madymo human models for euro ncap pedestrian safety assessment
TRANSCRIPT
MADYMO human models for Euro NCAP pedestrian safety assessment
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Contents
• Introduction – MADYMO Human Models
• Virtual testing in Euro NCAP
• Active bonnet safety performance
• Application of human body models
• MADYMO Human Pedestrian Models
• Ellipsoid Models
• Facet Models
• Conclusion
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Contents
• Introduction – MADYMO Human Models
• Virtual testing in Euro NCAP
• Active bonnet safety performance
• Application of human body models
• MADYMO Human Pedestrian Models
• Ellipsoid Models
• Facet Models
• Conclusion
Introduction - MADYMO Human Models
Fields of Application
– Accident reconstruction
– Real world vehicle safety assessment
– Integrated safety system design
– Safety of vulnerable road users
Typical for these use cases ► crash dummies fail in biofidelity
– non-standard occupant sizes
– non-standard, complex real world load cases
– low severity loading conditions (effects of muscle contraction)
MADYMO pedestrian HBM model
MADYMO occupant HBM model
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Introduction - Human models in MADYMO
Facet occupant human models • Most completely validated MADYMO Human Models
• Computationally efficient & robust performance
• Various anthropometries + scalable
• Model with stabilising spine available
• Recommended model for most applications
FE and facet segment models • Detailed validation for specific loading conditions
• Coupling with Facet Human Model almost always available
Pedestrian human models • Best validated model on the market
• Prediction of head impact location and velocity
• Various anthropometries + scalable
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Contents
• Introduction – MADYMO Human Models
• Virtual testing in Euro NCAP
• Active bonnet safety performance
• Application of human body models
• MADYMO Human Pedestrian Models
• Ellipsoid Models
• Facet Models
• Conclusion
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EuroNCAP - Numerical Assessment
• Over the last years virtual testing and approval has gained importance
• EuroNCAP recently (Feb. 2011, protocol 5.2.1.) adopted a Pedestrian Testing Protocol for the assessment of active bonnets
• The MADYMO ellipsoid pedestrian human models have been accepted as a numerical tool in this protocol
• (Info on protocol also via http://www.euroncap.com)
3yo 6yo 50%m 5%f 95%m
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Active bonnet systems
• Purpose: Generate additional deformation space between bonnet and underlying components (e.g. engine); reducing head injuries
• Triggered when impact of pedestrian with bumper is detected
• System should be fully deployed at time of impact of pedestrian head
• Pedestrian protocol is updated with a part to determine the state of the active bonnet to be used during head impact testing
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Active bonnets - Challenges for performance & Assessment
• Active bonnet performance can depend on full body kinematics of the pedestrian
• Timing of triggering, deployment and head impact
• Loading of bonnet by other body parts can reduce generated deformation space
• Hence, full body pedestrian representation needs to be included in the assessment, to be used in several load cases (locations / sizes)
• Hardware (pedestrian dummies) not feasible due to
• Limited availability of hardware pedestrian dummies in various sizes
• Complex to perform multiple tests at different locations in a well defined manner
• Hence, full body assessment done by means of numerical simulations
• MADYMO ellipsoid pedestrian models have been approved by EuroNCAP to be used for this purpose
3yo 6yo 50%m 5%f 95%m
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Active Bonnets in EuroNCAP - Assessment
• Determining impactor test conditions
• Detection of pedestrians - ‘hardest to detect simulations’
• Timing of bonnet deployment – ‘Deployed state for testing’
• Protection at speeds below the lower deployment threshold speed
• Numerical impactor & Physical tests (up to 3) to confirm the above
• Protection at higher impact speeds
• Physical impactor testing at 50 km/h to confirm triggering and initiation of deployment
• Bonnet deflection due to body loading – ‘Proof system does not bottom out’
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• Run numerical simulations to determine “Hardest to detect” loadcase
• Vehicle impact on (full size) pedestrian model at lower deployment threshold speed
• 4 different pedestrian model sizes (6 year old, 5th, 50th and 95th %-ile)
• 2 different impact locations per model size
• Pedestrian posture:
• Pedestrian in walking posture, moving perpendicular to the vehicle centreline
• Leg on impact side rearward, other leg forward
• Calculate effective mass for “Hardest to detect” loadcase
• Perform impactor tests on the bumper to check whether the system triggers
• Impactor mass: Calculated effective mass
• Impactor speed: lower deployment threshold
Bonnet state determination requirements - Detection of pedestrians
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• Time independent devices (e.g. pop-up bonnet) • Numerical simulations (or other means) required to determine head impact time (HIT)
• Vehicle impact on (full size) pedestrian model with 45 km/h
• Use smallest appropriate pedestrian model size (or 1 for adult and 1 for child/small adult).
