oSIST prEN 17149-3:2021

Railway applications - Strength assessment of railway vehicle structures - Part 3: Fatigue strength assessment based on cumulative damage

This European Standard specifies a procedure for fatigue strength assessment of rail vehicle structures based on cumulative damage.
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 variable amplitude load data with total number of cycles higher than 10000 cycles.
An endurance limit approach is outside the scope of this European Standard.
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  a fatigue strength assessment using cumulative damage is to be applied.

Bahnanwendungen - Festigkeitsnachweis von Schienenfahrzeugstrukturen - Teil 3: Betriebsfestigkeitsnachweis

Applications ferroviaires - Évaluation de la résistance des structures de véhicule ferroviaire - Partie 3 : Évaluation de la résistance à la fatigue basée sur la méthode des dommages cumulés

Le présent document spécifie la procédure à appliquer pour l'évaluation de la résistance à la fatigue des structures de véhicules ferroviaires selon la méthode des dommages cumulés.
Il fait partie d'une série de normes qui spécifient les procédures d'évaluation de la résistance des structures de véhicules ferroviaires qui sont fabriquées, exploitées et entretenues conformément aux normes applicables aux applications ferroviaires.
Le présent document est applicable pour des données de charge à amplitude variable avec un nombre total de cycles supérieur à 10 000 cycles.
La méthode d'endurance limite ne relève pas du domaine d'application du présent document.
La procédure d'évaluation spécifiée dans cette série de normes se limite aux matériaux ferreux et à l'aluminium.
Cette série de normes ne définit pas de cas de charge de conception.
Cette série de normes ne s'applique pas en cas de conditions corrosives ou d'exploitation à une température élevée dans la plage de fluage.
Cette série de normes est applicable à tous les types de véhicules ferroviaires. Toutefois, elle ne définit pas dans quels cas il est nécessaire de réaliser une évaluation de la résistance à la fatigue selon la méthode des dommages cumulés.

Železniške naprave - Ocenjevanje odpornosti konstrukcije železniških vozil - 3. del: Ocena odpornosti proti utrujenosti na podlagi kumulativne škode

General Information

• Status: Not Published
• Public Enquiry End Date: 15-Sep-2021
• ICS: 45.060.01 - Railway rolling stock in general
• Technical Committee: IