High-speed cameras
section of the aircraft. If they were able to prove that
simulations could accurately predict the damage to the
aircraft section, then they could use simulations for fullscale
testing.”
Both Boeing and Airbus were able to show
simulations can accurately predict damage sustained
during a crash. Furthermore, crash test simulations can
also give engineers a level of detail impossible with
physical tests, says Olivares.
“We’re working on developing human body models so
we can better understand the injury mechanics,” he says.
“Because with the level of complexity contained in some
of these mathematical models, we can look at the crash
impact right down to the level of organ tissue and bones.”
Another major advantage virtual testing offers is the
possibility for near-infinite variability in the parameters
of the test, says Olivares. Unlike with physical tests,
planes crash-tested in simulations can be dropped onto
any type of terrain and in any type of weather condition.
“Simulation is going to bring us to a more real world
understanding of the requirements because right now
with the physical testing we’re working in a very
constrained way,” he says.
The structural analysis techniques that inform the
models were first developed for the automotive sector.
Olivares says that while aerospace is generally
conservative when it comes to changes to flight safety – a
fact that he attributes to the heightened risk of fatalities
30 DECEMBER 2019 \\ AEROSPACETESTINGINTERNATIONAL.COM
VIRTUAL CRASH-TESTING
One of the most important steps in the use
of simulation technologies for crash testing
is convincing regulators that digital models
can accurately mirror reality.
At the National Institute for Aviation
Research (NIAR) in Wichita State University,
USA, proof-of-concept work is applying
simulations to real-world examples.
Recently this was done with an accident
reconstruction of a Turkish airlines 737 that
crashed on its approach to Schipol airport in
2009 with the loss of nine lives.
“We selected this accident to do a
reconstruction because we had already
carried out a drop test on a 737 section for
the FAA, so we already had the data on how
it behaves under impact,” says the Gerardo
Olivares, director and senior research
scientist at NIAR.
Olivares’ team built a virtual
reconstruction of the full aircraft using the
laboratory test data.
“At the end we compared the structural
deformations to see if our simulation
matched what actually happened.”
Olivares’ team found that the models
accurately predicted the damage to the
crashed 737’s airframe.
associated with plane crashes – there is a growing
understanding within aviation that the future of flight
testing is virtual.
Tacit recognition of this can be found in Advisory
Circular 20-146A, a document that the FAA put out in
2018 which offers guidance for certifying seats using
computer modelling.
“The circular allows OEMs who are certifying
aircraft to use simulations to identify worst case
scenarios and then run physical tests on those worst
cases. Whereas in the past they were required to run
tests for multiple conditions,” says Olivares. \\
Wichita. The Institute is set to move to a
new facility on the university campus
early in 2020.
VIRTUAL TESTING
While the new facility will continue to
carry out physical crash tests, Olivares
says that the NIAR is moving increasingly
towards virtual testing using computer
simulations. “Once we can convince the
authorities that the models are
predictable, the idea is to replace full-scale
physical testing,” he says.
He predicts that it will take around 15
years to spread the simulation models
currently being used in their labs
throughout the aviation industry.
Although, as Olivares notes, testing with
simulation models is already happening.
“When they started building the Boeing
787 and Airbus A350 out of composite
materials, the FAA was worried that they
wouldn’t have the same safety standards
as metallic airframes. So, they tried to get
the two OEMs to carry out full-scale drop
tests, but they refused,” he says.
“In the end they came to an
agreement that they could drop test a
4 // Researchers prepare
crash test dummies inside
the Fokker F-28.
“We can look at the impact down
to the level of organ tissue”
/AEROSPACETESTINGINTERNATIONAL.COM