F. D. Denia

• Polytechnic University of Valencia

The present work analyses the reduction of the radiated rolling noise by a Constrained Layer Damping (CLD) mounted on the railway wheel. For this purpose, a methodology has been developed combining the use of viscoelastic models that consider the dependence of the material properties on frequency with an integral vibroacoustic model of the wheel. T...

Railway noise has become a relevant problem, especially along the urban environments. In this sense, the pollution noise coming from the rolling noise can affect the health of people in the surrounding area. For this reason, the present work focuses in reducing the total rolling noise radiated by the wheel, rail and sleeper through a study of the i...

The influence of multimodal incident sound fields on the acoustic behaviour of large aftertreatment devices incorporating a monolith is modelled and analysed in detail. The analytical mode matching method is applied to the compatibility conditions of the three-dimensional acoustic fields at the device geometric discontinuities, leading to the compu...

The dynamic and acoustic behaviour of the railway wheel is defined by its numerous vibration modes and natural frequencies. The modes whose contribution to the rolling noise radiation are predominant generally have 2 or more nodal diameters and appear above 2 kHz. The vibration due to these modes is decoupled from the rest of the wheelset, allowing...

Resonance in internal combustion engines could represent a limiting factor in spark ignited engines, while constitutes a noise source in compression ignition configurations. The total resonance intensity is a combination between the noise source, for example, type of combustion, and the characteristics of the propagation medium, such as the combust...

Wheel/rail interaction generates an excitation due to the roughness present on the surface of both components that produces vibration and consequently rolling noise. In this work, the railway track properties that most influence rolling noise are identified and this influence is analysed to reduce noise emission. The acoustic calculation methodolog...

The dynamic and acoustic behaviour of the railway wheel is defined by its numerous vibration modes and natural frequencies. The modes whose contribution to the rolling noise radiation are predominant generally have 2 or more nodal diameters and appear above 2 kHz. The vibration due to these modes is decoupled from the rest of the wheelset, allowing...

A framework is described for predicting the airborne noise inside railway vehicles which is applied to rolling noise sources. Statistical energy analysis (SEA) is used to predict the interior noise by subdividing the train cabin into several subsystems. The dissipation loss factors are obtained from the measured reverberation time in the train cabi...

In this work, a vibroacoustic model is developed to predict the dynamic response and sound radiation of an axisymmetric railway wheel under a non-axisymmetric excitation. To do this, first, the energy equation of the wheel is analytically integrated along the circumferential direction after an expansion of its response as Fourier series. Then, the...

In previous works [1,2], different dynamic models of the railway wheel have been developed to predict its sound radiation; however, there are still certain aspects that can be improved. Specifically, the high computational cost of these models, either because they solve the fluid-structure interaction problem or because they solve the dynamics and...

The main goal of the present work lies in the identification of the railway track properties that influence acoustic radiation, as well as in the analysis of these properties for the reduction of sound levels. This is achieved through a dynamic model of the railway wheel and track that allows the study of rolling noise, produced as a result of whee...

Railway rolling noise is nowadays a major source of acoustic pollution in urban areas, with nearly up to 12 million people daily affected in Europe by this phenomenon [1]. Hence, the search for ways of decreasing such noise radiation has become a highly active and significant research field. Following this approach, a Genetic Algorithms-based shape...

p>In this paper, a wavenumber-domain boundary element (2.5D BE) approach is adopted to predict the transmission of noise from the wheels, the rails and the sleepers to the train external surfaces. In the 2.5D models, only the cross-section of the vehicle is created by using boundary elements, while the third direction is taken into account in terms...

This paper presents a virtual test method for structure-borne noise generated from railway running gear. This method combines a number of existing tools to form a system approach. The wheelset and bogie frame are modelled using FEM software Nastran to include details of their construction. The primary springs are simplified to standard CBUSH elemen...

A wheel shape optimization of a railway wheel cross section by means of Genetic Algorithms (GAs) is presented with the aim of minimizing rolling noise radiation. Two different approaches have been implemented with this purpose, one centred on direct Sound poWer Level (SWL) minimization, calculated using TWINS methodology, and another one emphasizin...

