madymo human models for euro ncap pedestrian safety assessment

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







• 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







• 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

http://www.euroncap.com/

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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







• 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







• 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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Car impact tests (Ishikawa)

Test #1 (25km/h)

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Car impact tests (Ishikawa)

Trajectory results of test #1, (25km/h)

Horizontal (m)

Vert

ical (m

)

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Contents







• 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!

madymo human models for euro ncap pedestrian safety assessment

Technology

impact of pedestrian

introduction human models

validated madymo human

size pedestrian model

facet human model

body pedestrian representation

facet segment models

model size pedestrian