Ho 2012- TMD for rail noise and corrugation control ppt.pdf

TMD presentation in 2012

1. Wilson Ho (presenter), Banting Wong
Wilson Acoustics Limited
David England, Alson Pang
MTR Corporation
TUNED MASS DAMPER FOR
RAIL NOISE AND CORRUGATION CONTROL

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2. CONTENT
Introduction
Rail Damper Design and Working Principles
Measurement Schedule
Measurement Apparatus and Standard
In-saloon Noise Measurement
Track Vibration Measurement
Rail Corrugation Measurement
Conclusion
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3. INTRODUCTION
New Tuned Mass Damper has been developed to reduce
Rail vibration
Noise radiation
Rail corrugation
A project was launched to investigate the effect of rail
dampers in an operational metro railway.
This presentation/paper presents the research findings.
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4. RAIL DAMPER DESIGN
Comprise multiple oscillating masses sandwiched by
resilient layers.
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Oscillation
Masses
Resilient
Layers

5. RAIL DAMPER DESIGN
3 MAJOR DESIGN FEATURES
1. Oscillation along shear directions of resilient layers.
Vibration absorption in both vertical and lateral direction.
Allows greater oscillation amplitude thus better vibration absorption.

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Oscillation
direction

6. 2. Gap filling material with high viscosity and low compressibility.
Static compressive mounting force → flexible solid, deformed to fill up the
movement gaps at the mounting interfaces.
Dynamic train excitation force → stiff solid, provides high adhesion force and
allows vibration energy to be effectively transferred.

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7. 3. Resilient buffer layers
Prevent structural damage of mounting components for exceptional high
vibration >12kN.
Provide restoring force after severe vibration.

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8. RAIL DAMPER WORKING PRINCIPLES
Direct Damping (Hysteresis dissipation)
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.
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9. RAIL DAMPER WORKING PRINCIPLES
Tuned Mass Damping
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Absorber, m2
Rail, m1
k2
k1 c1
c2

10. RAIL DAMPER WORKING PRINCIPLES
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RAIL DAMPER WORKING PRINCIPLES
Tuned Mass Damping
Absorber movement is amplified and anti-phase.
Energy is dissipated by hysteresis → higher amplitude, more dissipation
Effective for low frequency vibration (<1000Hz), and narrow bandwidth

11. Wilson Acoustics Limited www.wal.hk
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RAIL DAMPER WORKING PRINCIPLES
Tuned Mass Damping

12. Wilson Acoustics Limited www.wal.hk
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RAIL DAMPER WORKING PRINCIPLES
Tuned Mass Damping

13. MEASUREMENT SCHEDULE
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Month
Jul
2010
Aug
2010
Sept
2010
Oct
2010
Nov
2010
Dec
2010
Jan
2011
Feb
2011
Mar
2011
Apr
2011
May
2011
Jun
2011
Week 27 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
Rail Grinding


Damper Installation


Rail Grinding

 
Trackside
Noise &
Vibration
   
Track Decay
Rate
 
Rail
Corrugation
         

14. IN-SALOON NOISE MEASUREMENT
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15. 02468101214161820222426283032343638404244464850
Saloon Noise Level L
Aeq
, 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)
6 Months after Damper Installation (2 months after grinding)
11 Months after Damper Installation (7 months after grinding)
Transition
R=380 R=300
Tran-
sitionR=425
Transition
Tran-
sition
DamperSection
R=380 R=300 R=425 IN-SALOON NOISE MEASUREMENT RESULT (TIME
HISORY)

5dB
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16. 16
IN-SALOON NOISE MEASUREMENT RESULT
(NOISE SPECTRUM) 31.5 63 125 250 500 1000 2000 4000 8000 16000 dB(A)
Saloon Noise Level L
Aeq,0.5s
, dB(A)
1/3 Octave Band Frequency, Hz
11 Months after Damper Installation (7 months after grinding)
6 Months after Damper Installation (2 months after grinding)
2 Weeks after Damper Installation (4 months after grinding)
1 Day after Damper Installation (4 months after grinding)
1 Day before Damper Installation (4 months after grinding)
In-saloon Noise Spectrum L
Aeq,0.5s during passage of the middle damper section

17. 17
IN-SALOON NOISE MEASUREMENT RESULT
(NOISE LEVEL REDUCTION)
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Damper Section, 50m
Tunnel Reverberation Noise
Measurement Date
Time 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).

18. TRACK VIBRATION MEASUREMENT
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19. TRACK VIBRATION MEASUREMENT RESULT
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75
80
85
90
95
100
105
110
115
120
125 250 500 100020004000dB(A)
Average Rail Vibration Level, dB(A) re 10nm/s
1/3 Octave Band Center Frequency, Hz
High rail web, without damper
High rail web, with damper (1st day)
High rail web, with damper (2nd week)
Under high rail, without damper
Under high rail, with damper (1st day)
Under high rail, with damper (2nd week)
Average vibration level at high rail
Overall vertical vibration
levels ↓7dB(A).

Overall lateral vibration
levels ↓10dB(A).

20. TRACK VIBRATION MEASUREMENT RESULT
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Sleeper block has a
resonance peak at 300Hz.

The rail damper has little
effect on the sleeper
resonance. 70
75
80
85
90
95
100
105
110
115
120
125 250 500100020004000dB(A)
Average Sleeper Vibration Level, dB(A) re 10nm/s
1/3 Octave Band Center Frequency, Hz
Average, without damper
Average, with damper (1st day)
Average, with damper (2nd week)
Vibration level at sleeper block

21. TRACK VIBRATION MEASUREMENT RESULT
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Due to higher track decay rate after damper
installation, the rail vibration level drops by 40-50dB
between to bogies.

Vertical vibration time history at 800Hz 60
70
80
90
100
110
120
130
0 1 2 3 4 5 6 7 8 9 10
Rail Vibration Level, dB(A) re 10nm/s
Time (s)
Without damper 800Hz
With damper 800Hz
1
st
Bogie 16
th
Bogie

22. RAIL CORRUGATION MEASUREMENT
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23. RAIL CORRUGATION MEASUREMENT RESULT

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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
RMS Roughness (µm)
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

24. RAIL CORRUGATION MEASUREMENT RESULT

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Wavelength
RMS 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.

25. RAIL CORRUGATION MEASUREMENT RESULT

25 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
RMS Roughness (µm)
Grinding on 24/11/2010
Corrugation Growth Region
Thelinear 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.

26. CONCLUSIONS
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After damper installation on the test site,
In-saloon noise level reduced by ~3dB(A)
Overall vertical and lateral track vibration levels reduced
by 7dB(A) & 10dB(A).
Corrugation at wavelengths 50mm, 63mm & 80mm
reduced by 10%, 41% & 72%. Overall corrugation
growth rate reduced by 45%.

27. THANK YOU