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