Investigation about acting direction of acceleration stimulus vs. toppling direction of human body

Abstract

For the purpose of working out the passenger injury-minimizing technology in the event of a train collision, it is important first of all to estimate the probable reaction of passengers involved in the accident. Computer simulation is one of the means conceivable for investigation of this problem.
To get the basic data for the investigation, we have performed an experiment to know the toppling characteristics of passengers reacting to shock and accelerations in such a collision. The experiment revealed that the toppling liability and direction of passengers in response to rectangular waveform of acceleration stimulus depend on the standing apart width of their feet, and the duration and acting direction of the acceleration.
Meanwhile, the range of accelerations at which the human body may be regarded as a simple mass is assumed as the range of accelerations at which humans can no longer control the direction of their toppling and practically they fall in that direction. Then a minimum value of this acceleration is defined as the limit value for toppling control and as to adult female students, we presumed a value of 280cm/s² as this minimum. Further as a result of comparing the toppling directions of humans and a dummy model currently utilized in computer simulation by auto industry, we point out that there is a discrepancy in the toppling direction between humans and the dummy when the stimulus duration is 0.2-0.5s and the stimulus applied is short of 1400cm/s².