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A 3D pedestrian knee joint model was developed as a first step in a new description of the whole pedestrian body for computer simulations. The model was made to achieve better correlation with the results from previous tests with biological material. 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 were based on available biomechanical data. To verify the new developed model with results from tests with biological material previously performed at the Department of Injury Prevention, Chalmers University of Technology, the computer simulations were carried out with the model of the knee joint using the MADYMO 3D program.

Numerous studies of pelvic tolerance to lateral impact aimed at protecting car occupants have been conducted on Post Mortem Human Subjects (PMHSs) in a sitting posture. However, it remains unclear whether or not the results of these studies are relevant when evaluating the injury risk to walking pedestrians impacted by a car. Therefore, the first objective of the present study is to determine the injury tolerance and to describe the injury mechanisms of the human pelvis in lateral impacts simulating car-pedestrian accidents. The second objective is to obtain data for validation of mathematical models of the pelvis. In-vitro experiments were conducted on twelve PMHSs in simulated standing position. The trochanter of each PMHS was hit by a ram at speed of 32 km/h, and the pelvic motion was constrained by a bolt. This type of pelvic constraint is difficult to simulate in mathematical models.

The shearing and bending injury mechanisms of the knee joint are recognised as two important injury mechanisms associated with car-pedestrian crash accidents. A study on shearing and bending response of the knee joint to a lateral impact loading was conducted with a 3D multibody system model of the lower extremity. The model consists of foot, leg and thigh with concentrated upper body mass. The body elements are connected by joints, including an anatomical knee joint unit that consists of the femur condyles, tibia condyles and tibia1 intercondylar eminence as well as ligaments. The biomechanical properties of the model were derived from literature data. The model was used to simulate two series of previously performed experiments with lower extremity specimens at lateral impact speeds of 15 and 20 km/h.

The level at which forces are transmitted from the striking vehicle in side impacts may influence the response of the struck car in several different ways. A better contact between the front bumper of the striking and the sill area of the struck car has been considered to be desirable in this respect. In side impacts, the most frequent direction of the impact is from 3 and 9 o'clock, while the direction of the forces is usually from 2 and 10 o'clock due to the velocity of the struck car. A European car and the EEVC moving deformable barrier have, therefore, been used in a crabbed mode to study the problem of load transfer at different levels above the ground. Volvo and Saab cars were used as targets in 55 km/h side impact with an APROD-81 side impact dummy placed on the struck side in the front seat. The results indicate that a difference in the level at which the loads were applied could influence the deformations, the kinematics of the struck cars, and the loading of the occupant.

A new mathematical multibody-system model of the whole human body was developed to simulate the pedestrian in road accidents with cars. The aim with the model was to achieve better correlation with results from impact tests with cadaver specimens. The pedestrian model was created to be used with the Crash Victim Simulation (CVS) computer program. The model consists of fifteen segments connected by fourteen joints. The geometry and the characteristics of the body segments, and the mechanical properties of the joints are based on available anthropometrical and biomechanical data. In order to verify the pedestrian model with pervious cadaver experiments, the computer simulations were carried out in such a way that the set-up of simulations corresponded to those in the cadaver tests. The model response to following parameters was studied in the simulations: impact speed, bumper height and bumper compliance.

The compatibility problems of the mini car in car-to-car frontal collision and car-pedestrian accident are discussed using accident data and computer simulations. In our analysis of the accident data in Japan, the number of fatalities was investigated using the vehicle masses and classes. It was found that the cars with identical mass are most compatible since the injuries per accident are minimal and injury risks to the driver in both cars are the same. The analysis of the car class indicated that the mini car and the sports utility vehicle are the most incompatible car types, with low and high aggressivity, respectively. Our accident analysis in the present study shows that the safety of mini cars is the key point in achieving the compatibility in Japan. Computer simulations using MADYMO were carried out of crashes of mini car into a rigid wall and into a large car.