Accession Number : ADA638362


Title :   Characterization of Vertical Impact Device Acceleration Pulses Using Parametric Assessment: Phase II Accelerated Free-Fall


Descriptive Note : Interim rept. Jan 2013-Apr 2015


Corporate Author : INFOSCITEX CORP DAYTON OH


Personal Author(s) : Perry, Chris ; Burneka, Chris ; Christopher, Rachael ; Albery, Chris


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a638362.pdf


Report Date : 30 Apr 2016


Pagination or Media Count : 88


Abstract : Phase II of a research effort using the Vertical Impact Device (VID) located in Bldg 824, Wright Patterson AFB OH., was conducted to continue research of the facility's performance capabilities. The data analysis from Phase I indicated that the impact pulses had velocity changes that were below newly defined WIAMan program requirements, and a modification to the VID would need to be fabricated to generate velocity changes in excess of 32 ft/s (10 m/s). Phase II of the research focused on the design and assessment of the Accelerated Freefall Device (AFD) to increase the velocity change currently generated by the VID facility in order to meet the new program velocity change requirement. The AFD was composed of a bungee cord system interfaced between the VID free-fall carriage and the reaction mass to provide an initial velocity at carriage release. The approach was to conduct tests on the VID with the AFD installed using various energy attenuators, and then compare the acceleration and velocity change data to similar test conditions from the Phase I (no AFD) data set. The AFD progressively increased the peak acceleration and the velocity change with increasing drop height for both felt thickness configurations. A maximum velocity change with AFD at 80 inch drop height was found to be 39 ft/s (11.9 m/s). The third and final test series evaluated an additional requirement from the WIAMan program to determine whether the VID facility could produce velocity changes above 25 ft/s (7.6 m/s) with time-to-peak (TTP) values between 5 and 10 ms or greater. The time-to-peak velocity increased about a 3 ms, from approximately 3.5 ms to between 6.5 and 7.0 ms, as a function of using two layers of felt. The AFD can meet the new WIAMan program requirements.


Descriptors :   *LABORATORY EQUIPMENT , *TEST AND EVALUATION , BIOMECHANICS , DROP TESTS , IMPACT ACCELERATION , IMPACT TESTS , VELOCITY


Subject Categories : Medicine and Medical Research
      Test Facilities, Equipment and Methods
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE