Articles de revista
http://hdl.handle.net/2117/5360
2017-03-30T04:55:33ZSuppression of spurious frequencies in scattering problems by means of boundary algebraic and combined field equations
http://hdl.handle.net/2117/76996
Suppression of spurious frequencies in scattering problems by means of boundary algebraic and combined field equations
Poblet-Puig, Jordi; Valyaev, Valery; Shanin, Andrey
A numerical technique for solving scattering problems is presented. It is
based on a boundary integral equation idea, so the unknowns are localized on the contour (in 2D case) or the surface (in 3D case) of the scattering object. Two major difficulties of traditional boundary integral methods (the appearance of spurious resonances and the necessity to perform numerical integration of singular functions) are overcome by studying the problem in an approximate discrete formulation from the very beginning. The space is filled by cubic blocks, and the shape of the scatterer is formed by a set of blocks removed from the space. Thus, the formulation of the problem is discrete and the continuous Green’s function is substituted by a discrete mesh Green’s function. An analogue of combined field boundary integral equation (CFIE) is developed for this formulation.
2015-09-21T14:54:27ZPoblet-Puig, JordiValyaev, ValeryShanin, AndreyA numerical technique for solving scattering problems is presented. It is
based on a boundary integral equation idea, so the unknowns are localized on the contour (in 2D case) or the surface (in 3D case) of the scattering object. Two major difficulties of traditional boundary integral methods (the appearance of spurious resonances and the necessity to perform numerical integration of singular functions) are overcome by studying the problem in an approximate discrete formulation from the very beginning. The space is filled by cubic blocks, and the shape of the scatterer is formed by a set of blocks removed from the space. Thus, the formulation of the problem is discrete and the continuous Green’s function is substituted by a discrete mesh Green’s function. An analogue of combined field boundary integral equation (CFIE) is developed for this formulation.Evaluation of the GPR frequency spectra in asphalt pavement assessment
http://hdl.handle.net/2117/76524
Evaluation of the GPR frequency spectra in asphalt pavement assessment
Pedret Rodés, Josep; Pérez Gracia, María de la Vega; Martínez Reguero, Adriana Haydée
Ground penetrating radar (GPR) is frequently used in pavement assessments, mainly using the evaluation of wave travel times. However, GPR data provide further information that could be used in order to determine the inner conditions and characteristics about materials. In this paper, the possible analysis of the frequency spectrum of GPR signals is analysed and discussed. Several tests were carried out in a portion of a highway in two different stages of its service life. Results highlight the relationship between the shape of the spectrum and the frequency signature with the structure and conditions of the pavement.
2015-08-26T11:49:36ZPedret Rodés, JosepPérez Gracia, María de la VegaMartínez Reguero, Adriana HaydéeGround penetrating radar (GPR) is frequently used in pavement assessments, mainly using the evaluation of wave travel times. However, GPR data provide further information that could be used in order to determine the inner conditions and characteristics about materials. In this paper, the possible analysis of the frequency spectrum of GPR signals is analysed and discussed. Several tests were carried out in a portion of a highway in two different stages of its service life. Results highlight the relationship between the shape of the spectrum and the frequency signature with the structure and conditions of the pavement.Anticipar el futuro: una gran oportunidad para la ingeniería
http://hdl.handle.net/2117/28499
Anticipar el futuro: una gran oportunidad para la ingeniería
Macias Arau, Pere
The author, a professor of urban planning legislation, retraces the pioneering and visionary role in contemporary planning of Udefons Cerda, the progressive urban planner responsible for designing Modern Barcelona. This prospectr/e capacity is brought up to our current, more complex times in which, in the words of the philosopher Daniel Inneranty, there is no longer an optimum solution for each problem and it ncr/v fails to the stakeholders appearing in the debate to conduct an arduous discussion process.
El autor, profesor de legislación urbanística, rememora el papel innovador y visionario que tuvo Ildefons Cerdà, el gran urbanista que planeó la Barcelona Moderna, en el diseño del futuro. Y traslada aquella capacidad prospectiva a los tiempos actuales, mucho más complejos, en los que, según detecta el filósofo Daniel Innerarity, ya no existe una solución óptima para cada problema por lo que sólo cabe que la pléyade de actores que aparecen en el debate lleven a cabo un arduo proceso de discusión.
