Moving Deformable Barrier Test Procedure for Evaluating ...intrusion when compared to Oblique test procedure PAPER # 2012-01-0577 . SAE 2012 World Congress Detroit, Michigan 4/25/2012

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Moving Deformable Barrier Test Procedure for Evaluating Small Overlap/Oblique Crashes

James Saunders, NHTSA

Dan Parent, NHTSA

Matthew Craig, NHTSA

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2

Presentation Outline

PAPER # 2012-01-0577

Background

Part 1: Vehicle Characteristics ◦ Compare Oblique Vehicle-to-Vehicle to Oblique

RMDB-to-Vehicle

◦ Results of new vehicle design testing

Small Overlap / Oblique

Compare Small Overlap to Oblique

Part 2: Dummy Characteristics

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3

Background

PAPER # 2012-01-0577

Bean et al, 2009: Poor structural engagement resulted in largest number fatalities, excluding exceedingly severe crashes

Rudd et al, 2011: NASS/CIREN study showed Knee Thigh Hip AIS 3+ most frequent injuries followed by chest and lower leg

Saunders et al, 2011: Demonstrated that the use of the current FMVSS 214 barrier was not suitable for this type of test procedure

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4

RMDB Barrier Characteristics

PAPER # 2012-01-0577

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5

Oblique Vehicle-to-Vehicle comparison to RMDB-to-Vehicle

PAPER # 2012-01-0577

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6

Oblique Test Procedure Setup

PAPER # 2012-01-0577

Bullet

v

50 %

15 degrees

Bullet

v

35 %

15 degrees

Bullet vehicle speed was determined to achieve a 35 mph DV, in full frontal, in the stationary vehicle

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7

Top View of VtV to RMDBtV comparison

PAPER # 2012-01-0577

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Acceleration and Velocity PCb

PAPER # 2012-01-0577

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9

Interior Intrusion and Exterior Crush

PAPER # 2012-01-0577

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10

New Model Testing

PAPER # 2012-01-0577

11

Constant-energy test procedure

PAPER # 2012-01-0577

Moving deformable barrier impacts each vehicle at the same velocity ◦ Compare results across the fleet

◦ Procedure is more severe for smaller cars

◦ Potential to drive convergence of vehicle front-end stiffness

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12

Vehicle Selection

PAPER # 2012-01-0577

Vehicles introduced or redesigned in 2010-2011

Good structural rating from IIHS

Different classes of vehicles ranging from the lightest to the heaviest

Compare heavy vehicle with body-on-frame and uni-body design

8 SOI and 7 Oblique

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13

Test Setup

PAPER # 2012-01-0577

Bullet

v

Outer edge of MDB aligned with desired overlap (d) (measured from the outer edge of vehicle)

Angle of stationary vehicle relative to track (ѳ)

Small Overlap (SOI) Oblique

Test Setup

Rationale Test Setup

Rational

Barrier Closing Speed

56 mph Achieve 35mph Delta-V in average-mass

passenger car

56 mph Achieve 35mph Delta-V in average-mass passenger

car

Overlap 20% Engage structure outboard of

longitudinal rail for most vehicles

35% Represent vehicle-to-vehicle test with 50%

overlap (engagement of one longitudinal rail)

Angle Relative to Track

7 degrees 0 degrees bounced off 15 degrees deformed

rail inboard

15 degrees

PDOF of 10-20 degrees most prominent in field

after full frontal

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14

PC2 SOI and Oblique Top View

PAPER # 2012-01-0577

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15

PU1 SOI and Oblique Video

PAPER # 2012-01-0577

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16

PC1 and SUV1 SOI Video

PAPER # 2012-01-0577

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17

Velocity Traces

PAPER # 2012-01-0577

Small Overlap Oblique

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18

Intrusions

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19

AvgGs comparison between SOI and Oblique

PAPER # 2012-01-0577

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Summary

VtV to RMDBtV Comparison ◦ Oblique test procedure using the RMDB as a

surrogate for a vehicle was generally able to replicate VtV

New Vehicle Study ◦ DV decreased as mass of the vehicle increase

◦ SOI condition did not always produce greater intrusion when compared to Oblique test procedure

PAPER # 2012-01-0577

SAE 2012 World Congress Detroit, Michigan 4/25/2012

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Presentation Overview

Field exposure

Description of test device (THOR)

Vehicle-to-vehicle vs. RMDB

Occupant response

◦ SOI Kinematics

◦ SOI Restraint interaction

◦ SOI Injury Assessment

◦ Oblique vs. SOI

Summary

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4/25/2012

Review of CIREN and NASS Cases

(Rudd 2011)

Requirements ◦ Belted drivers with at least one

AIS 3+ injury

◦ Vehicle model year 1998 and newer

◦ Front or left side damage

◦ 320º < PDOF < 0º

◦ No under-, over-ride

SOI ◦ Engagement outside of left

longitudinal

Left Offset ◦ Left longitudinal engaged

AIS 3+: KTH > Chest > Head ◦ Independent of mode

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0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

HeadAIS 3+

ChestAIS 3+

KTHAIS 3+

Leg/FootAIS 2+

% o

f C

ases

SOI (N=124)

Left Offset (N=152)

SOI and Left Offset (N=276)

4/25/2012

Occupant Response Assessment:

THOR ATD

THOR-NT with Mod Kit (Ridella, 2011)

◦ Improvements to biofidelity, repeatability, durability, usability

Designed to demonstrate improved biofidelic kinematics vs. Hybrid III

◦ Flexible joints in thoracic and lumbar spine

◦ Improved restraint interaction

Increased measurement capability vs. Hybrid III

◦ Thorax: 4-point, 3-dimensional chest deflection

◦ Abdomen: 2-point, 3-dimensional lower abdomen deflection

◦ Knee-thigh-hip: Acetabulum load cells

◦ Lower Extremity: Upper, lower tibia loads; ankle rotations

Limitation: Injury Assessment Reference Values (IARVs) not yet established

◦ Provisional IARVs used for this study

◦ THOR-specific IARVs to be developed 2012-2013

◦ Example: Rotational Brain Injury Criterion (BRIC)

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4/25/2012

Rotational Brain Injury Criterion (BRIC)

THOR-specific critical values determined (per Takhounts 2011) ◦ Basis = 31 THOR small

overlap/oblique tests

◦ Result = injury risk curves • f(BRIC) = p(AIS 3+) and p(AIS 4+)

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valuecriticalvalueresultant maximummax

CG headat on acceleratiangular CG headat locity angular ve

maxmax

cr

BRICcrcr

Critical Values

ωcr

(rad/s)

αcr

(rad/s2)

Hybrid III 46.41 39,775

THOR 63.5 19,501

0.0

0.2

0.4

0.6

0.8

1.0

0.0 0.5 1.0 1.5 2.0

Pro

ba

bilit

y o

f In

jury

BRIC

BRIC Injury Risk Function

AIS 3+

AIS 4+

BRIC = 0.89 30% AIS 3+

4/25/2012

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

BRIC

PC1

PC2

PC3

PC4

PC5

PC6

SUV1

PU10.0

0.2

0.4

0.6

0.8

1.0

1.2

HIC15

PC1

PC2

PC3

PC4

PC5

PC6

SUV1

PU1

SOI: Head Response

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IAV

/ I

AR

V

Test: Head Contact Locations

Vehicle Airbag

Side

Curtain

Roof

Rail

Door

Panel IP

PC1 X

PC2 X X X X

PC3 X X X

PC4 X X

PC5 X

PC6 X X

SUV1 X X

PU1 X

Field Injury

Source

(Rudd, 2011)

4% 28% 12%

IAV

/ I

AR

V

4/25/2012

0.0

10.0

20.0

30.0

40.0

50.0

60.0

CMAX

PC1

PC2

PC3

PC4

PC5

PC6

SUV1

PU1

SOI: Chest Deflections

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Chest

Deflection (

mm

)

NASS/CIREN SOI: Chest injury sources Belt: 38%

Door: 32%

Steering wheel: 16%

SOI Tests: Chest deflection sources Primarily belt interaction

No evidence of door contact

Door often deformed outward

Evidence of steering wheel interaction in smaller vehicles (e.g. PC2)

