status of nhtsa’s thor 5th female meetings/sae... · 2016-07-11 · safer drivers. safer cars....
TRANSCRIPT
National Highway Traffic Safety Administration
Status of NHTSA’s THOR 5th Female Anthropomorphic Test Dummy
Ellen Lee Mechanical Engineer, NHTSA
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• Background / History • Design / Target Anthropometry • Biofidelity
– Scaling Strategy – Quantitative Evaluation Strategy – Testing Requirements / Results
• Long Term Plan
Outline
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• Small female injuries still a problem – Different restraint interactions than males – Different seating postures
• THOR 5th ATD designed to provide improved biofidelity compared to Hybrid III 5th – Head/neck motion – Restraint interaction (e.g. abdominal response in submarining) – Improved pelvis, knee-thigh-hip, lower leg
• THOR 5th ATD will have improved measurement capabilities compared to Hybrid III 5th – Multi-point chest deflection – Abdominal sensors – Hip load cells – Foot/ankle measurement capabilities
Background: Why THOR 5th?
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History
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2000 2005 2015
First prototype delivered to NHTSA
Contract initiated to build prototype THOR-05F ATD
2017
Contract initiated with Humanetics to build 3 THOR-05F ATDs
Expect delivery to NHTSA
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• Anthropometry of Motor Vehicle Occupants (AMVO) study (Schneider et al., 1983)
• Overall body mass: 48.2 kg • Sitting height: 93.3 cm • Stature: 151.3 cm • Fifth female stature and
weight in US do not currently differ significantly from AMVO study
• New pelvis geometry from UMTRI
Fifth Female Target Anthropometry
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• Equal stress/equal velocity scaling technique
• Assumes equal mass densities and elastic moduli of human tissue (muscle, bone, etc.) irrespective of gender
• Constant density assumption: λm = λx λy λz
• Scaling factors (λ) determined for each body region
– In some instances, scaling factors differ from earlier dummies
• Response characteristics (e.g. force, acceleration, moment, angle) scaled using appropriate factors
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Biofidelity Scaling Strategy
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“Characteristic Lengths” • Neck breadth/depth • Thorax depth • Abdomen depth • Femur length (seated) • Lower leg λx≈λy≈λz Comparison to Hybrid III • Erect seated height • Femur length
(standing)
Biofidelity Scaling Strategy
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Biofidelity Evaluation Strategy
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• Biofidelity Ranking System (Rhule et al., 2013)
– Quantitative assessment – “BRS” or “BioRank” – BRS Score < 2.0 = Good biofidelity
• ATD response as similar to the PMHS corridor as another individual PMHS response
– Requires +/- 1 standard deviation response corridors as time-histories
– Will have a defined “acceptance” criteria for biofidelity
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• Head – Forehead impact – Face rigid bar – Face rigid disk
• Neck – Frontal flexion (NBDL) – Lateral flexion (NBDL)
• Thorax – Blunt hub central impact – Lower oblique impact – Full dummy sled test
Biofidelity Evaluation
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• Abdomen – Upper SW impact – Lower rigid bar – Belt pull
• Knee/Thigh/Hip (KTH) – Femur compressive load – Full dummy KTH (large impactor) – Knee slider
• Lower Leg – Axial impact – Dynamic dorsiflexion – Inversion/eversion
Newer PMHS data
New Requirements
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• Frontal and lateral flexion requirements based on volunteer sled tests conducted at Naval Biodynamics Research Laboratory (NBDL) (Thunnissen, 1995)
• 15 g pulse (frontal); 7 g pulse (lateral) • Head/neck response defined by: head rotation angle, neck
rotation angle, and displacement of head CG relative to T1 • Key finding – Head rotation “lags” behind rotation of the neck • THOR 5th neck spring cables allow head lag
Neck Kinematic Testing
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Thorax Biofidelity – Prototype THOR 5th
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0
500
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0 10 20 30 40 50
Forc
e (N
)
Deflection (mm)
• Central “blunt hub” impact
• 4.3 m/s, 14 kg • Force vs. deflection
– Internal (Neathery, 1974)
– External (Lebarbe, 2012)
Internal Deflection
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Thorax Biofidelity – Prototype THOR 5th
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External Deflection
0 20 40 60 80External Deflection (mm)
0
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2000
2500
3000
3500
Forc
e (N
)
THOR 50th
THOR-NT Hybrid III 50th
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• 5 fifth female PMHS • Full-frontal, 30 km/hr delta-V, sled test • 3-point belt with 2 kN load limit • Knees and feet restrained rigidly
Full Dummy Sled Test
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NHTSA Biomechanics Database Test Numbers: 11491-11495
Opportunity for original fifth female corridors (not scaled)
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• New for THOR 5th • Based on tests done by Lamielle et al., 2008 • Rigid seat with fixed back • Seat belt loading applied at umbilicus (L2) level, oriented
horizontally • Velocity input • Response target is belt force vs. abdominal deflection
Abdomen Belt Pull
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• New for THOR 5th – tests whole KTH complex (incl. acetabulum)
• Based on tests done by Rupp et al., 2008 • Symmetric loading applied to both knees of seated subject • Large mass (255 kg)
pneumatic impactor • Speeds from 1.2 to 4.9 m/s
– we will focus on 4.9 m/s • Requirement is force-time
response of acetabulum
Knee/Thigh/Hip Testing
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• New for THOR 5th • Based on tests by Funk et al.,
2002 • Pure moments applied
dynamically (1000 °/sec) • Response target is ankle
moment vs. rotation angle
Ankle Inversion/Eversion (Dynamic)
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Eversion Inversion
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• Repeatability and Reproducibility • Development of Qualification Tests • Durability Testing • Development of Injury Criteria • Potential Applications
– Full Frontal and Oblique – Rear Seat – Low Speed
Long Term Plan
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