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This paper discusses an attempt to relate measured loading at the head neck junction of arestrained six year old ATD during a frontal crash, to the mechanism of upper cervical fracture dislocation in young children. Lap belt, lap shoulder belt anda four point restraint system are considered. The basis for the reconstructions is the fatal injury to lap-belt restrained young children seated in the rear seat of contemporary minivans. The study concludes that simple forces and bending moments measured on such an ATD may not provide a sufficient basis for judging the likelihood of such an injury. Suggestions for a more comprehensive injury analysis are made.

Abdominal injury to automobile occupants can be caused by the lap portion of the belt restraint if it is not well deployed below the wearer's iliac spines. A new test device, capable of providing a quantitative measure of lap belt fit is described. Based on the standard 3 dimensional “H-point machine”, the device has been validated with a large number of occupants seated in a wide variety of contemporary passenger cars. Procedures for employing the device are presented.

This paper describes the efforts of one group to improve the biomechanical fidelity of ATD headforms used in automotive crash testing. On the basis of recent cadaver head impact studies and on the literature dealing with facial bone tolerances, several refinements have been made to the Hybrid III head-form. These include a slight modification of effective skull stiffness, the addition of a frangible faceform sub-assembly and the introduction of a compliant mandible. The purpose of these modifications is to improve both the response characteristics to impact as well as to provide a direct means to monitor for facial bone injury.

Recently, several cases of mild traumatic brain injury to American professional football players have been reconstructed using instrumented Hybrid III anthropomorphic test dummies ATDs. The translational and rotational acceleration responses of injured and uninjured players'' heads have been documented. The acceleration data have been processed according to all current head injury assessment functions including the GSI, HIC and GAMBIT among others. A new hypothesis is propounded that the threshold for head injury will be exceeded if the rate of change of kinetic energy of the head exceeds some limiting value. A functional relation is proposed, which includes all six degrees of motion and directional sensitivity characteristics, relating the rate of change of kinetic energy to the probability of head injury. The maximum value that the function achieves during impact is the maximum power input to the head and serves as an index by which the probability of head injury can be assessed.

A new form of head and neck protection for racing car drivers is examined. The concept is one whereby the helmet portion of the system is attached, by way of a quick release clamp, to a collar-like platform which is supported on the driver's shoulders. The collar, which encircles the back and sides of the driver's neck, is held in place by way of the on-board restraint belts. The interior of the helmet portion of the assembly is large enough to provide adequate volitional head motion. The overall objective of the design is to remove the helmet from the wearer's head and thereby to mitigate the deleterious features of helmet wearing such as neck fatigue, poor ventilation and aerodynamic buffeting. Just as importantly, by transferring the weight of the helmet and all attendant reaction forces associated with inertial and impact loads to the shoulder complex (instead of to the neck), reduced head and neck injury probability should be achievable.