Search results for "Criteri"
showing 10 items of 807 documents
Dual Boundary Element Method for fatigue crack growth: implementation of the Richard’s criterion
2013
A new criterion for fatigue crack growth, whose accuracy was previously tested in the literature with the Finite Element Method, is here adopted with a Dual Boundary Element formulation. The fatigue crack growth of an elliptical inclined crack, embedded in a three dimensional cylindrical bar, is analyzed. In this way in addition to the propagation angle estimated by the Sih’s criterion, it is possible to take into account a twist propagation angle. The two propagation criteria are compared in terms of shape of the propagated crack and in terms of SIFs along the crack front. The efficiency of the Dual Boundary Element Method in this study is highlighted.
ALTERNATIVE MODELS FOR BUILDING ENERGY PERFORMANCE ASSESSMENT
2020
The research activity carried out during the three years of the PhD course attended, at the Engineering Department of the University of Palermo, was aimed at the identification of an alternative predictive model able to solve the traditional building thermal balance in a simple but reliable way, speeding up any first phase of energy planning. Nowadays, worldwide directives aimed at reducing energy consumptions and environmental impacts have focused the attention of the scientific community on improving energy efficiency in the building sector. The reduction of energy consumption and CO2 emissions for heating and cooling needs of buildings is an important challenge for the European Union, be…
Analysys and optimization of an end double-lap bonded joint for GFRP composite sandwich panels
2022
Although the best configuration of the joints used to connect a common GFRP sandwich panel with the main structures is the adhesively bonded one, that permit high static and fatigue performances as well as to avoid stress concentrations, mechanical or hybrid joints are still widely used in the industrial field. After a preliminary theoretical design, the optimal configuration of an end adhesively bonded double-lap joint constituted by a simple insert as internal adherent and the same face sheets as external adherent, has been researched. In detail, several experimental tests and successive numerical simulations under tensile and bending loading, performed by varying the main influence para…
Tecniche di ottimizzazione multi-obiettivo e metodologie di supporto alle decisioni per la progettazione di processi di stampaggio di lamiere
2010
CFD simulations of dense solid–liquid suspensions in baffled stirred tanks: Prediction of the minimum impeller speed for complete suspension
2012
Abstract In the literature on mechanically agitated solid–liquid systems, several methods are described to estimate the minimum impeller speed Njs at which all particles are suspended, but few studies have been devoted so far to their critical comparative assessment [67] . In the present paper, several alternative Njs prediction methods are applied to CFD results obtained for selected test cases covering a broad range of suspension conditions and impeller speeds. Results are compared with one another and with classic empirical correlations [88] . The aim of the work is to assess the adequacy of different methods for predicting Njs and, more generally, to contribute to a viable CFD-based str…
CFD Predictions of Sufficient Suspension Conditions in Solid-Liquid Agitated Tanks
2012
Abstract Most research efforts on mechanically agitated solid-liquid contactors have been devoted to the assessment of the minimum impeller speed for complete off-bottom suspension, N js . Actually, many industrial vessels are operated at impeller speeds slightly lower than N js (Oldshue, 1983; Rieger et al., 1988). This suggests that the sufficient suspension condition, which is quantitatively specified in this paper by introducing a suitably defined quantity N ss , may represent a valid alternative to that of complete suspension. In the present work time-dependent RANS simulations were carried out with the aim of predicting the achievement of sufficient suspension conditions. The Eulerian…