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Calculating head accelerations and neck loading is essential for understanding and predicting head and neck injury. Most of the desired information cannot be directly measured in experiments with human volunteers. Achieving accurate results after applying the necessary transformations from remote measurements is difficult, particularly in the case of a head impact. The objective of this study was to develop a methodology for accurately calculating the accelerations at the center of gravity of the head and the loads and moments at the occipital condyles. To validate this methodology in a challenging test condition, twenty (20) human volunteers and a Hybrid III dummy were subjected to forehead impacts from a soccer ball traveling horizontally at speeds up to 11.5 m/s. The human subjects and the Hybrid III were instrumented with linear accelerometers and an angular rate sensor inside the mouth.

The costs of low-velocity, front-to-rear crash tests include the bullet (striking) and target (struck) cars. Analyses of this type of tests led us to conclude that it may be technically feasible and economically advantageous to replace the bullet car with a simplified mechanical device. A bifilar pendulum with an impact face consisting of a mass-spring-damper system was designed to simulate the bullet car in car-to-car, collinear, low-velocity (delta-v <= 8 km/h) front-to-rear tests. The elements of the pendulum face were evaluated dynamically and quasi-statically. Also, car-to-car tests were initially performed with stationary target cars (brakes off). Repair or replacement of the minor damage observed in the cars was accomplished as needed. Tests were subsequently performed with the pendulum striking the same target cars and approximating the bullet cars' impact energies. The pendulum, bullet, and target cars were instrumented with translational acceleration and velocity sensors.

Previous literature has shown that serious neck injury can occur during rollover events, even for restrained occupants, when the occupant's head contacts the vehicle interior during a roof-to-ground impact or contacts the ground directly through an adjacent window opening. Confusion about the mechanism of these injuries can result when the event is viewed from an accelerated reference frame such as an onboard camera. Researchers generally agree that the neck is stressed as a result of relative motion between head and torso but disagree as to the origin of the neck loading. This paper reviews the principles underlying the analysis of rollover impacts to establish a physical basis for understanding the source of disagreement and demonstrates the usefulness of physical testing to illustrate occupant impact dynamics. A series of rollover impacts has been performed using the Controlled Rollover Impact System (CRIS) with both production vehicles and vehicles with modified roof structures.