The honeycomb barrier behaviour has a major influence on the vehicle structures designed to absorb a frontal crash, for ECE 94 or Euro NCAP and other NCAP frontal tests.

The increased use of modelling and the improvements made on numerical capacities forced us to be able to represent in a better and an in-depth manner the numerical behaviour of the honeycomb barrier in order to improve our prediction of the vehicle behaviour in a frontal crash test, especially on the load distribution in the car front-end.

PSA Peugeot Citroën launched a huge physical and numerical program on the behaviour of the regulatory honeycomb barrier in order to improve its numerical model available of the major crash software. This program focused on the instabilities generated by the industrial barrier that can lead to very different load distribution profiles.

Physical tests were performed from simple tests (honeycomb static compression) to more complex dynamic tests such as puncture tests, up to sub systems tests where a rigid car front end was propelled on a full ECE 94 barrier. This program highlighted new phenomena that were not represented up to now in the numerical barrier such as densification and effect of air pressure in the cells when high volume reduction and high velocities occurred. Other important scatterings due to bonding and cell wall thickness were also seen as major parameters to take into account.

All these mechanical characteristics as well as the aluminium mechanical behaviour are now included in the enhanced modelling developed in the crash software in order to represent all the simple tests performed up to the more complex ones. This led us to better predictive modelling of the honeycomb barrier.

The paper will conclude with a direct comparison between the standard barrier model and our enhanced model and their consequences on the prediction of the full car crash behaviour.

This brand new model is now used for the design of the new vehicle programs at PSA Peugeot Citroën.