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VIBROACOUSTIC LABORATORIES

SCS-Euroacoustic

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EUROACOUSTIC laboratoryopen on 2001 to deliver Noiseand VIbration services andtroubleshooting toTransportation industry.It is today within a group of over40 people (SCS_DETES con-sortium) to offer full-service tocustomers in a Full-outsourcingof an overall project or part of it.

Acoustic modeling, N&V full characterisation, Trouble shooting, Productsdefectology and Quality Assurance, Product Certification, Education andTechnology transfer, etc.

Consulting and Services

Noise and Vibration Applications knowledge

Contents

A brief introduction

what we doNoise and vibration research, measurements, analysis, sim-ulation, services on:Vehicles and automotive

Bus, train, city trainAerospace, helicopters

Household appliancesElectrical motors

Compressor and pumpsFan and airflow systems

Building materialsTextile and foam raw materials

Sintetic resin and derivativesEnvironmental control

SCS-Euroacoustic

Vehicle interior noise, Airborne insulationEfficiency of chassis elements and of trim materialsAcoustic transparence, Force to Noise ratioVehicle cabin Reverberation time, Acoustic powerNoise path analysis, Sound qualityTroubleshooting on full vehicle or componentsExhaust acoustic emissionAcoustic HolographyEngine mount filtering, Modal AnalysisAsynchronous rotation (Torsional)Exhaust dynamic suspensionVibration confortAbsorption coefficient of trim materials, Flow resistance of porous materialsLoss factor of damping materials, Materials researchCompetition analysis, Standard criteria assuranceBench marking

Noise and Vibration Consulting

Standard testing:

Cabin noise on road and onchassisPass-by testAirborne noise study: body partswith and without insulating mate-rials – P/PSound power, Sound insulationand Sound absorptionReverberation time inside pas-senger compartmentFRF Force/NoiseElastic suspension effectsTorsional vibrationExhaust systems dynamic char-acterizationRide comfortInput energy prediction

NVH laboratory (2.000 square meters):

Semi anechoic chamber with bench dynamometersSemi anechoic chamber faced with reverberant roomAccessories and in plant services Complete set of modern instrumentationScientific softwareBench marking toolingSkilled operators and R&D engineers

ServicesNoise and Vibration Consulting

Design and Engineering:

Technical center:Equipped with workstation from IBM, Hewlett Packard, SiliconGraphics, Sun, Design environment:EDS - Unigraphics, Computervision - Cadds5, PTC - ProEngineer, Matra Datavision - Euclid, IBM Dassault - Catia, Alias. Calculation softwares:I-Deas, Hypermesh, Aries, Nastran, Abaqus. Virtual reality:Matra Datavision - Megavision, Division -DVreality.

Testing and Troubleshooting:

NVH testing on chassis-dynamometer within 12 x 5m anechoic chamberVibration testing and compo-nents qualificationI-deas workstation for modalanalysis and noise-pathanalysis Head Acoustics and Cortex systems for Sound Quality SCS Material testing apparatus suitePortable multichannel analyzers for N&V analysis Acoustic holography systemListening room

EUROACOUSTIC delivers research services and testing in Acoustic,Noise and Vibration fields to: Transportation industry, Automotive,Aerospace, Components Suppliers, etc.; with specific focusing onvibro-acoustic materials characterization.

Automotive NVH

Simulation

Products know how:

MaterialsTechnologiesDesign

Function know how:

MeasurementsInstrumentsSoftwareModelling

Bench marking:

“Target setting” for new carComplete developmentmethodologies Development of insulatingFEM analysisComplete assistance on“Diagnosis groups”

Services

Sound quality

Modal analysis

System approach:

Complete study of thevehicleProblem solvingInput data to interfacesuppliersMaterials characterizationand use optimization

