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

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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

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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

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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

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Membrane-type acoustic metamaterial

Tunable resonator with dielectric elastomer prototype

Validation with different membrane pre-stretch ratio

Frequency shift with voltage

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Membrane-type acoustic metamaterial

Membrane with distributed mass

Comsol simulation vs. experiment

Mechanism study-vibration mode

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Acoustic metasurface

Fabricated sample

Metasurface for sound insulation

Transmittance Transmission Loss (dB)

Periodic waveguide

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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.

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If you have questions & needs about noise and vibration

control， acoustic product design, Please feel free to contact us:

Yu Xiang: yuxiang@ihpc.a-star.edu.sg

Cui Fangsen: cuifs@ihpc.a-star.edu.sg

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