R “ Far better an approximate answer to the right question, which is often vague, than an exact answer to the wrong question, which can always be made precise.” John W. TukeyRIGHT QUESTIONS LEAD TO RIGHT ANSWERS “I am not bound to swear allegiance to the dogmas of any master” HoraceTHE GOOD THING OF A PROBLEM WITHOUT ANOBVIOUS SOLUTION IS THE PLEASURE IN FINDING IT “I support that symbiogenesis is the result of a long time coexistence and that is the main source of evolutionary novelty in all superior non-bacterian organisms.” Lynn MargulisFLUENT COMMUNICATION IS THE KEY TO PROGRESS
A WORK METHOD History Noise and VibrationsICR is a company that works to solve noise For ICR, noise is closely connected toand vibration problems. vibrations, and vice versa, because vibrations make noise, and noise, when it touches a sur-It was established in 1995 by people with face, creates vibrations. A simultaneouswide experience in the world of acoustics. study is the only thing that makes theICR has always been involved in many impor- problem comprehensible and it enables thetant national and international technological company to find the solution.projects.To solve a problem, the company keeps aperfect balance between theoreticalknowledge and a pragmatic point of view ofthe treatment of experimental data. The com-pany’s spirit is also practical — it offersspecific answers to real problems, withmethods of analysis and the design ofsolutions.Thanks to its experience, its methodology isapplied successfully in a wide and variedrange of sectors.ICR currently holds a technical expertagreement with ENAC (National AccreditationEntity) to carry out noise and vibrationaudits. Analyser FFT 32 channels Theory and Tests, Measurements in Real Time an Optimal Combination ICR has up to 48 channels to measure noise and vibrations simultaneously, with the required accelerometers and microphones.For ICR it has always been important to All these elements analyse the signalinclude real tests in its studies, over the according to the frequency and in real timemany years of development and application — they can analyse spectra, transfer func-of its own methods. The reason for this is tions, coherence...that experimenting enables the company tounderstand the real situation and understand The tests required can be performed effec-the problem directly, while the theory tively to find solutions for real vibroacousticenables the company to understand the problems, thanks to the simultaneous controlanalysed reality and establish effective of a large amount of measurement points.modifications. The everyday work carried out at the com-This is why the company invests mostly in pany requires a large amount of technicaltwo areas: technology, to have the most instruments such as sound level meters, mi-advanced experimenting and analysis crophones, accelerometers, spectra analys-methodology always available; and the ers, etc. In order to carry out any project,ongoing training of its personnel. large or small.
ENGINEERING SERVICES RailwayICR has achieved an important position in therailway acoustic engineering sector in the lastdecade, thanks to its prediction techniques,based on real measurements and the appli-cation of the company’s own theoreticalmethods.The company is able to measure air-bornenoise and structural noise, including the con-tribution of forces (Transfer Path Analysis)and the quantification of the paths followedby noise and vibrations (Advanced Transfer Graphic of contributionsPath Analysis).ICR’s clients will be able to know exactly howmuch noise is made by each element of the Thanks to its experience, ICR hastrain, for example, the noise received from sound knowledge and latesteach point of attachment, the air condition- generation systems for the sector.ing, the auxiliary systems, etc.This way, the manufacturer can decide, with Based on these studies, ICR carries out otherthe information available, whether to change types of jobs in the railway sector—some ofthe anchoring methods and establish priori- them are specific to the sector, like the treat-ties for future modifications. For this, the ment of “squeal noise”. Others, however,company uses exact numerical criteria from have a more generic application, like the en-the results that can be obtained from each vironmental impact analysis, modal analysis,modification. theoretical numerical models of the train, etc.The knowledge of these contributions doesnot only establish priorities for modifica- Thanks to the company’s wide experience intions—in some cases it can reduce costs be- this market, it is able to solve any vi-cause after each test, ICR evaluates improve- broacoustic problems.ments with its own software for a new designand defines the necessary changes to fulfilthe required objectives. The full acoustic model of a train enables clients to see the effect produced by any modifications on the design. Activate or deactivate any modification and find out instantly about its effect on the total noise. Experimental setup
ENGINEERING SERVICES Wind PowerWind farm are gradually being built closer tobuilt-up areas and the noise they produce isstarting to be an essential factor in theirfeasibility. In order to establish this feasibilityin terms of acoustic impact on the environ-ment, ICR carries out a comprehensive studyto make sure that regulations are compliedwith.It also develops more specific and largerprojects in the design stage of wind turbines,with the aim of obtaining real predictions forthe future vibroacoustic performance or themechanism.Training is so another very important servicein the wind power sector. ICR gives veryspecific courses to companies that manufac-ture wind-driven turbines, with a syllabus thatis adapted to the sector and introducedconcepts on acoustics and its relation withcurrent legislation. ICR works on the acoustic feasibility the wind turbine in design phase as the environmental control of Sound power level measurement according to the wind farm. standard IEC 61400 part 11 Environmental impact study of the wind farm
ENGINEERING SERVICES BuildingPeople’s peace and quiet is often disturb bydifferent problems — entertainment, fairs,bars, discos, etc. To avoid this problem, cur-rent legislation establishes the maximumimmission level allowed for every activity de-pending on the area, as well as the insulationvalues for each type of activity.Taking this into account, ICR mainly developstwo types of studies: Noise prediction radiated by equipments• The objective of the first study is to assessand prevent the noise level generated by theactivities outside. This type of analysis is ICR offers a wide range of engineeringcarried out especially at discos, fairs, services and vibroacoustic consultancyrecreational centres, etc. service focused on the sector of architecture and building, namely:• The second one studies the transmissionpaths of noise and vibrations inside a • Functional solutionsbuilding. The aim of these projects is to as- • Insulation calculationsess the sound insulation between the • Acoustic and vibration measurementsaffected buildings. • Control and monitoring works • Acoustic conditioning and insulation design The company also carries out comprehen- • Acoustic and vibratory impact studysive interior acoustics projects (geometry,absorption, diffusion) in the field of Finally, we have to mention that ICR hasaudiovisuals—installing a sound system, developed new systems to identify the sourcemixing and recording systems, and control or of noise and vibrations in buildings, usingdesign of new and quieter recreational model inversion and other methods like TPA.centres. Special Buildings In the building sector, the company takes part in special and very complex projects, in which it evaluates the future influence of environmental vibrations in buildings where the maximum vibration level is very restricted. This study is carried out firstly by calculating the environmental vibrations that may affect the installations, and secondly, by characterising the terrain with the SASW method (Spectral Analysis of Surface Waves). The data obtained is used to create a finite Improve the insulation of a discotheque element model of the terrain and the building.
TECHNIQUES/METODOLOGY Environmental ImpactThe concern for noise impact created by thenew high-speed train tracks is no longer asecondary factor when planning infrastruc-tures.ICR carries out environmental projects to pre-dict noise and vibrations with a methodologybased generally on the combination of thecalculation of noise prediction with acoustic Acoustic impact caused by the train circulation in Gironameasurements. ICR believes that measuringproperly will lead to a good vibroacousticcharacterisation of the terrain, and therefore,to a good numerical model.The company also has the best calculationtools, such as CADNA A and SOUNDPLAN,which enables us to obtain highly reliableresults for our most demanding clients.Noise predictions for trains and road trafficare currently regulated by European stan-dards, which are integrated into the com- Acoustic impact by road traffic in Ronda de Daltpany’s calculation procedures. of Barcelona ICR carries out projects and evaluation measurements every day to calculate the impact of roads and railway tracks. Automotive Our work in the car industry ranges from ex- perimental studies on the transmission paths of noise and vibrations, to the creation of theoretical models to predict the noise of traffic. We must not forget the development of new To determine the noise transmission paths testing methods that optimise time and costs of each of the interior panels of vehicle in the current methodology to characterise a vehicle. Most acoustics laboratories Because the methods we use are transpar- of car industries apply theoretical ent, our clients have been able to gain more insight into vibroacoustics and thus reduce approach of TPA/ATPA costs when resolving noise and vibration developed by ICR problems.
