Effectiveness of SEAS in Car-to-Car
Frontal Crashes
JAPAN
19th Meeting of the Informal Group on Frontal Impact
1
Objective
• To examine the effectiveness of SEAS in
frontal impact between vehicles with a
vertical mismatch of PEAS
2
Test Procedure
Stage 1: FWRB test
Stage 2: Option 2 test
@ LCW force 200 kN
F3+F4 ≥ [100-LR] kN
No
F4 ≥ 35 kN
F3 ≥ 35 kN
LR = Min [(F2+F1-25 kN); 35 kN]
Yes
Pass
No
F>100 kN @ 400 mm
Fail
Yes
Pass
3
Test Condition
50 km/h Full Frontal Car-to-Car Tests
Small car
50 km/h
50km/h
SUV
Test 1: Original height
(front rails of SUV were higher than
that of small car)
Small car
SUV
Test 2: Adjusted height
(height of front rails of SUV was
aligned with that of small car)
Small car
lowered SUV
4
Test Vehicles
SUV (with SEAS)
Small car
Front rails
Front rails
Bumper cross beam
Bumper cross beam
SEAS
• Front structures: Front rails and
bumper cross beam
• Test mass: 1138 kg
• Front structures: Front rails,
bumper cross beam and SEAS
• Test mass: 1380 kg
5
Test Vehicle - Small car 830
6
US voluntary agreement
705
Ground height (mm)
5
580
508 (20 in.)
4
455
406 (16 in.)
3
330
2
PEAS (Front rail)
Metric
Option 1a [%] a/b
Option 1b [%] a/c
Requirement
(50)
(50)
Result
77.8
84.9
205
1
80
6
Test Vehicle - SUV 830
US voluntary agreement
6
705
Ground height (mm)
5
PEAS (Front rail)
580
508 (20 in.)
4
455
406 (16 in.)
3
Metric
Option 1a [%] a/b
Option 1b [%] a/c
330
2
205
1
80
Requirement
(50)
(50)
Result
2.0
2.1
FAIL
FAIL
SEAS
FIMCAR proposal
Metric for FWRB test
F3+F4 ≥ [100-LR] kN
F4 ≥ 35 kN
F3 ≥ 35 kN-LR
LR = Min [(F2+F1-25 kN); 35 kN]
FWRB @ 55 km/h (JNCAP)
Metric
F3+F4 [kN]
F4 [kN]
Requirement
(100-LR)
(35)
(35-LR)
F3 [kN]
F2 [kN]
F1 [kN]
LR (Limit Reduction) [kN]
Result
118.2
112.8
5.4
21.6
1.0
0.0
FAIL
7
Test Vehicle - SUV US voluntary agreement
Option 2 (Quasi-static test)
Pre-test
Vertical plane at the forward-mostpoint of the significant structure of
the vehicle
PEAS
Part 581
406.4[mm]
SEAS
Post-test
Photo No. 4
FR
Tire
Ground
8
Geometric Condition
Test 1: Original height
Small car
429
SUV
522
485
601
506
498 mm
Test 2: Adjusted height
Small car
431
SUV
524
487
526 430
423 mm
• Longitudinal distance between front end of bumper cross beam and front
end of SEAS for SUV: 248 mm
• Vertical overlap of front rails between two vehicles in Test 1: 16 mm
• For SUV in Test 2, not only the front rails but also the engine was lowered.
9
Test Videos
10
Vehicle Behavior
Test 1: Original height
Small car
SUV
The tire is in contact with the
road surface (= not overriding).
Test 2: Adjusted height
0 ms
30 ms
• • Overriding/underriding did not occur in both tests.
60 ms
Velocity Time History
Test 1: Original height
60
Small car
SUV
Velocity (km/h)
40
55.5 km/h
20
0
-20
45.7 km/h
-40
-60
0
50
100
150
200
Time (ms)
60
Test 2: Adjusted height
Small car
SUV
Velocity (km/h)
40
55.5 km/h
20
0
-20
45.7 km/h
-40
-60
0
50
100
150
200
Time (ms)
• The severity for the small car in the two tests is equivalent to FWRB @ 55 km/h.
12
Vehicle Deformation
Test 1: Original height
Small car
SUV
• Front rails passed each other.
• SEAS of SUV engaged the front structures of the small car.
13
Vehicle Deformation
Test 2: Adjusted height
Small car
SUV
• Front rails contacted each other.
14
Deformation - Small car Test 1: Original height
Front rail (R)
Front rail (L)
Bumper cross beam
Engine top
Engine bottom
Test 2: Adjusted height
Firewall
Original height
Steering column
Adjusted height
Toe board (driver)
Toe board (passenger)
-100
0
100
200
300
400
500
Longitudinal deformation (mm)
15
Deformation - SUV Test 1: Original height
Front rail (R)
Front rail (L)
Bumper cross beam
SEAS
345
70
Engine top
Test 2: Adjusted height
Engine bottom
Original height
Steering column
Adjusted height
Toe board (driver)
Toe board (passenger)
-100
0
100
200
300
400
500
Longitudinal deformation (mm)
• The contact with the front structure of the small car caused a significant
deformation of SEAS in Test 1.
