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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
[email protected] www.mech.kuleuven.be/mod
overview • who we are • 2 major research programmes :
o model based virtual sensing o metamaterials for lightweight NVH control
• resonant metamaterials for lightweight acoustic insulation
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
o Department of Mechanical Engineering • Division of Production engineering, Machine design and Automation
(PMA) • Noise and Vibration Research Group (MOD)
• research staff
o 5 academic and 1 associated o 1 industrial research manager o 11 postdoctoral researchers o 61 PhD incl. 10 industrial PhD res.
• areas of research application domains o vibro-acoustics o aero-acoustics o multi-body dynamics o smart system dynamics o structural reliability & uncertainty
- energy and environment - transport and mobility - health - advanced manufacturing
overview • who we are • 2 major research programmes :
o model based virtual sensing o metamaterials for lightweight NVH control
• resonant metamaterials for lightweight acoustic insulation
model based virtual sensing
• key drivers in mechatronic design: system reliability total cost of ownership
• important information in this context: dynamic loads and forces dynamic mechanical stress/strain energy/power flow system parameters …. often hard to measure directly …. Model Based Virtual Sensing to make this information available
model based virtual sensing focus technology:
coupled input/parameter/state estimators
that combine • real measurement signals • with virtual signals that are obtained from advanced high-fidelity
dynamic models, which are based on physical first-principles
model based virtual sensing model based virtual sensing
stress camera on a HONDA twist beam
model based virtual sensing model based virtual sensing
overview • who we are • 2 major research programmes :
o model based virtual sensing o metamaterials for lightweight NVH control
• resonant metamaterials for lightweight acoustic insulation
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 TL of lightweight materials
challenge Sound
Isolation
Novel Acoustic Insulation
resonant metamaterials
http://youtu.be/hMCfRHshjXc
What How Apply
Metamaterials with stop band behaviour
f2
f3
f1
... certain frequency zones do not propagate
Stop band behaviour
Tuned Vibration Absorbers
Mass
Damped Spring
Resonance Frequency
Power of metamaterials - example
Study average (RMS) displacement of plates under addition of tuned vibration absorbers (TVAs)
Localised input force
Power of metamaterials - example
Case 1 and 2: Same mass addition!
+20% mass (local)
+20% mass (spread) Target
Frequency [Hz]
Average Displacement
[dB]
Power of metamaterials – example 2 Larger plate
More input forces 2% added mass
Study effect of number of TVAs
Power of metamaterials – example 2
Power of metamaterials – example 2
Power of metamaterials – example 2
Power of metamaterials – example 2
1 TVA 240 TVAs
1 TVA 40 TVAs 240 TVAs
Stop Band
Target
Metamaterials: resonant additions
... on a subwavelength scale
What Blocked
Frequency Zones
Resonant Additions
How Apply
Unit Cell Definition
Unit Cell
Unit Cell Modelling 1. Make model of the unit cell
2. Find wave solution of the unit cell
3. Derive motion of infinite structure
Propagation Direction
Unit Cell Modelling
Mass ratio ↑
Resonance frequency ↑
Stop Band
Unit Cell Modelling what to remember
Stop bands are • due to resonant additions, • related to effective added mass, • driven by resonance of additions.
Unit cell modelling allows • quick estimation of stop bands, • deriving driving parameters, • fine-tuning of design in late stage.
240 TVAs x 20 x 12
Claeys, C. C., Vergote, K., Sas, P., & Desmet, W. (2012). On the potential of tuned resonators to obtain low-frequency vibrational stop bands in periodic panels. Journal of Sound and Vibration.
1 TVA 40 TVAs
Propagation Direction Propagation Direction
Infinite periodic structure
Unit cell
Stop Band Prediction
modelling
Propagation direction Dispersion diagrams
Unit cell Stop Band Prediction
modelling
Finite structure modelling
Propagation direction
Claeys, C. C., Sas, P., & Desmet, W. (Under Review). On the acoustic radiation efficiency of local resonance based stop band materials. Journal of Sound and Vibration.
What Blocked
Frequency Zones
Resonant Additions
How
Unit Cell Models
Driving Parameters
Apply
Application: lightweight structures...
Cover layer
(Hollow) Core
... good weight/stiffness, worse vibro-acoustic behaviour
Resonant inclusion
Mass
Spring
Mass
Spring
12.5 mm 12.5 mm
Metamaterial concept
Resonant Inclusions
Metamaterial demonstrator
Intelligent material use
15 dB additional noise reduction, no added weight
•
•
• Different shape
• Different resonator
• Combination of resonators
• Skin orientation
Numerical and experimental analyses •
Less wide/strong reduction •
No effect •
No effect •
Shift in stop band •
Multiple smaller bands •
No effect
• Less resonators
•
• Non periodic
Versatile concept Resonant structure
Hosting structure
Cover layer
Sound Isolation
Light Compact
Easy to Design
Metamaterials
some references metamaterials Claeys, C., Sas, P., Desmet, W. (2014). On the acoustic radiation efficiency of local resonance based stop band materials. Journal of Sound and Vibration, 333 (14), 3203-3213.
Claeys, C., Vergote, K., Sas, P., Desmet, W. (2013). On the potential of tuned resonators to obtain low-frequency vibrational stop bands in periodic panels. Journal of Sound and Vibration, 332 (6), 1418-1436.
Claeys C., Sas P. and Desmet W., Design of a resonant metamaterial based acoustic enclosure. ISMA2014-USD2014. Leuven (Belgium), 15-17 September 2014
Claeys, C., Vergote, K., Sas, P., Desmet, W. (2012). On the use of local resonators to obtain low frequency band gaps in the global response of finite periodic panels. . Inter-Noise 2012. New York City (USA), 19-22 August 2012 (art.nr. 939).
virtual sensing F. Naets, R. Pastorino, J. Cuadrado, W. Desmet (2013). Online state and input force estimation for multibody models employing extended Kalman filtering. Multibody System Dynamics, DOI 10.1007/s11044-013-9381-8.
F. Naets, J. Cuadrado, W. Desmet (2014). Stable force identification in structural dynamics using Kalman filtering and dummy-measurements. Mechanical Systems and Signal Processing, (in review).
F. Naets, J. Croes, W. Desmet (2014). An online coupled state/input/parameter estimation approach for structural dynamics. Computational Methods in Applied Mechanical Engineering, (in review).
F. Naets, F. Cosco, W. Desmet An extended Kalman filter approach for augmented strain/stress visualization in mechanical systems. In: Proceedings of the 10th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Application. Senigallia, Italy. 10 – 12 September 2014.
