vital outcomes so far
DESCRIPTION
Vital outcomes so far. tools to identify curving and rolling noise sources and allow prescription of reliable mitigation methods and to manage them. A standard process to select mitigation strategies based on costs and benefits. Motivation for Research. Rail noise issue now recognised - PowerPoint PPT PresentationTRANSCRIPT
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Vital outcomes so far• tools to identify curving and rolling noise
sourcesand
• allow prescription of reliable mitigation methods and to manage them.
• A standard process to select mitigation strategies based on costs and benefits
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Motivation for Research– Rail noise issue now recognised– Noise barriers are a “blunt instrument”– Some aspects are relatively simple to address by:
• changing operational procedures: yard noise; horns; idling • standard industrial noise control: locomotives, traction equipment • Vibration isolation: vibration reducing track
– but other aspects not simple, requiring research:• Curve noise • Noise source identification• tools to communicate cost / benefit of noise control
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Major Tools Now Available1. Curving noise
a. Mechanism identification: On-board and Trackside located.b. Standard definitions.c. Key mechanisms consolidated leading to effective mitigation.d. Mitigation method evaluation.
2. Rolling noisea. Noise prediction software (RRNPS) is now available, calibrated to Australian situations.b. Noise separation algorithm to direct mitigation method selection and management.c. A scientific method for evaluating potential mitigation strategies is now available.
3. Cost / benefit analysisa. A standardised approach to benefit and cost identification.b. A step by step guide to noise mitigation and management.c. Advice on the effectiveness of potential noise mitigation methods.
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General Process
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General Process
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General Process
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Curve Noise Mechanisms
Conventional theory
• Curve squeal– Lateral sliding
between the Inner wheel tread and rail head
• Flanging noise– HIGH rail flange
contact
New understanding
• Curve squeal– Flange contact on both
rails– Wheel tread on top of
both rails
• Flanging noise– HIGH and LOW rail
flange contact
8
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Curve Noise Mitigations (1)
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Curve Noise Source Identification (2)
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connection between bolster and carbody
connection between bolster and sideframe
connection between sideframe and axlebox
Vehicle Dynamics Modelling
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AOA of the Leading Axles by varying centre bowl friction and warp stiffness
new half-worn fully-worn-20
-18
-16
-14
-12
-10
-8
-6
A3
A2
AO
A o
f th
e le
ad
ing
axl
e(m
rad
)
friction wedge worn condition
centre bowl = 0.33case A1-A3 centre bowl = 0.5, case A4-A6 centre bowl = 0.1, case A7-A9
A1
A4
A5
A6
A7 A8A9
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1. The major influencing factors increasing AOA are, in sequence:• the centre bowl friction• the warp stiffness• the friction coefficient of sidebearers and• the preload of sidebearers • Rail gauge corner lubrication makes the leading wheelset AOA becomes
larger
2. The worst combination of bogie parameters in regards to AOA is• high centre bowl friction level combined with• low warp stiffness due to wedge rise.
17th July 2012
Summary
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RRNPS Rolling Noise Prediction
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Noise and Roughness Separation-Set Up
Ballast
Sleeper
Rail
Pad
A1
A2
A3
A4 A5R1, 2
O1, 2
Stick
7.5m
A1, 2
R1 R2
A3, 4
A5
O1 O2
M1
M2
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Field Trial - Noise Separation Method
102
103
20
30
40
50
60
70
80
Frequency(Hz)
So
un
d P
resu
re L
eve
l(d
B r
e 2
0 P
a)
Total radiationVehicle radiationRail radiationSleeper radiation
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Field Trial – Roughness Separation Method
31.5 20 12.5 8 5 3.15 2 1.25 -30
-25
-20
-15
-10
-5
0
5
10
15
20
Wavelength(cm)
Ro
ug
hn
ess
(dB
re
1 m
)
Total roughness variation rangeTotal roughness mean valueRun 1Run 2
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Economics of Noise Mitigation Strategies
Figure 1: Major "Players" and Transactions that Affect Rail Management
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What it means for you• NOW we have the tools to identify curving and
rolling noise sources• CAN use the tools to allow prescription of
reliable mitigation methods and to manage them.
• HAVE a standard process to predict or diagnose noise sources and select mitigation strategies based on costs and benefits