A New Approach to Multibody Model Development: Pedestrian Lower Extremity

Abstract

The use of a facet surface model of the lower extremity skin and simultaneous optimization of the model's structural response and contact parameters resulted in a model capable of accurately predicting the detailed kinematic response of the lower extremity under vehicle impact loading at 40 km/h. The model can be scaled to represent varying pedestrian anthropometries and can assess the risks associated with sustaining the most common pedestrian injuries. As a vehicle design tool, the model can be used to optimize front-end designs, or it can be used in combination with a detailed FEM to reduce the vast design space prior to FE simulations. Additionally, the model can be used as a tool to study pedestrian impact kinematics, real-world case reconstructions, or particular vehicle countermeasures.

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

“…Therefore, a new impactor test or even the whole dummy-vehicle simulation should be used for a better stiffness calibration of this region in a future pedestrian Downloaded by [McGill University Library] at 13:09 20 November 2014 buck design. The stiffness curve, obtained from the impact between the constrained impactor with a constant impact velocity (40 km/h) and the hood leading edge-grille component of the buck, showed a trend similar to the stiffness curve reported by Kerrigan et al [9].…”

“…While a design similar to the MS buck was able to reasonably approximate the stiffness characteristics in the lower stiffener component of the LS buck (Figure 7a), a different design approach was required for the LS bumper component. As in Kerrigan et al [9], an impact simulation with a rigid cylindrical impactor (800 mm length, 120 mm diameter) striking the MS buck complex of lower stiffener and bumper at 40 km/h was performed (Figure 7b). The structure consisted of two EPP foam layers that were shown to provide the best approximation of the LS vehicle bumper in terms of the stiffness characteristics during the impact simulation.…”

“…An impact simulation with a cylindrical impactor (300 mm length, 200 mm diameter) at a 40 • angle from the vertical was performed as in Kerrigan et al [9] (Figure 8). The thickness of the foam layer and the steel sheet was adjusted to approximate the stiffness characteristics of the leading edge structure of the LS vehicle.…”

“…Following Kerrigan et al [9], the rigid impactors were constrained to move in the impact direction with a prescribed velocity of 40 km/h. The stiffness curves obtained by FE simulations of that vehicle [9] were used to calibrate the lower stiffener, the bumper and the hood leading edge-grille components of the LS pedestrian buck. In the lower stiffener impact test, a cylindrical impactor (220 mm length, 120 mm diameter) was used.…”

“…The geometry of the LS buck was approximated based on the exterior contour of the LS vehicle [7]. Following Kerrigan et al [9], the rigid impactors were constrained to move in the impact direction with a prescribed velocity of 40 km/h. The stiffness curves obtained by FE simulations of that vehicle [9] were used to calibrate the lower stiffener, the bumper and the hood leading edge-grille components of the LS pedestrian buck.…”