Additive manufacturing for industrial benchmarking: An application to vehicle's under-hood design

All over the world, and mainly in United States, since 1977 to 1991 the research centers of automotive companies have processed several statistical data on real accidents between vehicles and pedestrians taking care, obviously, to pedestrians' injury. In latest years, a research group of EEVC (European Enhanced Vehicle-Safety Committee) had realized some documents about "pedestrian test" procedures. In reference papers of period 1977 - 1997 and in EEVC documents, the scientists describe a proposed homologating test for child-head impact; it is represented by the impact of some standardized impactors on car bonnet, in order to evaluate the child-head injury as deceleration of its gravity center. Injury evaluation criteria is an energy criterion and is quantified by the HPC index (see below) calculated by acceleration resultant vector, measured by an accelerometer mounted in the head- impactor. Our research wants to propose a new potential-injury evaluation method based on virtual reconstruction of the surface that envelope all the deformation surfaces in internal part of the bonnet and on its rapid prototyping. This surface is so processed and rapid prototyped as a puzzle of shells with their support. This prototyped surface is super-imposed on the real under-bonnet layout of a car and allows to evaluate easily where and how much our deformed bonnet could hit the hard-parts of the engine layout. This paper shows the results of this research project.