Papers by Author: José Domingos M. Costa

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Authors: Paulo N.B. Reis, José A. Martins Ferreira, José Domingos M. Costa, M.O.W. Richardson
Authors: Paulo N.B. Reis, José A. Martins Ferreira, Fernando Antunes, José Domingos M. Costa
Abstract: This paper is concerned with a notch sensibility study of a thermoplastic composite produced from a bi-directional woven E-glass fibres and polypropylene. Experimental tests were performed in three points bending using notched and unotched specimens of polypropylene glass fibres reinforced laminates to evaluate flexural properties and fatigue behaviour. Fatigue results were plotted as the stress range against the number of cycles to failure. The fatigue damage was measured in terms of the stiffness loss. The testes carried out using notched specimens present lower values of both static and fatigue strengths than the unnotched specimens tests.
Authors: Amilcar Ramalho, José Domingos M. Costa, José A. Martins Ferreira, Carlos Capela
Authors: L.M.P. Abreu, José Domingos M. Costa, José A. Martins Ferreira, Fernando Antunes
Authors: Henrique Silva, José A. Martins Ferreira, José Domingos M. Costa, Carlos Capela
Abstract: Present paper studied the improvement of the fracture toughness under mixed mode loading obtained by using carbon nanotubes reinforcement in fiber glass mats/ epoxy laminates. Mixed-mode bending tests were performed considering different loading ratios GII/GI. Laminates were manufactured using the epoxy resin Biresin® CR120 reinforced with fiber glass triaxial mats ETXT 450 and multiwalled carbon nanotubes with 98% of carbon. It was observed that the total fracture toughness increases linearly with the mode II loading component and that linear mixed-mode fracture criteria reproduces the GI versus GII relationship. The incorporation of small quantity, up to 0.5%, of carbon nanotubes into matrix improves significantly mixed-mode fracture toughness.
Authors: L. Martins, J.I. Martins, A.S. Romeira, Maria Elisabete V. Costa, José Domingos M. Costa, M. Bazzaoui
Authors: H. Silva, José Domingos M. Costa, José Maria F. Ferreira, M. Richardson
Authors: Carlos Capela, José A. Martins Ferreira, José Domingos M. Costa
Abstract: Low-density sheet moulding compounds incorporating hollow glass micro-spheres are being increasing used namely in automotive industry, boats and deep-water submarines and core materials. This paper presents the results obtained in a current study of the viscous properties on hybrid short fibre/hollow glass microspheres composites fabricated with epoxy binder. Dynamic mechanical analysis (DMA) was used to study the effect of the filler volume fraction and of the addition of glass fibre reinforcement on the dynamic stiffness modulus, damping coefficient and glass transition temperature in tensile mode. The specimens were cut from plates produced by resin transfer moulding in vacuum with microspheres weight contents up to 13%. Elastic modulus decreases significantly with the increasing of filler volume fraction. In contrary, it increases significantly with the glass fibre reinforcement content. Glass transition temperature apparently tends to decrease with microspheres and of glass fibre reinforcement’s content. Tmax temperatures tend to increase slightly with the addition of fibre reinforcements and the microsphere filler. Maximum damping coefficient is much lower for the foams when compared with net resin.
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