2-A Non-Contact Precision Measurement System for Dynamic

Report
iMetrum Video Monitoring
www.datahawk.com.au
Brisbane
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Rockhampton
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Townsville
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Sydney
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Wollongong
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Melbourne
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Hobart
● Adelaide ● Darwin ● Perth
DATAHAWK
DataHawk was established by UPG in 2013 in answer to the growing challenge in the rail
industry to increase efficiency and customer satisfaction all while minimising costs.
Alongside Trimble we recognised a real opportunity to focus our technology in the rail
industry.
DataHawk’s solutions span all stages of railway development and management including
planning and analysis, design and construction, safety and maintenance and project
operations.
DataHawk is Trimble’s only authorised distribution partner for rail technology in Australia
and PNG.
www.datahawk.com.au
Non-contact precision measurement for dynamic
structural monitoring
New Video based technology is the perfect solution to precision displacement
measurement of structures and geotechnical engineering projects. The ongoing need to
understand the health and welfare of valuable items such as Buildings, Bridges and
Tunnels is ever more prevalent within the strategies asset management teams both within
the public and private sectors. As cost of maintaining these asset increases over time so
has the pressure to develop more efficient and productive methods for collection of asset
knowledge.
The iMetrum Non-Contact Displacement Gauge Technology enables sub millimetre
displacement and deformation detection making it an ideal solution for monitoring
structures.
The History of Video Measurement
First Known Example is
the Tacoma Narrows
Bridge in 1940
There are a number of
companies offering
laboratory type
solutions.
iMetrum is the only
commercially available
video gauge tailored to
external use
Increasing use by
researchers from 1980s
onwards with iconic use
in crash testing autos.
Principals are used in
motion capture, optical
computer mice and DIC.
What we do
Creation of the iMetrum Video Gauge
iMetrum is a spinout of the Bristol University
with the technology first commercially available
in 1970. Technology first used in structural
monitoring of the Humber Bridge & Severn 2nd
crossing UK.
Class-leading resolution has resulted in a strong
uptake within aerospace industries
Material testing 2/3 of business, Structures 1/3.
Our Technology
Imetrum have developed & patented specialist software that measures movement in
materials and structures highly accurately in real time.
The system is a point to point and full-field optical measurement system - we use pattern
recognition technology and sub pixel interpretation of video images – ie non-contact.
UKAS Calibration to BS/EN/ISO 9513, class 0.5 and ASTM (E83) calibration to class B-2.
Resolution and frame rate are camera and setup dependent – for standard system, reliably
>1/100,000 of the lens Field of View (FoV) eg. 0.1mm resolution for a 10m FoV.
Resolutions of 1/2,000,000 of FoV can be achieved with an appropriately constructed
system.
Completed extensive comparative trials with other optical and traditional techniques with
Airbus, NPL & Strainstall.
3D measurements possible (multi-camera systems).
Videos & data can be stored for analysis later, or processed and transmitted in real time
(over 300Hz).
Proving the Technology
Year long project lead by UK National
Measurement Office (NPL).
Comparisons with conventional and new
methods.
Use in various weather conditions.
Proving the Technology
iMetrum setup 45m away in car park
Resolution of 0.02 mm.
Testing at night.
Real Word Application/ Strain Mapping
Rail Bridge Strain Mapping
Used for Monitoring Track, Monitoring Structures and during manufacture and
testing of components.
Displacement of Rail
Dynamic deflection monitoring of
track, sleepers & ballast.
Information on ground
movement, track displacement /
bending, gauge separation.
Measurements taken at
distance, under train loading.
Displacement of Rail
Graphical Display of Processed Data.
Dynamic
response of
various parts of
the track bed
identifiable.
Resolution
much better
than 0.1mm.
Tunnel Monitoring
Convergence & Ring Separation.
Track Monitoring within tunnels.
Demonstration project with Cross
Rail / ongoing.
250 measurement points, with 4
cameras.
Infra-Red lighting used, so no
obvious visible clue of monitoring
ongoing, and no negative impact
of work lights.
Measurement resolutions of
0.1mm
Remote access to equipment,
and live reporting of results
Tunnel Monitoring
Tunnel Monitoring
Graphical
display of
extensions over
3 month
monitoring
period.
Bridge and Structures
Dynamic Testing
under normal
traffic conditions,
and also specific
Load Testing.
Access costs
minimised, and
resolution
increased over
other noncontact
techniques.
Bridge Monitoring
4
3
6
1
2
5
Interpreting the Data
Graphical display of rotation data
Pattern of movement
closely matches,
suggesting primary mode
of rotation is as a rigid
body, rather than pivoting
around centre
Interpreting the Data
Graphical display of rotation data
Rotation approximately
mirrored, suggesting there
is a second mode of
rotation around the centre
line of the bridge.
From analysis, magnitude of Western deflection 6% greater than Eastern deflection
Vibration Analysis
One of the most common research applications for Imetrum system within Civil
Engineering.
Suspension Cables and Conductors.
Hard to access pipe work.
Vibrating machinery and components
Component Testing
Many automotive, power, aerospace & defence customers.
Easily scalable by using different lenses.
Use for a wide range of measurements including:
Strength of complex structures.
Crack growth investigation.
Structural deflection.
Deformation during heating & cooling.
Impact testing.
Conclusions
A flexible system, offering potential for substantial time & cost savings.
Turn up and measure solution for a wide range of structures.
Potential for extremely high resolution.

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