ENGINEERING SERVICES IndustryDeciding on the appropriate solutions to re-duce the noise that an industrial plant gener-ates in its environmental is often a difficultjob. To decide, the first step is to quantify theinfluence of each source of noise on the totalnoise in the affected points.ICR uses model inversion methods to obtainthe acoustic power (SWL) of all the sources ofnoise an vibrations belonging to a factory,without having to interrupt its operation.Then, we can decide in which order to silencethem and calculate how the situation im-proves with the proposed modifications.ICR also uses this methodology to measurethe noise from outside and achieve the re-quired reduction of the noise made by a ma- Acoustic impact study in the chemical plantchine (blower, shotblaster, etc.), in order to in Toulousecomply with the regulations and prevent theproblem-machine from getting closed down. sources of noise that can be treated sepa-The treatment is feasible because the rately, in order to design an intelligent noiseproblem-machine is divided into a group of treatment for each one of them. In the 21st century, uncontrolled noise and vibration in a machine mean low quality. Measurements of modal behaviour in the industrial factory
OTHER SERVICES Training SoftwareAt ICR there are highly qualified professionals One of ICR’s policies is always to be one stepwho are able to give courses on different ahead. This is proved in the field ofnoise and vibration topics. calculation tools, where the company has evolved significantly — it currently offers aThe training they give can fully adapt to the specific service to develop custom-madeclient’s needs. It always includes a syllabus programmes.divided into two parts — the first part with ageneric introduction of vibroacoustics, and a It has programmed specific software for thesecond specialised part, based on contents quality control of the production line, forthat are much more specific and adapted to measuring instruments, for signal treatment,the corresponding sector. and even software for methods like TPA (Transfer Path Analysis).These tailor-made courses enable us to guar-antee a sound theoretical knowledge, and, ifrequired, also practical knowledge, becausethe client’s interest is the only limit. Treatment software, frequency analysis and visualisation of bridge vibration signals Course about Advanced acoustic dBKAislaICR has always invested time and resourced One of the programmes worth highlighting isto provide training in vibroacoustics, at the programmes for the prediction of sounddifferent levels. insulation — dBKAisla. It has been designed to calculate the insulation of single panels,So, ICR has courses like that: multiple panels (double, triple, quadruple, etc.) and mixed panels, to offer the user the• Basic Acoustic option of calculating a group of specific solu-• Advanced Acoustic tions for each face.• Insulation• Vibrations dBKAisla also enables the development of the• Environmental Impact calculation of insulation from air-borne noise• Aeroacoustics and impact noise between two buildings, taking into account lateral transmission paths according to the detailed method ofTechnical and specific training which the UNE-EN 12354 standard (regulation established and recommended by the DB-HR no needs previous knowledge. of the Spanish Building Technical Code).
R+D Research & DevelopmentICR has always tried to be up to the techno-logical standard that is required, so it hasinvested time and money in its resources inorder to provide its clients with the most de-tailed and specific solutions in every case.Thanks to this it has achieved significant ad-vantages in the market, providing theoreticalsolutions as well as designing new experi-mental technologies within the vibroacousticfield. .Some of ICR’s most important research fieldsare: aeroacoustics, TPA, software develop-ment, model inversion, dynamic characterisa-tion of the terrain, design of materials, silenc- Structural transmission of signalsers, acoustic photography, etc.The R+D projects in which the company hastaken part have received public and private A problem well posedfunding. is usually a problem solvedCertain innovations achieved by the companyhave been exhibited at conferences or pub- Thanks to the company’s ongoing Research &lished in science articles and technical re- Development, most of the methods that ICRports and national and European magazines. uses every day have been designed in-house.For example, the mathematical bases of the The company has also adapted commercialTPA method have been published in the most methods.important international magazines and theyhave even been transferred to large multina- Then, some of these methods are briefly out-tional corporations. lined. CURRENT SITUATION FIRST SITUATION Soundproofed Machine EXPECTED IMPROVEMENT —> 15dBA OBTAINED IMPROVEMENT —> 14dBA Carry out an insulation treatment while the factory was in full operation
TECHNIQUES/METODOLOGY Model Inversion Method The core idea of the application of model in- version is to achieve the calculation of the causes based on the effects, using a cause- effect relation. Model Inversion method is a mathematical technique developed in geophysics, which ICR has applied to vibroacoustics. In this case, inversion is applicable to the establishment of the acoustic power of a col- lection of sources, which we know produce certain noise in a group of measured points. This involves using mathematical methods Acoustic power of panels of a car linked with statistics and uncertainty. Because there are not many analysis resources on the market, ICR has been motivated to adapt several methods in the science of vibroacoustics. Numerical MethodsFEM (Finite Element Method) and BEM(Boundary Element Method) are powerfulprediction methods for low frequencies. Bothof them are used to resolve vibroacousticproblems straight from the design and canestablish the exact validity of any solutionsproposed by clients.With these numerical methods, ICR evaluatesthe dynamic performance of structures withthe introduction of forces—mechanical,acoustic or aerodynamic. For example, theycan determinate the vibration response of a Motor-drive coupling calculation by FEMtrain carriage in the excitation that the en-gines, the auxiliary systems, etc. Introduce,taking into account the different middle Method) are among the many numericalstructures. methods used at ICR, according to the requirements of each study.So, FEM and BEM can provide prediction ofnoise and vibrations in the design stage, thusavoiding problems in the final product. ICR integrates vibroacousticsOther numerical methods such as the wave into the design stageequation or WEM (Wave Expansion
TECHNIQUES/METODOLOGY TPA / ATPATransmission Path Analysis is a techniqueinvented in the 1980s and developed exten-sively by ICR, especially in the treatment ofpaths and the application of the vibroacous-tics energy theory.This system quantifies the contributions ofeach one of the sources of noise that causesa problem and can be applied in general, thatis, it is valid for all fields. For example, on atrain, each one of the parts of the vehicle thatmakes a certain noise can be analysed. And Process of Transmission Path Analysisthis can also be done in heavy machinery,small mechanisms, etc.The main idea of this analysis is that the ob- With this method we can also evaluate theject to be studied is divided into parts and forces that operate on a mechanical system,the contribution of each part to the overall for example, dynamic forces that an enginenoise is defined. This is the only way to find can introduce into the bodywork of a vehicle.the best solutions to the problem. This provides solutions that reduce forces — changing the points of support or the use of appropriate elastic support devices. ICR gives ongoing training in all the So, with this test method and a theoretical disciplines that gradually improve development, we can obtain the necessary prediction. data to define the necessary improvements to resolve the problem. Examples of TPA/ATPA application in diferents sectors
