JMLIT Compatibility Research

GRSP, May 2004

JMLIT

Informal document No. GRSP-35-9(35th GRSP, 3-5 May 2004,

agenda item A.6.)

JMLIT Compatibility Research

• Development of test procedures– Accident analysis– Crash tests

• Cooperation with IHRA• The research are conducted in JMLIT

Compatibility WG

Vehicle Fleet in JapanV

ehic

le r

egis

trat

ion

s (*

1000

)

0

2,000

4,000

6,000

8,000

10,000

12,000

1992 1993 1994 1995 1996 1997 1998 1999 2000

Year

Minicar

Small car

Medium car

Large car

Wagon

MPV

SUV

Key Factors of Compatibility

• Structural interaction• Force matching• Compartment strength

1. Full-Width Tests for Structural Interaction Evaluation

Full-Width Crash Tests

• Full-width rigid barrier crash tests have already been in the regulations of Japan, US and Australia as a high-acceleration test for restraint systems.

• Barrier force distributions are measured for structural interaction evaluation.

• Full-width tests are agreed as phase I in IHRA compatibility WG.

Full-Width Tests in Japan

• 125 x 125 mm load cells• 44 rigid barrier tests (42 JNCAP + 2 additional tests)• 6 (TRL) deformable barrier tests

Rigid barrier

Deformable barrierRigid barrier

Force Distributions in Full-Width Rigid Barrier Tests

45-5040-4535-4030-3525-3020-2515-2010-155-100-5

50-

unit : kN

Honda AccordAHOF: 410 mm

Nissan LibertyAHOF: 434 mm

Honda StepwgnAHOF: 487 mm

AHOF=average height of force

H(t)

FFi=

Car-to-MPV - Similar AHOF -

5 mm

AHOF difference is 24 mm

Honda AccordAHOF: 410 mmKerb mass: 1441 kg

Nissan LibertyAHOF: 434 mmKerb mass: 1516 kg

Car-to-MPV - Different AHOF -

Honda AccordAHOF: 410mmKerb mass: 1440 kg

45 mmAHOF difference is

77 mm

Honda StepwgnAHOF: 487 mmKerb mass: 1528 kg

AHOF can be an effective parameter to predict override/underride in car-to-car crashes.

Full-Width Deformable Barrier Tests• Structural forces are seen clearly

without engine footprint.• Forces from lower cross member can

be seen?• Relative homogeneity assessment

has been proposed in deformable barrier tests.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16S1

S3

S5

S7

0

20

40

60

80

Force (kN)

Excite shear deformation like car-to-car crashes

0.28 0.32 0.24 0.210.45

0.90

0.090.18

0.15 0.14

0.10

0.30

0.130.07

0.06 0.05

0.20

0.32

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Wagon R Vitz Legacy Forester STEPWGN SURF

ColumnsRowsCells

Relative Homogeneity AssessmentVariability of peak load (Individual cells, each

row and each column)

Force from lower cross member or force dispersion by honeycomb?

Force Distributions by Load Cell Alignment

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

S1

S2

S3

S4

S5

S6

S7

S8

Ground height 125 mm Load cell

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

S1

S2

S3

S4

S5

S6

S7

S8

12

34

56

78

910

1112

1314

1516S1

S2

S3

S4

S5

S6

S7

S8

0

10

20

30

12

34

56

78

910

1112

1314

1516S1

S2

S3

S4

S5

S6

S7

S8

0

10

20

30

Londitudinal impact load cell

Ground height 50 mm

Target load = 7.1 kNTarget load = 6.8 kN

Ground level 125 mm 50 mm

0

0.1

0.2

0.3

0.4

0.5

0.6

125 mm 50 mm

Columns

Rows

Cells

Relative homogeneity assessment

Load cell ground height

45-5040-4535-4030-3525-3020-2515-2010-155-100-5

50-

unit : kN

Unrealistic Deformation by Deformable Barrier

Large cross-section of front-end, which will be useful for structural interaction, can be disadvantageous in full-width deformable barrier tests.

Deformable barrier test

Satellite sensor

Car structures

Car-to-car testCar-to-car test

Injury Criteria of Driver Dummy in Full-Width Rigid and Deformable Barrier Tests

• Injury criteria are comparable between rigid and deformable barrier tests.• Due to crash sensing time differences, injury criteria in deformable barrier tests

can be higher than rigid barrier tests, especially for high-acceleration cars.

Minicar

0.0 0.2 0.4 0.6 0.8 1.0

Rigid barrierDeformable barrier

Small car

0.0 0.2 0.4 0.6 0.8 1.0

Medium car

0.0 0.2 0.4 0.6 0.8 1.0

Femur left

Femur right

Chestdeflection

Chest acc

HIC

SUV

0.0 0.2 0.4 0.6 0.8 1.0

Small SUV

0.0 0.2 0.4 0.6 0.8 1.0

Femur left

Femur right

Chestdeflection

Chest acc

HIC

Femur left

Femur right

Chestdeflection

Chest acc

HIC

Femur left

Femur right

Chestdeflection

Chest acc

HIC

Femur left

Femur right

Chestdeflection

Chest acc

HIC

Injury criteria/IARV Injury criteria/IARV

AHOF in Full-Width Rigid and Deformable Barrier Tests

400

450

500

550

400 450 500 550

AHOF in rigid barrier tests (mm)

AH

OF

in T

RL

barr

ier

test

s (m

m)

Full-Width Deformable Barrier Tests

• Forces from structures can be seen clearly.• It is still not clear if the foot print of cross

members can be seen in deformable barrier tests. • AHOF is comparable between rigid and

deformable barrier.• Load cell alignments affect force distribution

measurements and relative homogeneity assessments.

• Unrealistic deformation can occur. • Deformable barrier tests can be used as high

deceleration tests for restraint system evaluation.

Full-Width Tests for Structural Interaction Evaluation

• AHOF is a useful criterion to evaluate underride/override.

• To determine the AHOF, the force distributions measured in either rigid or deformable barrier tests can be used.

• Further research is necessary for deformable barrier and homogeneity assessment criteria.

2. Compartment Strength Effectiveness and its Evaluation

Car-to-Car Tests (50 km/h)

Vitz(Echo) 2001 Australia test Vitz 2003

Overload Tests (80 km/h)

2002 Vitz 2003 Vitz

Compartment Strength Criteria• Maximum structural force• End of crash force

Barrier force at the time when the difference between engine inertia force and barrier force is maximal

• Rebound forceBarrier force at the time when car starts to rebound

Rebound forceB

arri

er f

orce

Displacement

Engine inertial force

End of crash force

Overload and Car-to-Car TestsFi

rew

alli

ntr

usi

on o

f sm

all c

ar in

a

cras

h in

to a

larg

e ca

r (m

m)

0

50

100

150

200

250

300

0 50 100 150 200 250

Rebound force in overload tests (kN)

Vitz 2003(vs. Legacy)

Civic 1999 (vs. Crown)

Vitz 2000(vs. Legacy)

Wagon R 2001(vs. Crown)

Move 2000(vs. Crown)

vs. Crown (55 km/h)

vs. Legacy (50 km/h)

Rebound Force in 80 and 64 km/h Tests

Rebound force in overload 80 km/h tests (kN)

Reb

oun

d fo

rce

in O

DB

64

km

/h t

ests

(k

N)

0

50

100

150

200

250

0 50 100 150 200 250

Vitz 2002

Vitz 2003

Civic 1997

Move 2000

Wagon R 2001

Summary – Compartment Strength

1. It was demonstrated that a strong compartment is effective in improving the self-protection.

2. Overload tests are useful for predicting the compartment strength.

3. Some criteria have been examined to evaluate the compartment strength.

4. Compartment strength may be evaluated in ODB 64 km/h tests.

JMLIT Compatibility Research Report for IHRA Compatibility WG

ODB 64 km/h • Barrier force?• Force matching

• Rebound force?• Compartment strength

ODB 64 km/h(Overload 80 km/h?)

• AHOF• Initial stiffness• Relative homogeneity

assessment

• Structural interaction

Full-width test (Rigid barrier or deformable barrier)

CriteriaCriteriaKey factorsKey factorsTest proceduresTest procedures