AEROSPACETESTINGINTERNATIONAL.COMAPRIL 2015 |^93
Supplier interview z
BELOW: Quick and accurate identification
of in-cabin sound sources through array-
based techniques (Photo: Belgian Defense)the environmental requirements for
lighter, greener and more eco-friendly
aircraft. For example, the new
composite structure definitely reduces
the weight, but this weight reduction
typically has a negative impact on the
aircraft’s acoustic performance.
Finding the balance between
conflicting requirements is a day-to-
day issue for acoustic engineers.
WHAT TYPES OF NEW TECHNOLOGY
ARE AVAILABLE FOR ON-GROUND OR
INFLIGHT ACOUSTIC TESTING?
There are some exciting developments
to help engineers meet these tough new
noise level targets and make the right
choices, acoustically speaking. One
solution is a specific array-based
technique that has been developed
in partnership with a major aircraft
integrator for interior sound source
localization. The system is based on a
3D rigid sphere acoustic camera. The
sphere contains numerous integrated
microphones, which span the entire
3D space and detect noise sources at
any location around the sphere. The
results are strikingly fast, yet offer
unprecedented insights into noise
source localization and source
ranking for selected frequencies
and configurations. Many customers
say it’s a real shortcut to optimized
cabin comfort. Most only need a few
minutes of flight testing, instead of
several hours, to create a precise
sound profile of the aircraft interior
and clearly identify realistic paths
for acoustic optimization. It is also
a speedy troubleshooting tool and it
keeps expensive inflight testing
to a minimum.
CAN YOU GIVE SOME MORE EXAMPLES FOCUSING ON
ACOUSTIC TESTING?
Well, I can’t name names, but we have customers who
manufacture small business jets and they have very high
expectations regarding acoustic comfort. Low sound
transmission from exterior sources, such as the engine and
turbulence noise to the cabin, is very important. The acoustic
and vibration teams were looking for tools to help identify
acoustic weak spots and analyze sound transmission inside
the cabin during flight. They also needed a tool to improve and
validate the experimental setup for panel transmission loss.
Our high-definition acoustic camera solution has proven
to be a superb tool. Its ‘point and shoot’ functionality
delivers quick feedback on the acoustic performance
to identify and quantify acoustic weak points inside
the aircraft cabin or inside the transmission loss room.
But our acoustic work goes further. Recently, a customer
completed an extensive acoustic and vibration study on a US
aircraft carrier in compartments under the flight deck to
reduce noise levels and prevent overexposure to the soldiers
due to aircraft launch operations. On the flipside, we also
helped a military aircraft manufacturer quantify pilot noise
exposure during various flight conditions. An extra-small LMS
SCADAS system with 12 channels was attached directly to the
pilot’s body to accurately acquire data from several microphones
positioned at the pilot’s ears and various locations inside the
cockpit. It verified that no excessive noise levels occur in the
cockpit and that the pilot could operate safely.
Here is another one: flyover noise measurements. These
are now a mandatory step in the certification process for a
new aircraft. Noise is measured at specific locations on the“A SYSTEM WITH 12 CHANNELS
WAS ATTACHED DIRECTLY TO
THE PILOT’S BODY TO
ACCURATELY ACQUIRE DATA
FROM SEVERAL MICROPHONES”ground while the aircraft flies over it
and follows a well-controlled trajectory.
The data acquisition system must be
integrated into a fully certified process
that is approved by the certification
authorities. The SCADAS system has
been approved for this type of testing.
Based on testing and extensive
validation work, the data acquisition,
analysis, recording and reproducing
system complies with the technical
standards of International Civil
Aviation Organization Annex 16,
Volume 1, Fourth Edition, Appendix 2.WHERE DO YOU SEE THE FUTURE
OF AIRCRAFT TESTING?
Certainly, safety remains the key
priority in the aviation industry,
but market demands, such as better
fuel economy, increased comfort,
reduced emissions and noise levels,
and lower operating costs, will
continue to force the aircraft industry
to rethink traditional engineering
methods. Successful development
programs must deal with new
materials such as composites, new
technologies, more control systems,
and overall much more inter-system
complexity. Not to mention staying
within budget and on schedule.
The end goal is to achieve the earliest
possible aircraft maturity. To succeed,
we see a continuous need for integrated
simulation and testing throughout the
development process. This is why we
constantly work on developing faster
and better simulation and testing tools
to provide more in-depth engineering
insight to help OEMs, integrators and
suppliers design the best possible
aircraft of the future. zFREE READER INQUIRY SERVICESiemens PLM Software(^) To learn more about this advertiser, visit http://www.ukipme.com/info/tea NOW!
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