AM General, and the U.S. Army Tank Automotive Research, Development, and Engineering Center.
The supplier’s approach to optimizing an occupant protection system during rollovers was to substitute the conven- tional three-point (i.e., Type 2A – single shoulder and lap) seat belts with its elec- tronic pre-tensioning, load-limiting, and - ligent seat belts. TRADOC arranged for October 2010. The feedback from Sol- diers was positive, especially favoring the automatic retracting of the two shoulder and two lap belts.
PROVING ‘DYNAMIC’ FUNCTION
With the focus on rollovers, demonstrat- ing combined side-curtain air bags and intelligent seat belts in action would coincide with the dynamics of a vehicle physically undergoing a rollover test event.
Although Federal Motor Vehicle Safety Standard (FMVSS) No. 208, Occupant Crash Protection, accounts for vehicle lat- eral rollovers, it pertains only to a vehicle being driven on a paved road at 30 mph and calls for it to be released using a test apparatus angled at 23 degrees.
An industry-practiced test method com- monly known as the Dolly Sled Test conveys this information for a vehicle
moving at a particular speed and angled as detailed in SAE (Society of Automo- tive Engineers) International’s Standard J2114, Dolly Rollover Recommended Test Procedure. A test method for lateral ditch rollover events does not currently exist.
To ensure viability in physical rollovers of a HMMWV, the supplier ventured to - bilities to simulate the two types of lateral rollovers using a HMMWV body, whole or segmented, but discovered limitations
We even investigated creating a specially Trainer, but achieving a fast roll rate in seconds was impractical. All these factors led to using a modeling and simulation
In January 2011, AM General coordinated with the supplier for a computer-aided engineering (CAE) M&S effort of HMMWV ditch and dolly rollovers. The models as seated occupants to simulate Soldiers. AM General provided to the supplier a CAE model of the vehicle.
CHOOSING TYPES OF SEATED OCCUPANTS GFE vehicle assets to be consumed dur- ing rollover test and evaluation (T&E) led to examining combinations of the 50th
male, 95th male, and 5th female percen- tile adult human types and placement as driver, commander, and rear-seated occu- pants. The best solution for a practical arrangement of ATDs would then have to be part of the M&S for assessing levels
TRADOC determined that the use of 95th and 5th percentile types ensured the effectiveness of those extremes, thus eliminating the need to use iterations of of all 95th and all 5th types seated was an option.
The solution deemed best was to seat com- binations of 95th driver, 5th commander side, 5th left rear side, and 95th right rear side for one vehicle asset, and to reverse the arrangement for a second vehicle.
Using such combinations of occupants meant two vehicle test assets for ditch sequence of rollovers based on anticipa- tion that assets for ditch testing would be - quent dolly testing.
MODELING AND SIMULATION
The supplier began M&S using FMVSS neck, and lower body—criteria typical
SAFETY CENTER SHOW THAT OCCUPANTS WHO WEAR SEAT BELT RESTRAINTS PROPERLY ARE MORE LIKELY TO SURVIVE A ROLLOVER, SUFFERING LESS SEVERE INJURIES WHILE REMAINING INSIDE THE VEHICLE.
ASC.ARMY.MIL 63
SCIENCE & TECHNOLOGY
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