2015-07-01T16:07:51ZMacias Arau, PereThe author, a professor of urban planning legislation, retraces the pioneering and visionary role in contemporary planning of Udefons Cerda, the progressive urban planner responsible for designing Modern Barcelona. This prospectr/e capacity is brought up to our current, more complex times in which, in the words of the philosopher Daniel Inneranty, there is no longer an optimum solution for each problem and it ncr/v fails to the stakeholders appearing in the debate to conduct an arduous discussion process.
El autor, profesor de legislación urbanística, rememora el papel innovador y visionario que tuvo Ildefons Cerdà, el gran urbanista que planeó la Barcelona Moderna, en el diseño del futuro. Y traslada aquella capacidad prospectiva a los tiempos actuales, mucho más complejos, en los que, según detecta el filósofo Daniel Innerarity, ya no existe una solución óptima para cada problema por lo que sólo cabe que la pléyade de actores que aparecen en el debate lleven a cabo un arduo proceso de discusión.Assessment of the adhesive capacity of asphalt binders in the aggregate-binder bonds by means of new methodology
http://hdl.handle.net/2117/28498
Assessment of the adhesive capacity of asphalt binders in the aggregate-binder bonds by means of new methodology
Valdés Vidal, Gonzalo A.; Miró Recasens, José Rodrigo; Martínez Reguero, Adriana Haydée
The main goal of this study is to present a new methodology to characterize the adhesive capacity (cohesion and adhesion capacity) of asphalt binders by means of new mechanical parameters. This methodology is based on the Fenix test, a test recently developed in Spain. This method assesses the cracking resistance of the asphalt mixtures, and it has been adapted to characterize the bonding power of asphalt binders. The main parameters achieved with this procedure are related to the energy dissipated during the breaking between the asphalt binder and the aggregate, when these materials are subjected to tensile stress; essential parameters related to the adhesive capacity of asphalt binders. The results of an experimental stage are presented in this research, in which the proposed methodology has been applied to analyse the behaviour of the binder in the aggregate-binder matrix according to temperature variation and the effect of water and ageing; taking into account aggregates of the same origin and with a different shape pattern. The results show that the parameters achieved from this new methodology allows characterizing the adhesive capacity of asphalt binders in the different conditions assessed.
2015-07-01T14:24:43ZValdés Vidal, Gonzalo A.Miró Recasens, José RodrigoMartínez Reguero, Adriana HaydéeThe main goal of this study is to present a new methodology to characterize the adhesive capacity (cohesion and adhesion capacity) of asphalt binders by means of new mechanical parameters. This methodology is based on the Fenix test, a test recently developed in Spain. This method assesses the cracking resistance of the asphalt mixtures, and it has been adapted to characterize the bonding power of asphalt binders. The main parameters achieved with this procedure are related to the energy dissipated during the breaking between the asphalt binder and the aggregate, when these materials are subjected to tensile stress; essential parameters related to the adhesive capacity of asphalt binders. The results of an experimental stage are presented in this research, in which the proposed methodology has been applied to analyse the behaviour of the binder in the aggregate-binder matrix according to temperature variation and the effect of water and ageing; taking into account aggregates of the same origin and with a different shape pattern. The results show that the parameters achieved from this new methodology allows characterizing the adhesive capacity of asphalt binders in the different conditions assessed.Candilis-Josic-Woods y Le Corbusier: “Las ventanas no son un hueco en la pared”
http://hdl.handle.net/2117/28363
Candilis-Josic-Woods y Le Corbusier: “Las ventanas no son un hueco en la pared”
Fontana, Maria Pia; Mayorga Cárdenas, Miguel Yuri; Alzate, Edisson
This article analyses the comparison between several of Candilis-Josic-Woods’ representative projects between 1947 and 1955 and Le Corbusier’s Villas and Unité works. Through this analysis it establishes the interaction between their approaches while simultaneously defining and exemplifying their general and specific contribution to the understanding of the façade as a space and not as a surrounding. Analysis of the thickness of the façade and of its relation with the interior and exterior space is an important design criterion when contemplating a more urban architecture, and an architecture that is more liveable and more integrated with the environment. This is a quality that is ever more relevant and pertinent as an answer to the densification and horizontalization of cities.