An approach is presented for modelling the noise propagation beneath the train floor and this is applied to rolling noise sources. It is assumed that the sound incident on the train floor is made up of a direct and a reverberant component. A combination of two numerical modelling approaches is considered to deal with these: an equivalent source mod...

En esta comunicación se presentan los trabajos desarrollados en el marco de un proyecto de innovación y mejora educativa llevado a cabo durante los dos últimos cursos en el Máster Universitario en Ingeniería Mecánica de la Universitat Politècnica de València. Uno de los principales objetivos de este proyecto es el desarrollo y puesta en marcha de n...

This article presents a topology optimization (TO) method developed for maximizing the acoustic attenuation of a perforated dissipative muffler in the targeted frequency range by optimally distributing the absorbent material within the chamber. The finite element method (FEM) is applied to the wave equation formulated in terms of acoustic pressure...

In order to be able to predict train interior noise, it is first important to calculate the external sound pressure distribution on the floor, sidewalls and roof. This can then be combined with the transmission loss of the train panels to determine the interior noise. Traditional techniques such as the finite element and boundary element (FE/BE) me...

Rolling noise emitted by railway wheels is a problem that affects human health and limits the expansion of the railway network. It is caused by the wheel vibration due to the wheel-rail contact force, and it is important in almost all the vehicle velocity range. The minimization of noise radiation associated with changes on the wheel web is discuss...

En esta comunicación se presentan las actividades más relevantes desarrolladas en los dos últimos cursos desde el Equipo de Innovación y Calidad Educativa de la Universitat Politècnica de València, INTEGRAL, para trabajar y evaluar competencias transversales en asignaturas del ámbito de la Ingeniería Mecánica y de Ciencia de los Materiales. La idea...

Railway interaction is characterised by the coupling between the train and the track introduced through the wheel/rail contact. The introduction of the flexibility in the wheelset and the track through the finite element (FE) method in the last four decades has permitted to study high‐frequency phenomena such as rolling noise and squeal, whose orig...

This article presents a study of the backward bending mode of a simply supported rotating Rayleigh beam with internal damping. The study analyses the natural frequency behaviour of the backward mode according to the internal viscous damping ratio, the slenderness of the beam and its spin speed. To date, the behaviour of the natural frequency of the...

Regarding acoustic attenuation, reactive silencers show a good behaviour at low to mid frequencies, whereas dissipative silencers, i.e., those containing absorbent material, are used in exhaust system applications due to their good performance in wide frequency bands, essentially at high frequencies. The combination of both types of configurations...

Rolling noise emitted by railway wheels is a problem that affects human health and limits the expansion of the railway network. This problem is caused by the wheel-rail contact, and it is predominant over the rest of noise sources from the vehicle/track system for the usual speed conditions in urban areas. The minimization of rolling noise through...

This work presents an efficient numerical approach based on the combination of the mode matching technique and the finite element method (FEM) to model the sound propagation in silencers containing granular material and to evaluate their acoustic performance through the computation of transmission loss (TL). The methodology takes into account the p...

Natural fibres can be a suitable alternative for traditional synthetic materials used in noise control systems. Such fibres are not pollutant neither harmful for human health. They can also be obtained from industrial scrap. In this work, coconut and sisal fibres are characterized by means of a technique based on the simultaneous two source excitat...

Acoustic components have been extensively studied supposing perfectly rigid behavior. Although some works have been performed for the radiated sound in the case of a flexible element, an important lack of information exists concerning transmission loss analysis. The current investigation proposes the study for a generic flexible expansion chamber....

Railway curve squeal is an intense tonal and annoying type of noise commonly attributed to self-excited vibrations during curving. The mechanisms for its generation remain unclear and it is still a subject of discussion among researchers. Most of them have considered the falling behaviour of the friction coefficient with the slip velocity essential...

This work presents a robust methodology for calculating inter-penetration areas between railway wheel and rail surfaces, the profiles of which are defined by a series of points. The method allows general three-dimensional displacements of the wheelset to be considered, and its characteristics make it especially suitable for dynamic simulations wher...

