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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
www.mech.kuleuven.be/mod
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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
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who we are
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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
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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
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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
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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
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vibro-acoustics (2/2) • NVH of lightweight materials (metamaterials) • inverse material characterisation • gear dynamics – rattle/whine noise • sound synthesis • (rolling) tire dynamics
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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
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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
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multi-body dynamics (1/2)
• flexible multi-body dynamics for time-varying topology systems • (Parametric) Model Order Reduction (system level / component level)
• virtual sensing
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multi-body dynamics (2/2) • contact mechanics • gears and bearings (wind turbine drivetrains, industrial machinery)
• vehicle dynamics (impact of body flexibility on ride/handling)
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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
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• multiphysical simulation • (real-time) state observers (Kalman filters, MHE) • Hardware-in-the-Loop • model based control (IMC, MPC)
smart system dynamics (2/2)
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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)
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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
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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
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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
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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
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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 …
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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
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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
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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
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large subdomain
complex wave function
1 2
3
p
p
small element node simple shape function
WBM
FEM
Wave Based Method Basic formulations
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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
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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
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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
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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
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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
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• 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
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• 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
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WBM FEM
example – 2D interior acoustics
Wave Based Method Basic formulations
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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
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measurement FEM
measurement WBM
FEM and WBM: same computational efforts (40 sec/frequency)
3D interior vibro-acoustics
Wave Based Method
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35
HFE-WBM - acoustic
hybrid Method: best of two worlds
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Hybrid FE-WBM for 3D vibro-acoustics
hybrid Method: best of two worlds
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• 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
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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
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lightweight materials
motivation • lower weight • higher strength
price to pay • worse NVH properties • different (complex) dynamics
woven carbon fibre honeycomb panels composite panels
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similar stiffness, lower mass • fe1 • fg strongly reduced insulation
Static stiffness Mass Coincidence
Bending stiffness
Mass Damping
fe1 fg
lightweight materials: TL
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acoustic meta-materials
two major principles - inclusions - local resonators to create stopband behaviour
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resonant meta-materials
acoustic meta-materials
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resonant meta-materials
http://www.youtube.com/watch?v=NorFxojXo04
acoustic meta-materials
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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
![Page 45: KU Leuven – Noise and Vibration Research GroupKU Leuven – Noise and Vibration Research Group Wim Desmet Department of Mechanical Engineering Celestijnenlaan 300B – box 2420 3001](https://reader030.vdocuments.site/reader030/viewer/2022041008/5eb3ad8165243d4bce214b13/html5/thumbnails/45.jpg)
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
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• 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
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• front wall o steel frame o different sizes
o fully closed o A4 o A3 o A2 o A1
novel characterisation
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• 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
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JAXA standard TL facility vs. Sound Box 3mm Aluminum A2-size (simply supported vs. clamped)
comparison with TL facility
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acoustic absorption
comparison (random incidence in reverberation room vs KU Leuven test room)
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comparison (normal incidence in Kundt impedance tube vs KU Leuven test room)
acoustic absorption
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Contact
• Wim Desmet
Celestijnenlaan 300B – box 2420 3001 Leuven, Belgium +32 16 32 24 80 [email protected]
www.mech.kuleuven.be/mod