This study describes a Health Hazard Assessment (HHA) method for evaluating exposures to repeated shocks in tactical ground vehicles (TGV). This method will predict the risk of injury to the crew of a TGV given its acceleration signature. The HHA will identify both acute and chronic health risks resulting from either a single shock, or prolonged exposure due to travel over rough terrain. The HHA is based partly on existing models, human response and injury data, as well as partly on experimental data obtained from volunteers exposed to a range of shock profiles and to prolonged repeated shock exposures. The HHA consists of three components: dynamic response models which predict seat-to-spine transmission of acceleration; a dose-recovery model for exposure to repeated shocks based on fatigue failure theory and subjective tolerance data; and an injury risk model based on the cumulative probability of failure. A biomechanical model was also developed which analyses spinal compression in response to shock. This model does not form part of the HHA model, but will provide an independent evaluation of the HHA using the experimental data from this study. The components of the HHA are outlined and some test results presented.
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