2015-06-19T18:55:07ZFontana, Maria PiaMayorga Cárdenas, Miguel YuriAlzate, EdissonThis article analyses the comparison between several of Candilis-Josic-Woods’ representative projects between 1947 and 1955 and Le Corbusier’s Villas and Unité works. Through this analysis it establishes the interaction between their approaches while simultaneously defining and exemplifying their general and specific contribution to the understanding of the façade as a space and not as a surrounding. Analysis of the thickness of the façade and of its relation with the interior and exterior space is an important design criterion when contemplating a more urban architecture, and an architecture that is more liveable and more integrated with the environment. This is a quality that is ever more relevant and pertinent as an answer to the densification and horizontalization of cities.Using spectral finite elements for parametric analysis of the vibration reduction index of heavy junctions oriented to flanking transmissions and EN-12354 prediction method
http://hdl.handle.net/2117/28104
Using spectral finite elements for parametric analysis of the vibration reduction index of heavy junctions oriented to flanking transmissions and EN-12354 prediction method
Poblet-Puig, Jordi; Guigou-Carter, Catherine
The vibration reduction index of heavy junctions is predicted by means of a model based on spectral finite elements. This is equivalent to a finite element method but faster and with smaller computational costs. This advantage is used in order to perform a parametric analysis of the vibration reduction index for several junction types: T-shaped, L-shaped and +-shaped. The influence of several parameters such as: damping, junction dimensions or the mass ratio on the vibration reduction index is observed. The study is focussed to provide data and guidelines oriented to the EN-12354 design method for flanking transmission in buildings.
2015-05-29T13:52:00ZPoblet-Puig, JordiGuigou-Carter, CatherineThe vibration reduction index of heavy junctions is predicted by means of a model based on spectral finite elements. This is equivalent to a finite element method but faster and with smaller computational costs. This advantage is used in order to perform a parametric analysis of the vibration reduction index for several junction types: T-shaped, L-shaped and +-shaped. The influence of several parameters such as: damping, junction dimensions or the mass ratio on the vibration reduction index is observed. The study is focussed to provide data and guidelines oriented to the EN-12354 design method for flanking transmission in buildings.Stopover and hub-and-spoke shipment strategies in less-than-truckload carriers
http://hdl.handle.net/2117/27790
Stopover and hub-and-spoke shipment strategies in less-than-truckload carriers
Estrada Romeu, Miguel Ángel; Robusté Antón, Francesc
This paper presents a methodology to identify when freight consolidation strategies are cost-efficient in the less-than-truckload carriers operations. Shipments are assigned based on proximity and cost criteria to build an initial long-haul shipment solution. This initial solution is later improved by the implementation of Tabu Search algorithm. The proximity criterion takes into account the spatial distribution of shipments loads among centers. The results show that the proposed methodology may reduce the transportation cost by 20% compared to the solution of those heuristics only considering cost criterion. (C) 2015 Elsevier Ltd. All rights reserved.
2015-05-06T12:57:57ZEstrada Romeu, Miguel ÁngelRobusté Antón, FrancescThis paper presents a methodology to identify when freight consolidation strategies are cost-efficient in the less-than-truckload carriers operations. Shipments are assigned based on proximity and cost criteria to build an initial long-haul shipment solution. This initial solution is later improved by the implementation of Tabu Search algorithm. The proximity criterion takes into account the spatial distribution of shipments loads among centers. The results show that the proposed methodology may reduce the transportation cost by 20% compared to the solution of those heuristics only considering cost criterion. (C) 2015 Elsevier Ltd. All rights reserved.Numerical estimation of coupling loss factors in building acoustics
http://hdl.handle.net/2117/27722
Numerical estimation of coupling loss factors in building acoustics
Díaz Cereceda, Cristina; Poblet-Puig, Jordi; Rodríguez Ferran, Antonio
A study on the optimal procedure for obtaining SEA (statistical energy analysis) coupling loss factors (CLF) numerically is presented. The energies of an SEA system with two subsystems (one excited, the other one unexcited) are obtained from deterministic numerical simulations. Three different ways of isolating the CLF are explored: from the power balance of the excited subsystem (first approach) or the unexcited subsystem (second approach) and from the power transmitted through the connection (third approach). An error propagation analysis shows that the first approach is unreliable and that the second approach is the best option. As application examples, the CLF between some typical building structures is computed. These examples illustrate the potential of the estimated CLFs to solve larger problems with SEA and show the influence of the type of excitation on the coupling loss factor estimation. Finally, a simplified technique to account for the effect of studs in double walls with SEA is presented.
