Honeycomb sandwich material modelling for dynamic simulations of a crash-box for a racing car

Aluminium sandwich construction has been recognized as a promising concept for structural purposes in lightweight transportation systems. The aim of the present study is to investigate, through experiment as well as numerical approaches, the energy absorbing capabilities of a thin-walled crash-box, made of sandwich material, for a racing car. The basic considered structures are panels composed of two aluminium alloy sheets and an aluminium hexagonal cells honeycomb core. Several crash tests were performed, in the conditions related to a frontal impact at the velocity of 12 m/s, in order to acquire information on the dynamic behaviour of the mentioned structure; during these tests the load-deformation diagram, the deceleration and the energy absorbed by the structure were measured. A finite element model is then developed using the non-linear, explicit dynamic code LS-DYNA. In order to characterize the material and to set up the numerical model, a series of strength tests were carried out on aluminium honeycomb-cored sandwich panel specimens. By means of these preliminary tests some necessary material parameters were determined. The simulation results accurately predicted the average deceleration, the specific absorbed energy and the total deformation of the specimen, but appeared to slightly overestimate the initial peak load obtained in the crash tests. Therefore the performed investigation can help to build confidence in the future possibility of using non-linear dynamic finite element code LS-DYNA for the design of sandwich primary structures subjected to crash loading, especially after a further tuning up of the models and material characteristics.