Page 5 - Dallara_ENG

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design the crash structures according
to the limits set by the rulebooks in
terms of shape and dimensions, the
structural calculus office, which do all
the calculations, the composites
development office, which define and
develop the best process to produce
them, and the assembly department
that usually prepares the structures for
real-life testing.
What is the role of computer
In Dallara we've been analyzing
the passive crash components for
many years, I'm talking about the
chassis supporting the nosecone and
the lateral cones. Over this time we
developed a robust way of calculating
things and identified optimized
solutions to analyze and define the
lamination. This enables us to create
structures that not only pass the crash
test with flying colors but are also
light and performance-oriented once
on the car. In the last few years we
started to concentrate on the
simulation of proper composite crash
structures. It's a borderline and really
complex activity because we're talking
about many physical reactions tough
to describe and depending on the
speed, the geometry, the kind of
material used. In addition to that
we're talking about materials in which
we have three different directions, all
with a different behavior, and the
structures are multi-material ones.
There's no need to say that the
problems we're facing aren't easy to
approach. In order to conduct these
studies in a more efficient way, we
started to co-operate with some
specialized laboratories. Altair, the
software house that provides us with
the calculation software, has been
deeply interested in the question and
we started a successful co-operation
with them.
The simulation today has a key
role in how a test is performed
because it allows to build structures
able to perform in the real world in
the same way that was expected. With
the less complicated structures, the
simulation is so reliable that the crash-
tests are conducted directly in front of
the officials without prior testing.
Does simulation bring room for a
further developments?
There are a lot of frontiers that
can be opened by simulation. For
example, the ability to represent
crashes with composite materials
opens the road, in the automotive
field, to the use of composites where
aluminium was used before, while in
racing we can push beyond in studying
the shape of the nose as we can
analyze the possible interaction of two
cars during a contact.
Are the tests conducted in the Dallara
The Dallara factory is provided
with an R&D department where we do
all the static tests on the chassis (roll
bar deflection and push-off tests are
the most common), in addition to
some crash tests on smaller
components (steering columns etc).
The tests on the crash-absorbing
structures are generally conducted
outside in specific laboratories that are
specifically accredited and certified. In
order to complete a frontal impact test
we need an environment longer than
50 meters with sophisticated launch
and data acquisition systems. Due to
the high cost, it's not financially viable
to develop an internal laboratory.
Can you take us through the steps of a
crash test from when the parameters
are set to the moment when the
conclusions are drawn?
Usually it all start from the
aerodynamics department as they
define the crash structure or at least
the volume that they are expected to
fit in. This phase features a tight co-
operation with the crash test specialist
that study the possible outcome of a
crash involving a specific shape. At
that point, the technical department
design the component and the tools
needed to build it. Then we move to
the crash test simulation where we
define the basic parameters of the
structure (thickness of the sidewalls,
number, size and orientation of the
carbon skins and so on…). We define
the production procedures for the
structure that we need to build. In
practice, three days before the date
scheduled for the crash test, we start
to assembly the chassis with all the
needed parts. We mount the fuel tank,
the safety harness, the battery, the fire
extinguisher and all the other
components that can have a role in a
crash. Then we start with the first
static tests (typically to prevent the
detachment of the structures from the
chassis in the event of a crash) and
move to the laboratory certified for
the selected test. Right after the test,
we evaluate the deceleration curves to
analyze if the limits set by the rules
are met, and we also analyze the
videos that have been recorded. The
crash is a matter of a few tenths of a
second, and an high-speed video is
needed to see what happened in each
moment in order to evaluate the
structure's performance.
Who decides what are the standards to
be met?
It's usually the technical
rulebook which defines the types of
crash tests to overcome and the
specific requirements. More advice can
come from the Dallara experience in
terms of engineering and production
in order to find a solution that can not
only pass a crash test but also be
functionally optimized (aero, weights,
“there are a lot of frontiers that can be opened by simulation.
For example, the ability to represent crashes with composite materials
opens the road, in the automotive field, to the use of composites
where aluminiumwas used before”