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 - PowerPoint PPT Presentation

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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

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Design of a Biofidelic, Instrumented 2.5 Kg Infant Dummy N. Rangarajan, Ph.D., J. Mc Donald, BSME, T. Shams, Ph.D., R. Delbridge, MSME GESAC, Inc – PowerPoint PPT presentation

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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


1
Design 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
2
Aprica 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
12
Response 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

13
Aprica 2.5 infant dummy
14
Design of Body Segments Head - 1
  • Two-stiffness casting or Urethane.
  • Scalp stiffer than flesh.
  • Flesh stiffness about durometer 30A

15
Design of Body Segments Head - 2
Assembled view of head with sensors
16
Design of Body Segments Head - 3
Bottom view of head casting
17
Design of Body Segments Head - 4
Head instrumentation holder with 3
accelerometers
18
Design of Body Segments Neck - 1
Neck showing housing for accelero- meters at top
and bottom.
19
Design of Body Segments Neck - 2
Neck mounted on T-spine with accels
20
Design of Body Segments Neck - 3
Neck with neck shroud
21
Design of Body Segments Thorax - 1
Thorax consists of 1. Shoulder 2. Thoracic
and lumbar spines 3. Thoracic flesh and
response element
22
Design of Body Segments Thorax 2 Skeleton
Skeletal layout showing shoulder, T-spine and
tri-axial accels
23
Design of Body Segments Thorax 3 Shoulder
Delrin shoulder block showing ball joint for the
arm.
24
Design of Body Segments Thorax 4 T-spine
Urthane and Aluminium T-spine with tri-axial
accels
25
Design of Body SegmentsThorax 5 Response Unit
Foam response unit and tri-axial accelerometers
26
Design of Body SegmentsThorax 6 Thoracic
flesh
Infant dummy showing thoracic flesh
27
Design of Body Segments Pelvis 1 Pelvic Bone
Infant dummy pelvic bone
28
Design of Body Segments Pelvis 2 Pelvis
Accels
Pelvis tri-axial accelerometers
29
Sample static response data - Neck
Neck response data against scaled Mertz corridor
30
Sample 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.

39
Aprica 2.5 infant dummy
40
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