Tuned Mass Damper for Rail Noise and Corrugation Control

Wilson Ho, Banting Wong

Wilson Acoustics Limited

Tuned Mass Damper for

Rail Noise and Corrugation Control

1

第五屆兩岸三地聲學技術交流研討會

2Year 2004

3

4

How can it work with such

thin layer of metal? ? ?

5

Test Site Damper Type Track Condition Measured Noise Reduction Performance

Hong Kong Alom @10u8 Resiliently Booted Sleeper <1dBA

Hong Kong Vossloh (not specified) <1dBA

Portland [3.1] Shrey & Veit Concrete Sleeper on Ballast Track Noise increased by 1-2dBA due

to resonance of mounting

Netherland [3.2]

Alom @10u8 Concrete Sleeper on Ballast Track 1.6dBA for Freight Trains

0.5-1.1dBA for Passenger Trains

0.8-1.1dBA for Intercity Trains

Shrey & Veit HSL Concrete Sleeper on Ballast Track 2.2dBA for Freight Trains

0.6dBA for Passenger Trains

1.2dBA for Intercity Trains

Shrey & Veit Modified

Concrete Sleeper on Ballast Track 1.3-2.2dBA for Freight Trains

0.5-0.6dBA for Passenger Trains

1.0-1.7dBA for Intercity Trains

Silence Project [3.3]

Corus Silent Track (not specified) 5.6dBA for trains fitted with wheel

dampers

Germany [3.4] Corus Silent Track Concrete Sleeper on Ballast Track 1.6-3.5dBA

Austria [3.5] Calmmoon Concrete Sleeper on Ballast Track 2-4dBA (To be verified)

Rail Dampers Performance

Shrey & VeitVolkerRail (Corus)

Wilson Acoustics Limited www.wal.hk

6

Vossloh

SEKISUI STRAIL asticWilson Acoustics Limited www.wal.hk

Rail Dampers Performance

Effective (3 to 10dB) only at High Frequency (>700Hz)

Ineffective (1 to 2dB) at Low Frequency (<500Hz)

Material Damping - broadband but only effective at high frequency

Tuned Mass Damping -Effective at Mid & Low freq (<1000Hz)

But narrow band and single direction


8

Working Principles

Material Damping (Hysteresis disipation)

Rail vibration displacement is very small, in the order of μm

Small strain in damping material small energy dissipation

Effective at high frequency only (>1000Hz)

Broadband absorption

Tuned Mass Damping

Absorber, m2

Rail, m1

k2

k1 c1

c2



Tuned Mass Damping

Absorber movement is amplified and anti-phase.

Energy is dissipated by hysteresis higher amplitude, more dissipation

Effective for mid & low frequency (<1000Hz), and narrow bandwidth


WAL Rail Damper History

→ 2nd Prototype (2007)

Vibration absorption for both rail foot and web

Absorption to both vertical and lateral vibration

Multiple resonance frequency

Attach to rail by magnets, 1 to 2kN adhesive force

↑1st Prototype (2006)

Tonal saloon noise at curve track

Tuned Mass Damper with single resonance

Absorption to rail web vibration

Attach to rail by magnets


WAL Rail Damper History

← 3rd Prototype (2008)

2 clamping clips

~5kN clamping force

→ 4th Prototype (2009)

3 clamping clips

~12kN clamping force

Structural components are strengthened to sustain ~40kN force


WAL Damper 1st Trial at KTL in 2010 (50m)

14

WAL Rail Damper 2nd at Trial in 2012 (100m)

15

WAL Rail Damper Characteristics

TMD Shear direction oscillation

Each oscillation mass response to

both lateral and vertical vibration

Large oscillation mass for low

frequency vibration control

Multiple Frequency Tuning

for broadband vibration control

Reduce rail noise radiation

Rail Corrugation Control

(1st reported evidence in the world)


Damper Frequency Tuning800Hz

400 &

800Hz315Hz

630Hz

1000Hz

12

2

11 eqt

bM

GAf

where

G is dynamic shear modulus of the resilient layer

A is the surface area of resilient layer

b is the thickness of the resilient layer

M is the oscillation mass

Frequency Rubber Type Dimension

315Hz 55o Neoprene 40 x 45 x 1.25 mm

400Hz &

800Hz

55o Neoprene 50 x 55 x 1.25 mm

55o Neoprene 50 x 56 x 1 mm

630Hz 55o Neoprene 40 x 40 x 1 mm



Mechanical loss factor is chosen to be 0.1 ~

0.5 to cover the entire vibration bandwidth.

