In order to reduce delays of development of new vehicles, PSA
has been using since 1998 a strategy based on sharing conception
into several and hierarchical steps (V cycle). At the very
beginning of a project, when only a few information are known,
classical (and complex) FE models are replaced by simplified
models, composed of sets of springs and loads elements containing
properties (flexion, compression, shear) equivalent to complex FE
pieces.
Up to now, these simplified models are created using FE models
of vehicle with approximately same architecture. Sets of spring
elements and properties are adjusted in order to reproduce FE model
behavior. When simplified models behavior is judged representative
of the physics, they can be used for conducting many investigations
not only for studying a wide range of design parameters but also
for evaluating the robustness of a specific design. The results
permit to write technical specifications, for design departments,
which in fact build the car pieces.
Using simplified models reduces delays of building numerical
models (by a factor of five) and divides by 100 solving delays. It
makes easier modelling modifications (a day instead of a week).
Finally, simplified models improve efficiency of crash
simulation engineers by diminishing modelling time, by increasing
the numbers of iterations and permitting a better understanding of
the physics.
In the future, the aim of this method is to build simplified and
classical FE models by using directly the CAD parts with additional
physical properties in order to dispose automatically of a model
which complexity depends on the available CAD data.