2015-05-04T13:13:13ZDíaz Cereceda, CristinaPoblet-Puig, JordiRodríguez Ferran, AntonioA study on the optimal procedure for obtaining SEA (statistical energy analysis) coupling loss factors (CLF) numerically is presented. The energies of an SEA system with two subsystems (one excited, the other one unexcited) are obtained from deterministic numerical simulations. Three different ways of isolating the CLF are explored: from the power balance of the excited subsystem (first approach) or the unexcited subsystem (second approach) and from the power transmitted through the connection (third approach). An error propagation analysis shows that the first approach is unreliable and that the second approach is the best option. As application examples, the CLF between some typical building structures is computed. These examples illustrate the potential of the estimated CLFs to solve larger problems with SEA and show the influence of the type of excitation on the coupling loss factor estimation. Finally, a simplified technique to account for the effect of studs in double walls with SEA is presented.The block Gauss-Seidel method in sound transmission problems
http://hdl.handle.net/2117/27708
The block Gauss-Seidel method in sound transmission problems
Poblet-Puig, Jordi; Rodríguez Ferran, Antonio
Sound transmission through partitions can be modeled as an acoustic fluid–elastic structure interaction problem. The block Gauss–Seidel iterative method is used in order to solve the finite element linear system of equations. The blocks are defined, respecting the fluid and structural domains. The convergence criterion is analyzed and interpreted in physical terms by means of simple one-dimensional problems. This analysis highlights the negative influence on the convergence of a strong degree of coupling between the acoustic domains and the structure. A selective coupling strategy has been developed and applied to problems with strong coupling (e.g. double walls).
2015-04-30T16:36:50ZPoblet-Puig, JordiRodríguez Ferran, AntonioSound transmission through partitions can be modeled as an acoustic fluid–elastic structure interaction problem. The block Gauss–Seidel iterative method is used in order to solve the finite element linear system of equations. The blocks are defined, respecting the fluid and structural domains. The convergence criterion is analyzed and interpreted in physical terms by means of simple one-dimensional problems. This analysis highlights the negative influence on the convergence of a strong degree of coupling between the acoustic domains and the structure. A selective coupling strategy has been developed and applied to problems with strong coupling (e.g. double walls).The finite strip method for acoustic and vibroacoustic problems
http://hdl.handle.net/2117/27707
The finite strip method for acoustic and vibroacoustic problems
Poblet-Puig, Jordi; Rodríguez Ferran, Antonio
The finite strip method, widely employed in structural mechanics, is extended to solve acoustic and vibroacoustic problems. The acoustic part of the formulation, including how to handle the most typical acoustic boundary conditions and the fluid structure interaction, is presented. Several realistic problems where the three-dimensional domain of interest has extrusion symmetry are solved. These examples illustrate the advantages of the method: it has smaller computational costs than the finite element method and consequently the analyzed frequency range can be increased.
2015-04-30T16:24:32ZPoblet-Puig, JordiRodríguez Ferran, AntonioThe finite strip method, widely employed in structural mechanics, is extended to solve acoustic and vibroacoustic problems. The acoustic part of the formulation, including how to handle the most typical acoustic boundary conditions and the fluid structure interaction, is presented. Several realistic problems where the three-dimensional domain of interest has extrusion symmetry are solved. These examples illustrate the advantages of the method: it has smaller computational costs than the finite element method and consequently the analyzed frequency range can be increased.