Resilient Layers


17



19Vibration of every mass is always anti-phase and amplified.


Vibration of every mass is always anti-phase and amplified.

Collaboration with MTR to Investigate

Noise reduction and corrugation control


21

MonthJul

2010Aug 2010

Sept 2010

Oct 2010

Nov 2010

Dec2010

Jan 2011

Feb 2011

Mar 2011

Apr 2011

May2011

Jun 2011

Week 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

Saloon Noise

Dam

pe

r In

sta

lla

tio

n

Rail

Gri

nd

ing

Trackside

Noise &

Vibration

Track Decay

Rate

Rail

Corrugation

Laboratory Testing Resonance frequency and damping ratio is checked for

every oscillation mass by impact test


22

In-saloon Noise Measurement


24

25

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

Sa

loo

n N

ois

e L

evel

LA

eq,

dB

(A)

Time from Train Start (s)

Saloon Noise Level Time History

Before Damper Installation (4 months after grinding)

1 Day after Damper Installation (4 months after grinding)

2 Weeks after Damper Installation (4 months after grinding)

Tra ns ition R=380 R=300Tra n-s ition

R=42

5Tra ns ition

Tran-s ition

Damper Section

R=380 R=300 R=425

In-Saloon Noise Measurement Result

5dB

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

Salo

on

No

ise

Lev

el L

Aeq

, d

B(A

)

Time from Train Start (s)

Saloon Noise Level Time History

Before Damper Installation (4 months after grinding)



6 Months after Damper Installation (2 months after grinding)


Tra ns ition R=380 R=300Tra n-s ition R=425 Tra ns ition

Tra n-s ition

Damper Section

R=380 R=300 R=425

In-Saloon Noise Measurement Result (Time History)

5dB

26

27

In-Saloon Noise Measurement Result (Noise Spectrum)

31.5 63 125 250 500 1000 2000 4000 8000 16000 dB(A)

Sal

oon

Noi

se L

evel

LA

eq,0

.5s, d

B(A

)

1/3 Octave Band Frequency, Hz





1 Day before Damper Installation (4 months after grinding)

In-saloon Noise Spectrum LAeq,0.5s during passage of the middle damper section

5dB

28

In-Saloon Noise Measurement Result (Noise Level Reduction)

Wilson Acoustics Limited www.wal.hk Damper Section, 50m

Tunnel Reverberation Noise

Measurement DateTime after Damper

Installation

Months from Last

Grinding

Noise Reduction,

dB(A)

22 / 07 / 2010 Before Installation 4 months N/A

26 / 07 / 2010 1 Day 4 months 2.7

11 / 08 / 2010 2 Weeks 4 months 2.8

25 / 01 / 2011 6 Months 2 months 2.5

24 / 06 / 2011 11 Months 7 months 1.7

With a sufficiently long section of rail dampers, saloon noise

reduction is anticipated to be around 4dB(A).

Track Vibration Measurement


29

Track Vibration Measurement Result

- Average vibration level at high rail


30

Vertical vibration levels

reduced by 5~7dB(A).

Lateral vibration levels

reduced by ~10dB(A).

5dB 5dB

5dB


- Vibration Level at Sleeper Block


31

Sleeper block has a

resonance peak at 300Hz.

The rail damper has little

effect on the sleeper

resonance.



32

Due to higher track decay rate with damper, rail vibration

level drops by 40-50dB between to bogies.

