Analysis of CREW 3.1 System Center of Mass (COM)

Report No. ARL-TN-0405
Authors: Michael LaFiandra and Richard Kozycki
Date/Pages: September 2010; 24 pages
Abstract: The CREW 3.1 System is an Improvised Explosive Device (IED) jamming device that is worn on the back of a Warfighter. Jack human figure modeling software (Siemens, 2010) was used to help examine the load placement and center of mass (COM) for dismounted Soldiers wearing the CREW 3.1 System and possible implications for metabolic cost. The composite COM of the CREW 3.1 System and the Soldier (including Interceptor Body Armor [IBA], Small Arms Protective Inserts [SAPI], and a full hydration system) was calculated using the methods outlined in Winter (1990) and based on the joint locations of a standing Jack figure. Three digital human models of Soldiers (95th, 50th and 5th percentile male by body weight) wearing IBA with two SAPI plates and a full hydration system were compared to the same three models wearing IBA with two SAPI plates, a full hydration system, and the CREW 3.1 System. In general, the effect of carrying the CREW 3.1 System is to raise the composite COM and to shift it further back from the carrier. Based on the relatively small amount of COM shift that occurs, it is likely that the effect of this shift on metabolic cost is very small.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2010