KU Leuven – Noise and Vibration Research GroupKU Leuven – Noise and Vibration Research Group Wim...

KU Leuven – Noise and Vibration

Research Group

Wim Desmet

Department of Mechanical Engineering Celestijnenlaan 300B – box 2420

3001 Leuven, Belgium +32 16 32 24 80

wim.desmet@mech.kuleuven.be

www.mech.kuleuven.be/mod

overview

• who we are • helicopter view on the major lab activities • novel vibro-acoustics modeling approaches • vibro-acoustics of lightweight materials:

– novel acoustic metamaterials – novel characterisation approach

who we are

4

www.kuleuven.be

www.mech.kuleuven.be

KU Leuven • founded in 1425 • 40000 students • 15 faculties, 50 departments • 62 academic programmes • 750 MEUR total revenues

Department of Mechanical Engineering • 4 divisions • 23 professors • 15 postdocs • 180 PhD researchers • 9 spin-off companies • 100-120 master students/year

who we are

team • KU Leuven

– Department of Mechanical Engineering • Division of Production engineering, Machine design and Automation (PMA)

– Noise and Vibration Research Group (MOD)

• research staff

– 5 academic and 1 associated – 1 industrial research manager – 9 senior postdoctoral researchers – 59 PhD incl. 10 industrial PhD res.

• areas of research application domains

– vibro-acoustics – aero-acoustics – multi-body dynamics – smart system dynamics – structural reliability & uncertainty

- energy and environment - transport and mobility - health - advanced manufacturing

overview

• who we are • helicopter view on the major lab activities • novel vibro-acoustics modeling approaches • vibro-acoustics of lightweight materials:

– novel acoustic metamaterials – novel characterisation approach

vibro-acoustics (1/2) • full-frequency numerical techniques

(WBM, FMBEM, acceleration techniques, (P)MOR)

• uncertainty and variability (fuzzy FEM, Lorentzian averaging, …)

• virtual sensing • transfer path analysis • Time Waveform Replication

COROT

Baffle

Secondarymirror

Primarymirror

Camera

onzekerheid

belasting

materiaal

niet-deterministisch resultaat?

?

?variabiliteit

? =

Y Z

X

vibro-acoustics (2/2) • NVH of lightweight materials (metamaterials) • inverse material characterisation • gear dynamics – rattle/whine noise • sound synthesis • (rolling) tire dynamics

aero-acoustics (1/2)

numerical analysis of low-Mach number confined flows • time domain DG schemes for LEE and LNS • finite volume LES schemes • stochastic noise reconstruction approaches • AA analogies (Lighthill, FW-H) • aerodynamic/acoustic splitting procedures

aero-acoustics (2/2)

• experimental analysis and characterisation: – (active) two-port characterisation of network components – directivity and sound emission – acoustic (pressure, intensity) and fluid dynamic (PIV, hotwire) characterisation – uniform (Rootsblower) and pulsed (cold engine) flow excitation

• impedance eduction of lightweight liner materials

multi-body dynamics (1/2)

• flexible multi-body dynamics for time-varying topology systems • (Parametric) Model Order Reduction (system level / component level)

• virtual sensing

multi-body dynamics (2/2) • contact mechanics • gears and bearings (wind turbine drivetrains, industrial machinery)

• vehicle dynamics (impact of body flexibility on ride/handling)

smart system dynamics (1/2)

• active and adaptive systems (suspension, bearing, exhaust)

• active noise and vibration control • Time Waveform Replication • MIMO control Passenger Cavity

Firewall

Engine Cavity

Acoustic

Source

• multiphysical simulation • (real-time) state observers (Kalman filters, MHE) • Hardware-in-the-Loop • model based control (IMC, MPC)

smart system dynamics (2/2)

structural reliability & uncertainty

• fuzzy FEM • identification of scatter in structural model parameter (interval

fields, random fields) • Structural Health Monitoring (bearings and gears) • multi-axial fatigue testing (torsion and bending)

infrastructure

• fully equiped noise and vibration lab • unique infrastructure:

