Transcript presentation Ilaria Corni

Real-time on-board
condition monitoring
of train axle bearings
Dr Ilaria Corni
The Stephenson Conference – Research for Railways
21st-23rd April 2015
Industrial-academic partnership:
• This work is a collaboration between:
• This collaboration started just over a year ago.
• The initial results achieved within this project are here
presented.
2
The Perpetuum WSN
• Bolt onto the bearing housing
• Self powered
• Tri-axial accelerometer
Schematic drawings of a wireless sensor node (WSN)
• Records data for 4 s every 3 min
• Data are sent wirelessly and in
real time to the cloud
Wheel
WSN
Sensor node
bolted to train
3
Southeastern trains
• Over 1000 miles of track
• Electrostar fleet
• 148 units
• 32 wheels per unit
• 1 sensor per wheel
Schematic of wheels on train
4763 sensors/
monitored bearings
Damaged bearings
5
Schematic of the project
Vibration
data
Analysis
Relationship
vibration-damage
Metrology
Damaged
bearings
Inputs
Failure
analysis
Activities
Mechanism and
progression of
damage
Outputs
6
Schematic of the project
Vibration
data
Analysis
Relationship
vibration-damage
Metrology
Damaged
bearings
Inputs
Failure
analysis
Activities
Mechanism and
progression of
damage
Outputs
7
Vibration data
In 4 s 192,000 data points are
recorded.
• rms X, rms Y, rms Z
• peak X, peak Y and peak Z
• Bearing Health Index (BHI)
• Wheel Health Index (WHI)
Speed of the train
Direction of travel
8
Example of vibrations
Vibrations for a good
wheel and a good
bearing for 1 month
all over the
Southestern track
• 6,900 data points for each variable.
• The vibrations in X and Y are higher than in Z.
• The vibration changes from point to point.
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Vibrations are affected by:
• Conditions of the rail
Load path
Load
• Wheel conditions
Bearing
• Bearing conditions
• Loading during turning
• Speed of the train
Wheel
Rail
Bearing position respect to
wheel and rail.
10
Filtering of the data
Most of these variables are
eliminated using:
• only one part of the track
Tonbridge
• only one side of the train
Baseline characteristic
for a train, that
particular part of the
track and that
particular time
Scheme of a train
Ashford
International
11
For geometrical reasons we use rms X.
12
After filtering:
• 210 journeys.
• Speed profile highly
reproducible.
• General rms X profile
for good bearings and
Tonbridge
good wheels
• This is independent
from the position on the
train.
• The vibrations still vary
very much
Ashford
International
13
Examples of vibrations (1)
11 days
48 days
5g
7g
14
Examples of vibrations (2)
The 3 examples show that vibration
grows at different rates.
62 days
5g
There is not an obvious relationship
between visible damage and:
• Highest vibration value
• How long the vibration differs
from the baseline
Better characterization of the
damage is required.
15
Schematic of the project
Vibration
data
Analysis
Relationship
vibration-damage
Metrology
Damaged
bearings
Inputs
Failure
analysis
Activities
Mechanism and
progression of
damage
Outputs
16
Damaged bearings
Bearing inner ring and spacer
No RCF of inner ring or rollers
Showing outer ring
with 95 mm RCF on
inboard raceway
Showing debris/
flakes in grease on
cage and rollers
17
Surface Profilometry (Talyrond)
5.23.13.23
5.23.13.23
Modified
Profile
Roundness
MI Circle with RONv
RON/MI Circle/None/
19/03/2014 16:37:27
20mm - W orn Area
360°/Admin/TR 595
19/03/2014 14:43:04
90°
180°
200
100
100
0
MI Circle
None
-100
micrometres
RONv
Pa
Difference
delta R -7.357µm
delta Theta 45.00°
-200
-300
-300
µm
489.59
-400
-400
-500
-500
-600
0°
270°
-100
Spindle
-200
Parameters
-600
180
Reference Point
R 0.000µm
Theta 0.00°
Current Point
R -7.357µm
Theta 45.00°
20/03/2014 08:50:09
19/03/2014 14:43:04
0
Specification
Reference Type
Filter Type
Datum
Wear Area - P/149.981mm/LS Arc
20mm - Worn Area - 360°/Admin/TR 595
200
•
•
•
•
Z Position
R Position
Attitude
Contact Direction
Contact Speed
•
•
micrometres
Scale 0.2mm/div.
65.1476
190
200
210
220
230
240
250
260
270 280 290
millimetres
300
310
320
330
340
350
360
370
µm
5 line profiles in the rolling direction
Length of damage
Max depth of damage
Roughness (Ra) and other metrology
parameters
Area worn
Harmonics
Conditions
95.000
92.694
0.5
mm
mm
Vertical
R Positive
mm/s
18
Surface Profilometry (Talyrond)
19
Computed Tomography (CT)
3D image produced by
collating all the slices 1 mm
apart
Example slice
420 kV at 143 µA, using 6 mm
of copper filtration. 200 ms
exposure per line with 1801
projections (lines) per
20
sinogram (slice).
Symonds N. et al. http://dx.doi.org/10.1016/j.engfailanal.2015.02.008
21
Volume missing
Calculated by Talyrond:
Average area loss of the 4 traces * 40 mm = 1162 mm3.
Calculated by CT:
Missing area of each slice measured
using Fiji.
The total volume missing = 1245 mm3.
Difference between the two methodologies = 7%
22
Schematic of the project
Vibration
data
Analysis
Relationship
vibration-damage
Metrology
Damaged
bearings
Inputs
Failure
analysis
Activities
Mechanism and
progression of
damage
Outputs
23
Relationship vibration-damage
• Filtered vibration
• Comparison of vibration
up to removal
•
•
•
•
Volume loss
Profile parameters
Damage length
Area missing
With more examples we will possibly be able to find a
relationship
24
Conclusions and further work
The relationship between vibration and damage is very complex.
Vibrations
Filtering of the data
Extreme value statistic
Damage
Quantify the damage
Progression of the damage with CT and failure
analysis techniques
25
Thank you for listening
Dr Ilaria Corni
[email protected]
Study funded by the EPSRC IAA support