A revision of the SOLI model of rigid bodies in EUROPLEXUS
This report presents a revision and re-formulation of the so-called old model for the simulation
of rigid bodies (SOLI model) in the EUROPLEXUS code. This model is based on the substitution
( decomposition ) of the discretized rigid body by a mechanically equivalent set of four points in
3D space (two points in 2D space, but the 2D version of the model has not been implemented yet).
The rigidity of the equivalent mechanical system is enforced by a suitable set of constant-distance
constraints on the equivalent points via the Lagrange multipliers method.
Although EUROPLEXUS is primarily dedicated to the simulation of deformable mechanical sys
ems (both uids and structures), it is not infrequent that at least some (solid) parts of the numerical
model behave at least approximately as rigid, non-deformable bodies.
A class of problems where a rigid model might be useful is that of crashes. For example, when
treating the impact and crash of vehicles in the framework of protection of public spaces against
terrorist attacks, e.g. by means of road barriers, some parts (typically the vehicle body and some
components) are highly deformable while others (e.g. the engine) are comparatively much sti er and
could be treated as rigid. Modelling such nearly-rigid parts as a very sti solid severely penalizes the
transient explicit solution because of the drop it causes on the stability step of the time integration
procedure.
What is needed is the possibility of treating a rigid body in a more rigorous, but also in a more
general manner than by simple blockages. The present report presents a possible approach to this
task (the SOLI model) that was historically implemented in EUROPLEXUS and has been recently
completely revised and enhanced by several new features (NODE, ELE2, HYBR, FEXT directives) in order
to make it more functional to vehicle crash simulations for the protection of public spaces.
CASADEI Folco;
MARKOVIC Damijan;
LARCHER Martin;
2025-01-24
Publications Office of the European Union
JRC140247
978-92-68-23984-1 (online),
1831-9424 (online),
EUR 40198,
OP KJ-01-25-040-EN-N (online),
https://publications.jrc.ec.europa.eu/repository/handle/JRC140247,
10.2760/2438690 (online),
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