En esta comunicación se presentan las actividades de evaluación desarrolladas en el marco de un Proyecto de Innovación y Mejora Educativa, junto con algunos resultados preliminares. El principal objetivo de este proyecto es el diseño de actividades de evaluación que fuercen a los estudiantes a desarrollar sus competencias transversales, al mismo ti...

The acoustic modelling of automotive exhaust devices, such as catalytic converters (CC) and diesel particulate filters (DPF), usually requires the use of multidimensional analytical and numerical techniques. The presence of higher order modes and three-dimensional waves in the expansion and contraction subdomains, as well as sound propagation withi...

Perforated concrete shows nowadays a high potential for many construction and building engineering applications. This work is devoted to the analysis of the acoustic properties of perforated concrete made from arlite lightweight aggregates. Concrete produced from these materials is an environmentally friendly alternative to traditional materials an...

As it is well known, there are various phenomena related to railway train–track interaction, some of them caused by the high frequency dynamics of the system, such as rolling noise when the vehicle runs over the track, as well as squeal noise and short-pitch rail corrugation for curved tracks. Due to these phenomena and some others unsolved so far,...

Free access to article valid until October 4, 2015 http://authors.elsevier.com/a/1RXqL1LkiP5xze This work presents a mathematical approach based on the point collocation technique to compute the transmission loss of perforated dissipative silencers with transversal temperature gradients and mean flow. Three-dimensional wave propagation is considere...

The use of sustainable materials is becoming a common practice for noise abatement in building and civil engineering industries. In this context, many applications have been found for porous concrete made from lightweight aggregates. This work investigates the acoustic properties of porous concrete made from arlite and vermiculite lightweight aggre...

Abstract: A mixed finite element model has been derived for the acoustic analysis of perforated dissipative silencers including several effects simultaneously: (1) High temperature and thermal gradients in the central duct and the outer absorbent material; (2) a perforated passage carrying non-uniform axial mean flow. For such a combination, the pr...

Some industrial processes are modelled by parametric partial differential equations. Integrating computational modelling and data assimilation into the control process requires obtaining a solution of the numerical model at the characteristic frequency of the process (real-time). This paper introduces a computational strategy allowing to efficientl...

La acreditacion internacional de los titulos de Grado y Master en nuestra universidad, junto con las demandas de los empleadores, han puesto en evidencia que los planes de estudio deben especificar no solo lo que se ha estudiado, sino tambien lo que se es capaz de hacer realmente. Este trabajo presenta los resultados obtenidos en el marco de un pro...

La acreditacion internacional de los masteres y grados ofertados por la universidad y la actual exigencia de los contratantes, han llevado a la necesidad de especificar en los planes de estudio, que se ha estudiado (contenido) y las competencias adquiridas. En los ultimos anos el enfoque basado en competencias del Espacio Europeo de Educacion Super...

Cylinder resonance phenomenon in reciprocating engines consists of high-frequency pressure oscillations excited by the combustion. The frequency of these oscillations is proportional to the speed of sound on pent-roof combustion chambers and henceforth the resonance frequency can be used to estimate the trapped mass, but in bowl-in-piston chambers...

The international accreditation for the Master and Bachelor degrees offered at our university, together with the demands of the employers, have made it clear that the students’ curricula should specify not only what they have studied, but also what they are actually able to do. Although the competence based curricula approach has been used in the d...

The international accreditation for the Master and Bachelor degrees offered at our university, together with the demands of the employers, have made it clear that students’ curricula should specify not only what they have studied, but also what they are actually able to do. Although the competence based curricula approach has been used in the devel...

Article link with free access until July 5, 2015: http://authors.elsevier.com/a/1R1mW_,OamrbIT

A finite element approach is proposed for the acoustic analysis of automotive silencers including a perforated duct with uniform axial mean flow and an outer chamber with heterogeneous absorbent material. This material can be characterized by means of its equivalent acoustic properties, considered coordinate-dependent via the introduction of a hete...

In this work, a finite element approach is presented for modeling sound propagation in perforated dissipative mufflers with non-homogeneous properties. The spatial variations of the acoustic properties can arise, for example, from uneven filling processes during manufacture and degradation associated with the flow of soot particles within the absor...

