Browsing by Author "Reia da Costa, Elisabete F."

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    Modelling flow and filtration in liquid composite moulding of nanoparticle loaded thermosets
    (Elsevier Science B.V., Amsterdam., 2012-04-13T00:00:00Z) Reia da Costa, Elisabete F.; Skordos, Alexandros A.
    This paper presents analytical and numerical models of liquid moulding of hybrid composites. An 1-D analytical solution of Darcy's problem, accompanied by nanoparticle filtration kinetics and conservation, has been developed. A non-linear finite difference model incorporating variations in permeability, porosity and viscosity as a function of local nanoparticle loading was formulated. Comparison of the two models allowed verification of their validity, whilst a mesh sensitivity study demonstrated the convergence of the numerical scheme. The limits of validity of the analytical solution were established over a range of infiltration lengths and filtration rates for different nanoparticle loadings. The analytical model provides an accurate and efficient approximation of through thickness infusion of hybrid composites, whereas use of the numerical scheme is necessary for accurate simulation of in-plane filling processes. The models developed here can serve as the basis of process design/optimisation for the production of hybrid composites with controlled distribution of nano-reinforcement.
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    RTM processing and electrical performance of carbon nanotube modified epoxy/ fibre composites
    (2012-04-30T00:00:00Z) Reia da Costa, Elisabete F.; Skordos, Alexandros A.; Partridge, Ivana K.; Rezai, Amir
    This investigation focuses on nanoparticle filtration in the processing of multiscale carbon and glass fibre composites via resin transfer moulding. Surface modified and unmodified carbon nanotubes (CNTs) were incorporated into a commercial epoxy resin. The dispersion quality was evaluated using electrical measurements of the liquid suspensions. The manufacturing process was adapted to the challenges posed by the modified rheological behaviour of the CNT loaded resin. Nanoparticle filtration was observed; with some of the unmodified systems following so called ‘cake filtration' behaviour. This resulted in nonlinear flow behaviour that deviated from the ideal response observed in RTM filling in conventional composites. The electrical conductivity of relatively high fibre volume fraction multiscale carbon and glass laminates increased by less than an order of magnitude with the addition of the nanotube