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In this paper human volunteer head/neck dynamic response is compared with that of a Hybrid III head and neck. The data base used for the comparison was taken from the extensive Naval Biodynamics Laboratory data base of human and manikin sled runs for various thrust vector directions. Significant differences were identified in the human volunteer and manikin responses for the −X and +Z runs, while an unexpected similarity was observed in the head trajectories for the +Y and −X+Y runs. A detailed analysis of 15 g −X vector exposures is presented. Math model simulations using a linkage model to simulate the response of the beam-like Hybrid III neck to −X sled acceleration profiles are presented, as well as simulations of human runs using a similar linkage model. Improved simulations were obtained by making changes to the linkage model parameters which could presumably be implemented relatively easily on the physical Hybrid III neck.

Significant kinematic parameters of the head are compared between a Hybrid II head and neck (per Parr 572, Federal Motor Vehicle Safely Standard 208) and human volunteers subjected to the same -Gx sled acceleration profiles. Comparison time profiles between the dummy and human subjects for component's of linear acceleration, velocity, and displacement of the head center of gravity and the first thoracic vertebral body (T1) anatomical origin, as well as components of angular acceleration, velocity, and displacement of the anatomical coordinate systems are presented for 6, 10, and 15G peak sled acceleration in the -Gx environment. Significant differences between the dummy and human volunteers are discussed in regard to peak values of parameters, time latencies, and overall shape agreement in a time window where motion is significant.

Head linear and angular accelerations of humans were investigated during exposure to abrupt linear deceleration (-Gx). The 14 subjects were restrained with three different restraints: lap belt only, Air Force shoulder harness-lap belt and air bag plus lap belt. Peak sled decelerations ranged from 7.7-10.3 g. The results indicated that peak head angular and linear resultant accelerations were elevated with the air bag in contrast to the Air Force shoulder harness or lap belt only restraints. However, the peak angular and linear accelerations may have less traumatic consequences than the degree of head-neck hyperextension.

The Naval Biodynamics Laboratory (NBDL) has collected a database which describes human dynanic responses for −X acceleration exposures as a function of mass distribution variations of the head. Kinematic responses were measured on subjects with, (a) no mass addition; (b) with a helmet and weight-carrier mass addition; (c) and with the helmet and added weights symmetrically located with respect to the mid-sagittal plane of the head. The total mass addition to the head with the weights was approximately 30 percent. The helmet and weights were positioned with reference to the head anatomical coordinate system for each subject, with mass moments of inertia and variations in center of gravity then being determined. This paper compares responses both as a function of a mass distribution parameters and as a model to simulate the observed responses.