Noise and Vibration Consulting

Gearbox

Exhaust flex junction

Some Experiences:Exhaust sound quality Shaft torsional vibration Road testing for tire noise, exhaust, vibration comfort Mechanical transmission noise reduction Shift leverage noise Motor bike chassis modal analysisMaster errors correction Safey belts rattling noiseFuel supply pump defects determination Power windows motor noise controlClimatic system dumper actuator efficiencyBracking material squeals controlStearing wheel vibration reductionSqueak & Rattle and noise sources identification

Components development and testing

ServicesNoise and Vibration Consulting

Motorbike chassis

Suspension

Safety belts

Brakes

Vibration Testing

Windows motor

Radiator fan

Vibration Testing

Certification ofMaterial proper-ties:

Flow Resistance,Porosity andTortuosity ofporous materialsAlfa coefficientmeasurementYoung ModulusBulk elastic ModulusDamping Loss Factor Transmission loss measurementCharacteristic Impedance on plane wavesMaterial Data base porting to most common simulationsoftwares: ESI, LMS, MSC, etc.

Acoustic Materials observatory

Transportation

City train interior noise

Household

Services

High Speed vessel propeller studies

Washing machine

Chiller modeling

Noise control certification

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Noise and Vibration Consulting

Case histories

Light Truck Pass-by Noise Modelling with Boundary Elements Method

One of the first studies performed on automobile pass-by and internal noises, adopt-ed a hybrid method involving source identification and numerical analysis, achievedthrough a partnership between SCS and other partners: a major Acoustic materialmanufacturers and a firm performing analysis and design, providing solutions forautomobile manufacturers. SCS was charged to perform numerical analysis of theacoustic and vibration expertise and experimental analysis development; the objec-tive of this study was to improve the acoustic behaviour of a light weight truck. The important outcome of this study and its partners is that relevant solutionsand improvements were investigated with a numerical model (based on theCAD model) of the van before a prototype was available.

The project was conducted in 2 phases: 1. A complete investigation was conducted on an existing van in order to vali-date the hybrid method contained in Rayon Solver (I-deas components) inwhich the experimental part consisted of: pass-by noise, engine noise radiationand internal noise measurements. 2. The second phase was the acoustic design of the new light truck with anumerical model by using the engine source of the existing van (the newengine was not yet available). Results were then updated when the new enginewas characterized. A proper source model of the engine was derived by using anInverse Boundary Element scheme involving experimental data and a boundary ele-ment model of the engine defined as a set of prescribed acceleration surfaces.Once the engine noise model has been derived, the Pass-by Noise is computed byusing the standard Variational Boundary Element Method.

Pass-by Noise estimated at 300 Hz

Engine Noise Modelling with Boundary Elements Method

A simplified BEA model of the engine is built using 442 Linear quadran-gular elements sufficient to perform calculation up to 1300Hz (accordingto a 4 elements per wavelength mesh criterion). The model is subdivid-ed in 18 surfaces defined as prescribed acceleration pistons. Theground is taken into account as an infinite rigid plane. At this stage,transfer functions (Hik) between measurement point pressure (i) andeach panel acceleration (k) are derived by using BEA solver. Then, theequivalent engine source model is achieved by finding panel accelera-tion auto interspectra (Akl), which minimize the error between experi-mental pressure spectra (Sijexp) and those derived from the model(Sijnum). This task is performed by using a Linear Least squares mini-mization technique. The total energy by summing all the autospectra ispredicted with an error less than 0,5dB. Localresult comparison shows discrepancies lessthan 2dB at harmonic peaks.

Engine modelling mesh

Engine noise results:calculated (top) andmeasured (bottom)comparison (150 Hz)

Noise and Vibration Consulting

Case histories

Air conditioning external unit (chiller) SEA noise modelling

At the design stage of a new chiller and in order toachieve a possible noise reduction, it becomes nec-essary to study the emission sources/causes andseparate the airborne radiation from the structureborne radiation (compressor vibration). The existingCAD has been used to build a simplified SEA modelfrom which the influence of the structure born compo-nents have been identified. As a first result of thestudy, it was the inconsistency of increasing themass of the insulation enclosure around the com-pressor, because the vibrational excitation wouldhave neglected the theoretical result; in effect it wasclear that a suitable damping material will give amuch better noise reduction.

