Optimization of passenger car design for the mitigation of pedestrian head injury using a genetic algorithm

Abstract

The problem of pedestrian injury is a significant one throughout the world. In 2001, there were 4724 pedestrian fatalities in Europe and 4882 in the US. Significant advances have been made by automotive safety researchers and vehicle manufacturers to address this issue with respect to the design of vehicles, but the complex nature of pedestrian accident scenarios has resulted in great difficulty when using traditional statistical methods. Specifically, problems have been encountered when attempting to study the effects of individual parameters of vehicle front-end geometry on pedestrian head injury. This paper attempts to demonstrate the feasibility of applying the field of evolutionary computation to the problem of pedestrian safety by using a simple genetic algorithm to optimize the centre-line geometry of a car's front-end for the reduction of pedestrian head and thoracic injury. The fitness of each design is assessed by creating a multi-body mathematical model of the vehicle front and simulating impacts with models of different sized pedestrians, and ranking according to the combined injury scores.

Development of Economical Vehicle Model for Pedestrian-Friendly Front-End Profile Study

“…This modelling method's usage of rigid planes and ellipsoids with pre-determined contact characteristics offers the advantage of unsurpassed processing speed [12,18,24] as well as ease of build and validation. It is therefore not surprising that we see the literature being inundated with wide applications of MB models particularly in motor vehicle crash researches [12,18,25].…”

“…Generally, for human models and dummy models, when bio-fidelic considerations are not the focus, structural deformations are less of a factor in determination of fall pattern and most injury criteria. This is largely due to the padding effect afforded by the muscles and tissues of body [12,19]. Unfortunately, this is not the case for deformable impacting structures such as vehicle models.…”

“…It is also necessary for the model to be highly cost effective, both in terms of preprocessing time i.e. model building, as well as processing time [12,21]. Additionally, for the intended purpose of the model, it is essential that deformability is retained in the critical parts of the profile in order to capture local deformations.…”

“…acceleration [12,19,26,30], although for the purpose of validation, other injury criteria are also referred to [18,19].…”

“…The advent of Multi-body (MB) modelling technique, though initially developed for studying the gross motion of occupant models during vehicle impact, has evolved to include pedestrian models as well [11]. The advantage of fast modelling and processing speed coupled with model simplicity, despite some limitations in its application, has enabled more exhaustive multi-parametric optimization studies to be carried out [12][13][14]. Nevertheless, some drawbacks such as the non-deformable nature of the models, curtail the broader application of the exclusive usage of this method.…”