Development and validation of pedestrian sedan bucks using finite-element simulations: a numerical investigation of the influence of vehicle automatic braking on the kinematics of the pedestrian involved in vehicle collisions

Abstract

2010) Development and validation of pedestrian sedan bucks using finite-element simulations: a numerical investigation of the influence of vehicle automatic braking on the kinematics of the pedestrian involved in vehicle collisions, International Journal of Crashworthiness, 15:5, 491-503,Previous vehicle-to-pedestrian impact simulations and experiments using pedestrian dummies and cadavers have shown that factors such as vehicle shape, pedestrian anthropometry and pre-impact conditions influence pedestrian kinematics and injury mechanisms. Generic pedestrian bucks, which approximate the geometrical and stiffness properties of current vehicles, would be useful in studying the influence of vehicle front-end structures on pedestrian kinematics and loading. This study explores the design of pedestrian bucks, intended to represent the basic vehicle front-end structures, consisting of five components: lower stiffener, bumper, hood leading edge and grille, hood and windshield. The deformable parts of the bucks were designed using types of currently manufactured materials, which allow fabricating the bucks in the future. The geometry of pedestrian bucks was approximated according to the contour cross-sections of two sedan vehicles used in previous pedestrian dummy and cadaver impact tests. Other cross-sectional dimensions and the stiffness of the buck components were determined by parameter identification using finite-element (FE) simulations of each sedan model. In the absence of a validated FE model of human, the FE model of the POLAR II pedestrian dummy was used to validate a mid-size sedan (MS) pedestrian buck. A good correlation of the pedestrian dummy kinematics and contact forces obtained in dummy-MS pedestrian buck with the corresponding data from dummy-MS vehicle simulation was achieved. A parametric study using the POLAR II FE model and different buck models -an MS buck and a large-size sedan (LS) buck -were run to study the influence of an automatic braking system for reducing the pedestrian injuries. The vehicle braking conditions showed reductions in the relative velocity of the head to the vehicle and increases in the time of head impact and in the wrap-around-distances (WAD) to primary head contact. The head impact velocity showed a greater sensitivity to the different buck shapes (e.g. LS buck versus MS buck) than to the braking deceleration. The buck FE models developed in this study are expected to be used in sensitivity and optimisation studies for the development of new pedestrian protection systems.

A Review of Pediatric Lower Extremity Data for Pedestrian Numerical Modeling: Injury Epidemiology, Anatomy, Anthropometry, Structural, and Mechanical Properties

“…In addition, test targets which mimic a running child (5 km/h) are used in a new test for evaluation of pedestrian automatic emergency braking (AEB) systems introduced in 2016. While an adult pedestrian dummy (50th male Polar ATD) was designed and evaluated against PMHS tests [ 94 – 96 ], no child pedestrian ATD has been developed yet. Rapid advancement in computational power makes numerical child pedestrian models important tools for safety research.…”

Lightweight Foam Impact Attenuator Design for Formula Sae Car

“…1. EPP 100 g/l foam material Strain-Stress Curves (Untaroiu et al, 2010) To define the EPP foam material model, LAW70 material card and P14_solid property card were used. Stress-strain curve was defining in Radioss solver code (Altair University).…”

Potential of Pedestrian Protection Systems—A Parameter Study Using Finite Element Models of Pedestrian Dummy and Generic Passenger Vehicles

“…Two FE models of simplified bucks corresponding to mid-size and large sedans were developed in a previous study (Untaroiu, Shin, et al 2010 These simplified vehicle models were approximated with 4 subsystems: the lower stiffener, the bumper, the hood leading edge, and the hood (Figure 1). The geometry of these buck components was developed based on the contour cross sections corresponding to a mid-size and a large-size sedan vehicle used in previous vehicle-to-dummy and PMHS tests (Kerrigan et al 2005(Kerrigan et al , 2007.…”

“…Impact simulations between rigid impactors and vehicle front-end components were used to calibrate the stiffness and thickness of the deformable buck parts. The dummy kinematic and kinetic data recorded during dummy-vehicle tests and simulations were used to validate the mid-size buck until the first head-vehicle contact (Untaroiu, Shin, et al 2010).…”

“…The scaled Polar II dummy model was obtained by scaling the Polar II dummy model to the dimensions of a 95th-percentile male (Untaroiu et al 2008) using data from an anthropometric database (Gordon et al 1989). The pedestrian dummy models were positioned with lower limbs in a left-leg forward midstance posture with its left side oriented against the buck in the buck centerline position (Untaroiu, Shin, et al 2010). The preimpact speed of the buck (at the time when the bumper hit the leg) was set at 40 km/h in all simulations for all head-impact configurations.…”