6 DOF hydraulic shaker table Flow acoustic characterisation of duct systems

Open circuit aero-acoustic wind tunnel

Accelerated multi-axial fatigue experiments

Characterization of lightweight panels

Impedance tube Rolling element bearing test rig

torsional vibration gear test rig

17

computational and experimental facilities

COMPUTATIONAL • Hardware: LINUX clusters (in-house 11 nodes + Flemish VSC cluster >350 nodes) • Modelling and simulation software: LMS/Virtual.Lab, LMS/Test.Lab, LMS/Imagine.Lab,

MSC/NASTRAN, PATRAN, Fluent, MATLAB, UNIGRAPHICS, LABVIEW, …

MEASUREMENT FACILITIES • data acquisition systems LMS-DIFA (12ch), LMS-SCADASII (12ch), LMS-SCADASII (24ch), 3

LMS-SCADASIII (40 (+4) ch in, 6 (+2) ch out), LMS-SCADAS III Mobile (16 ch), LMS-PIMENTO (24ch), NI PXI-4472 (32ch), NI DSA4551 (2 ch in, 2 ch out), NI Crio (16ch)

• sensors: more than 300 accelerometers (PCB), more than 100 microphones (PCB, B&K), 4 impedance heads (PCB), multi-axial dynamometer (Kistler), force and pressure transducers, displacement probes, PU probe (Microflown), scanning laser-vibrometer (Ometron), laser vibrometers for translational and torsional vibrations (Polytec), acoustic intensity probe and analyser (B&K), holographic camera system (Vidispec), laser distance sensors (Baumer), CMM (Krypton K600)

• exciters: 12 electromagnetic shakers ranging from 10 to 2500N (The Modal Shop, B&K, MB, Unholtz-Dickie, Link), 6-DOF hydraulic shaker table (Team - Cube), LMS-Qsources Low-Mid Q-LMF and Mid-High Q-LHF volume sources, multi-loudspeaker simulation and reference sources

• signal conditioning equipment (analog and digital filters, digital signal processors, multi-channel ADC's, wave synthesizers....)

• MIMO Adaptive active noise and vibration control systems (dSpace1103, dSpace1104, dSpace 1006)

• semi-anechoic measurement room

some key numbers

September 2012 • 48 research projects (40% EU FP7 and COST) • 50 personal fellowships (50% Marie Curie, 25% IWT Flanders) • 10 industrial PhD’s (IWT Baekeland, Marie Curie or bilateral) • IOF Mandate – Dynamics and mechatronics: oxygen for an innovating industry • LMS Chair on Vehicle Mechatronics • Full list of projects: www.mech.kuleuven.be/mod/projects

• Spin-offs: LMS International, DAP/Co-Services, SoundTalks

selection of projects • EU

– EU FP7 ITN, EMVeM: Energy efficiency Management for Vehicles and Machines (coordinator) – EU FP7 EID, eLiQuiD: Best Engineering Training in Electric, Lightweight and Quiet Driving

(coordinator) – EU FP7 IP, ALIVE: Advanced High Volume Affordable Lightweighting for Future Electric Vehicles – EU FP7 IP, ENLIGHT: Enhanced Lightweight Design – EU FP7 CP, IDEALVENT: Integrated Design of Optimal Ventilation Systems for Low Cabin and Ramp

Noise – EU FP7 ITN, FLOWAIRS: Silent Air Flows in transport, buildings and power generation

– EU FP7 IAPP, INTERACTIVE: Innovative Concept Modelling for Multi-Attribute Optimization of Active Vehicles

– EU FP7 ITN, GRESIMO: Best Training for Green and Silent Mobility

– EU FP7 IAPP, Tire-Dyn: Experimental and Numerical Analyses of the Dynamic Behavior of Rolling Tires (coordinator)

