Changes in Automobile Design for Safety - Analysis of the ...TRENDS IN AUTOMOBILE SAFETY: ANALYSES OF RECENT NCAP FRONT CRASH TESTS This article discusses some findings about automobile
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ATD from several crash tests. In calculating the NCAP score, the measured chest displacement
is compared to a reference value (63 mm for the driver, 52 mm for the passenger).
Similar results are observed for measured chest displacements of passenger ATD (not
shown here). Since this ATD represents a fifth percentile female for which a ‘base’ value
published by NHTSA (52 mm) is lower than that for the driver, it is obvious that the
passenger ATD has relatively larger influence on the vehicle’s NCAP ratings. Some of
the shown vehicles (C, D, J) with high values of chest compression therefore have a
relatively large ‘relative risk’ and lower star ratings.
Neck Injury Parameters:
The NHTSA defines [1] a parameter Nij which combines the
possible modes of neck loading - tension or compression combined
with either flexion or extension (forward or rearward bending):
Nij= Fz/ FCritical + My/ Mcritical
The values for Fcritical and Mcritical are defined differently for the two
ATDs. The neck injury probability calculation is based on
comparing Nij and the tension/compression to ‘base’ values.
Fz
My
Fz
My
NCAP Data for 2011 & 2012 Vehicles -
Analysis of Frontal Velocity-vs-Time History
-5
0
5
10
15
20
0 0.02 0.04 0.06 0.08 0.1Time (sec)
V (
m/s
ec
)
A (5D,5P,5F) RSXM V B (5D,4P,4F) RSXM V C (3D,2P,3F) RSXM VD (5D,4P,4F) RSXM VE(5D,4P,5F) RSXM VF (4D,3P,4F) RSXM VG(5D,4P,4F) R XM VH (5D,5P,5F) RSXM VJ(5D,4P,4F) RSXM V K(4D,2P,3F) RSXM V
NCAP Data for 2011 & 2012 Vehicles - Analysis of
Driver Chest X Displacement (mm)
-60
-40
-20
0
20
0 0.1 0.2 0.3
Time
MM
A (5D,5P,5FD Chest D mmB (5D,4P,4F) D Chest D mmC(3D,2P,3F)D Chest D mmJ(5D,4P,4F) D Chest D mmH (5D,5P,5F) D Chest D mmF (4D,3P,4F) D Chest D mmG(5D,4P,4F) D Chest D mmD (5D,4P,4F) D Chest D mm
NCAP Data for 2011 & 2012 Vehicles - Analysis of
Driver Chest X Displacement (mm)
-60
-40
-20
0
20
0 0.1 0.2 0.3
Time
MM
A (5D,5P,5FD Chest D mmB (5D,4P,4F) D Chest D mmC(3D,2P,3F)D Chest D mmJ(5D,4P,4F) D Chest D mmH (5D,5P,5F) D Chest D mmF (4D,3P,4F) D Chest D mmG(5D,4P,4F) D Chest D mmD (5D,4P,4F) D Chest D mm
2. Verma and Goertz, “Evaluation of Pre-Crash Safety Systems Effectiveness”, SAE
Paper 2010-01-1042.
NCAP Data for 2011 & 2012 Vehicles -
Analysis of Driver Neck Moment My (N-M)
-60
-40
-20
0
20
40
60
80
100
0 0.1 0.2 0.3Time
N-M
A (5D,5P,5F D Neck My NMB (5D,4P,4F) D Neck My NMC(3D,2P,3F) D Neck My NMJ(5D,4P,4F) D Neck My NMH (5D,5P,5F) D Neck My NMF (4D,3P,4F) D Neck My NMG(5D,4P,4F) D Neck My NMD (5D,4P,4F)D Neck My NM
NCAP Data for 2011 & 2012 Vehicles -
Analysis of Driver Neck Moment My (N-M)
-60
-40
-20
0
20
40
60
80
100
0 0.1 0.2 0.3Time
N-M
A (5D,5P,5F D Neck My NMB (5D,4P,4F) D Neck My NMC(3D,2P,3F) D Neck My NMJ(5D,4P,4F) D Neck My NMH (5D,5P,5F) D Neck My NMF (4D,3P,4F) D Neck My NMG(5D,4P,4F) D Neck My NMD (5D,4P,4F)D Neck My NM
NCAP Data for 2011 & 2012 Vehicles -
Analysis of Driver Neck Force Fz (N)
-1000
0
1000
2000
3000
0 0.1 0.2 0.3Time
Ne
wto
n
A (5D,5P,5F) D Neck FzB (5D,4P,4F) D Neck FzC(3D,2P,3F) D Neck FzJ(5D,4P,4F) D Neck FzH (5D,5P,5F) D Neck FzF (4D,3P,4F) D Neck FzG(5D,4P,4F) D Neck FzD (5D,4P,4F) D Neck Fz