vibration & Acoustic testing
“Having equipped some of the
biggest vibration test facilities in
five continents, Siemens has
collected a wealth of experience”
engineers to perform the relevant
engineering analysis. This type of data
measurement and analysis can be done
with the Simcenter Testlab data analysis
software and the Simcenter SCADAS
acquisition system.
ACOUSTIC TESTING
For satellites and components, the vibroacoustic
test is a milestone for the
qualification campaign. In the space
industry, these tests have been historically
carried out in dedicated facilities called
reverberant chambers. A digital controller
in these chambers is needed to ensure that
the acoustic level and the spectrum reach
desired levels within the required
tolerances. The dedicated solution, the
Simcenter Testlab Acoustic Control, has
been added to the environmental products
family to supply a state-of-the art control
system ready for critical tests. The
Simcenter Testlab software offers
flexibility together with extra safety
options for engineers working in space
labs. It has been designed and developed to
consider all the necessary features for
providing lab engineers and technicians
with a comfortable system to carry out the
delicate job of qualifying the satellite to
acoustic loading.
Added features in the Simcenter Testlab
software, such as the definition of the
reference profile in an excel-editable table
format, a check-box to select which
microphone will be included in the loop for
measurement or setting any abort
parameters on both acoustic or vibration
channels, give peace of mind to the users.
The control system can also work using
multiple drives by simply setting the
bandwidth of each drive so that each
amplifier-modulator can be fed with an
optimized drive with the desired crest
factor value.
The control system has been conceived
to give full flexibility starting from a
previous drive, for example, from a lower
level test using the automatic control to
adjust the drives for each octave being
controlled; or by allowing the operator to
run tests in full manual mode with a
graphical equalizer to adjust the drive as
AEROSPACETESTINGINTERNATIONAL.COM // SHOWCASE 2020 37
1 // Simcenter also
provides Multi-Input-Multi-
Output control for Direct
Field Acoustic Noise tests
2 // The data acquisition
solution of Simcenter
Testlab and SCADAS is
engineered to acquire
and process online data
coming from hundreds
of different sensors
during vibe, pyro and
acoustic tests
The type and level of excitation to which
space hardware will be subjected to
depends on a number of factors. For
example, the spacecraft structure and
equipment should be capable of
withstanding the maximum expected
launch vehicle ground and flight
environments, and whether it can is
determined by running tests.
Simcenter testing solutions provides a
full suite for the mechanical
environmental testing of space hardware,
consolidating years of expertise and endusers
feedback from leading companies in
the space industry.
VIBE TEST
Simcenter Testlab Sine Control is a closedloop
control solution for swept sine
vibration tests. Together with the
Simcenter SCADAS hardware, it provides
an integrated feature for force and moment
limiting. Simcenter Testlab Sine Control
can realistically notch spacecraft
resonances and limit responses to protect
the spacecraft structure and hardware
from exceeding design strength
capabilities. The control system also
provides all of the necessary features to
define and control a random vibration
excitation that matches a predefined
power spectral density profile. Among
several safety features, it offers response
limiting and sigma limiting. The
implementation of a phase optimization
algorithm for sigma limiting with no
amplitude distortion and out-of-band noise
is an added value, compared to traditional
sigma clipping algorithms.
Simcenter Testlab Shock Control is a
time-domain control solution that can use
a previously measured pulse as reference
waveform, a classical waveform such as a
half sine pulse, or the result of a synthesis
for control. Simcenter Testlab Shock
Control offers a unique Shock Response
Spectrum (SRS) limiting algorithm for test
specimen protection and online SRS
calculation with a wide range of post-test
data analysis capabilities.
All closed-loop solutions have set trends
in the industry for safety features. Since
the first systems, installed over 20 years
ago, when a smooth ramp-down of the
voltage was used to reduce jolts in the ampshaker
system. Parameters have been
added to the software to create the most
flexible and safest vibration control system.
PYROSHOCK
A pyroshock is a very violent event
characterized by its short duration of a few
milliseconds and a high magnitude with
extreme acceleration levels. In the space
industry, pyrotechnic devices such as
explosive bolts are routinely used, for
instance, in the release mechanisms
employed for stage separation or payload
release. The resulting pyroshock event may
cause damage to the payload’s electronics
and may distort mechanical parts, such as
bearings, gears and worm wheels.
Because of the criticality of this type of
tests, given the impulsive nature of the
events (in the order of milliseconds), and
since a pyro event is unique, the aquisition
system must therefore be reliable enough
not to miss the event. It must sample high
enough frequencies, 200kHz is best
practice and it must process data very
quickly to provide engineers all relevant
information. Shock Response Spectrum
must be available at all instances to enable
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