– EU FP7 CP, ESTOMAD: Energy Software Tools for Sustainable Machine Design

– EU FP7 ITN, MID-FREQUENCY: CAE Methodologies for Mid-Frequency Analysis in Vibration and Acoustics (coordinator)

– EU FP7 ITN, VECOM: Vehicle Concept Modelling

• IWT - Flemish agency for Innovation by Science and Technology – IWT O&O project no. 120245, ALARM: Low noise design methodology for rotating machines – IWT Innovation Mandate no. 110590, PROTEUS: Simplified gearbox design variable assessment by

testing and simulation – IWT O&O project no. 110268, ASTRA: Advanced STRuctural Acoustics for lightweight structures and

advanced materials – IWT O&O project no. 110360, HEV-NVH: A new generation of NVH methods for hybrid and electric

vehicles – IWT Baekeland project no. 090290, Integration of model predictive control in vehicle development

• BELSPO - Belgian Science Policy Office – BELSPO - Interuniversity Attraction Poles, DYSCO: Dynamical systems, control and optimization

full list of projects: www.mech.kuleuven.be/mod/projects

partner network

Research cooperation network: – Industry: 3E, 3T, AIMEN, Agusta, Airborn, Airbus SP, Airbus UK, Akeryards, AleniaAermacchi,

Alma Space, AMAG, Asco, Atlas Copco, Audi, Autoneum, AVL, B&W, B+B, Barco, BASF, Bekaert, Benteler, BMW, Bombardier, BOSAL, BOSCH, BSR, CAF, CDM, CEA, Cedrat, CEIT, CG Power, CNH, CRF, CSL, Daimler, DANA-Spicer, Davin Optronics, DAF, Delphi, DDS, DLR, Donaldson, DoW, DSM, EADS Astrium, ECE, El Araby, Embraer, EM Diesels, ESA, EVA, Europower, Faurecia, FEV, FIDIA, FORD, Fos&S, G&G, GDM, Georg Fisher, Gilbos, Glafo, Goodyear, Hansen TI, Hexagon, Huntsman, Hyundai, ICOS, IDIADA, IFP, Imagine, Ipcos, Jaguar, JAXA, JOBS, JTEC, LAB, Laborelec, LMS, LTS, LVD, Magna Steyr, Marelli, Materialise, Melexis, Microflown, Microtest, Mitsubishi, Muller-BBM, MU Technologies, NanoGap, NI, Nissan, NITTO, Numeca, Onera, Optidrive, ORONA, Ostec, Oxeon, PCB, PE, Philips Electronics, Picanol, Porsche, Pratt&Whitney, PSA, Punch Powertrain, Qinetiq, Recticel, Renson, Ricardo, Ridley, Rofix, RWEnPower, Saint Gobin, Scania, SCIA Group, SEAT, Sener, Sispra, SKF, SNCF, SNT, SoundTalks, Swerea, Swidnik, Tata Motors, Technum, Techspace Aero, Tecnaro, Tenneco, TOYOTA, Toyota Motor Europe, Triphase, TVS Motor, TWI, UTC, VAN DE WIELE, Van Hool, VCST, Verhaert Innovation, Vestas, ViF, VHA, Voest Alpine, Volvo Trucks, VW, WindFix, Yamaha, ZF, ZF Wind

– RTO’s and Associations: Agoria, AIT, ASBE, AVERE, CEVAA, CIDAUT, CLEPA, CSL, CTTM, DLR, EAA, EARPA, EASN, EFFRA, ERTRAC, EUCAR, FLAG, Flanders’ Drive, FMTC, Fraunhofers (various), GENERATIES, IKERLAN, IMEC, ITIA, MIRA, NREL-GRC, OCAS, OWI, PASCI, Risø, SCK, SIRRIS, SP, Swerea, TNO, VALEO, VKI, VTT

