Information on the Flexible Pedestrian Legform Impactor (Flex-PLI)

from J-MLIT Research

INF/GR/PS/106

Ministry of Land, Infrastructure and Transport Government of Japan

(J-MLIT)

Construction

Thigh(RIGID)

Leg (RIGID)

Damper

KneeJoint

(Steel KneeBending Plate)

TRL-LFI Flex-PLI 2003

Thigh(FLEXIBLE)

Leg(FLEXIBLE)

Knee Joint*(ligament restraint

system)

Flex-PLI has higher biofidelic construction than the TRL-LFI

Validation of biofidelity

Biofidelity

Flex-PLI has high biofidelity

-100

0

100

200

300

400

500

600

0 10 20 30 40 50 60

Deflection (mm)

Mom

ent (

Nm

)

Corridor Lower

Corridor Upper

Corridor Avg.

FlexPLI 2003R Avg.

UVA Mid-Thigh Dynamic Bending Corridor

DDV/DCV Rating0.30 0 to 1 Excellent

1 to 2 Good2 to 3 Moderateover 3 Poor

-50

0

50

100

150

200

250

300

350

400

0 10 20 30 40 50

Deflection (mm)

Mom

ent (

Nm

)

Corridor LowerCorridor UpperCorridor Avg.FlexPLI 2003R Avg.

UVA Mid-Leg Dynamic Bending Corridor

DDV/DCV Rating0.33 0 to 1 Excellent

1 to 2 Good2 to 3 Moderateover 3 Poor

0

20

40

60

80

100

120

140

160

180

200

0 2 4 6 8 10 12 14 16

Angle (deg.)

Mom

ent (

Nm

)

Corridor Lower

Corridor Upper

Corridor Avg.

FlexPLI 2003R Avg.

UVA Knee Dynamic Bending Corridor

RatingDDV/DCV 0 to 1 Excellent

1.27 1 to 2 Good2 to 3 Moderateover 3 Poor

Flex-PLI 2003

Thigh(FLEXIBLE)

Leg(FLEXIBLE)

Knee Joint*(ligament restraint

system)

IHRA/PS/290

TRL-LFIcannot bend

TRL-LFIstiffer knee joint

TRL-LFIcannot bend

Measurement System

for Knee ligamentsinjury assessment

(Angle, Disp.)

for Leg injuryassessment

(Acc.)

Knee Shearing(displacement)

Knee Bending(angle)

Leg 0(acceleration)

TRL-LFI

Knee Joint

65 mm

Impact

for Leg Injury assessment

(strain)

for Knee ligamentsinjury assessment

(Elongation)PCL (elongation)MCL (elongation)

ACL (elongation)

LCL (elongation)

Flex-PLI 2003

Leg 1 (strain)

Leg 2 (strain)

Leg 3(strain)

Leg 4(strain)

Leg 5 (strain)

Thigh 1 (strain)

Thigh 2 (strain)

Thigh 3 (strain)

Thigh 4 (strain)

Knee Joint

92 mm

172 mm

252 mm

332 mm

93 mm

173 mm

253 mm

333 mm

413 mm

Lateral and Medial Condyle (force)

Impact

Flex-PLI has higher injury assessment ability than the TRL-LFI

no measurement

Kinematics

Flex-PLI Human FE-Model (THUMS)

TRL-LFI FE-Model of TRL-LFI

JASIC 2003 Report

Flex-PLI can simulate human lower extremity bending motion properly.(TRL-LFI can bend the knee joint portion only)

Knee bending only

Over all lower extremity bending motion is observed.

Repeatability for Thigh in dynamic certification test

Flex-PLI Thigh has high repeatability in dynamic certification test.

Repeatability test (20 times loading)

0

50

100

150

200

250

300

350

400

450

500

0 5 10 15 20 25 30 35 40 45

Deflection (mm)

Mom

ent (

Nm

)Thigh4-1

Thigh4-5

Thigh4-10

Thigh4-15

Thigh4-20

Repeatability for Leg in dynamic certification test

Flex-PLI Leg has high repeatability in dynamic certification test.

0

50

100

150

200

250

300

350

400

450

0 5 10 15 20 25 30 35 40 45

Deflection (mm)

Mom

ent (

Nm

)

Leg2-1

Leg2-5

Leg2-11

Leg2-16

Leg2-20

Repeatability test (20 times loading)

Re-product-ability for Thigh in dynamic certification test

Flex-PLI Thigh has high re-product-ability in dynamic certification test.

0

50

100

150

200

250

300

350

400

450

500

0 5 10 15 20 25 30 35 40 45

Deflection (mm)

Mom

ent (

Nm

)Thigh1-1

Thigh1-2

Thigh3-1

Thigh3-2

Thigh4-1

Thigh4-2

Re-product-ability test (3 products)

Re-producta-bility for Leg in dynamic certification test

Flex-PLI has high re-product-ability in dynamic certification test.

0

50

100

150

200

250

300

350

400

450

500

0 5 10 15 20 25 30 35 40 45

Deflection (mm)

Mom

ent (

Nm

)Leg2-1

Leg2-2

Leg4-1

Leg4-2

Leg6-1

Leg6-2

Re-product-ability test (3 products)

Flex-PLI 2003R Subsystem test

Repeatability in subsystem test

Flex-PLI has high repeatability in subsystem test.

Flex-PLI 2003 R

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

0.02

Thigh 4 Thigh 3 Thigh 2 Thigh 1 Leg 1 Leg 2 Leg 3 Leg 4 Leg 5

Str

ain

FR-T1FR-T2FR-T3

0

2

4

6

8

10

12

14

ACL PCL MCLE

long

atio

n (m

m)

FR-T1FR-T2FR-T3

Thigh and Leg (strain) Knee (ligament elongation)

Discussion

Flex-PLI

TRL-LFI

Knee bending only

Over all lower extremity bending motion is observed.

from the KinematicsTRL-LFI has a possibility to mislead the protection way for the pedestrian lower extremity, since it cannot simulate the human lower extremity motion properly.

from the Measurement

TRL-LFI has a possibility to mislead the protection way for the pedestrian lower extremity, since it doesn’t have a measurement system for the injury assessment of the lower part of the leg.

for Knee ligamentsinjury assessment

(Angle, Disp.)

for Leg injuryassessment

(Acc.)

Knee Shearing(displacement)

Knee Bending(angle)

Leg 0(acceleration)

TRL-LFI

Knee Joint

65 mm

Impact

no measurement

TRL-LF cannot detect the lower part of the leg severity

Conclusions

•Flex-PLI has high biofidelity,higher injury assessment ability than the TRL-LFI,high repeatability and re-product-ability in

dynamic certification test,and high repeatability in the subsystem test with

production car.•TRL-LFI with the lack of biofidelity and insufficient

injury assessment ability may mislead the countermeasure for the pedestrian lower extremity protection.

•J-MLIT recommends to utilize the Flex-PLI as a tool for GTR/PS legform test .

Conclusions

Thank you for your attention!