Evaluation of the Efficacy of an Inflatable Attenuation System for Human Fall Protection




Freund, Mark Anthony

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The purpose of this research was to determine how an inflatable attenuation device ("stunt bag") alters a falling person's impact pulse and injury potential. This research will determine if the impact pulse is dependent on drop height and the internal bag pressure. The stunt bag can be used as a recreational or a safety device that may prevent injuries from a fall at varying heights. Further, this research will document if an Anthropomorphic Test Device (ATD), in whole or in part, can be used in place of a human subject to determine the efficacy of the inflatable attenuation device. Our hypothesis is the accelerations will increase as the drop height increases and the accelerations will decrease as the internal bag pressure decreases. Our methods include a human subject instrumented at the head, upper thoracic and lower lumbar region, a complete and fully instrumented ATD, and an ATD's headform which were dropped on to the inflatable attenuation device. The drop heights varied from 5 feet to 20 feet and the bag pressure varied from fully inflated to half inflated. Accelerometers mounted to the human and ATD recorded data using a data acquisition system sampling at 10,000 Hz and was processed per SAE J211 recommendations. As the drop height increased, the accelerations measured for the human and complete ATD increased. When the bag pressure was decreased, the accelerations increased at the head and decreased at the thoracic and lumbar regions. The human and complete ATD acceleration versus time plots were similar in shape and duration. The acceleration of only the ATD headform was greater in terms of the acceleration but the impact duration was similar to the human and complete ATD. The head injury criterion (HIC-15) was low in all experiments and represented 2x10-10 % risk of a minor injury (AIS 1+) in the test with the highest HIC-15.


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impact, stunt bag



Biomedical Engineering