TECHNIQUES/METODOLOGY Aeroacoustics calculations Modal AnalysisA problem with vibrations can have different The modal or experimental analysis, or withorigins and natures. For example, it can numerical methods, involves establishing thecome from a source of noise, of electromag- parameters of each one of vibration modes ofnetic forces, or dynamic unbalance. a structure, which are the natural vibration frequency, mode shepes and damping.Fluid motion around a body (a train, a car, ablower, etc.) at great speed is an important Vibration in the low frequency range in anysource of noise and vibrations. The science structure can be obtained as the superimpo-that studies this phenomenon is Aeroacous- sition of the contribution of each of thetics. modes. For the calculation of the contribution of each mode you only need the vibrationalICR is currently working on the prediction of excitation force and modal parametersinterior noise caused by aerodynamic effects, mentioned above, so the analysis results of aeither in a train running at high speed, or in a structure enable the calculation of thewind-driven generator. vibrational response when it is subject to any excitation. Because we are able to know the contribution of each mode, the corrective measurements to be taken to reduce the level of global vibra- tions effectively can be focused on the pre- ponderant vibration modes. ICR has success- fully applied these techniques in many differ- ent fields of industry. Vibrations control is a current work of ICR Aeroacoustic study of a trainUntil recently, it was inconceivable that anyprediction could be made in the field ofaeroacoustics. However, computing hasadvanced so much that very complex calcula-tions can be carried out now.ICR has its own calculation methods in thelatest CFD (Computational Fluid Dynamics)and CAA (Computational Aeroacoustics),which, combined with the classic FEM andBEMs, enable the company to quantify thecontribution of the aerodynamic load in thevibration of a structure or the noise inside avehicle. Modal Analysis of a structure
TECHNIQUES/METODOLOGY Ray-Tracing ICR applies its knowledge to any field,Whether it happens because of the buildings’acoustics or propagation outside, this tech- when it is required.nique is based on step-by-step calculationsthat provide results in the case of homogene- The final result is Know-How for theous environments. manufacturing company, which is a solid base of knowledge that can beIn the high frequency limit, the wave equationturns into an eikonal equation that enables used in the future, once it has beenthe interpretation of the noise propagation introduced into the production cycle.with rays. Statistical Energy Analysis (SEA) The high frequency study in complex systems cannot be studied with wave equations. The methodology that is normally used is SEA (Statistical Energy Analysis), a vibroacoustic calculation method based on energy transfer between the parts of the system. These transfers are characterised Ray-Tracing prediction with coupling factors that depend on the modal density. Complex systems with medium to high For medium and high frequencies, frequencies can be studied with the SEA, in ICR has wide experience in the field order to make more realistic diagnoses, which is unfeasible and impossible with other of energy theories. techniques. Ratiation Acoustic calculation (right) from the velocity distribution (left)
TECHNIQUES/METODOLOGY Sources LocalisationOne of ICR’s main objectives is to quantifyand locate the sources of noise andvibrations, in order to optimise the solutionto a vibroacoustic problem. For this, thereare methods like holography and acousticantennas. Software to obtain the acoustic photography Source localisation technology can be the first step to approach a vibroacoustic problem. Graphic of acoustic antenna sensivity Acoustic Antennas are microphone networks that show the direction from which the noise comes from, by processing the signalsAcoustic Holographic is a specific inversion received.technique which calculates the vibrations in avibrating body, based on the pressures Acoustic antennas are generally based on ameasured in the sound field of the body. hypothesis of the emitted sound field, like, for example, flat waves, spherical waves, etc.This is carried out with Green’s integral equa-tion, which applies both variables—pressure ICR also has correlation antennas that evenon space and speed on a closed surface. locate noise in reverberating fields. Noise sources localisation on a movement car
PUBLISHED PAPERS MODEL INVERSION METHODTRANSMISSION PATH ANALYSIS CONTROL APPLICATIONS AERODYNAMIC NOISE
PAPERS Then, you will find some scientific articles and technical papers about R+D by ICR, which had been published in prestigious journals. Abstracts MODEL INVERSION METHOD An model inversion method to obtain the acoustic power of the noise sources in a large factory. O. Guasch, F.X. Magrans & P.V. Rodríguez. Applied Acoustics 63, pp. 401-417 (2002).AbstractA common problem for large factories that wish to decrease their environmental acoustic im-pact on neighbouring locations is to find out the acoustic power of every noise source. As thesefactories cannot stop their activity in order to measure each source individually, a procedure isneeded to obtain the acoustic powers with the factory under normal operating conditions. Theircontribution to the overall sound pressure level at each neighbouring location can then be ob-tained and it is possible to calculate the improvements obtained after any modification of thesources. In this paper an inversion modelling method is used to do so. Acoustic powers areobtained by means of field sound pressure level measurements and with the use of a soundpropagation software. A careful analysis of the solution has been carried out by simulating er-rors on the measured data in order to detect possible correlations between the acoustic powerof different sources and avoid misleading interpretations of the results. The whole methodologyhas been applied to a liquid-gas production factory. An model inversion method to obtain the acoustic power of a car cabin panels in the mid-high frequency range. O. Guasch, F Magrans & P Rodríguez. Proceedings of the 14 Jornada Técnica de Au- .X. .V. tomoción, UPNA-STA. Pamplona, (2002).AbstractThe Inverse Problem Theory is a quite complete mathematical theory that integrates methodsfor extracting as much information as possible from measured data, in order to find the mostprobable values for an a priori unknown physical model. It is based on probability calculus andbrings a natural extension of the minimax, least absolute and least squares optimisation crite-ria. The theory has found several applications in a wide variety of fields such as mathematics,astrophysics, geophysics, engineering or economy.In this paper, the theory is applied to reconstruct the medium-high frequency acoustic field inthe cabin of a Ferrari 456. The acoustic powers of the car cabin panels are obtained by meansof sound pressure spectra measurements and with the use of a diffuse model of radiation fol-lowing Lambert’s law. Once all the acoustic powers are known, their influence to the acousticpressure at any point inside the car cabin can be calculated. A careful analysis of the solutionhas been performed by simulating errors on the measured data in order to obtain correlationsamong the acoustic powers and avoid a misleading interpretation of the results. The methodhas proved encouraging and saves a large amount of time when compared with more classicalapproaches.
