ISO/TR 7861:2003

Road vehicles — Injury risk curves for evaluation of occupant protection in frontal impact

ISO/TR 7861:2002 presents injury risk curves that can be used for injury risk assessment in the evaluation of occupant protection in road-vehicle frontal impact. The measurements were made on frontal-impact crash test dummies which present acceptable levels of biofidelity response in accordance with ISO 12349-1 and ISO 12349-2 and which are used in the frontal-impact test procedures of existing International Standards.

Véhicules routiers — Courbes de risques de blessures pour évaluer la protection des occupants en choc frontal

General Information

• Status: Published
• Publication Date: 07-May-2003
• ICS: 43.020 - Road vehicles in general
• Technical Committee: ISO/TC 22/SC 36 - Safety and impact testing
• Drafting Committee: ISO/TC 22/SC 36/WG 6 - Performance criteria expressed in biomechanical terms
• Current Stage: 6060 - International Standard published
• Completion Date: 08-May-2003

Relations

• Consolidated By: ISO 15883-1:2006/Amd 1:2014 - Washer-disinfectors — Part 1: General requirements, terms and definitions and tests — Amendment 1
• Effective Date: 06-Jun-2022

Standards Content (Sample)

TECHNICAL ISO/TR
REPORT 7861
First edition
2003-04-15

Road vehicles — Injury risk curves for
evaluation of occupant protection in
frontal impact
Véhicules routiers — Courbes de risques de blessures pour évaluer la
protection des occupants en choc frontal




Reference number
ISO/TR 7861:2003(E)
©
ISO 2003

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ISO/TR 7861:2003(E)
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©  ISO 2003
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ii © ISO 2003 — All rights reserved

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ISO/TR 7861:2003(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Injury risk curves . 1
3.1 General. 1
3.2 Head injury risk curves. 1
3.3 Neck injury risk curves. 1
3.4 Thoracic injury risk curves . 2
3.4.1 General. 2
3.4.2 Shoulder belt loading . 2
3.4.3 Distributed loading . 3
3.5 Lower extremity fracture curves . 3
3.5.1 Knee-thigh-hip fractures . 3
3.5.2 Tibia shaft fractures. 3
3.5.3 Ankle/foot fractures . 3
Annex A (normative) Injury risk curves . 4
Bibliography . 16

© ISO 2003 — All rights reserved iii

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ISO/TR 7861:2003(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In exceptional circumstances, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for example), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides are considered to be no
longer valid or useful.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TR 7861 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 12,
Passive safety crash protection systems.
iv © ISO 2003 — All rights reserved

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ISO/TR 7861:2003(E)
Introduction
A number of researchers have proposed injury risk curves for various dummy measurements, based on their
analyses of published biomechanical data. These curves, summarized in this Technical Report, can be used
by regulatory authorities as well as car manufacturers to set occupant protection levels based on the injury
risks they believe are acceptable for the frontal collision being simulated. No limits are given because it is the
view of ISO/TC 22 that the setting of performance levels is a responsibility for regulatory authorities.
© ISO 2003 — All rights reserved v

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TECHNICAL REPORT ISO/TR 7861:2003(E)

Road vehicles — Injury risk curves for evaluation of occupant
protection in frontal impact
1 Scope
This Technical Report presents injury risk curves that can be used for injury risk assessment in the evaluation
of occupant protection in road-vehicle frontal impact. The measurements were made on frontal-impact crash
test dummies which present acceptable levels of biofidelity response in accordance with ISO/TR 12349-1 and
ISO/TR 12349-2 and which are used in the frontal-impact test procedures of existing International Standards.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO TR 12349-1, Road vehicles — Dummies for restraint system testing — Part 1: Adult dummies
ISO TR 12349-2, Road vehicles — Dummies for restraint system testing — Part 2: Child dummies
3 Injury risk curves
3.1 General
All the injury risk curves, presented in Annex A, are shown plotted on normal probability graph paper. Values
for mean value (denoted with a superscript dash over the parameter) and standard deviation (σ) for each risk
curve are shown on the graphs.
3.2 Head injury risk curves
Three head injury risk curves are given for forehead impacts. The bases for these curves are discussed by
[1] [2, 3]
Prasad and Mertz and Mertz et al. . The risk of skull fracture as functions of 15 ms HIC (head impact
criteria) and peak acceleration of the centre of gravity of the head are given in Figures A.1 and A.2,
respectively. The risk of AIS (abbreviated injury scale) W 4 brain injury as a function of 15 ms HIC is given in
Figure A.3.
3.3 Neck injury risk curves
Three normalized risk curves for AIS W 3 neck injury based on measurements made at the occipital condylar
joint for tension-extension neck loading are given for CRABI and Hybrid III dummy families. These curves are
[4] [5]
based on the work described by Mertz et al. and Mertz and Prasad and include a factor for variation in
[5]
failure stress as a function of age . Figures A.4, A.5 and A.6 are the risk curves for peak normalized neck
tension, peak extension moment and an index for the peak combination of tension and extension moment,
respectively. Normalizing values for various dummy sizes are listed in the legends of the graphs and
correspond to 3 %, 5 % and 2 % risks of AIS W 3 neck injury with minimum passive muscle tone, respectively.
[20]
These normalizing values are the limit values for out-of-position airbag testing specified in FMVSS 208 .
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ISO/TR 7861:2003(E)
These curves can also be used to estimate injury risk with various amounts of muscle pretension. The
procedure for making such estimates is as follows.
a) Determine the maximum values of each normalized function from the test data.
b) Subtract from these values the values of loading assumed to be carried by the muscles, or
1) neck tension, F /F
T 3
  
FF F
TT M
=−m
  
FF F
33 3
  
max
2) neck extension moment, M /M
E 5
  
MM M
EE M
=−m
  
MM M
55 5
  
max
3) combined tension and extension moment, N
TE
 
MF F
ET M
Nm=+ −
TE 
MF F
22 2
max
where
F , M are the maximum tension and extension moment due to pretensing of the neck muscles;
M M
m is the fraction of the maximum passive muscle tensing assumed (0 u m u 1).
These differences are used to estimate the injury risks from the curves of Figures A.4, A.5 and A.6.
[5]
Mertz and Prasad provide estimates for the maximum values for tension and extension moment due to
pretensioning of the neck muscles for various sizes of dummies based on static strength tests. These values
are given in Table A.1. No values are listed for the CRABI infant dummies because it is unreasonable to
expect an infant to be aware of an impending collision.
3.4 Thoracic injury risk curves
3.4.1 General
There are two types of thoracic loadings for which injury risk curves have been developed:
a) shoulder belt loading with and without air bags;
b) distributed thoracic loading such as is produced by air bags without belts.
3.4.2 Shoulder belt loading
[6]
Mertz et al. correlated field accident observations of thoracic injuries of occupants restrained with
three-point belts with force-limiting shoulder belts to Hybrid III sternal deflections measured for the simulated
accident conditions. These data were used to formulate the AIS W 3 thoracic injury risk curve of Figure A.7 as
a function of Hybrid III sternal deflection. This risk curve can be used whenever the torso is restrained by a
shoulder belt, even if an air bag is part of the restraint system. Since the field accident data was not
normalized for size of occupants, the curve overestimates the injury risk for the 50th percentile adult male at
low risk levels.
2 © ISO 2003 — All rights reserved
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