• Pedestrian posture as for “Detection of Pedestrians”
If deployment completed before HIT • Test in deployed state
If deployment completed before HIT of adults headform locations but not before HIT of child/small adult headform locations
• Test adult headform in deployed state and child / small adult in undeployed state
If deployment not completed before HIT • Test in undeployed state
• Time dependent devices (e.g. airbag): • All head impact tests are dynamic
• Numerical simulations (or other means) required to determine head impact time as function of WAD, in order to determine deployment timing in head impact test
Bonnet state determination requirements - Timing of bonnet deployment
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• Run numerical simulations
• Vehicle model excluding underbonnet components (engine, battery etc.)
• Vehicle impact on (full size) pedestrian model with 40 km/h
• Use pedestrian model size that loads the least supported part of the bonnet to have maximum deflection.
• Pedestrian posture as for “Detection of Pedestrians” head on vehicle centreline
• 2 simulations to determine bonnet deflection
• Bonnet in undeployed state
• Deflection = z1
• Bonnet in deployed state
• Deflection = z2
• Requirements
• h2 + h3 > z2
• z2 – z1 < 0.75 * h2
Bonnet state determination requirements - Bonnet deflection due to body loading
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Contents
• Introduction – MADYMO Human Models
• Virtual testing in Euro NCAP
• Active bonnet safety performance
• Application of human body models
• MADYMO Human Pedestrian Models
• Ellipsoid Models
• Facet Models
• Conclusion
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MADYMO Ellipsoid Pedestrian human models
• The available MADYMO Pedestrian models are: h_ped3yel
h_ped6yel h_ped05el h_ped50el h_ped95el
• Following models have been approved for numerical assessment of Pedestrian protocol
• Performance
• Adult models validated for impact speeds up to 40 km/h
• Realistic kinematics, accelerations & global injury criteria
• Robust & limited CPU usage
• Multibody
• Ellipsoid surfaces
• Bending & fracture joints in legs
3yo 6yo 50%m 5%f 95%m
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MADYMO Ellipsoid Human Models: Validation
• Tibia & femur static 3-point bending
• PMHS side impactor tests
• Pelvis, thorax and shoulder
• PMHS leg impactor tests
• Bending and shear (Kayzer 1990, 1993)
• PMHS full body pedestrian impact tests
• Yang (1999)
• Ishikawa (1993)
• INRETS (1998)
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Pedestrian human ellipsoid models: Validation Example
Full-body pedestrian-car PMHS tests
INRETS test 00 at 32 km/h
= dents in vehicle
(experimental)
= contacts vehicle-
pedestrian model
1 = contact with lower &
upper leg
2 = contact with pelvis
3 = contact with upper thorax
4 = contact with head
1 2
3 4
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Contents
• Introduction – MADYMO Human Models
• Virtual testing in Euro NCAP
• Active bonnet safety performance
• Application of human body models
• MADYMO Human Pedestrian Models
• Ellipsoid Models
• Facet Models
• Conclusion
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Facet 50th% pedestrian human model
• Completely new model, however based on several released human models.
• The model is validated for typical pedestrian impacts.
• The legs are capable to bend and fracture.
Features compared to ellipsoid model:
• Improved and more realistic contact with FE cars
• Anatomically more human-like
• Additional validation
• Improved respones within corridors
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Facet pedestrian human model - Validation
Frontal, lateral and oblique impacts:
• Head (2 and 5.5 m/s)
• Shoulder (static and 4.5-7 m/s)
• Thorax (velocity 3.3-9.9 m/s, mass 10.4-23.4 kg)
• Abdomen (velocity 4.5-10.4 m/s, mass 18-63.6kg)
• Pelvis (velocity 3.5-9.8 m/s, mass 23.4 kg)
• Knee shear (15 and 20 km/h)
• Knee bending (15 and 20 km/h)
Car impacts:
• Full body (25, 32 and 55 km/h)
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Facet pedestrian human model - Validation
Car impact tests (Ishikawa)
Test #1 (25km/h)
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Facet pedestrian human model - Validation
Car impact tests (Ishikawa)
Trajectory results of test #1, (25km/h)
Horizontal (m)
Vert
ical (m
)
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Contents
• Introduction – MADYMO Human Models
• Virtual testing in Euro NCAP
• Active bonnet safety performance
• Application of human body models
• MADYMO Human Pedestrian Models
• Ellipsoid Models
• Facet Models
• Conclusion
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Current developments
• Human occupant behaviour (for integrated safety)
• Human model validation for pre-crash state prediction
• Motion controlled human model development
• Human pedestrian behaviour
• Facet model family completion for EuroNCAP
• 6yo, 5th%, 95%th
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Conclusion
• Numerical simulation is gradually becoming part of automotive safety assessment protocols, as illustrated by Euro NCAP
• MADYMO human pedestrian models are adopted as a virtual assessment tool in the Euro NCAP pedestrian safety protocol
• MADYMO human pedestrian models can be used in MADYMO standalone simulations as well as in co-simulation with RADIOSS, DYNA, PAM-CRASH & ABAQUS
• A MADYMO facet human pedestrian model family with enhanced model detail and validation is now being developed by TNO & TASS
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Thank you for your kind attention!