation, the image was sharpened with Contrast-Limited Adaptive Histogram Equalisation, a threshold was set for conversion to binary and then a masking image was rotated at a number of seed points over the image to find the angles with the minimum sum of intensity at each point. The data generated was then used to validate new rules-of-mixture equations for natural fibre composites.

Composites Part B-engineering, Mar 1, 2019

Enhanced rules-of-mixture for natural fibre reinforced polymer matrix (NFRP) composites (comment ... more Enhanced rules-of-mixture for natural fibre reinforced polymer matrix (NFRP) composites (comment on Lau et al in volume 136)

Rubber Chemistry and Technology, 2020

ABSTRACTThe effect of two different types and particle sizes (micronized cryo-ground 74 μm or amb... more ABSTRACTThe effect of two different types and particle sizes (micronized cryo-ground 74 μm or ambient-ground 400 μm) of recycled rubber powder (RRP) was studied during fatigue crack growth (FCG) in a natural rubber/butadiene rubber (NR/BR) compound using a fracture mechanics approach. Absolute and relative hysteresis losses using single-edge notch tensile specimens were determined with a displacement-controlled strain compensating for the permanent set of the samples throughout the FCG experiments. Differences in relative hysteresis loss showed that additional energy dissipation, due to multiple new crack surfaces at the crack tip, contributes to the FCG of the RRP compounds. At higher tearing energy, beside other factors affecting the FCG performance of the RRP compounds, both higher absolute and relative hysteresis loss are slightly detrimental to the crack growth rates. At lower tearing energy, the larger RRP-filled compound showed slower, but not significant, different crack gro...

Biocomposites for High-Performance Applications

International Journal of Materials, Mechanics and Manufacturing, Aug 1, 2018

Ground rubber from waste tyres may be added to elastomers with economic and environmental benefit... more Ground rubber from waste tyres may be added to elastomers with economic and environmental benefits. The untreated or treated fillers have been investigated in different types of virgin rubber matrix. A principal concern is their crosslinked structure and large particle sizes. These additives introduce flaws leading to micro-crack initiation especially under dynamic loading. The incorporation of smaller particles at a suitable concentration may avoid deterioration in the key properties. The present work studies the effect of commercial cryogenic micronised rubber particle (MRP) (apparent particle size diameter less than 100 µm) as filler at either 10 or 30 parts per hundred rubber (pphr) on the fatigue properties of natural rubber (NR), butadiene rubber (BR) or NR/BR blends (without carbon black in the host matrix). In non-crystallising rubber, BR compound containing MRP shows an enhancement in the fatigue properties. However, in NR and NR/BR blends the fatigue properties are reduced. Scanning electron microscope (SEM) observations have been used to correlate the fatigue properties with the morphology of the fracture surfaces. For NR or higher ratio of NR matrix, a scale-like texture dominated the fatigue behaviour of the compound. The fracture surface of MRP-filled compound had increased surface roughness compared to their control compound.

Journal of Composites Science, 2022

Lignocellulosic natural fibres are hydrophilic, while many matrix systems for composites are hydr... more Lignocellulosic natural fibres are hydrophilic, while many matrix systems for composites are hydrophobic. The achievement of good mechanical properties for natural fibre-reinforced polymer (NFRP) matrix composites relies on good fibre-to-matrix bonding at the interface. The reinforcement is normally coated with an amphiphilic coupling agent to promote a strong interface. A novel alternative approach is to dissolve the coupling agent in the hardener for the resin before creating the stoichiometric mix with the base epoxy resin. During composite manufacture, the hydrophilic (polar) end of the coupling agent migrates to surfaces (internal interfaces) and bonds to the fibres. The hydrophobic (non-polar) end of the coupling agent remains embedded in the mixed resin. Mechanical testing of composite samples showed that silane added directly to the matrix produced a NFRP composite with enhanced longitudinal properties. As pre-process fibre coating is no longer required, there are economic (...

$Research paper thumbnail of The use of fractal dimensions to analyse fabric architecture for fibre reinforced composites produced by RTM$

Online event, not submitted for REF2021.Fibre-reinforced plastics composites are widely used in t... more Online event, not submitted for REF2021.Fibre-reinforced plastics composites are widely used in the marine industry because they can survive in the wet environment far longer than traditional engineering materials (wood, aluminium, steel) with minimal maintenance. Integrated structures may have dimensions in excess of 100m, but thermosetting resin materials are not easily recycled. The talk will consider some of the larger structures that already exist, then discuss a number of environmental considerations that need to be understood for the benefit of future generations

Marine Composites, 2019

This chapter considers the component materials used in fibre-reinforced polymer-matrix composites... more This chapter considers the component materials used in fibre-reinforced polymer-matrix composites/laminates or sandwich structures intended for use in the marine environment. The majority of large marine structures use thermosetting resins as the matrix (supplied as a liquid and caused to go solid by the addition of chemicals, and sometimes heat). There is increasing interest in the use of thermoplastic matrix systems as they are more easily recycled, but they normally require higher energy during manufacture to melt the polymer. The most common reinforcement fibres are glass (low cost, strong and relatively flexible) or carbon (higher costs, strong and stiff). The reinforcement fibres are normally converted to a planar fabric form by weaving, stitching or knitting. Brief consideration is given to core materials for use in sandwich structures

Journal of Composite Materials, 2020

The aim of the current work was to illustrate the effect of the fibre area correction factor on t... more The aim of the current work was to illustrate the effect of the fibre area correction factor on the results of modelling natural fibre-reinforced composites. A mesoscopic approach is adopted to represent the stochastic heterogeneity of the composite, i.e. a meso-structural numerical model was prototyped using the finite element method including quasi-unidirectional discrete fibre elements embedded in a matrix. The model was verified by the experimental results from previous work on jute fibres but is extendable to every natural fibre with cross-sectional non-uniformity. A correction factor was suggested to fine-tune both the analytical and numerical models. Moreover, a model updating technique for considering the size-effect of fibres is introduced and its implementation was automated by means of FORTRAN subroutines and Python scripts. It was shown that correcting and updating the fibre strength is critical to obtain accurate macroscopic response of the composite when discrete model...