PAPERS An innovative approach for the noise reconstruction and analysis at the medium-high frequencies. O. Guasch, F.X. Magrans, P.V. Rodriguez & G. Manacorda, Proceedings of Euro-Noise, Munich, Germany, October, Vol. I, pp.503-509 (1998).AbstractIn the last 30 years the Inverse Problem Theory has been mainly developed by geophysicianstrying to model the Earth’s interior from data collected at the Earth´s surface. As the Earth’sinterior is unaccessible, methods for extracting as much information as possible from data hadbeen carried out. These methods turned out to be really efficient and have been applied tomany other fields of applied physics and mathematics, engineering and economy. A quite com-plete mathematic theory has been built for them.In our study we used some of these methods to reconstruct the medium-high frequencies noisefield in the cabin of the new Ferrari 456. Our purpose was to know in what ways each of thepanels in the total interior surface contribute to the measured noise at different points in thecabin. The results we obtained are very hopeful and we think that will improve in the future aswe will have more information and a priori data to manage. TRANSMISSION PATH ANALYSIS Path Analysis F.X.Magrans, Proceedings Nag Daga (2009)AbstractThe title of this paper is Path Analysis, and not Transfer Path Analysis, because the latter namehas been assigned to the Forces method which, as it is used, is a contribution analysis method,more than a path method.The origins of the method lie in the need to solve two different problems. The first problem con-sists in quantifying the contribution of each part of a vibrating system to the total noise meas-ured at a given location. This problem will be called problem A. The second one, called prob-lem B, consists in determining the noise produced by each one of the forces acting on a me-chanical system.In the 60’s the method used to solve the problem A was called the “Strip” method. In thismethod the noisy object was totally covered with insulating blankets in order to attain a veryreduced noise. Then the surfaces were uncovered one by one and the contributions of each sur-face deduced from measurements. The “Strip” method has been applied to motors, whole carsor even to whole train coachs, and it is still being applied today.A typical case of problem B was to estimate the contributions to interior noise of each one ofthe engine supports on a car. In order to solve this problem, the practical method was to unlinkthe engine from the car and then to attach the supports one by one. Low and mid-high frequency advanced transmission path analysis. F.X. Magrans, P.V. Rodriguez & G. Cousin, Proceedings of the 12 International Congress on Sound and Vibration, Lisboa, Portugal (2005).AbstractAdvanced Transfer Path Analysis (ATPA) is a test-based numerical technique allowing the diag-nosis necessary to solve vibro-acoustic problems. For vehicle applications, the main purposeconsists in ranking the contributions of potential sources or potential transmitting points, dis-tributed around a cabin, and creating noise at a receiving passenger location. The classic
PAPERSof the sources at the receiver points, independently of their transmission path. Using the ATPAtechnique, the transmission paths are quantified and ranked. This technique complements thepossibilities of the classical TPA method by allowing the determination of the relative contribu-tions of the selected structure and airborne transmission paths. Using the information ex-tracted from the application of this theory, the mechanical component to be modified can beidentified. From that point, the decision can be taken to act directly on the source or on thestructural elements. This paper starts by giving a short theoretical description of the method.Then, the steps of the experimental procedure applied, the tools used, and the exploitation ofthe data are described based on an experimental case realized in controlled conditions. Finally,the range of application of the method and of the tools used is described based on a real case. Method of measuring transmission paths. F.X. Magrans, Journal of Sound and Vibration 74 (3), pp. 321-330 (1981)AbstractA theoretical explanation and experimental proof are presented of a method for localizing andevaluating the transmission paths of any signal in a “black box” among a set of points previ-ously defined in it. The signal should behave linearly and the system should be able to receiveexternal excitations separately at each of its points. Such excitations need not be the signal un-der study but they should be linearly related to it. Also presented are the equations that, oncethe transmission paths have been determined, allow the evaluation of the excitations which acton the system. Definition and calculation of transmission paths within a SEA framework. F.X. Magrans, Journal of Sound and Vibration 165 (2), pp. 277-283 (1993).AbstractGenerally, the problem of soundproofing buildings has employed the concept that energy istransmitted along different paths from the source to the receiver. The S.E.A. systematizes theexistence of acoustic and mechanical coupling in mechanical complexes. This study intends tosystematize the concept of transmission paths, its numerical treatment and its classification,taking the equations of S.E.A as a reference framework. Direct transference applied to the study of room acoustics. F.X. Magrans, Journal of Sound and Vibration 96 (1), pp. 13-21 (1984).AbstractIn a recent article Kruzins and Fricke  applied the method of Markov chains to represent the“random walk” of phonons inside an enclosed space and to predict stationary state acousticpressure levels, at sufficiently high frequencies, in geometrically complex spaces. In this paperit is demonstrated that with the same initial hypothesis the exact solution can be obtained di-rectly by using the method of direct transference. Explicit expressions for the coefficients of thesolution matrix are found, their physical significance is made evident, and a simple method forcalculating the solution is presented.
PAPERS The Global Transfer Direct Transfer method applied to a finite simply supported elastic beam. O. Guasch & F.X. Magrans, Journal of Sound and Vibration 276 (1-2), pp. 335-359 (2004).AbstractThe Global Transfer Direct Transfer (GTDT) method is a two-step transmission path analysismethod. It is used to analyse the signal transmission among subsystems from a general N-dimensional linear network, representing a physical model under study. In the first step, theGlobal Transfer Functions (GTFs) are measured and the Direct Transfer Functions (DTFs) arecalculated from them. In the second step, the signal vector is measured for the network run-ning under the desired operational conditions. It is then possible to reconstruct the signal atany subsystem from the contributions of all other subsystems plus its own external excitation.This is done by means of the previously calculated DTFs.This paper is intended to clarify how the GTDT method works. This is done by means of an ana-lytic study of the bending wave transmission between three points in a simply supported finiteelastic beam. This problem constitutes a particular 4-dimensional example of the general N-dimensional network. Concerning the first step of the method, special emphasis is given to therelationship among the DTFs and the GTFs, as well as to elucidate the role of the DTF matrix asa connectivity matrix. As for the second step of the method, the particular case of a correlatedforce vector acting on the beam is addressed. It is shown how the signal at any subsystem canbe reconstructed from the signals at all the other subsystems. In practical implementationsthis allows to identify problematic subsystems in order to perform appropriate design modifica-tions and avoids the necessity of having to measure operational forces. The role of the direct transfer function matrix as a connectivity matrix and application to the Helmholtz equation in 2D: relation to numerical methods and free field radiation example. F.X. Magrans & O. Guasch, Journal of Computational Acoustics 13(2), pp.341-363 (2005).AbstractThe Direct Transfer Function (DTF) matrix was developed in the framework of the Global Trans-fer Direct Transfer (GTDT) method of transmission path analysis. This method aims at solvingthe problem of transmission paths among subsystems from a general N-dimensional linear net-work, representing a vibro-acoustical model under study. The DTF matrix can be calculatedfrom the Global Transfer Functions (GTFs), which are measurable quantities, and it is builtfrom all the Direct Transfer Functions (DTFs) between subsystem pairs. The DTFs allow to de-fine transmission paths by relating the signals between two network subsystems when the re-maining ones become somehow blocked. In this paper, the role of the DTF matrix as a connec-tivity matrix is first shown by solving the Helmholtz equation in a two-dimensional grid. Theresults are compared with those arising from the analysis of the stencils of various numericalmethods. Some finite difference and finite element methods have been considered. The con-nectivity role of the DTF matrix is also elucidated by means of a free field radiation example. A compact formulation for conditioned spectral density function analysis by means of the LDLH matrix factorization. O. Guasch & F.X. Magrans, Journal of Sound and Vibration 277 (4-5), pp. 1082-1092 (2004).