– Universities: Aalborg, AAST, ASU, Auckland, Braunsweig, Bucharest, Cachan, Calabria, Cambridge, Chalmers, Cracow, Darmstadt, DTU, ECL, ETH Zurich, Ferrara, Firenze, Gdansk, Heidelberg, Helwan, ika, Imperial, INSA Lyon, isvr, ITA, KTH, LeMans, Lisbon, Liverpool, Ljublijana, Madrid, McGill, Napoli, Nile, Polito, Porto, Prague, RMIT, Rome, Thessaloniki, TU Berlin, TU Delft, TU Graz, Tue, TUM, UA, UCL, UGent, ULg, UNESP, UNSW, USP, Valencia, VUB, Warsaw, Warwick

And many more …

events

• biennial international conferences

– hard- and software exhibition – over 600 industrial and

academic participants – September 15-17, 2014

http://www.isma-isaac.be/

• two annual short courses – course on modal analysis testing

methods – course on advanced numerical

and experimental techniques in applied acoustics

– September 12-13, 2013

overview

• who we are • helicopter view on the major lab activities • novel vibro-acoustics modeling approaches • vibro-acoustics of lightweight materials:

– novel acoustic metamaterials – novel characterisation approach

mid- and high frequency technique: Wave Based Method

– enhanced convergence characteristics

• structural dynamics • vibro-acoustics • acoustic radiation simulations

frequency

low-frequency FEM, BEM

high-frequency SEA, EFEM

no efficient techniques available

Wave Based Method

large subdomain

complex wave function

1 2

3

p

p

small element node simple shape function

WBM

FEM

Wave Based Method Basic formulations

basic concept – 2D interior acoustics

Helmholtz equation:

2 20 , qp k p j r r q

Boundary conditions:

0

0

0:

:

:

0

0

p p

Z

v v n

n

Z

p rjp v r

n

p p

r R

r R

r R

r p r

p r p rjp

n Z r

Wave Based Method Basic formulations

Indirect Trefftz approach: approximation of the field variables by expansions of globally defined, exact solutions:

1

ˆ, , ,an

a a q

a

x y p x y p x yp

basic concept – 2D interior acoustics

)(p r

Wave Based Method Basic formulations

cos,

cos

ya

xa

jk y

x

xa

a jk

ya

k x ex y

ye k

acoustic wave functions:

Indirect Trefftz approach: approximation of the field variables by expansions of globally defined, exact solutions:

1

ˆ, , ,an

a a q

a

x y p x y p x yp

basic concept – 2D interior acoustics

)(p r

200,

4q q

qx y H krp

particular solution (point source):

Wave Based Method Basic formulations

cos,

cos

ya

xa

jk y

x

xa

a jk

ya

k x ex y

ye k

acoustic wave functions:

Indirect Trefftz approach: approximation of the field variables by expansions of globally defined, exact solutions:

(! solutions !)

22 2 2

2xa yak kc

k

requirement:

1

ˆ, , ,an

a a q

a

x y p x y p x yp

basic concept – 2D interior acoustics

)(p r

200,

4q q

qx y H krp

particular solution (point source):

Wave Based Method Basic formulations

field variable expansion:

with

wave function selection:

sufficient condition for convergence: convex domain

2 2

2 2

cos,

cos

xa

ya

j k k y

xa

aj k k y

ya y

k x ex y

e k

(n,m=0,1,…)

xa

x

ya

y

n

L

mk

L

k

)(p r

Lx

Ly basic concept – 2D interior acoustics

1

ˆ, , ,an

a a q

a

x y p x y p x yp

Wave Based Method Basic formulations

• Non-convex problem domains:

basic concept – 2D interior acoustics

p p

),(

I

• Domain partitioning into convex subdomains

• Continuity conditions imposed explicitly along : ),(

I

( ) ( ) ( ) ( ), 0I p p p rR r p

Wave Based Method Basic formulations

• non-convex problem domains:

• weighted residual formulation of the boundary and continuity conditions:

• → square WBM system of equations:

basic concept – 2D interior acoustics

p p

),(

I

• Domain partitioning into convex subdomains

• Continuity conditions imposed explicitly along : ),(

I

( ) ( ) ( ) ( ), 0I p p p rR r p

( , )

