Characterization of Vertical Impact Device Acceleration Pulses Using Parametric Assessment: Phase I

Abstract

Abstract : The research effort was conducted to identify the performance capabilities of the Vertical Impact Device (VID) test located in Bldg 824, Wright Patterson AFB OH. The performance requirements for the VID were required to support the Warrior Injury Assessment Manikin (WIAMan) program. The test program approach used a parametric analysis with the objective to define and evaluate the performance effect of various impact attenuators on VID impact acceleration. Over 100 impact tests were completed and consisted of varying the energy attenuators, defined as the high-density (red) urethane programmers and industrial felt of varying density and thickness, while progressively increasing the drop height of the VID's drop table. One red urethane programmer, 4 felt densities, and 4 felt thicknesses were evaluated, and were used as the basis to separate the data analysis into three sub-phases. The measured response was the acceleration recorded on the VID drop carriage, and the calculated velocity change and TTP velocity change. The first phase of the assessment evaluated the VID's red urethane programmers on the drop carriage at 8 different drop heights that ranged from 5 to 50 inches. The acceleration pulse width was used as an estimator of the time-to-peak velocity. The second phase of testing indicated that the felt density variation had a minimal effect on the peak acceleration or velocity change at two drop heights, and was shown by calculating a percent difference in the response relative to a baseline which was the least dense felt. The third phase of testing indicated that the felt thickness variation had a very little effect on the velocity change at the two drop heights, but had a large effect on the peak acceleration and the acceleration pulse width at the two drop heights. This was shown by calculating a percent difference in the response relative to a baseline which was the least thick felt.