STEPHEN DUFFY (TRC) PRESENTATION FOR 2002 SAE GOVT/INDUSTRY MEETING 


SLIDE 1:
TEST PROCEDURES FOR EVALUATING EJECTION MITIGATION SYSTEMS
Stephen Duffy, Transportation Research Center, Inc.
under contract to the National Highway traffic safety administration vehicle research and test center


SLIDE 2:
EJECTION FATALITIES
10,302 Ejected fatalities in 1999 (32%)
 - 70% completely ejected
 - 30% partially ejected
 - 74% through glazing
 - 57% through side windows
	60% of these occur in rollovers


SLIDE 3:
TOTAL EJECTIONS	
51,078 Ejected Occupants in 1999 (1%)
 - 64% completely ejected
 - 36% partially ejected
 - 69% through glazing
 - 50% through side windows


SLIDE 4:
EJECTION PROBLEM SUMMARY

- 1/3 of fatalities are ejected
  * over represented based on ejection occurrence
- 2/3 of ejections are complete
  * almost all were unbelted
  * partial ejection not insignificant
- 3/4 of ejections are through glazing
- 1/2 of ejections are through side windows
  * 3/5 of these are in rollovers


SLIDE 5:
PREVIOUS TEST PROCEDURE DEVELOPMENT

Full-scale rollover tests
 - evaluated full-dummy ejection
 - not repeatable

Full-dummy inverted drop tests
 - evaluated full-dummy ejections
 - not rollover simulation
 - demonstrated ejection mitigationn capability of advanced glazing systems


SLIDE 6:
PREVIOUS TEST PROCEDURE DEVELOPMENT

Potential compliance tests for advanced glazing systems
 - retention test [18kg guided impactor]
 - head injury assessment test [FMVSS 201 free-motion headform]
 - could include pre-impact roof crush

Sled tests
 - measure neck loading


SLIDE 7:
EJECTION MITIGATION - POTENTIAL COUNTERMEASURES (passive systems)
 - advanced glazing systems 
 	[only possibility, until recently]
 - inflatable systems
 - combination of above

SLIDE 8:
EJECTION MITIGATION - EVALUATING POTENTIAL COUNTERMEASURES (passive systems)
- Advanced Glazing Systems 
  * demonstrated capability to mitigate ejections
  * component tests developed

- Inflatable and/or Combination systems
  * are they effective in mitigating ejections?
  * is retention test developed for glazings suitable?


  

SLIDE 9:
EJECTION MITIGATION
 CURRENT RESEARCH PROGRAM

- Are inflatable and/or combined systems effective in mitigating ejections?
[developed dynamic rollover fixture (DRF)
  * produces repeatable, full-dummy ejections
  * allows measurement of dummy responses
  * research tool only

- Is retention test developed for glazings suitable for inflatable/combined systems?
[18kg guided impactor]


SLIDE 10:
DYNAMIC ROLLOVER FIXTURE
 - acceleration controlled by adjustable weight stack
 - currently using a C/K 1500 test buck
 - testing using 50th, 5th and 6YO dummies

  
SLIDE 11:  
DRF OPERATIONAL FEATURES
 - achieve angular roll rates up to 360 deg/sec
 - lateral position from roll center is adjustable - vary occupant trajectory
 - test buck yaw angle adjustable - vary occupant-to-window impact location
 - drop height and mass adjustable (not explored yet)
 - inflatable devices can be actively depolyed


SLIDE 12:
DRF RESTRICTIONS	
 - not a potential compliance test
 - does not simulate linear vehicle accelerations {rollover sensor performance evaluation may be limited]
 - does not evaluate effects of vehicle damage
  * roof crush
  * distortion of anchorage locations


SLIDE 13:
DYNAMIC ROLLOVER FIXTURE
[photo stills from crash test DRF21 - video excised]
  
SLIDE 14:  
ROLL RADIUS EFFECT
[photo stills from crash test DRF43 - video excised]


SLIDE 15:
YAW ANGLE EFFECT
[photo stills from crash test DRF45 - video excised]


SLIDE 16:
HEAD IMPACT SPEED
[photo stills from video clips - video excised]
impact speed 14 kmph (9mph)
impact speed 18kmph (11mph)
impact speed 20kmph (18mph)
impact speed 30.5 kmph (19mph)
  

SLIDE 17:  
DRF TESTING 50th MALE	
PROTOTYPE INFLATABLE SYSTEM #1 - PRE-DEPLOYED
[photo stills from video clips - video excised]


SLIDE 18:
DRF TESTING - 5th FEMALE
PROTOTYPE INFLATABLE SYSTEM #2 - ACTIVELY DEPLOYED
[photo stills from video clips - video excised]


SLIDES 19-20:
INFLATABLE SYSTEMS
FINDINGS FROM DRF TESTS - TO DATE

Occupant Retention
- adult dummies - mitigates full ejection
  * upper body loads air bag
  * lower body loads door
  * allows arms to 'escape' beneath air bag
  * are dummies as flexible as humans?

- child dummy - TBD

Injury Causing Potential
- HIC responses very low (3 to 156)

Neck Loading low
- compressing from 181 N to 2520 N
- tension from 240 N to 1120 N
- lateral shear loads from 315 N to 950 N
- lateral bending moment from 14 N-m to 61 N-m


SLIDES 21-23:  
18kg GUIDED IMPACTOR

- developed as retention test for advanced glazing systems

- details in first NHTSA status report for advanced glazing research, November 1995

- impactor weight from effective mass study using full dummy [sled & linear pendulum testing]

- impactor face represents aggregate front and side of head

- impact speed range 10 to 15 mph [based on crash test film analysis]

[photo of impactor]


SLIDE 24:
18kg GUIDED IMPACTOR
Inflatable Systems

prototype inflatable system #2 - actively deployed - 10 mph impact
[photos]


SLIDE 25:
18kg GUIDED IMPACTOR
Inflatable Systems

LEFT [photo]prototype inflatable system #1 only - 10mph
RIGHT [photo] prototype inflatable system #1  with advanced glazing - 15mph
  

SLIDEs 26-28:  
SUMMARY
- Ejection through side windows is a significant safety issue
  * over 25,000 ejections per year
  * over 5,000 fatal ejections per year

- Substantial research completed for advanced glazing systems
  * demonstrated ejection mitigation capability
  * component tests developed to evaluate them

- DRF developed to evaluate occupant retention capability for ejection mitigation systems.
  * produces repeatable, realisetic roll rates
  * produces full-dummy ejection through open windows
  * allows measurement of dummy responses
  * occupant trajectories and impact areas are variable
	- dummy size
	- initial dummy position
	- buck configuration

- DRF testing to evaluate inflatable systems is ongiong. Limited evaluation indicates:
  * good potential to mitigate full-body ejections
  * may be susceptible to ejection of arms below air bag
  * low potential to produce head or neck injuries
  * limited potential to evaluate rollover sensor performance [linear vehicle acceleration is not simulated]

- 18kg guided impactor testing is ongoing. Limited evaluation indicates:
  * more concentrated loading area than full-dummy in DRF tests
  * evaluation with roof deformation not straight-forward
  * no potential to evaluate rollover sensor performance