0

( , ) ( ) ( )

( ) ( ) ( )

( , ) 0v p Z

I

v p Z

I

p rjp r R p d R p d p r R p d

n

p r R p p d

a aA p b

Wave Based Method Basic formulations

WBM FEM

example – 2D interior acoustics

Wave Based Method Basic formulations

main properties of WBM models:

+ small model size + no accuracy decrease for derived variables + easy model refinement + reduced numerical pollution errors → high convergence rate - moderate geometrical complexity - fully populated, complex and frequency dependent matrices + complex and frequency system properties do not jeopardize WBM performance - complex numerical integrations - bad conditioning

WBM model properties

Wave Based Method

measurement FEM

measurement WBM

FEM and WBM: same computational efforts (40 sec/frequency)

3D interior vibro-acoustics

Wave Based Method

35

HFE-WBM - acoustic

hybrid Method: best of two worlds

Hybrid FE-WBM for 3D vibro-acoustics

hybrid Method: best of two worlds

• acoustic problems: – 2D + 3D bounded problems – 2D + 3D unbounded problems

• elastodynamic problems: – membrane problems – plate bending problems – non-coplanar assemblies – stress singularities

• vibro-acoustic problems: – 2D + 3D bounded problems – 2D unbounded problems

• poro-elastic problems: – 2D bounded problems – Stress singularities

Wave Based Method applications

overview

• who we are • helicopter view on the major lab activities • novel vibro-acoustics modeling approaches • vibro-acoustics of lightweight materials:

– novel acoustic metamaterials – novel characterisation approach

lightweight materials

motivation • lower weight • higher strength

price to pay • worse NVH properties • different (complex) dynamics

woven carbon fibre honeycomb panels composite panels

similar stiffness, lower mass • fe1 • fg strongly reduced insulation

Static stiffness Mass Coincidence

Bending stiffness

Mass Damping

fe1 fg

lightweight materials: TL

acoustic meta-materials

two major principles - inclusions - local resonators to create stopband behaviour

resonant meta-materials

acoustic meta-materials

resonant meta-materials

http://www.youtube.com/watch?v=NorFxojXo04

acoustic meta-materials

overview

• who we are • helicopter view on the major lab activities • novel vibro-acoustics modeling approaches • vibro-acoustics of lightweight materials:

– novel acoustic metamaterials – novel characterisation approach

novel characterisation

current test methods for trim characterisation (acoustic absorption, vibration damping, STL): • dedicated test rigs per quantity with dedicated acoustic

environment (diffuse, reverberant, normal incidence, ...) – allows simple models (diffuse field, planar field)

• limited frequency range (acoustic assumptions)

KU Leuven: • complex acoustic environment that allows a single shot

test rig. – requires complex (numerical) models – innovative simulation strategies

• acoustic cavity o compact (0.8m³, 3 ton) o concrete walls (40-50dB

noise reduction) o non-parallel walls (modal

distribution, diffuse from 3,3 kHz)

195

853

novel characterisation

• front wall o steel frame o different sizes

o fully closed o A4 o A3 o A2 o A1

novel characterisation

• excitation (air-borne and structure-borne) o full range speaker o hammer o electrodynamic shaker

• acquisition

o radiated sound intensity (intensity probe)

o structural velocity (Laser vibrometer / Microflown)

o acceleration (lightweight sensors)

o Sound Pressure Level (Mic In-Out)

novel characterisation

JAXA standard TL facility vs. Sound Box 3mm Aluminum A2-size (simply supported vs. clamped)

comparison with TL facility

acoustic absorption

comparison (random incidence in reverberation room vs KU Leuven test room)

comparison (normal incidence in Kundt impedance tube vs KU Leuven test room)

acoustic absorption

Contact

• Wim Desmet

Celestijnenlaan 300B – box 2420 3001 Leuven, Belgium +32 16 32 24 80 wim.desmet@mech.kuleuven.be

www.mech.kuleuven.be/mod