16
Injury Measures - Small car Passenger's Dummy
Passenger's
dummy
Driver's dummy
Dummy
Driver's
HIC 36
HIC 36
Neck Fz
Neck Fz
Neck Fx
Neck Fx
Neck My
Neck My
Chest Deflection
Chest Deflection
Chest G-3ms
Chest G-3 ms
50 km/h CTC
Org Height
Force
50km/hFemur
CTC
Adj. Height
Femur Force
55 km/h
FWRB Tibia Index
Tibia Index
0
20
40
60
80
100
Ratio of injury measures to IARV (%)
120
0
20
40
60
80
100
120
Ratio of injury measures to IARV (%)
• Injury levels were comparable between Test 1 (original height)
and Test 2(adjusted height).
17
Injury Measures - SUV Passenger's Dummy
Passenger's
dummy
Driver's dummy
Dummy
Driver's
HIC 36
HIC 36
Neck Fz
Neck Fz
Neck Fx
Neck Fx
Neck My
Neck My
Chest Deflection
Chest Deflection
Chest G-3ms
Chest G-3 ms
50 km/h CTC
Orig. Height
50 km/hFemur
CTC Force
Adj. Height
Femur Force
55 km/h
Tibia Index
FWRB
Tibia Index
0
20
40
60
80
100
Ratio of injury measures to IARV (%)
120
0
20
40
60
80
100
120
Ratio of injury measures to IARV (%)
• Injury levels were comparable between Test 1 (original height)
and Test 2(adjusted height).
18
Conclusions
 In the SUV-to-small car test with vertical mismatch of
PEAS, the SUV did not override the small car because
the SEAS of the SUV engaged the front structures of the
small car.
 Injury levels for the driver and passenger dummies in
the small car were comparable between the two tests.
 From the two tests, it was shown that SEAS is an
important structure for structural interaction between
vehicles.
 Therefore, when a test procedure on structural
interaction is developed, it is necessary to consider an
evaluation of not only PEAS but also SEAS.
19
Appendix
Vehicle Acceleration
Small car
Acceleration (m/s2)
200
Right B-pillar
0
-200
-400
Original height
Adjusted height
-600
-800
0
100
Time (ms)
SUV
200
Acceleration (m/s2)
50
150
200
Right B-pillar
0
-200
-400
Original height
Adjusted height
-600
-800
0
50
100
Time (ms)
150
200
21
Dummy Response - Small car Head resultant acc. (m/s2)
Neck extension moment (Nm)
1200
100
Driver
Original height
Adjusted height
1000
Moment (Nm)
Acceleration (m/s2)
Driver
800
600
400
Original height
Adjusted height
50
0
-50
200
0
-100
0
50
100
150
0
50
Time (ms)
150
Time (ms)
Chest deflection (mm)
Femur-R force (kN)
100
10
Driver
Driver
Original height
Adjusted height
50
Original height
Adjusted height
5
Force (kN)
Deflection (mm)
100
0
-50
0
-5
-100
-10
0
50
100
Time (ms)
150
0
50
100
Time (ms)
150
22
Dummy Response - SUVHead resultant acc. (m/s2)
Neck extension moment (Nm)
1200
100
Driver
Original height
Adjusted height
1000
Moment (Nm)
Acceleration (m/s2)
Driver
800
600
400
Original height
Adjusted height
50
0
-50
200
0
-100
0
50
100
150
0
50
Time (ms)
150
Time (ms)
Chest deflection (mm)
Femur-R force (kN)
100
10
Driver
Driver
Original height
Adjusted height
50
Original height
Adjusted height
5
Force (kN)
Deflection (mm)
100
0
-50
0
-5
-100
-10
0
50
100
Time (ms)
150
0
50
100
Time (ms)
150
23
Engine Behavior
Test 1: Original height
Small car
Small car
SUV
1000
Small car
1000
900
900
800
800
700
700
600
600
500
500
400
400
300
300
200
200
100
100
SUV
post-test
0
- 5 00
pre-test
0
- 3 00
Test 2: Adjusted height
1000
- 1 00
100
Small car
300
- 5 00 5 0 0
- 3 00
1000
900
900
800
800
700
700
600
600
500
500
400
400
300
300
200
200
100
100
0
0
pre-test
- 1 00
100
300
500
SUV
post-test
Small car
SUV
- 5 00
- 3 00
- 1 00
100
300
- 5 00 5 0 0
24
- 3 00
- 1 00
100
300
500