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Vibro-acoustic modeling, analysis and
optimization using COMSOL Multiphysics
2017-11-22
Xiang YUFangsen CUI
AcknowledgementKui Yao (IMRE)
Zhenbo Lu, Eddie Lau (NUS)Xu Song, Wei Zhai (SIMTech)
HDB
Contents
• Building-Development of noise mitigation window
• Research-Acoustic metamaterial
• Material-Porous absorbing material
Interests & capabilities
Vibro-acoustic modeling; Noise and vibration control;
Architectural acoustics; Aerospace and automotive
engineering; Active noise control; Acoustic metamaterial
2
3
Ventilation window
Sound barrier simulation
HDB window
Sound transmission loss
of small aperture
Oldham, JSV, 1993
TL
(dB
)
Frequency (Hz)
Sound Reduction Index
Sound reduction index (SRI)𝑅 = 10 × 𝑙𝑜𝑔10(𝑊in/𝑊𝑜𝑢𝑡)
Indoor noise level𝐿𝑖𝑛 = 𝐿𝑜𝑢𝑡 − 𝑆𝑅𝐼 + 𝐶𝑟
4
Testing facility at HDB
Source room Receiving room
+ +
Outdoor noise level Window SRI Room correction
Why SRI is important?
Measuring window sound insulation
ISO-10140
Sound Reduction Index
5
10SRI 10log ( / ) W W
S R S RW W L L
/10
0 0
10( ) 10log
2
SL
W
S c
S
AL f
c N
Sound power of a diffuse room:
Predicting SRI using FEM:
Reverberation in source room
Prediction vs. Experiment
6Predicted SRI shows good agreement with full-scale experimental results
Experimental data from Delta acoustics, Denmark
Typical window
configurations
Active Noise Cancellation
7
ANC concept
Traditional loudspeaker Transparent speaker
Vs.
ANC configurationSimulation and experiment results
P1: Primary; P2: Secondary
ANC Target: P2 cancels P1 1 2' ( / )q q P P
8
Acoustic metamaterial
• Artificial structure
• Acoustic stop-band
• Negative effective parameters
• Sub-wavelength property
• Tunable performance…
Sheng et al.
Decorated membrane resonator
Both reflection & absorption
Fang, Nature materials 5, 2006
Periodic Helmholtz resonators
Physical Review B 85, 2012
3D periodic resonators
Nature communications, 2014
Wave modulation
Li and Assouar, APL 2016
Low-frequency absorption
9
Membrane-type acoustic metamaterial
Tunable resonator with dielectric elastomer prototype
Validation with different membrane pre-stretch ratio
Frequency shift with voltage
10
Membrane-type acoustic metamaterial
Membrane with distributed mass
Comsol simulation vs. experiment
Mechanism study-vibration mode
11
Acoustic metasurface
Fabricated sample
Metasurface for sound insulation
Transmittance Transmission Loss (dB)
Periodic waveguide
12
Metallic foam
0.754 0.7320 00
0.700 0.595 10 00
( ) [1 0.0571( ) 0.087( ) ]
( ) [1 0.0978( ) 0.189( ) ]
f ff j
f fc f c j
Impedance tube
IN625 Open-cell foam
tetrakaidecahedron pore
FEM model
Impedance calculation
Conclusions
• Comsol Multiphysics is a useful FEM tool to
conduct vibroacoustic research.
• Knowledge and experience is important to
build correct models.
• The Optimization Module and Application
Builder can be integrated to serve a wide range
of industrial projects.
13
14
If you have questions & needs about noise and vibration
control, acoustic product design, Please feel free to contact us:
Yu Xiang: [email protected]
Cui Fangsen: [email protected]
Thank you!
• Acknowledgment:
• Singapore Ministry of National Development and National Research
Foundation under L2 NIC award No. L2NICCFP1-2013-9.
• Metal Foam Designs with Acoustic Damping Properties: Experimental
and Simulation Studies, Inter-RI project with SIMTech