Mesquita, L.M.R.; Piloto, P.A.G.; Vaz, M.A.P.; Vila Real, P.M.M.
Lateral unrestrained steel beams when subjected to high temperatures may collapse in service by lateral torsional buckling. This instability state may be predicted in the resistance, temperature and time domain. In this work the beam strength is determined in the temperature domain from a batch of numerical and experimental tests, with a specified degree of utilisation and a typical accident temperature rise.
The experimental set-up is a reaction portal frame especially designed for beam elements under elevated temperatures. The specimens were heated by means of electroceramic resistances and a fibre mat specimen cover is used to increase the thermal efficiency. The...
Cruz, Maria; Jalali, Said
Este artigo apresenta os resultados de um trabalho de investigação realizado para avaliar os efeitos da utilização de cimento nos solos residuais graníticos, sob o ponto de vista da capacidade da carga e da durabilidade. Registaram-se as resistências à compressão simples e à tracção por compressão diametral, para avaliação das características mecânicas, enquanto que para a durabilidade, foi avaliada a absorção de água por capilaridade e a perda da resistência à compressão por saturação, de ciclos de molhagem-secagem e de gelo-degelo. Para melhorar o desempenho das misturas de solo-cimento foram estudados os efeitos da utilização de activadores de baixo custo...
Rosa, Sérgio; Pinho, Fernando T.
The laminar flow of Newtonian fluids in axisymmetric diffusers has been numerically investigated to evaluate the pressure-loss coefficient
as a function of Reynolds number, diffusion angle and expansion ratio. The numerical simulations were carried out with a finitevolume
based code using non-orthogonal collocated grids and second order accurate differencing schemes to discretize all terms of the
The calculations were carried out for Reynolds numbers between 2 and 200, diffusion angles from 0 to 90 and expansion ratios of 1.5
and 2 and the data are presented in tabular form and as correlations. A simplified 1D theoretical analysis helped explain the various
contributions to the...
Escudier, Marcel; Rosa, Sérgio; Poole, Rob
New experimental data are presented and discussed for fully developed pipe flow of shear-thinning, viscoelastic polymer solutions in the transitional regime between laminar and turbulent flow. The data confirm that such transitional flows exhibit significant departures from axisymmetry in contrast to the fully developed pipe flow of Newtonian fluids or both laminar and turbulent flows of such drag-reducing liquids. The azimuthal structure of the asymmetry is investigated together with its axial development and also the velocity fluctuation levels. These data do not lead to an explanation for the asymmetry but do suggest that the influence of the flow geometry both...