Title: Design%20of%20a%20Biofidelic,%20Instrumented%202.5%20Kg%20Infant%20Dummy%20%20N.%20Rangarajan,%20Ph.D.,%20J.%20Mc%20Donald,%20BSME,%20T.%20Shams,%20Ph.D.,%20%20R.%20Delbridge,%20MSME%20GESAC,%20Inc%20T.%20Fukuda,%20Y-M.%20Liu,%20MD,%20K.%20Kawasaki,%20H.%20Morishima,%20%20%20%20%20Y.%20Tokushige%20Aprica,%20Inc
1Design of a Biofidelic, Instrumented 2.5 Kg
Infant DummyN. Rangarajan, Ph.D., J. Mc
Donald, BSME, T. Shams, Ph.D., R. Delbridge,
MSMEGESAC, IncT. Fukuda, Y-M. Liu, MD, K.
Kawasaki, H. Morishima, Y.
TokushigeAprica, Inc
2Aprica 2.5 infant dummy
3 Presentation Sequence
- Need for an infant dummy
- Anthropometry of dummy
- Instrumentation
- Design of body segments
- Response of dummy under static loading
- Reproducibility and repeatability
- Future work
- Acknowledgement and References
4 Need for an infant dummy
- Children and infants spend more and more time in
cars. - Infants have difficulty supporting their heads.
Therefore, when an infant is seated in a
traditional child seat, there is concern that the
oxygen saturation level in the blood stream may
be compromised due to positional apnea. - Test tools for conducting dynamic tests of
infants on car seats and car beds not currently
available.
5 Data needed to design
infant dummy
- Anthropometric data.
- Static and dynamic response data for various body
segments - Injury reference values for various body
segments. These are needed to decide on
instrumentation for body segments.
6 Anthropometry of infant
dummy - 1
- Anthropometry of dummy corresponds to 10th
percentile Japanese infant JMoT data. - Segment and other data obtained by measuring 4
infants at a hospital in Osaka, Japan. - Where needed, infant anthropometry data from
CMVSS 213.5 was used. - Range of Motion RoM data were estimated from
adult RoM.
7 Anthropometry of infant
dummy - 2
Item 1st infant Avg. 3 infants Design goal
Mass 2,572g 2,603g 2,600g
Height 0.45m 0.44m 0.45m
Arm length 0.18m 0.183m 0.18m
Leg length crotch to heel 01.5m 0.152m 0.15m
Top of head to shoulder 0.11m 0.108m 0.11m
8 Anthropometry of infant
dummy - 3
Item 1st infant Avg. 3 infants Design goal
Head circum. 0.31m 0.34m 0.35m
Head length 0.118m 0.118m 0.118m
Head width 0.88m 0.88m 0.95m
Head Depth 0.14m 0.14m 0.112m
Neck Circumf. 0.18m 0.187m 0.172m
Neck length 0.05m 0.054m
9 Anthropometry of infant
dummy - 4
Item 1st infant Avg. 3 infants Design goal
Shldr circum. 0.3m 0.322m 0.297m
Chest circum. 0.29m 0.315m 0.298m
Waist circumf. 0.31m 0.323m 0.318m
Hip circumf. 0.28m 0.285m 0.286m
Upr arm circumf 0.08m 0.093m 0.08m
Thigh circumf. 0.13m 0.13m
10 Anthropometry of infant
dummy - 5
Item 1st infant Avg. 3 infants Design goal
Head mass 0.8 kg
Upr arm mass 0.029 kg
Lwr arm mass 0.022 kg
Upr leg mass 0.082 kg
Lwr leg mass 0.048 kg
11 Anthropometry of infant
dummy - 6
Estimated Joint Loads
Joint Max. Load (N)/Torque (Nm)
Neck 1, 000 / 60
Shoulder 100 / 10
Pelvis / lumbar 2,000 / 200
Hip 300 / 30
Knee 100 / 5
12Response and Injury Assessment Reference Values
IARV
- Static and dynamic response data for
- body segments estimated from available
- adult response data. Available response
- corridors shown with dummys response in
- static tests.
- Injury reference values to be developed
13Aprica 2.5 infant dummy
14Design of Body Segments Head - 1
- Two-stiffness casting or Urethane.
- Scalp stiffer than flesh.
- Flesh stiffness about durometer 30A
15Design of Body Segments Head - 2
Assembled view of head with sensors
16Design of Body Segments Head - 3
Bottom view of head casting
17Design of Body Segments Head - 4
Head instrumentation holder with 3
accelerometers
18Design of Body Segments Neck - 1
Neck showing housing for accelero- meters at top
and bottom.
19Design of Body Segments Neck - 2
Neck mounted on T-spine with accels
20Design of Body Segments Neck - 3
Neck with neck shroud
21Design of Body Segments Thorax - 1
Thorax consists of 1. Shoulder 2. Thoracic
and lumbar spines 3. Thoracic flesh and
response element
22Design of Body Segments Thorax 2 Skeleton
Skeletal layout showing shoulder, T-spine and
tri-axial accels
23Design of Body Segments Thorax 3 Shoulder
Delrin shoulder block showing ball joint for the
arm.
24Design of Body Segments Thorax 4 T-spine
Urthane and Aluminium T-spine with tri-axial
accels
25Design of Body SegmentsThorax 5 Response Unit
Foam response unit and tri-axial accelerometers
26Design of Body SegmentsThorax 6 Thoracic
flesh
Infant dummy showing thoracic flesh
27Design of Body Segments Pelvis 1 Pelvic Bone
Infant dummy pelvic bone
28Design of Body Segments Pelvis 2 Pelvis
Accels
Pelvis tri-axial accelerometers
29Sample static response data - Neck
Neck response data against scaled Mertz corridor
30Sample static response data - Thorax
Thorax force-displacement data showing repeat-
ability in static tests
31 Future work - 1
- Dummy needs to be dynamically tested to confirm
biofidelity. Test methodology to be developed.
Scaled response corridors developed. Following
tests are under consideration - Kroell test for thorax
- Head-neck pendulum test for neck to compare data
with Mertz corridor - Head drop tests.
32 Future work - 2
- Injury causation mechanism to be evaluated.
- Measurable variables relating to injury to be
developed. - Dynamic sled testing needs to be conducted to
evaluate sled performance of dummy. - Robustness of the dummy needs to be evaluated
through repeated testing. - Repeatability needs to evaluated.
- Reproducibility to be evaluated.
33 Future work - 3
- Data from dynamic and sled tests to be used to
develop appropriate lumped mass and FE models.
34 Acknowledgement
- Development of dummy was supported by funding
from Aprica Child Care Institute, Japan.
35 References - 1
- McPherson, G, T. Kriewall. 1980. The elastic
modulus of fetal cranial bone A first step
towards an understanding of the biomechanics of
fetal head modling. Journal of Biomechanics, Vol.
13, 1, pp 9-16. - Melvin, J. 1995. Injury assessment reference
values for the CRABI 6-month infant dummy in
rear-facing infant restraint with airbag
deployment. SAE Paper No. 950872 -
36 References - 2
- Mertz, H. 1984. A procedure of normalizing
impact response data. SAE Paper No. 840884 - Mertz, et al. 1989. Size, weight and
biomechanical impact response requirements for
adult size small female and large male dummies.
SAE Paper No. 890756 -
37 References - 3
- Ratingen, M, et al. 1997. Biomechanically based
design and performance targets for a 3-year old
child crash dummy for frontal and side impact.
SAE Paper No. 973316 - Robbins,D. 1983. Anthropometric specifications
for mid-sized male dummy. Final report.
Contract DTNH22-80-C-07502. -
38 References - 4
- Schneider, L, D. Robbins, M. Pflug, and R.
Snyder. 1983. Development of anthropometrically
based design specifications for an advanced adult
anthropometric dummy family. UMTRI Report Np.
UMTRI-83-53-1. -
39Aprica 2.5 infant dummy
40Thank you