Chiller modeling

Noise emission increased (red line) byadding vibrational components onheavy mass enclosure

Noise emission increased (green line)by adding vibrational components onlight mass enclosure

FEM model to SEA model

Body in white

The goals of the project were to finalize a methodology of noisereduction possibilities by creating a specific materials data-basefor SEA simulation, to be used to optimize weight of added trimsduring car new models development. Materials acoustic charac-teristics have been determined with SCS 902A materials suiteand with direct measurements on car subsystem (trunk andabitacle) of specific characteristics, i.e. sound absorption andinsulation.The car subsystem is then analyzed in terms of modal density,stiffness and damping, the later was related to the real need ofdamping materials addition vs. efficiency in terms of noise reduc-tion.Experimental data on body in white elements have been used totune the SEA simulation model of the car, while further on, thematerials data-base has been merged to the SEA model toobtain a “real” and validated development model fo prototyping.

Car Noise reduction using SEA

Noise and Vibration Consulting

Case histories

Acoustic design of a new trucks (Ovatex-Iveco)Acoustic insulation on cars based on Acoustic Olography (Ovatex-Fiat)Research on insulation materials (Ovatex)SEA Modelling: complete acoustic package design (Lear-FIAT, IRAN KHODRO)On Road Noise Measurements: tire, exhaust, vibration comfort(Bridgestone, Ovatex, Lear, Flexider, Euroacoustic)Experimental Structural Analysis of Space Transducer (CERN Geneve)Agriculture vehicles sound quality studies (Ovatex-Same)Improvements of gearbox noise (Carraro)Noise reduction of gearbox leverage (Fiat)Structural studies on pile foundations and Fatigue studies of motorways bridges(Sicec)Damping Materials characteristics on ship bridges (Fincantieri)Civil Structural damage by Railways (Ferrovie Suzzara, ATM Torino, FS NationalRailways)Environmental Noise Impact from Railways city tunnel (FS National Railways)Electrical Lifter Noise characterization (Carraro)Earth moving machine noise reduction (Case)Helicopter shaft defects definition (Iran Aircraft Industry)Test bench for dynamic stiffness of flexible coupling (Fiat Research Center,Flexider)Automatic control of a decoking tower in petrochemical plant, based on noiseemissionPower plants noise emission monitoring system (AEM Torino)Anechoic chambers design and manufacturing (Fiam, Ovatex, Itrac, Euroacoustic,Askoll)Projects based on vibration and/or noise emission of:

Air Collectors (Magneti Marelli)Refrigerators (Electrolux)Washing machines (Electrolux)Electrical motors (Electrolux)Common Rail Injectors (Fiat Research Center)Security belts (TRW)Gearboxes (Graziano Trasmissioni, Ferrari cars, Iveco, Euroricambi, IranKhodro)Seats (Lear Corporation, Johnson Control)Turbine blades (Ansaldo Energia)Gas Valves (Sit la Precisa)Automotive Electronic Devices - Vibration screening test bench (Facet)Vibration absorbers (Integra - Fiat)

Some Projects and Examples

Noise and Vibration Consulting

Sede operativa e rappresentanze locali

EUROACOUSTIC s.r.l.10051 Avigliana (Torino)Via Gandhi, 13Tel.:+39.011.9348705Fax:+39.011.9348703

SCS-AVINTECH35011 Campodarsego (PD)Via Antoniana, 278Tel.: +39.049.9200975Fax: +39.049.9201239

SCS Controlli e Sistemi20090 Cesano Boscone (MI)Via R.Sanzio, 5Tel.:+39.02.45864250Fax:+39.02.45864091

SCS Controlli e Sistemi00192 RomaVia Vigliena, 10Tel.:+39.06.3610954Fax.:+39.06.36001107

Il Vs. agente locale: