prEN 17149-2
(Main)Railway applications - Strength assessment of railway vehicle structures - Part 2: Static strength assessment
Railway applications - Strength assessment of railway vehicle structures - Part 2: Static strength assessment
This document describes a procedure for static strength assessment of rail vehicle structures that are manufactured, operated and maintained according to standards valid for rail system applications.
The assessment procedure is restricted to ferrous materials and aluminium.
This document does not define design load cases.
This document is not applicable for corrosive conditions or elevated temperature operation in the creep range.
This document is applicable to all kinds of rail vehicles.
Bahnanwendungen - Festigkeitsnachweis von Schienenfahrzeugstrukturen - Teil 2: Statischer Festigkeitsnachweis
Applications ferroviaires - Évaluation de la résistance des structures de véhicule ferroviaire - Partie 2: Évaluation de la résistance statique
Železniške naprave - Ocenjevanje odpornosti konstrukcije železniških vozil - 2. del: Ocena statične odpornosti
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 17149-2:2022
01-november-2022
Železniške naprave - Ocenjevanje odpornosti konstrukcije železniških vozil - 2.
del: Ocena statične odpornosti
Railway applications - Strength assessment of railway vehicle structures - Part 2: Static
strength assessment
Bahnanwendungen - Festigkeitsnachweis von Schienenfahrzeugstrukturen - Teil 2:
Statischer Festigkeitsnachweis
Applications ferroviaires - Évaluation de la résistance des structures de véhicule
ferroviaire - Partie 2: Évaluation de la résistance statique
Ta slovenski standard je istoveten z: prEN 17149-2
ICS:
45.060.01 Železniška vozila na splošno Railway rolling stock in
general
oSIST prEN 17149-2:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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DRAFT
EUROPEAN STANDARD
prEN 17149-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2022
ICS
English Version
Railway applications - Strength assessment of railway
vehicle structures - Part 2: Static strength assessment
Applications ferroviaires - Évaluation de la résistance Bahnanwendungen - Festigkeitsnachweis von
des structures de véhicule ferroviaire - Partie 2: Schienenfahrzeugstrukturen - Teil 2: Statischer
Évaluation de la résistance statique Festigkeitsnachweis
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 256.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17149-2:2022 E
worldwide for CEN national Members.
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Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Stress and strain determination . 7
4.1 General. 7
4.2 Calculation of equivalent stress with linear elastic material behaviour . 7
4.3 Calculation with nonlinear material behaviour . 7
4.3.1 Material models . 7
4.3.2 Equivalent stress . 9
4.3.3 Equivalent plastic strain. 9
4.4 Determination of stresses and strains by test . 9
5 Static strength . 10
5.1 Material properties . 10
5.1.1 General. 10
5.1.2 Parent material . 10
5.1.3 Heat affected zone (HAZ) and weld metal . 11
5.2 Admissible plastic strain . 12
5.2.1 Exceptional design loads . 12
5.2.2 Ultimate design loads . 13
6 Partial factors . 14
6.1 General. 14
6.2 Partial factor for loads γ . 14
L
6.3 Partial factor for the component static strength γ . 14
M
6.3.1 General. 14
6.3.2 Partial factor for the consequence of failure γ . 14
M,S
6.3.3 Partial factor for the degree of the validation process γ . 14
M,V
6.3.4 Partial factor for the material hardening γ . 15
M,T
6.3.5 Partial factor for casting γ . 15
M,G
6.4 Partial factor for instability γ . 15
I
7 Static strength assessment procedure . 15
7.1 General. 15
7.2 Linear elastic analysis . 16
7.2.1 Stress criterion . 16
7.2.2 Deformation criterion . 16
7.2.3 Instability criterion . 17
7.3 Nonlinear elastic plastic analysis . 17
7.3.1 General. 17
7.3.2 Stress criterion . 17
7.3.3 Strain criterion . 17
7.3.4 Deformation criterion . 18
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7.3.5 Instability criterion . 18
Annex A (informative) Additional information for the section factor n . 19
pl,ε
Annex B (informative) Example for an assessment with a one-time redistribution of stresses
due to plastification . 20
B.1 Situation . 20
B.2 Load cases . 20
B.3 Assessment . 21
Annex C (informative) Post processing of plastic strain/stress . 22
Bibliography . 24
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European foreword
This document (prEN 17149-2:2022) has been prepared by Technical Committee CEN/TC 256 “'Railway
applications”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document is part of the series EN 17149 Railway applications — Strength assessment of railway
vehicle structures, which consists of the following parts:
— Part 1: General
— Part 2: Static strength assessment
— Part 3: Fatigue strength assessment based on cumulative damage
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Introduction
This document provides procedures and criteria for the static strength assessment of exceptional load
cases and ultimate load cases based on linear analysis or nonlinear elastic plastic analysis.
It does not define load cases and does not define in which cases, for which structural components or for
which kinds of rail vehicles a static strength assessment is to be applied.
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1 Scope
This document specifies a procedure for static strength assessment of rail vehicle structures.
It is part of a series of standards that specifies procedures for strength assessments of structures of rail
vehicles that are manufactured, operated and maintained according to standards valid for railway
applications.
This document is applicable for exceptional load cases and ultimate load cases.
The assessment procedure of the series is restricted to ferrous materials and aluminium.
This document series does not define design load cases.
This document series is not applicable for corrosive conditions or elevated temperature operation in the
creep range.
This series of standards is applicable to all kinds of rail vehicles. However, it does not define in which
cases or for which kinds of rail vehicles a static strength assessment is to be applied.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
EN 12663-1:2010+A1:2014, Railway applications - Structural requirements of railway vehicle bodies - Part
1: Locomotives and passenger rolling stock (and alternative method for freight wagons)
EN 12663-2:2010, Railway applications - Structural requirements of railway vehicle bodies - Part 2: Freight
wagons
EN 13749:2021, Railway applications — Wheelsets and bogies — Method of specifying the structural
requirements of bogie frames
EN 15227:2020, Railway applications - Crashworthiness requirements for rail vehicles
EN 15827:2011, Railway applications - Requirements for bogies and running gears
prEN 17149-1:2021, Railway applications — Strength assessment of railway vehicle structures — Part 1:
General
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3 Terms and definitions
For the purposes of this document, the terms and definitions, symbols and abbreviations given in
prEN 17149-1:2021 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Stress and strain determination
4.1 General
The assessment procedure is based on stresses or strains. These can be derived from calculation or from
measurement during testing. Unless otherwise stated, the stress or the strain is determined for each
individual load case separately without a corresponding load case.
Stresses and strains may be determined with linear elastic material behaviour or nonlinear material
behaviour. Annex C gives guidance for the determination of plastic strains and stresses from an FEA. For
welded joints, the eccentricity between the midpoint of the weld throat and the connected plate e needs
W
not to be considered. This is also applicable for stress determination from strain measurements.
4.2 Calculation of equivalent stress with linear elastic material behaviour
For the calculation of equivalent stress, the plane stress tensor on the surface of the component should
be used as characteristic stress value for the static strength assessment. The stress components of the
plane stress tensor are σ , σ , τ .
x y xy
The equivalent stress for ductile material is determined according to von-Mises-Formula:
2 22
σ σ−σσ⋅+σ+⋅3τ (1)
eq x x y y xy
The equivalent stress for brittle material is determined according to Rankine:
2
1
2
σ σ+σ+ σ−σ+⋅4τ (2)
( )
eq x y x y xy
2
For a more general approach, the derivation of the equivalent stress for the triaxial stress state may be
taken from the technical literature.
4.3 Calculation with nonlinear material behaviour
4.3.1 Material models
The real material behaviour (Figure 1) may be approximated by bi-linear (Figure 2), three-linear
(Figure 3), multilinear or continuous material models. Hardening effects for strains exceeding the proof
strength may be applied but also the application of an elastic ideal-plastic material law is allowed.
Depending on the material model, the limit for the elastic behaviour represented by the proof strength
R can be either the yield strength R or the 0,2 % proof strength R as defined in EN ISO 6892-1.
p eH p0,2
NOTE [1] and [2] give hints about the definition of the material law for the nonlinear stress strain calculation.
7
=
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Key
1 True stress strain behaviour
2 Engineering stress strain behaviour
Figure 1 — Real material behaviour a) without distinctive yield stress
b) with distinctive yield stress
Key
1 True stress strain behaviour
2 Bi-linear approximation
Figure 2 — Bi-linear material model a) without distinctive yield stress
b) with distinctive yield stress
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Key
1 True stress strain behaviour
2 Three-linear approximation
Figure 3 — Three-linear material model a) without distinctive yield stress
b) with distinctive yield stress
4.3.2 Equivalent stress
The calculation of equivalent stress with nonlinear material behaviour follows the procedure for linear
elastic material behaviour given in 4.2.
4.3.3 Equivalent plastic strain
The equivalent plastic strain is generally calculated according to Von-Mises-Hypothesis and may be
determined following the technical literature or by applying Formula (3).
24
2 2 2 2 2 2
ε ε++εε+ ε+ε+ε (3)
( ) ( )
p,eq p,x p,y p,z p,xy p,yz p,xz
33
4.4 Determination of stresses and strains by test
In real components, residual strains due to manufacturing or preloading can occur. Measured strains
during tests incorporate influences of such residual strains. The strength assessment procedure given in
Clause 7 is applicable for stresses and strains derived from such measurements and sufficiently covers
effects of such residual strains.
Dependent on the kind of assessment procedure (see Clause 7), the stresses shall be determined from
measured strains with linear elastic material behaviour or nonlinear material models as given in 4.3.1.
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5 Static strength
5.1 Material properties
5.1.1 General
The material properties shall represent the component strength values as defined in prEN 17149-1:2021,
Clause 7. Strength values taken from material standards fulfil these requirements.
This clause describes the material properties for the static strength assessment of the parent material
and welded joints under the application temperature within the range given in the material specification.
If the scope of the application is exceeded, an assessment method shall be chosen which accounts for the
specific application (e.g. temperature range).
In accordance with 7.1, at welded joints the assessment is required for the weld metal, the HAZ and the
adjacent parent material considering the width of the HAZ. The relevant thickness and the strength values
are given in Table 1.
Table 1 — Relevant thickness and strength values
Area Relevant thickness Strength values R , R , A
p m
Parent material Plate thickness Strength value of the parent material
Heat-affected zone Plate thickness in the heat-affected Minimum of the parent material and the
a
HAZ zone HAZ
Minimum of the parent material, the
Weld metal Effective throat thickness a
a b
HAZ and the weld metal
a
If the permanent elongation at rupture A for the HAZ is not available, the value for the parent material may be
applied.
b
Welding results in mixing of the weld metal with the parent material. Therefore, the effective strength value of a
weld can be higher than the minimum value of the weld metal and the heat-affected zone. Higher strength values
respectively the values of the heat-affected zone may be used if this is demonstrated, e.g. with tensile strength tests.
5.1.2 Parent material
Material properties shall be valid for the assessment location.
If the strength properties of semi-finished products consider the original wall thickness, the influence of
the component size is normally covered.
NOTE Semi-finished products can have significantly varying strength properties over their cross section.
Anisotropy effects due to manufacture processes are addressed by the anisotropy factor f . For rolled
A
sheets and extrusions an anisotropy factor f shall be considered in the direction transverse to the main
A
direction of rolling in accordance with Table 2, unless this is already considered or explicitly excluded in
the material standard or component specification.
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Table 2 — Anisotropy factor f for steel and aluminium
A
Material R f
m,N A
2
[N/mm ]
Rolled Steel ≤ 600 0,9
> 600 ≤ 900 0,86
Rolled sheets and extrusions of aluminium ≤ 200 1,0
> 200 ≤ 400 0,95
> 400 ≤ 600 0,9
All other material applications 1,0
Heat-affected zone 1,0
For casted materials and in case of a compression stress state, an enhanced compressive yield strength
and compressive strength may be considered in the static strength assessment. The applicable
compression strength factor f for different groups of casted material is given in Table 3.
C
Table 3 — Compression strength factor f
C
Non-casted
Cast
a
Material group GS GJS GJL GJM
materials
aluminium
f 1,0 1,3 2,5 1,5 1,5 1,0
C
As a conservative approach, the compression strength factor f may be generally set to 1,0.
C
The static material strength values of parent material for the static strength assessment are
R = f ⋅⋅fR
m A C m,N
(4)
R = f ⋅ fR⋅
p A C p,N
5.1.3 Heat affected zone (HAZ) and weld metal
For aluminium, the width of the heat-affected zone is presented in Figure 4.
Key
b width of the heat-affected zone
HAZ
Figure 4 — Width of the heat-affected zone b
HAZ
Values for the width of the heat-affected zone are given in Table 4. Alternatively, the width of heat-
affected zone may be determined by a measurement of hardness.
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Table 4 —Width of the heat-affected zone b
HAZ
b b
HAZ HAZ
[mm] [mm]
t [mm]
MIG TIG
0 < t ≤ 6 20 30
6 < t ≤ 12 30 30
12 < t ≤ 25 35 35
> 25 40 40
The strength values of the weld metal and the heat-affected zone are given in appropriate standards,
guidelines (see bibliography), or material specifications.
5.2 Admissible plastic strain
5.2.1 Exceptional design loads
The determination of the admissible plastic strain ε shall be calculated under consideration of the
p,adm
number of occurrences N of the load case. Based on the principles of the Manson-Coffin approach and
fitted to test data (see [37], [38]), the admissible plastic strain ε is given in Formula (5)
p,adm
m
N
εε= min ⋅ ;ε (5)
p,adm p,adm,B p,adm,max
1 000
Where:
A permanent elongation at rupture
ε maximum admissible plastic strain (see Table 4)
p,adm,max
ε admissible plastic strain for N = 1 000 (see Table 4)
p,adm,B B
m exponent of the E-N curve (see Table 4)
N number of occurrences
For a conservative approach, the admissible plastic strain may be set to ε = ε .
p,adm p,adm,B
NOTE 1 For carbody structures, information on numbers of occurrences is given in [25].
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Table 5 —Parameters for the admissible plastic strain ε
p,adm
Material m [-] ε [-] ε [-]
p,adm,max p,adm,B
Steel (rolled or forged) −0,52 0,2 A 0,02 A
Steel castings (GS) −0,58 0,2 A 0,02 A
Stainless steel in annealed −0,36 0,2 A 0,02 A
condition
Spheroidal graphite cast iron −0,70 0,2 A 0,01 A
(GJS)
Ausferritic spheroidal graphite −0,56 0,2 A 0,01 A
cast iron (ADI)
a
Grey cast iron (GJL) −0,50 0,004 0,001
Annealed cast iron (GJM) −0,70 0,1 A 0,01 A
Aluminium (all types, including −0,83 0,2 A 0,02 A
cast aluminium)
Welded joints of steel −0,61 0,15 A 0,02 A
(HAZ and weld metal)
Welded joints of aluminium −0,93 0,1 A 0,02 A
(HAZ and weld metal)
a
For GJL the elongation at rupture A may be set to A = 0,006.
NOTE 2 The parameters m and ε in Table 5 are empirically determined for a range of number of occurrences
p,adm,B
between 10 and 1 000. The parameter ε represents the upper limit for the admissible plastic strain.
p,adm,max
The admissible plastic strain given in the Manson-Coffin equation represents a strain amplitude of two
alternating load cases. This value covers the separated assessment of individual load cases.
5.2.2 Ultimate design loads
The plastic admissible strain ε for the assessment against ultimate design load is given in Table 6.
p,adm
These values cover the effects of the multiaxiality of the stress state. If validated material models and
effects of multiaxiality of the stress state are considered the plastic admissible strain may be raised in
accordance with technical literature or experimental results.
Table 6 — Plastic admissible strain ε for the assessment against ultimate design load
p,adm
Area Plastic admissible strain ε
p,adm
Parent material 0,5 A
Heat-affected zone 0,5 A
HAZ
Weld metal 0,4 A
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6 Partial factors
6.1 General
Partial factors are applied for the derivation of the stress or the strain and with respect to the static
strength.
6.2 Partial factor for loads γL
The design load incorporates any necessary allowance to account for uncertainties in its value. It is the
representative load multiplied with the partial factor γ . This is applicable for exceptional loads as well
L
as for ultimate loads.
The representative load may be derived from normative loads, simulations or specifications.
Unless otherwise stated, loads derived from EN 12663-1:2010+A1:2014 and EN 12663-2:2010 for car
body structures, EN 13749:2021 and EN 15827:2011 for bogies and running gear structures, and
EN 15227:2020 for crash simulations are design loads. In these cases, a partial factor of γL = 1,0 is
applicable.
If the load is derived from simulations, an appropriate partial factor γ ≥ 1,0 shall be considered
L
depending on the simulation parameters and the uncertainties of the simulation.
6.3 Partial factor for the component static strength γM
6.3.1 General
The partial factor γ for the component static strength is given by
M
γ =γγ⋅⋅γ ⋅γ (6)
M M,S M,V M,T M,G
These partial factors are explained in the following subclauses.
6.3.2 Partial factor for the consequence of failure γ
M,S
A consequence of failure 'high' should be applied if a failure of the structural detail leads to consequential
events with personal injuries and breakdown of the overall function and the component structure does
not provide alternative load paths.
NOTE The consequence of failure can be a result of a risk assessment (e.g. FMECA).
In all other cases a consequence of failure 'moderate' may be applied.
Depending on the consequence of failure, the partial factor γ is given in Table 7.
M,S
Table 7 — Partial factor for the consequence of failure γ
M,S
Consequence of failure Partial factor γ
M,S
Moderate 1,0
High 1,15
6.3.3 Partial factor for the degree of the validation process γ
M,V
If the structural validation plan consists of the validation process as defined by the relevant standard e.g.
in EN 15827:2011, EN 13749:2021 and EN 12663-1:2010+A1:2014 the partial factor is γ = 1,0. Where
M,V
the design is a development of an earlier product any previous test data, that is still applicable may be
used as validation of the revised product and the corresponding partial factor is γ = 1,0. In all other
M,V
cases the partial factor is γ = 1,15.
M,V
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6.3.4 Partial factor for the material hardening γ
M,T
The static strength of the component shall be assessed against both, the yield strength R and the tensile
p
strength R of the material. Both assessments are covered by a combined partial factor γ according to
m M,T
Formula (7).
R
1,3
p
γ max⋅ ;1,0 (7)
M,T
1+ AR
m
As a conservative approach, in Formula (7) the elongation at rupture may be set to A = 0.
6.3.5 Partial factor for casting γ
M,G
The partial factor for casting γ is given in Table 8. For non-cast components the partial factor shall be
M,G
set to γ = 1,0.
M,G
Table 8 — Partial factor for casting γ
M,G
Type Partial factor γ Partial factor γ
M,G M,G
for GS, GJS, ADI, GJL, for cast aluminium
GJM
a a
subjected to NDT 1,1 1,25
not subjected to NDT 1,25 1,4
a
For local regions, a reduced value of 1,0 may be applied if proof is given by corresponding
tests with test specimen taken from these regions and corresponding quality assurance
measures for the manufacturing process.
6.4 Partial factor for instability γI
For the calculational assessment against the instability criterion a special partial factor is needed.
If the relevant structural requirements standard doesn't define a particular value, a partial factor of
γ = 1,5 shall be applied. For an analysis covering material and geometrical nonlineariti
...
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