Export Date: 16 September 2013, Source: Scopus

This article presents a technique for modelling the dynamic response of rotating flexible solids with internal modal damping. The method is applicable to solids with geometry of revolution that rotate around their main axis at constant spinning velocity. The model makes use of an Eulerian modal coordinate system which adopts the vibration modes in...

This work presents a finite element approach for the assessment of temperature effects on the acoustic performance of perforated dissipative mufflers. The main acoustic properties of the propagation media, air and absorbent material, are discussed considering the presence of a non-uniform temperature field. Thermal gradients lead to heterogeneous a...

In this work, the finite element method (FEM) has been applied to the acoustic analysis of multichamber silencers with microperforated and constant impedance central pipes. A search of new designs based on the use of two different duct surfaces is presented. On one hand, microperforated surfaces exhibit an effective performance at low frequencies,...

The study of the three-dimensional acoustic field inside an exhaust muffler is usually performed through the numerical solution of the linearized equations. In this paper, an alternative procedure is proposed, in which the full equations are solved in the time domain. The procedure is based on the CFD simulation of an impulsive test, so that the tr...

Acoustic transfer matrices are commonly found in the finite element modelling of devices associated with the exhaust system of internal combustion engines. These matrices provide a relationship between the acoustic fields (usually pressure and velocity) associated with the nodes located at both sides of a particular region. For example, the acousti...

In this work, a three-dimensional analytical model is presented for the propagation of sound in circular dissipative reversing chamber mufflers with perforated frontal plates and bulk-reacting fibrous material. The procedure is based on the mode matching method that couples the acoustic pressure and particle velocity at each geometrical discontinui...

In this work, an experimental technique is presented for the acoustic characterization of materials and devices. The developed technique is based on the two source method with simultaneous excitation, thus reducing the time requirements in comparison with the standard two source technique. A decomposition technique is applied to the pressure measur...

In this work, a multidimensional analytical model is presented for the sound attenuation assessment of axisymmetric catalytic converters. Bessel functions are considered for the circular ducts, while spherical Hankel and Legendre functions are used for the expansion/contraction tapered ducts. Two alternative modelling techniques are implemented and...

In this work the finite element method is applied to predict the acoustic behaviour of catalytic converters. Two different modelling techniques are considered and compared for the mono-lith: (1) First, the procedure described in previous works, in which the wave propagation in the monolithic catalytic converter is assumed to be analogous to the pro...

In this paper, the extended finite element method (X-FEM) is considered for the analysis of fretting fatigue problems. A two-dimensional implementation of the X-FEM is carried out within the finite element software ABAQUS TM by means of user subroutines, and crack propagation in fretting fatigue problems is investigated. On utilizing the non-linear...

The sound attenuation of perforated dissipative circular mufflers including a folded resonator and a short expansion chamber is investigated in detail by means of a two-dimensional axisymmetrical analytical approach based on the mode matching technique. The acoustical properties of the bulk reacting porous material and the perforated screen are tak...

This work presents a modal approach to evaluate the transversal modes and wavenumbers for dissipative mufflers with mean flow. The method is based on the division of the transversal section of the muffler into subdomains, for which two simple sets of modes are considered. The first set of modes satisfies the condition of zero pressure at the common...

An analytic mode matching scheme that includes higher order modes is developed for a straight-through circular dissipative silencer. Uniform mean flow is added to the central airway and a concentric perforated screen separates the mean flow from a bulk reacting porous material. Transmission loss predictions are compared with experimental measuremen...

This article presents a technique for modelling the dynamic response of spinning solids of revolution. The method is especially adequate for considering those cases where the interesting displacements and the external forces are associated with points at which the Eulerian coordinates are constant. The method is based on the modal properties of sol...

To carry out the acoustic analysis of dissipative silencers with uniform cross-section, the application of the mode matching method at the geometrical discontinuities is an attractive option from a computational point of view. The consideration of this methodology assumes, in general, that the modes associated with the transversal geometry of each...

The acoustic behavior of perforated dissipative circular mufflers with empty extended inlet/outlet is investigated in detail by means of a two-dimensional (2D) axisymmetric analytical approach that matches the acoustic pressure and velocity across the geometrical discontinuities, and the finite element method (FEM). The complex characteristic imped...