PAPERSAbstractSeveral methods have been developed in the last decades to deal with the subject of TPA(Transmission Path Analysis) in noise and vibration problems. A distinction can be made be-tween the so called one-step methods and two-step methods. The MISO method is a one-stepTPA method because it only requires operational measurements among subsystems in a linearN-dimensional network. That is to say, the method allows to factorise the signal (usually accel-eration, velocity or displacement in a given direction, or the acoustic pressure at a given loca-tion) at one network subsystem in terms of the signals or forces at the remaining ones, with theonly use of operational measured data. This is to be compared with two-step TPA methods likethe GTDT method (Global Transfer Direct Transfer) or the FTF method (Force Transfer Func-tions), which require to measure transfer functions in a first step, with the network stationary.Operational measurements are carried out in a second step and the previously measured trans-fer functions are then used to obtain the desired signal factorisations.The basis of most TPA methods were developed in the mid 70’s. Since then much work hasbeen done in order to solve some of their numerical problems, as well as to enlarge their rangeof applicability. In this paper attention will be paid to the MISO method. It will be shown thatthe conditioned spectral density functions analysis developed to deal with partially correlatedsignals on a linear network corresponds in fact, to the LDLH factorisation of the network signalcross-spectra matrix. Although this may be a known result because the MISO method datesfrom the 70’s, the authors have not found any published proof of it. A proof is derived in thispaper that might be found interesting by itself and serve as a compendium to obtain the MISOfactorisations in a compact and straightforward way. CONTROL APPLICATIONS Application for measuring material acoustic properties in an impedance tube. D. Castro. Customer Solution, National Instruments site. (2005).AbstractThe two-microphone transfer function method has been implemented to find the acousticproperties of materials using an impedance tube. The application generates a broadband noiseinside the tube, while it acquires the acoustic pressure at two microphones located at the tubeshell. Then, the Frequency Response Function (FRF) between the two channels is computed. Amathematical procedure allows obtaining the following acoustic parameters:1. Reflection coefficient.2. Absorption coefficient.3. Acoustic impedance.4. Acoustic admittance.Finally, all interesting process data is transferred to an Excel worksheet (via ActiveX) to bestored and to let the user generate a report. Automated noise test bank for the quality control of isolation pulleys. D. Castro, “Worldwide Conference on Virtual Instrumentation. National Instruments Days Fall 2002 - Spring 2003” , pp. 22-23. AbstractIsolation pulleys are submitted to noise tests in order to detect any manufacturing fault. Thepulley real operational conditions are simulated inside an insulated cabin and the overall sound
PAPERSpressure level (SPL) in dBA is measured for a one second period. A comparison with a previ-ously selected threshold value decides whether the pulley is acceptable or not. Three parame-ters depending on the pulley type are fixed before carrying out each noise test:1. Maximum allowed SPL in dBA (threshold value).2. Pulley strap tension.3. Pulley revolutions per minute (r.p.m.).This paper presents an application that automatically manages the whole pulley validationprocess. The application controls the noise measurement equipment, the testing conditions(parameter values), the PLC (Logical Programmable Controller) communication and the datapost process. The results are automatically stored in an Excel data sheet by means of ActiveX.An additional storage in a main computer is also performed using a serial port communica-tion. AERODYNAMIC NOISE Calculation of aerodynamic noise generated by the airflow around a body. Simulation with stabilised finite element methods. O. Guasch & R. Codina, Proceedings of Métodos Computacionais em Engenharia, incor- porant VIII Congresso Nacional de Mecánica Aplicada e Computacional i VI Congreso de Métodos Numéricos en Ingeniería APMTAC_SEMNI, Lisboa, Portugal (2004).AbstractThis article presents a methodology to carry out computational aeroacoustics subsonic calcula-tions. The method is based on Lighthill’s acoustic analogy, which involves three stages: In thefirst one, Navier-Stokes equations are solved for an incompressible flow, with the aim of obtain-ing the term that acts as a source of sound (Reynolds tensor is used as an approximation toLighthill’s tensor). In the second stage, this source is transformed into the frequency domainand, in the third stage, the corresponding Helmholtz differential equation is solved, in order toobtain the acoustic pressure field. All the equations are solved with stabilised finite elementmethods. The case of air flow round a cylinder for different Reynolds numbers is presented as anumerical application. In cases when the Kármán vortex street is formed, we observe that thesimulations reconstruct the dipolar side of the generated acoustic field with no problems. Time depend subscales in the stabilized finite element approximation of incompressi- ble flow problems. Ramon Codina, Javier Principe, Oriol Guasch and Santiago Badia, Computer Methods in Applied Mechanics and Engineering. (2007)AbstractIn this paper we analyze a stabilized finite element approximation for the incompressible Na-vier–Stokes equations based on the subgrid-scale concept. The essential point is that weexplore the properties of the discrete formulation that results allowing the subgrid-scales todepend on time. This apparently ‘‘natural’’ idea avoids several inconsistencies of previous for-mulations and also opens the door to generalizations.
PAPERS An algebraic subgrid scale finite element method for the convected Helmholtz equation in two dimensions with application in aeroacoustics. Oriol Guasch, Ramon Codina, CMAME_196 (45_48) pp 4672-4689,(2007)AbstractAn algebraic subgrid scale finite element method formally equivalent to the Galerkin Least-Squares method is presented to improve the accuracy of the Galerkin finite element solution tothe two-dimensional convected Helmholtz equation. A stabilizing term has been added to thediscrete weak formulation containing a stabilization parameter whose value turns to be the keyfor the good performance of the method. An appropriate value for this parameter has been ob-tained by means of a dispersion analysis. As an application, we have considered the case ofaerodynamic sound radiated by incompressible flow past a two-dimensional cylinder. FollowingLighthill’s acoustic analogy, we have used the time Fourier transform of the double divergenceof the Reynolds stress tensor as a source term for the Helmholtz and convected Helmholtzequations and showed the benefits of using the subgrid scale stabilization. A heuristic argument for the sole use of numerical stabilization with no physical LES modelling in the simulation of incompressible turbulent flows. O. Guasch & R. Codina, Journal of Computational Physics (2007).AbstractWe aim at giving support to the idea that no physical LES model should be used in the simula-tion of turbulent flows. It is heuristically shown that the rate of transfer of sub-grid kinetic en-ergy provided by the stabilization terms of the Orthogonal Subgrid Scale (OSS) finite elementmethod is already proportional to the molecular physical dissipation rate (for an appropriatechoice of the stabilization parameter). This precludes the necessity of including an extra LESphysical model to achieve this behavior and somehow justifies the purely numerical approachto solve turbulent flows. The argumentation is valid for a fine enough mesh with characteristicelement size, h, so that h lies in the inertial sub-range of a turbulent flow.
SOME PROJECTS RAILWAY WIND POWER BUILDINGENVIRONMENTAL IMPACT INDUSTRY AUTOMOTIVE
PROJECTSThen, you will find some projects carried out by ICR in every sector that it works. RAILWAY Noise and vibration Transmission Path Analysis of a prototype high speed train (AGV). (ALSTOM Transport).Carrying out static and dynamic vibroacoustic measurements on the high-speed train, following the TPAmethod in order to know the contribution to the overall noise of each one of the noise sources of everyelement of train. Experimental tests of vibration in the power motor system of diesel units carried out in the laboratory of Voith in Hamburg, Germany. (CAF, Construcciones y Auxiliar de Ferrocarriles)To characterise the vibrations of several configurations of the diesel power unit system for the RENFE-TDMD project units. For this, acceleration measurements are carried out, by measuring the operation ofthe tensile modulus in several conditions, all of them carried out in the test bench, with differentconfigurations.
