sound & vibration testing
“The aerospace and defense
industry and its demand for
reliable and long-lasting
products has always been a
part of Brüel & Kjær’s core”
monitor structural integrity, and
maximize performance.
Brüel & Kjær offers a complete solution
to address experimental structural
dynamics purposes, with a full coverage of
the measurement and analysis chain, based
on BK Connect software, LAN-XI
hardware, modal shakers and/or hammers,
and transducers.
For large test specimens, often
associated with a large channel count, the
LAN-XI hardware platform allows the
set-up of distributed configurations by
chaining frames and/or standalone power
over Ethernet (PoE) modules to organize
the front-end location in an optimized way.
The benefits are many: fewer and shorter
cables, signal conditioning and A/D
conversion closer to the transducer. A great
variety of modules and front panels
completes the advantages of such a
platform by proposing different
conditioning modes, input types and
input numbers.
Our software offering is based on a
modern user interface, with tasks and
subtasks that are fully customizable. So, the
end user can organize the software to fit to
his own workflow. To improve productivity
and to reduce test campaign preparation
time, dedicated pre-test tools exist for
optimizing the test set-up based on finite
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element analysis (FEA) results. A variety of
excitation signals are also supported –
random, stepped sine and even userdefined
waveforms – for single or multiple
inputs test configurations.
Dedicated applications for structural
dynamic purposes, like time and frequency
domain Operating Deflection Shapes,
Experimental Modal Analysis, Operational
Modal Analysis, Structural Health
Monitoring and Test-FEA model
correlation, are available. Our feature-rich
applications include unique and patented
functionality to have the right tools at
hand in every given situation. Finally, our
software base is an open platform, with a
large variety of supported file formats, to
facilitate its integration in the customer
existing workflow.
MANAGING A SUBMARINE’S
ACOUSTIC SIGNATURE
In the cold, unforgiving world of the
submariner, the importance of acoustic
stealth cannot be underestimated. The
acoustic signature – the noise and
vibrations a vessel and its on-board
equipment and systems make in the water
– is a key concern for such vessels and
must be kept as low as possible to avoid
detection. Self-noise monitoring systems
are essential to manage the ship’s acoustic
signature and to ensure acoustic stealth.
Based on the PULSE scalable platform,
the Bruel & Kjær Self Noise Monitoring
System is made up of a network of COTS
equipment and includes sensors, DAQ and
vibration measurement and analysis
capabilities. Space on a warship is at a
premium, so the low footprint of the
solution is an important factor. The DAQ
units can be distributed throughout the
ship in small spaces, and the network
architecture provides installation
flexibility and radically reduces the
amount of sensor cabling throughout
the ship – providing a valuable cost and
weight reduction.
The acoustic signature is managed by
monitoring structure-borne vibration
and reviewing the vibro-acoustic
information. This helps ship staff to
control noise sources coming from
machinery, hydrodynamic noise and
propeller cavitation.
VTS
Brüel &Kjær is the only full solution
provider that can offer the complete
measurement chain – from excitation to
sensors and all the way through data
acquisition and evaluation. Shaker
excitation is needed when the natural
source isn’t available, or the test must run
under defined parameters or
environmental conditions. A great deal
of effort has been taken to ensure
that acquired data is accurate and valid
and repeatable.
An example of the many ways that Brüel
& Kjær leverages experience and
innovation to ensure quality measurements
is ensuring the isolation of the reaction
forces of the shaker body from the floor to
prevent structural damage on buildings.
Depending on system size and the type
of test applications to be undertaken,
shaker body isolation can be achieved in
several ways. Small shaker systems,
including small trunnion mounted
versions, used for testing small payloads
4 // Operational modal
analysis is ideal for flight
flutter testing using the
natural excitation as
unmeasured input
5 // Simulation data from
FEA can be used to
optimize the test setup
before performing a
ground vibration test
4
5
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