Pedestrian Head Impact Conditions Depending on the Vehicle Front Shape and Its Construction--Full Model Simulation

Abstract

For the evaluation of pedestrian protection, the European Enhanced Vehicle-Safety Committee Working Group 17 report is now commonly used. In the evaluation of head injuries, the report takes into account only the hood area of the vehicle. But recent pedestrian accident data has shown the injury source for head injury changing to the windshield and A-pillar from the hood. The head contact points are considered to fall on a parallel to the front shape of the vehicle along the lateral direction, but the rigidity of the outer side construction is different from the center area. The purpose of this study is to consider the reason for the change in injury source for recent vehicle models. The head contact points and contact conditions, speed and angle, are thought to be influenced not only by the vehicle's geometry, but also its construction (rigidity). In this study, vehicle-pedestrian impact simulations were calculated with a finite element model for several hitting positions, including the outer side areas. Full dummy sled tests were conducted to confirm the simulation results. These results show that, for impacts at the outer sides of the vehicle, the head contact points are more rearward than at the vehicle center. In addition, the speed and angle of the head contact were found to be influenced by the pedestrian height.

Crash reconstruction of pedestrian accidents using optimization techniques

“…Therefore, a preliminary scaling of the pedestrian model (50th percentile male) according to the anthropometric characteristics of the pedestrian involved in accident is recommended [39,40]. The geometry and stiffness of vehicle front end components influence the pedestrian kinematics during pedestrian crashes [36]. Therefore, in the current study, vehicle models with detailed geometries and vehicle-pedestrian contacts with combined stiffness curves (based on test or FE data) were used to simulate vehiclepedestrian impacts.…”

Head boundary conditions in pedestrian crashes with passenger cars: six-degrees-of-freedom post-mortem human subject responses

“…In the present study, the influence of this effect could not be determined directly since there was only one subject with considerably different stature. Okamoto et al [22] found the head impact velocity increasing with pedestrian HBM stature and attributed this relation to the aforementioned geometric effect. They have provided theoretical calculations of the relation between pedestrian stature and head impact velocity based on a simple rigid one-body model.…”

“…Vehiclerelated influencing factors such as vehicle front geometry, stiffness, speed and braking were reported by many authors [8,16,19,22,26,27,31,32]. In these studies, subject-related factors were difficult to quantify since the number of subjects tested in each configuration was one to two.…”

Pedestrian fatality and impact speed squared: Cloglog modeling from French national data

“…Regarding factor 2, studies of the influence of vehicle type (Ballesteros et al 2004;Roudsari et al 2004) or shape on resulting lesions were likewise based on real-world crash data (Crandall et al 2002;Henary et al 2003;Mallory et al 2012;Martin et al 2011;Otte 1999); there have also been studies using simulations, which have the advantage of being able to take body kinematics after impact into account (Crocetta et al 2015;Gupta and Yang 2013;Han et al 2012;Okamoto et al 2003). Impact against the ground or secondary obstacles has been less studied, mainly due to lack of precise observations and the wide variety of possible obstacles (Badea-Romero and Lenard 2013).…”