PROJECTS Transmission Path Analysis of one unit of the suburban train CIVIA model. (CAF, Construcciones y Auxiliar de Ferrocarriles) Acoustic study and Transmission Path Analysis of a Diesel Locomotive 251 of RENFE.(ATENASA) Custom software development. (TIFSA) To carry out treatment software, frequency analysis and visualisation of bridge vibration signals. Main functions: synthesis and application of all kinds of digital filters, polynomial interpolations or with splines, re-randomisation of signals, conversion of data formats, management of the group of signals as a project, establishment of the main frequencies and associated damping, calculation of remaining and stabilised values, etc. The software includes subprogrammes for the mass treatment of data and the creation of personalised summary reports. Transmission Path Analysis of the cabin of two diesel units series 333 and 334 of Vossloh. (ATENASA) Sound pressure level measurements in the train AVR 121 in order to fulfil the noise regulation according to technical specification as defined by RENFE and European regulations ETI. (CAF, Construcciones y Auxiliar de Ferrocarriles) Vibroacoustic numerical model of the whole train. Advice consultancy for air conditioning of train. Carrying out some testing measurements of Madrid Subway. (CAF, Construcciones y Auxiliar de Ferrocarriles) Noise and vibrations Transmission Path Analysis of the Chamartín Railway Station. Solution consultancy. Project 051180. (TIFSA) Numerical model for the interior and exterior noise forecast of the new subway of Madrid. (CAF, Construcciones y Auxiliar de Ferrocarriles)
PROJECTS Experimental Modal Analysis in the power motor system of diesel units ADR. (CAF, Construcciones y Auxiliar de Ferrocarriles)Carrying out a Experimental Modal Analysis in order to know the different real modes that exist andtake part in the movement of the assembly, which includes the support frame joined elastically withthe car, the propulsion unit and the turbocompressor unit on the engine. A study of the influence of the flow separation and the pressure fluctuations beneath the turbulent boundary layer of the new generation high speed trains AGV (Automotrice à Grande Vitesse), France. (ALSTOM Transport)Acoustic study of the aerodynamics generated by the noise and excitation of the mechanisms of thenew high-speed train.The study has three main parts: the noise in the cabin by the aerodynamic excitation of glass, thenoise in the cabin caused by the ventilation system, and last, the noise in the passenger area behindthe cabin. Noise and vibration Transmission Path Analysis of the driver’s cabin of the diesellocomotive 250 -028 - 8 of Renfe. (ATENASA) Complete aerodynamic acoustic study of the mid-high speed train TAV – S104 “Lanzaderas” Project. A study of the influence of the non-stationary aerodynamic load on the noise levels inside the high speed train TAV – S104. (ALSTOM Transport)
PROJECTS META X research project based on Transmission Path Analysis and vibroacoustic study for WEST COAST MINE LINE TRAIN in Asfordby, United Kingdom. (ALSTOM Transport) Design of a silencer for the exit of foul air in the Rome Subway, and comparison of the sound insulation between two types of doors for the underground train, provided by the client. (CAF, Construcciones y Auxiliar de Ferrocarriles)Design of the silencing elements required to reduce the noise level generated by the extraction of foulair system in a box under the base of the Rome Subway.An acoustic study of three different door designs carried out with the dBKAisla programme to calculatemultiple insulations, developed by ICR, in order to compare the sound insulation of each door. Vibroacoustic advanced design tools for the characterization of the noise of the train. (ALSTOM Transport)To develop testing techniques that define the vibroacoustic features of the different train subsystems —interior and exterior noise when the train is stopped.To evaluate the contributions to the interior noise of the different subsystem of a train in normaloperating conditions.To evaluate the contributions to the exterior noise of the subsystems of a train in static operatingconditions. Noise and vibrations Advanced Transmission Path Analysis of a diesel train in South of Ireland. (CAF, Construcciones y Auxiliar de Ferrocarriles) Complete acoustic study of the CIVIA 2.000 Train. (CAF, Construcciones y Auxiliar de Ferrocarriles) Advanced Transmission Path Analysis of the Warsaw Metro, Poland. (ALSTOMTransport)
PROJECTS Complete acoustic study of a diesel train of Northern Ireland Railways, Ireland. Model and study of the engine coupling by experimental and theoretical methods. (CAF, Construcciones y Auxiliar de Ferrocarriles) Acoustic study of the diesel units for N.I.R. Based on the calculation of rolling noise, the levels of noise and establishment of solutions to reduce the vibrations caused in the train by the auxiliary engine. Description of the results of the model carried out in order to evaluate the predictions of the noise pressure level inside the N.I.R. diesel trains. Complete acoustic study of the Xin Min Line in China. (ALSTOM Transport)Vibroacoustic tests on a similar train, including an analysis of the ways noise and the vibrations of thetrain are transmitted, and measurement of the equipment and components. Subsequently, a numericmodel in order to predict the noise and vibrations of the new Xin Mine Line train model.Monitoring of the manufacturing of the first unit of the new model, and vibroacoustic test to check theestimated prediction.Re-design of the cabin doors and intercommunicating doors of the train. An acoustic study of the “floating floors” of the units Line 5 Train of Barcelona Subway.(ALSTOM Transport)
PROJECTS Complete acoustic study of the Northern Spirit (Leeds-Skipton) and noise transmission path analysis of the Heathrow Express (Heathrow-Paddington) in United Kingdom. (CAF, Construcciones y Auxiliar de Ferrocarriles) Project to determine how the rail’s roughness affects the noise inside the train along its usual route in Ireland. (ALSTOM Transport) Identification the noise and vibrations origin in the Barcelona Subway. (CAF, Construcciones y Auxiliar de Ferrocarriles) An acoustic study of the “floating floors” of the 8.000 series of the Madrid Subway. (CAF, Construcciones y Auxiliar de Ferrocarriles) Complete acoustic study of the new 6.000 series of the Madrid Subway. (CAF, Construcciones y Auxiliar de Ferrocarriles) A study of the contributions of every subsystems to the overall noise that’s perceived in the Driver’s Cab for units of 2 Line Barcelona Subway. This project used Advanced Transmission Path Analysis (Direct transference approach). (CAF, Construcciones y Auxiliar de Ferrocarriles) WIND POWER Full specialised course to study the environmental noise impact assessment of a wind farm. (VESTAS)Course customized to client needs. The course syllabus, prepared by ICR, is based on the prediction ofthe acoustic impact calculation of a wind farm. It made up of three parts: an introduction to acoustics,an environmental noise impact study of the installation of a wind farm, and practical examples.
PROJECTS Environmental impact study prior to the operation of a future wind farm. (GAMESA Corporación Tecnológica SA)Noise analysis in pre-operational stage and estimation of noise level in post-operational stage. Assessingthe environmental noise impact expected in the wind farm and to identify potential solutions. Experimental tests to characterise an acoustic tonal problem in the prototype of a wind turbine nacelle. (ALSTOM Wind) Course of Acoustic and Aeroacoustics of rotors based on basic acoustics, aeroacoustics principles and applications in rotary engines. (ALSTOM Wind) Custom course of environmental noise impact assessment for the installation of a new wind farm. (GAMESA Corporación Tecnológica SA) Development of Experimental Modal Analysis in a wind turbine. (Astom Wind) Experimental Modal Analysis in rear frame of a prototype wind turbine. (ALSTOM Wind)Determining the vibration modes of the frame structure of a wind turbine and any local modes of somecomponents, using experimental modal analysis in order to compare with the modes which have beencalculated and to know the frames dynamic behaviour. Modal Analysis of gearbox of a wind turbine to determinate its vibration modes in situ. (ALSTOM Wind) Acoustic measurement in a prototype wind turbine in order to evaluate the contribution to overall noise of the ventilation systems. (ALSTOM Wind)
PROJECTS Environmental noise impact evaluation in a wind farm. (GAMESA Corporación Tecnológica SA)Environmental noise impact assessment in two phases: acoustic measurements in situ and then,proposing solutions. Study of acoustic impact prediction expected by the operation of three future wind farms, and propose solutions. (GAMESA Corporación Tecnológica SA) Acoustic measurement and Transmission path analysis of sound and vibration of a refrigeration system of a wind turbine. (GAMESA Corporación Tecnológica SA)Acoustic measurements and transmission path analysis (TPA) in order to quantify the noise that radiatedirectly for each one of mouths (aspiration and expulsion), and quantify the noise that radiate by thestructure of wind turbine. BUILDING Acoustic study to determine the necessary treatment in order to improve acoustic characteristics of a sports centre in Cornellà de Llobregat, Barcelona. (EMDUCSA) Monitoring and technical supervision in the Light Laboratory Synchrotron ALBA in order to control the vibrations over a slab, and the vibrations caused by a crane bridge. (Master de Ingeniería)Evaluation of the vibrations in the construction works. This monitoring process involves severalmeasurements with and without activity on site, controlling vibrations caused by the operation of acrane bridge that travels over the site, and characterising the vibration levels of a slab. Diagnosis and prediction of noise and vibrations transmission path in building - VITRASO. (FCC Construcción SA) (Development project)The aim of Vitraso project is the detection of the path transmission of harmful noise and vibration in abuilding, as well as a new design and its implementation in order to void these paths. From the methodof Transmission Paths Analysis (TPA) it is possible to detect the paths with to better contribution and soit be facilitated localized intervention in the elements that conform them. The results obtained by thesemethods it will be compared with experimental tests and numerical simulations carried out.Furthermore, the contribution of different transmission paths will allow to evaluate the prediction limitsaccording to the standard UNE EN ISO 12354.