Vertical vibration time history at 800Hz

1st Bogie 16th Bogie

10dB

Rail Corrugation Measurement by CAT


33

34

0

5

10

15

20

25

13.30 13.31 13.32 13.33 13.34 13.35 13.36 13.37 13.38 13.39 13.40 13.41 13.42

RM

S R

ou

gh

nes

s (μ

m)

Chainage (km)

low rail 25/1/11 (2months after grinding) low rail 2/3/11 (3months after grinding)

low rail 7/5/11 (5.5months after grinding) low rail 10/6/11 (6.5months after grinding)

Damper Section Control SectionTransition

SectionTransition

Section

R=380m to R=300m

Train speed = 72km/hR=300m to R=380m

Train speed = 72km/h

Curve radius = 300m


Curve radius = 300m


Figure 7-2: Overall roughness (wavelengths of 10–160 mm) along Low Rail

Rail Corrugation Measurement Result


35

0.1

1

10

Overall

10-160mm

160mm

125Hz

125mm

160Hz

100mm

200Hz

80mm

250Hz

63mm

315Hz

50mm

400Hz

40mm

500Hz

31.5mm

630Hz

25mm

800Hz

20mm

1000Hz

16mm

1250Hz

12.5mm

1600Hz

10mm

2000Hz

RM

S R

ou

gh

nes

s (µ

m)

1/3 Octave Band Wavelength (mm)

Low Rail - With Dampers 10/6/11

Low Rail - W/O Dampers 10/6/11

High Rail - With Dampers 10/6/11

High Rail - W/O Dampers 10/6/11

ISO 3095

TSI Limit

(freq. corresponds to train speed 72km/h)

1/3 Octave band roughness 7 months after grinding


36

WavelengthRMS roughness at low rail (µm)

Without dampers With dampers % reduction

80 mm (250 Hz) 6.32 1.76 72.2%

63 mm (315 Hz) 7.48 4.40 41.2%

50 mm (400 Hz) 3.44 3.09 10.2%

Overall 10-160 mm

(125 – 2000 Hz)10.86 6.03 44.5%

Comparison of corrugation with and without dampers 7 months after grinding

Rail roughness at the damper section is found lower than that at

the control section, particularly at 50mm, 63mm & 80mm.


37


38

0

2

4

6

8

10

12

24/11/2010 24/12/2010 24/1/2011 24/2/2011 24/3/2011 24/4/2011 24/5/2011

RM

S R

ou

gh

ness (

µm

)

Grinding on 24/11/2010 Corrugation Growth Region

The linear equations are curved fitted using data from 2/3/2011

Roughness at wavelengths of 50mm, 63mm and 80mm from 4/11/2010 to 10/6/2011

Corrugation growth approx. linear and independent of

original roughness.


Conclusions

39

Shearing TMD Rail Damper invented by WAL

Two trials in 2010 and 2012 in Hong Kong

Trackside noise level reduced by ~4dB(A)

In-saloon noise level reduced by ~3dB(A)

Rail vibration levels reduced by ~8 - 10dB(A).

Corrugation growth rate reduced by 45%

(The 1st evidence reported in the world)

Hope to have more trials & applications outside Hong Kong.

Reference

1. Wilson Ho, Banting Wong, David England, Alson Pang and C.W.S To, Reduction of

Corrugation Growth Rate by Rail Dampers (To be published in TDHRail Magazine Nov 2012

Issue)

2. Wilson Ho, Banting Wong, David England and Alson Pang, Tuned Mass Damper for Rail

Noise and Corrugation Control, Proceeding of Aoustics 2012

3. Wilson Ho, Banting Wong and David England, Tuned Mass Damper for Rail Noise Control,

Noise and Vibration Mitigation for Rail Transit System, NNFM Vol. 118, page 89-96, Springer-

Verlag Berlin Heidelberg 2011

THANK YOU


40

Documents

Tuned Mass Damper for Rail Noise and Corrugation Control