Characterizing Posture, Body Shape, and Belt Fit for Older Occupants"
Matthew P. Reed Sheila M. Ebert-Hamilton
Jonathan D. Rupp
Jason J. Hallman, Toyota Technical Center
Motivation
2010
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over 64�
13.0%
over 64�
26.1%
2030
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over 64�
19.3%
over 64�
30.2%
The fraction of the population over age 65 is increasing rapidly in the U.S., Japan, and most other high-income countries.
Motivation Older occupants are at increased risk of injury in crashes, particularly fractures
in the thorax (ribs) and lower extremities.
Young Ribs Old Ribs
Head!
Thorax!
Spine!Abd!
UX!
LX!
0%!
2%!
4%!
6%!
8%!
10%!
12%!
14%!
16%!
18%!
20%!
10! 20! 30! 40! 50! 60! 70! 80! 90!
Ris
k of
AIS
3+
Inju
ry (%
)!
Age (yr.)!
Male, 3pt Belted, Driver, Pass Car, 35 mph DV, BMI=25 kg/m2!
Head (OR=4.6)!Thorax (OR=Male:11.6,Female:37.6)!Spine (OR=5.9)!Abdomen (OR=7.0)!UX (OR=2.6)!LX (OR=4.0)!
From Rupp et al. SAE GI 2011 Presentation
Young Bone
Images from Nalla et al. (2004)
Old Bone
35 YO Female 75 YO Female
Motivation Occupant shape, mass distribution, and posture affect injury potential in crashes.
Change in body shape with age at the same total body mass for midsize men and women (Example from UMTRI analysis of U.S. CAESAR Data)
Age 20 yrs Age 65 yrs
Normal
Obese
Age 85 yrs
?
From Turkovich et al. 2010
Differences in posture and belt fit between young and old.
Motivation Vehicle restraint systems are developed and tested using crash test dummies and computational models that represent specific occupant shapes and sizes.
Dummy images from Humanetics Current 5th, 50th, and 95th %ile weights from NHANES 2005-2006
Hybrid III 95th %ile male
Hybrid III 50th %ile male
Hybrid III 5th %ile female
Dummy Specification
6’2” 226 lb.
5’9” 172 lb. 5’0”, 103 lb.
Current Population 6’3”, 271 lb. 5’9”, 189 lb 5’0”, 113 lb.
Midsize elderly male and midsize male and Hybrid III midsize male ATD in the same seat.
Research Questions
Do elderly drivers and passengers sit differently from younger drivers and passengers?
Are body shapes of elderly and younger occupants different at the same stature and body weight?
Do elderly occupants experience different belt fit in driving postures?
Load-sharing between belts, airbags, and knee bolsters; patterns of injury across body regions
Amounts of soft tissue between belt and skeleton; load sharing between restraints, occupant kinematics
Belt loading could be changed by patterns of soft tissue shape and by elderly belt routing preferences
Questions What Would Be Affected
Research Objectives 1. Quantify differences in
– posture – body shape – belt fit between young and old in driver and rear-seat passenger environments.
2. Create design and analysis tools: add “age” effect to: – vehicle interior design tools – crash-dummy-positioning methods – models of seated body shape – belt-fit prediction model
Participants Study participants with a wide range of body size and age (N=200)
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60% over age 60
Research Methods: Driving Posture
Research Methods: Passenger Posture
Research Methods: Body Shape • Standard anthropometry • Whole-body laser scanner • Additional landmarks with FARO Arm • Standing and seated postures
Red laser beam
Hand-held laser scanner to augment towers
Laser Scanner
Results – Body Scans
Hybrid-III ATD
Potential Application: Parametric Modeling
BMI 20 BMI 26 BMI 32 BMI 38
Example of torso shape modeling using statistical model from a previous study.
THUMS 4 - baseline BMI 30 BMI 35
Acknowledgements This research was funded by the
Toyota Collaborative Safety Research Center
http://www.toyota.com/csrc/
For more information:
http://mreed.umtri.umich.edu
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