PROJECTS Noise and vibration measurements in the facilities of the Microelectronics Institute of Madrid in order to determine whether background levels comply the specifications of the equipment to be installed in a room. (Instituto de Microelectrónica de Madrid) Vibration control for the construction of the white chamber in Nano-manufacturing unit. (Contratas y Obras, Empresa Constructora S.A) Measurements of noise radiated by ventilation equipment in a parking area in order to assess compliance with the environmental regulations of Barcelona (OGMAUB). And propose solutions for reduce it. (Subcomunidad Propietarios Parking) Study of vibrations and noise prediction for the project of building the Light Laboratory Synchrotron ALBA in Cerdanyola del Vallès, Barcelona. (Master Ingeniería)This complex study is composed for several tasks: vibration measurements of ground, assessment andprediction of vibrations on critical area, calculation of vibrations insulation of this critical area, acousticanalysis of machinery and the facilities, noise and vibration control of auxiliary equipments, predictionof vibrations caused by a crane bridge and insulation calculation of slab. Acoustic study for the construction of the Thermal Centre Prestige Jafre in Jafre del Ter, Girona. (Bovis Lend Lease - Grupo Prestige) Soil vibration characterisation for the future installation of a nano-manufacturing centre for the Centro Nacional de Microelectrónica in the UAB-Bellaterra Campus. Design consultancy to fulfil vibration criteria. (CSIC-CNM y Master de Ingeniería, S.A)Assessment of the current charges to quantify the insulators methods necessaries and quantify thelimits allowable of exterior disturbance. Monitoring of the execution floating slab built in the works.All of these with the aim of get a correct execution and verify that the solution brings the right vibrationbehaviour.
PROJECTS Acoustic study of CETOSS - QUERÉTARO Building in México. (RHEINHOLD & MAHLA, S.A.) Acoustic conditioning project of Centre d’Art Santa Mònica in Barcelona. (Generalitat de Catalunya) Transmission paths analysis from exterior to interior through windows in a Hotel of Barcelona. (Hotels Rosincs)Measurements in two windows of the building to determine the noise transmission from outside thebuilding inside through the windows. Preliminary report about vibratory impact of works in Gas Natural Headquarter in Bar- celona. (GAS NATURAL, S.A.) Measurement of sound pressure level in “Bikini” discotheque in BARCELONA. (Bikini) Acoustic behaviour assessment of a new office building of CIBA GEIGY in Barcelona. (MASTER S.A. de Ingeniería y Arquitectura) Localization of a vibration of unknown origin in a building in Bordeaux, France that various institutions had previously failed to localize for many years. The problem was solved using our self-developed Vibrography Method: Graphical localization of vibration sources. (Bureau Veritas in Toulouse, France)Creation of a prior treatment of the temporary signal in order to obtain a cross-correlation between thepairs of accelerometers with enough information. Subsequently, tests are carried out to obtain the posi-tion of all the noise sources in order of importance from a visual image.
PROJECTS Prediction of vibration levels at the IBM Data Processing Center in San Fernando, due to the partial demolition and amplification works. (MASTER S.A. de Ingeniería y Arquitectura)The aim of this study is to determine the vibration levels that the future extension work of the IBM DataProcessing Centre San Fernando—Madrid will produce. The study is made up of several stages:A series of acceleration measurements to obtain the direct vibration transfer between differentsubsystems of one specific sector of the centre.Creation of model with finite elements of a part of the building. This model enables the calculation ofvibration transfers between the sectors that are further away from the building, and a more detailedstudy of the low frequency range, which is hard to study in an experiment.Measurement of the vibration caused by a hammer-robot to calculate the vibration level predictable intwo areas of the building.To determine if the predicted vibration values can alter the correct operation of the centre. Acoustic behaviour assessment of the water treatment plant PEMBROKE R.O. in Malta. (BUREAU VERITAS-Toulouse) Vibroacoustic consultancy services for shopping center Diagonal Mar in Barcelona (89.000 m2). (DIAGONAL MAR, S.A.) ENVIRONMENTAL IMPACT Nocturnal vibration measurements of the activity produced by drilling a tunnel boring machine in section 4 of the new line 9 of subway of Barcelona. (UTE GORG). Vibration measurements produced at two places in section 2 of works of the new line 9 of subway of Barcelona according to the Local, Regional and State Normative. (UTE GORG). Control and monitoring of vibration levels inside industry caused by the works of the AVE in the industrial of Montmeló, Barcelona. (Confidential client) Assessment of noise level produced by the commercial premise of client in order to assess compliance with current regulations. Barcelona. (Metalistería J. RUIZ) Sound level measurement carried out to assess the noise impact due to the operation of a diesel generator. (Sociedad Mercantil Estatal TVE, S.A)
PROJECTS Study of the sound pressure levels produced by the future High Speed Line Vitoria – Bilbao – San Sebastián in Durango, Bizkaia, when the train passes over the viaduct. (TIFSA)To study, with reception points, all the areas and/or buildings in the viaduct area that are sensitive tothe noise levels caused by the circulation of different trains, in order to carry out a noise prediction thatcomplies with the previsions of the DIA regulations formulated by the corresponding informative studyof the New Railway Project in País Basco carried out by the General Environmental Department, on 22October 2000. Acoustic measurement of external environment on works of the Line 9 Train of Barcelona Subway according to regulation . (UTE Arquitectura) Development of the noise map of the council of Bezana, Asturias. (INSOTEC) Control and monitoring of vibrations produced by the AVE works in the section between Sagrera and Nus Trinitat in Barcelona. (ACCIONA Infraestructuras)To monitor the vibration levels received in two different control points of the high-speed train AVEconstruction works, for 36 months. An evaluation, in each one of the points, of the compliance withcurrent legislation and a detailed weekly and quarterly report of any problems caused during themonitored period. Presentation of a communiqué informing on the situation, whether there areproblems during the week or not, and on the compliance or not of current legislation. Acoustic impact control in works of a new 9 Line in Barcelona Subway. (GEOCAT Gestió de Projectes SA) Acoustic control measurement to justify the external noise emitted by the air conditioning unit of a hospital in Barcelona. (CLINICA IVI) Environmental acoustic impact assessment produced by the AVE rail Levante. Solution consultancy. (TIFSA)
PROJECTS Measurement of sound pressure level (dBA) to comply with regulations in newresidential zone in Villalba Saserra - between Barcelona and Granollers. (BarcelonaGranollers Edificis S.L.) Modelling the noise impact produced by the operation of the C-31 which it passesthrough the house Mas Mortera in Mont-Ras, Girona. (INTRAESA) Environmental impact of the FUNOSA foundry in Odena. Acoustic solution consultancy. (FUNOSA)To evaluate the noise impact caused by the company Funosa in the surrounding area, based onmeasurements carried out by the LGAI to determine the situation of the company and its environmentalaccording to the regulations by the Department of Environment, thinking about the future practicalapplication by Igualada town hall.A comprehensive study to find out the values of sound power of each noise source, in order to designoptimal acoustic solutions to reduce the level of sound pressure on the reception points. Environmental acoustic impact assessment of the discotheque “Café Mambo” inEivissa. (Café Mambo) ZIMA-041189-ES Project with Adjudication nº 041190. Vibration measurement of thesubsoil and prediction of environmental impact though model of propagation thevibrations in terms of distance (Calculations to predict the impact of environmentalvibration from the construction of airport Montflorite). (TIFSA) Noise level reduction of rotary blower in the ENAGAS plant in Cartagena according tothe Model Inversion Method. (TÉCNICAS REUNIDAS SA) Environmental Impact assessment (noise and vibrations) produced by the extension ofprinting press room of Prensa Española S.A. (Diario ABC)
