This paper develops a method for studying pedestrian to car impacts through detailed multi-body modelling of various pedestrian anthropometries and vehicle types. The pedestrian models constitute a multi-body representation of the global joint kinematics and inertia for five representative body sizes. Advanced injury criteria are defined for the pedestrian lower extremities, knee, thorax and head. The vehicle model of a small family car is defined by a facet element mesh for the front-end and windshield of the car. The contact stiffness is variable over the location on the vehicle mesh and has been validated against experimental results and FE simulations of the EEVC impactor tests. The underlying structures of the hood are defined as rigid ellipsoids. The developed model is applied to the reconstruction of two PCDS cases with a small family car. Injury risk data was collected from the simulation model and compared to the injury outcome for the pedestrians involved in these two cases. Results of this study show that the detailed model can distinguish the injury severity for various body parts at impact locations on the vehicle. For the covering abstract see ITRD E825082.

Pedestrian crash reconstruction using multi-body modeling with geometrically detailed, validated vehicle models and advanced pedestrian injury criteria

A Study of Influences of Vehicle Speed and Front Structure on Pedestrian Impact Responses Using Mathematical Models

The most important factor in pedestrian injuries from vehicle collisions is the impact velocity. In cases where the impact configuration can be ascertained, the most common method now used to determine vehicle speed involves the pedestrian projection distance. The more traditional method of using tyre brake marks is losing applicability as ABS braking systems become more common. The two most common impact configurations are wrap projection and forward projection, these being determined by the vehicle/pedestrian geometry and the initial conditions of the impact. In this paper, two models are presented for pedestrian forward and wrap projection impacts. These models are predicated on separating the total projection distance into the individual projection distances occurring during three principal phases of the collision. The models are novel as they use a rigid single-segment body representation of the pedestrian, include explicit modelling of the impact phase, and also allow for uncertainty in the ...

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Vehicle-pedestrian collisions: Validated models for pedestrian impact and projection

This chapter reviews the basic features of some mathematical occupant simulation models. Models reviewed include 2D/3D complicated gross-motion simulators, such as MADYMO 2D/3D and CAL3D, an integrated crash victim simulator (CVS) model with various finite element analysis (FEA) airbag models and their couplings with CVS programs for automotive safety applications. Historical development, analytic formulation/solution, experimental validation, application, and the experience with these models is discussed. Development trends in FEA approaches by integrating structure/occupant simulation models for safety/crashworthiness analysis are also discussed, and state-of-the-art simulation models for predicting injuries of human brain, neck, and lower extremities are presented.

A review of mathematical occupant simulation models

Analysis of results from previous mathematical simulations of pedestrian impacts shows that a standard description of the pedestrian model used in the MADYMO is not comparable with simulations performed with biological materials. A 3D pedestrian knee joint model was developed to achieve a better correlation with the results from previous cadaver experiments. The model of the knee joint includes the articular surfaces, ligaments and capsule represented by the ellipsoid and plane elements as well as the spring-damping elements, respectively. The mechanical properties of the knee joint are based on available biomechanical data. To verify the pedestrian model with previous cadaver experiments, the computer simulation have been carried out with our new model of the knee joint by the MADYMO 3D program. To simulate different test conditions which correspond to previous cadaver tests, the following parameters have been varied in our simulations: impact speed, bumper height and bumper compliance. Four computer simulations were performed which were compared with four cadaver test series with five experiments in each series. The bumper force, the condyle interface forces, the ligament forces and the ligament relative elongations were calculated and compared with the results of the cadaver experiments. The output parameters calculated from the new knee joint model correspond well to what was observed in cadaver studies. Two complementary computer simulations were performed to study influence of the upper body to distribution of the forces in the simulated knee structures. From this simulation it seems that body mass has influence on the condyle forces and the trajectory of the lower extremities.

Computer Simulation of Impact Response of the Human Knee Joint in Car-Pedestrian Accidents

In this paper four pedestrian models will be presented: three 2-dimensional models with 2, 5 and 7-segments respectively and one 3-dimensional model with 15 segments. All these models were formulated with the general Crash Victim Simulation package MADYMO. Model results will be compared with the experimental results of a Part 572 dummy impacted lateral at two velocities (30 and 40 km/h). The reliability of the models with respect to their complexity will be discussed. Special attention will be given to the mathematical representation of the contact between the pedestrian and sharp vehicle edges and the visualization of the complex 3-dimensional pedestrian motions with a recently developed 3D-Graphics Package.

L. Wittebrood

Papers

MADYMO Pedestrian Simulations