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CDRsp - Comunicações em conferências internacionais

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http://hdl.handle.net/10400.8/8023

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Percorrer CDRsp - Comunicações em conferências internacionais por Domínios Científicos e Tecnológicos (FOS) "Engenharia e Tecnologia::Engenharia Mecânica"

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  • Cyclic plastic behaviour of 7075 aluminium alloy
    Publication . Nogueira, F.; Cunha, J.; Mateus, A.; Malça, C.; Costa, J. D.; Branco, R.
    This paper aims at studying the cyclic plastic behaviour of the 7075-T651 aluminium alloy under fully-reversed strain-controlled conditions. Tests are conducted under strain-control mode, at room temperature, in a conventional servo-hydraulic machine, from smooth samples, using the single step method, with strain amplitudes (∆ε/2) in the range ±0.5 to ±2.75%. This material has exhibited a mixed behaviour, i.e. cyclic strain-hardens at higher strain amplitudes (∆ε/2/>1.1%) and cyclic strain-softens at lower strain amplitudes (∆ε/2<1.1%). A linear relationship between the degree of cyclic strain-hardening and the strain amplitude has been established for higher strain amplitudes. Fatigue-ductility and fatigue-strength properties agree with those found in the open literature for the same loading conditions.
    2020Comunicação em conferência Acesso aberto Ver mais
  • Thermo-kinetic curing model for stereolithographic applications
    Publication . Bártolo, Paulo
    A thermal-kinetic model, using the finite element method to study, simulate and optimise stereolithography, is presented in this paper. The model, which is theoretically rigorous and practical in its implementation, describes both the heat transfer effects and the course of the chemical reaction. This model includes the effects of photo-initiator concentration, temperature and light intensity, predicting the diffusion-controlled effects that occur after vitrification, the phenomenon of unimolecular termination and the shrinkage effects. Light intensity values at the resin surface are defined by assuming an appropriated Gaussian intensity distribution. The Beer-Lambert law enables to describe the decrease in light intensity with depth. The non-linear variation of the glass transition temperature with fractional conversion can be determined and consequently the mechanical behaviour of the resin sample predicted.
    2012Comunicação em conferência Acesso restrito Ver mais