4/25/2012

0.0

0.5

1.0

1.5

2.0

2.5

3.0

FemurL FemurR

PC1

PC2

PC3

PC4

PC5

PC6

SUV1

PU10.0

0.5

1.0

1.5

2.0

2.5

3.0

AcetabL AcetabR

PC1

PC2

PC3

PC4

PC5

PC6

SUV1

PU1

SOI: Knee-Thigh-Hip

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IAV

/ I

AR

V

IAV

/ I

AR

V

4 test exceeded acetabulum IARV

2 tests exceeded femur IARV

2 tests that exceeded acetabulum IARV did not exceed

femur IARV

Rudd (2011) showed that over half of acetabulum

injuries occurred in absence of femur injury

4/25/2012

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Max Ankle Rotation

PC1

PC2

PC3

PC4

PC5

PC6

SUV1

PU10.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Max Tibia Index

PC1

PC2

PC3

PC4

PC5

PC6

SUV1

PU1

SOI: Lower Extremity

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IAV

/ I

AR

V

IAV

/ I

AR

V

Highest Toepan Intrusion

4/25/2012

Head response, SOI vs. Oblique

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SOI (PC2)

Oblique (PC2)

IAV

/ I

AR

V

0.0

0.5

1.0

1.5

2.0

2.5

3.0

SOI Oblique All

Max

Mean+SD

Mean

Mean-SD

Min

HIC15

4/25/2012

Oblique vs. SOI: Head, Chest

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0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

SOI Oblique All

Max

Mean+SD

Mean

Mean-SD

Min

Chest D

efle

ction (

mm

)

Chest Deflection

0

5

10

15

20

25

30

Avg

Gs X

SOI

Oblique

4/25/2012

PC1 PC2 PC3 PC4 PC5 PC6 SUV1 PU1

0.0

0.5

1.0

1.5

2.0

2.5

3.0

SOI Oblique All

Max

Mean+SD

Mean

Mean-SD

Min

0.0

0.5

1.0

1.5

2.0

2.5

3.0

SOI Oblique All

Max

Mean+SD

Mean

Mean-SD

Min

Oblique vs. SOI: Knee-Thigh-Hip

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IAV

/ I

AR

V

Peak Acetabulum Force Peak Femur Axial Force

IAV

/ I

AR

V

4/25/2012

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

SOI Oblique All

Max

Mean+SD

Mean

Mean-SD

Min

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

SOI Oblique All

Max

Mean+SD

Mean

Mean-SD

Min

Oblique vs. SOI: Lower Extremity

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IAV

/ I

AR

V

Maximum Tibia Index Maximum Ankle Rotation

IAV

/ I

AR

V

4/25/2012

SOI Test vs. Real World

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NASS/CIREN data from case study of MY 1998 to 2009 with AIS3+ head,

chest, and/or KTH

NASS/CIREN data represents older vehicle designs

0%

10%

20%

30%

40%

50%

60%

70%

Head Chest KTH LowerExtremity

Pe

rce

nt o

f C

as

es

Injury Distribution

NASS/CIREN SOI (N=124)

AIS 3+ AIS 3+ AIS 3+ AIS 2+

0%

10%

20%

30%

40%

50%

60%

70%

Head Chest KTH LowerExtremity

Pe

rce

nt o

f T

es

ts

IAV > IARV

SOI Tests (N=8)

4/25/2012

0%

10%

20%

30%

40%

50%

60%

70%

Head Chest KTH LowerExtremity

Pe

rce

nt o

f C

as

es

Injury Distribution

NASS/CIREN Left Offset

(N=152)

Oblique Test vs. Real World

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NASS/CIREN data from case study of MY 1998 to 2009 with AIS3+ head,

chest, and/or KTH

NASS/CIREN data represents older vehicle designs

AIS 3+ AIS 3+ AIS 3+ AIS 2+

0%

10%

20%

30%

40%

50%

60%

70%

Head Chest KTH LowerExtremity

Pe

rce

nt o

f T

es

ts

IAV > IARV

Oblique Tests (N=7)

4/25/2012

Summary

RMDB test shows similar occupant kinematics to Vehicle-to-vehicle test

SOI and Oblique test conditions show similar kinematics but different injury risk ◦ Head, chest higher risk in Oblique

◦ Knee-thigh-hip higher risk in SOI

◦ Lower extremity similar risk in Oblique and SOI

SOI and Oblique conditions demonstrate field injury risk

SOI and Oblique test conditions demonstrated usability, durability, and utility of Mod Kit THOR ATD

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4/25/2012