Design of experiment about foam CF45 for pedestrian safety in car design

A statistical approach based on the variance analysis allows to appraise the influence of the foam that covers leg impactors on results of the tests required by European New Car Assessment Program [EuroNCAP, Pedestrian Testing Protocol, Rel. 3.1.1, Gennaio, 2002] and ACEA (European Automobile Manufacturers Association) for the safety of the pedestrians in case of accident. Impactor used to evaluate the damage in pedestrian test is made by TRL and is quite similar to the structure of the human femur: it has a very complicated system to simulate the whole bone–flesh–skin apparatus and, in particular, has two layers of special Confor™ Foam CF45 Blue that has the same mechanical behaviour of human flesh; we have made a dynamic characterization of that foam at medium and high impact velocity; in order to simulate the whole leg impactor, in PamCrash environment, using the ESI formulation of the skin and using the results of characterization of all other elements with experimental tests. Experimental data coming from tests on foam have a medium value and dispersion around the mean; that dispersion can affect significantly the results of final simulation. So we have applied several statistical methods in order to optimize the final simulation results.This analysis is a part of a more complex design of experiment that analyse the difficulties when we simulate, using finite element method (FEM) simulation, the impact pedestrian–car. In problematic that is complex and not linearly influenced by many factors even a numerical simulation could be improved and optimised by statistic techniques.