PSA Peugeot Citroën collaborated with Altair, Ecole Polytechnique Laboratoire de Mécanique des Solides (LMS) and PRACE to perform a study of automotive crash rupture simulations, investigating ways to improve material failure criteria and better predict cracks.
The full text of the case study can be found here.
Project Title: Study of failure criteria for crash automotive simulations
Project Leader: Mrs Geraldine Graff, PSA Peugeot Citroen, France
Resource Awarded: 200 000 core hours on Curie hosted by GENCI at CEA, France
Research Field: Engineering and Energy
- Mr. Eric Lequiniou, Altair Development France, France
- Mr. Olivier Wienholtz, Altair Development France, France
- Mr. Laurent Caplain, Psa Peugeot Citroen, France
- Mr. Yan Marut, Psa Peugeot Citroen, France
- Mr. Pierre Gillis, Psa Peugeot Citroen, France
- Mr. Patrick Madela, Psa Peugeot Citroen, France
- Mr. Joel Perou, Psa Peugeot Citroen, France
Automotive regulations impose levels of CO2 emission lower and lower. One way to reach the targets is to decrease mass structures, by optimizing design and using new materials such as high strength steels.To introduce such new materials PSA design rules and numerical tools must evolve. In the automotive development scheme the physical tools and parts are available late, that impose to make decisions according to simulation results.
The material failure criteria used today in crash simulations are not accurate enough and can lead to an oversizing of structural parts. To improve its knowledge on that field PSA joined the Fracture Consortium managed by MIT (ICL) in partnership with Ecole Polytechnique (LMS).
That is why PSA wants to evaluate the robustness of this advanced failure criterion for steel sheets in the context of industrial computing (shock subsystem) with RADIOSS, its standard code for crash simulations. The main difficulty is the need to describe highly localized deformation fields (because failure is a local phenomenon) in a whole vehicle crash simulation. The researchers of fracture consortium recommend the use of solid elements of 75µm size to obtain accurate predictions of the onset of fracture using their recently developed criterion.
The use of solid element meshes with 75µm edge length is not yet realistic in industrial environment. However, in view of developing simplified methodologies, it would be essential to know the “exact” solution of a car crash simulation, i.e. the solution for a full vehicle respecting the modeling guidelines for accurate fracture predictions.
The project will be executed in three major steps:
– The first step requires “preparatory access” to ensure the capability of the tools (handling models, robustness of the management interfaces, visualization of results), to validate capability to represent and manage failure (for qualitative point of view) and the consistency of the sequence of calculations stamping then crash.
– The second step requires “Regular Access” to realize the simulation “side crash to failure” taking into account the stamping effect, the accurate material laws, elements deactivation at failure in order to qualify the performance of the failure criterion.
– The third step (after the project) will aim at proposing a strategy that fits industrials constraints with regards to time restitution, model preparation and post-processing.
Note that the regular access only makes sense if the results of the first step are satisfying.