PROJECTS Sound impact study of the high-speed train when travelling through Guadarramamountain range (Segovia - Soto del Real). Prediction of the noise levels, pressure pulse inthe mouth of the tunnel, environmental noise impact of the construction works of the tunneland rails, and design of solutions. (INIMASA) Environmental noise impact caused by road traffic in a stretch (Canyelles industrial estate) of Ronda de Dalt in Barcelona. Optimisation of new solutions. (EUROPROJECT)Study to reduce noise levels caused by traffic in a stretch of Ronda de Dalt, approximately 300 metreslong. Stages of the study: noise diagnosis, creation of an acoustic model and propose solutions forsound barriers. Development of an model inversion method to determine the noise contributions of alarge textile factory at environment. Girona. (ANTEX) Vibration measurement in the facilities of NorControl in Tarragona caused by thecirculation of train . (NORCONTROL) Carrying out multiple measurement of insulation and absorption of sound barriers on site according to the France Regulations. Environment acoustic impact study of Girona, when the train crosses through citycenter. Prevision of noise and vibrations levels and design the solutions. (Ajuntament deGirona) Environmental acoustic noise assessment of the facilities of client. (INBESA) Study of environmental acoustic impact in order to reduce the noise level in two zones of PROQUIMED plant. Design the solutions too. (Productos Químicos del Mediterráneo SA) Environmental acoustic impact assessment caused by the operational performance of8 multipurpose rooms in the village Montauban. (PZ Toulouse)
PROJECTS Application of an model inversion method to the factory AGA-Toulouse (Portet sur Garonne), France, in order to determine the contributions of acoustic sources to various external control points and neighbours. The study was performed while the factory was in full operation. (BUREAU VERITAS)Measurements of the sound pressure level in the area surrounding the factory and in several monitoringpoints in the areas that are possibly the most affected. Application of the model inversion method todetermine the sound power of the exterior noise emitters in the AGA production plant in Toulouse. INDUSTRY Study for reducing the noise of a small industrial pump. (Laboratorios Grífols SA)The first step to reduce noise generated by a pump that is part of a piece of equipment used in thelaboratory analysis has been performing several acoustic and vibratory measurements. The aim of thesehas been characterizing the source of the noise as well as how to determine the structural and acoustictransmission paths. Design the correction solution. Acoustic study in the industrial factory in order to know the acoustic pressure level generate by each of machines individually at a receiver point. Barberà del Vallès, Barcelona. (KAO Corporation SA) Acoustic behaviour study of every part of an industry while it was operational. (Confidential client)
PROJECTS Vibration characterization of one kind of crane. (Industrias Electromecánicas GH)Transmission Path Analysis of one of the pulley equipments made by Industrias Electromecánicas GHin order to quantify each one of the noise and vibration sources that compose it. So that, it is possibleto determine optimal processing to reduce of noise level generated by the whole assembly. A posteriori,proposing modifications to reduce noise. Transmission Path Analysis and acoustic photography in a large format plotter. Taj Mahal Project. (HEWLET PACKARD) Measurement of absorption coefficient (alpha energy) of different materials with Kundt tube. (TEXSA)Measurements of noise characterisation (acoustic impedance and absorption ratio) of differentmaterials from the company Texsa S.A., based on the specifications in the standard UNE-EN ISO 10534–2 for measurements with a Kundt tube according to the transfer function method. Acoustic study to reduce noise level an engine of Abamotor by designing of a new more effective muffler. (Tekniker-Abamotor) Assessment of potential noise impact, both internal and external facilities in Ashland. (Ashland Chemical Hispania SL) Study of the vibratory behaviour of machine-tool for RECMAN (APPLUS) Study of the dynamic behaviour of the production plant floor, PURAC Bioquímica, induced by the product elevator machinery. Proposal and calculations of the necessary modifications to correct this behaviour. (Technip Coflexip & Purac Bioquímica)
PROJECTS Noise emission study of automatic doors of a elevator. (SELCOM ARAGÓN)Carrying out an acoustic measurements and study following the TPA method on an automatic door ofelevator in order to diagnose the origin of noise. Besides, quantifying the noise contribution of each partof elevator that come of the overall noise. Propose solutions for reduce it. AUTOMOTIVE Interior noise reduction for a hybrid bus . (Castrosua)This study consisted of simultaneously measuring the vibration levels above the pump and its supportson the vehicle’s exterior as well as the acoustic pressure at various points in both the interior andexterior. This allowed diagnosing the causes of the noise transmission from its origin to its final receiverpoint. Finally, propose the optimal solutions for improving the bus’s acoustic quality. Acoustic study in order to characterize a reverberation chamber. (FICOSA) Measurement of the contribution to the overall noise of each one of the noise sources in the external points of CH-350 vehicle AUSA. Design solutions. (AUSA, Automóviles Utilitarios S.A.)
PROJECTS Study to reduce the noise levels generated by one of trailers carrying freight containers in Sant Boi de Llobregat, Barcelona. (Llinás e Hijos SL)Measurements of noise emitted by the trailer carrying both the empty container and full container andoperating at different appropriate distances. Propose solutions for reduce this noise level. Advanced Transmission Path analysis; contribution of the vibroacoustic sources the structure and air to the noise level perceived in the driver’s cab and at an external control point. (AUSA, Automóviles Utilitarios, S.A.)Evaluation of the contributions of the different subsystems of the model CH-150 to the noise received inthe driver’s position and in an exterior spot, with the aim of establishing the modifications that the vehi-cle needs in order to reduce the sound pressure level received in both points.Measurements with the vehicle stopped, following the TPA methodology, in order to know how muchnoise comes directly from the holes and how much comes from the structure vibration. Characterisation of the engine following the mobility method and source descriptor. Vibration power injected in the bodywork. (AUSA, Automóviles Utilitarios S.A.)Determination of the vibration power transmitted from the engine to the bodywork of the vehicle CH-150by AUSA, through the different points of attachment.Evaluation of the power transmitted by the main engine-bodywork points of attachment, using theMobility and Source Descriptor Method, which enables us to find a solution to reduce the currentvibration level.
PROJECTS Design of acoustic solutions for the final check cabins at the VW factory in Pamplona, Iruña. (Volskwagen) Complete vibroacoustic study of gear changes of the car (characterization, numerical modelling and design solutions). (FICOSA)Creation of a computer application in Matlab language, so that the user can use the data supplied tocalculate for the characterisation of the changes of gear and the representation of the results obtained.Full characterisation of a gear changing system that establishes the required modifications to achievethe vibroacoustic requirements that the client establishes for these mechanisms. Development of an Inversion Modelling Method to determine the panel contributions to the Ferrari 456 cabin noise at the mid-high frequency range. (FERRARI)Measurement of the sound pressure in different spots and in controlled working conditions of the Ferrari456. Application of the model inversion methodology with the aim of knowing the noise level of each ofthe interior surfaces, in order to treat them and to improve them with the modifications.