The acoustic behaviour of perforated dissipative circular mufflers including a folded resonator and a short lateral chamber is investigated by means of a two-dimensional axisymmetric analytical approach based on the mode matching technique. The acoustical properties of the absorbing material and the perforated surface are taken into account to obta...

Two-tailpipe mufflers have become a usual solution for flow noise abatement in turbocharged Diesel engines. since the mean flow velocity at the exhaust outlet may be reduced without increasing the tailpipe diameter, which would give rise to an increase of noise associated with engine orders. In this communication, the acoustic characteristics of mu...

An analytical model is presented for the acoustic attenuation performance analysis of circular hybrid mufflers consisting of two short lateral chambers and a central dissipative cavity filled with sound absorbing material. The two-dimensional axisymmetric analytical approach developed to evaluate the muffler performance is based on an eigenequation...

This study presents a modal substructuring method suitable for the calculation of the acoustic field in mufflers with complex geometry that involves fibrous materials and perforated elements. The methodology evaluates the transversal pressure field in each subcomponent of uniform cross-section by means of a substructuring technique and applies the...

Railway vehicles running with wheel tread defects are known to cause abnormally high forces between wheel and rail which reduce the life of track and vehicle components. Hertzian wheel-rail contact model is used by most of the vehicle-track dynamic interaction models at present. However, for wheel tread defects like shells or fresh wheel flats the...

The current study considers the acoustic characteristics of partially-filled perforated dissipative circular mufflers with extended inlet/outlet. In addition to the finite element method (FEM), a two-dimensional (2-D) axisymmetric analytical approach is developed that matches the acoustic field across the discontinuities by applying the continuity...

An analytical description of the acoustic performance of mufflers with elliptical cross-section has been obtained via the point source method and truncated modal superposition. First, the problem of natural frequencies and mode shapes has been addressed considering the Helmholtz equation in an elliptical domain, whose solution can be expressed by m...

This Thesis is focused on the development and implementation of efficient methods for the acoustic modelling and design of exhaust mufflers for internal combustion engines, by means of tools based on analytical and numerical solutions of the governing wave equation. First, the finite element method is considered. The acoustic modelling of perforate...

The acoustic behavior of a circular dual-chamber muffler is investigated in detail by: (1) a two-dimensional (2-D) axisymmetric analytical approach based on the mode-matching technique for the concentric configurations; (2) the finite element method; and (3) experimental work. A number of effects is studied, including (1) the presence of a rigid ba...

Expansion chambers with single-inlet and double-outlet are used in the exhaust system of internal combustion engines since they provide noise attenuation similar to simple chambers (single inlet/outlet), and reduce the flow noise and back pressure. This work presents a detailed analysis of the acoustic attenuation performance of elliptical expansio...

The finite element method has been applied to the analysis of acoustic problems with several natural frequencies and mode shapes. First, a recovery-based error estimation is performed following the well-known procedures of structural problems. Then, an h -adaptive refinement strategy is proposed that leads to a finite element mesh with the minimum...

The finite element method has been applied to the analysis of acoustic problems with several natural frequencies and mode shapes. First, a recovery-based error estimation is performed following the well-known procedures of structural problems. Then, an h -adaptive refinement strategy is proposed that leads to a finite element mesh with the minimum...

The effects of side ports in the elliptical configuration of engine breathing systems were discussed. The effect of locations of end outlet ports was examined. The acoustic behavior of short elliptical chambers with end offset and side outlets was found to be similar at low frequencies. A diametral wave propagation was formed that resulted in broad...

The present work studies in detail the acoustic behaviour of mufflers with elliptical cross-section. The effect of the chamber length and the location of the inlet and outlet ports is considered. In addition, the eccentricity of the ellipse is taken into account, since it generates important discrepancies with respect to those results obtained for...

The mode-matching technique has been applied to the reversing chamber muffler to obtain an accurate prediction of its acoustic performance that includes the effect of wave propagation in inlet and outlet pipes. Results have been compared with those given by other analytical approaches, such as the point source method and the piston-driven model. Th...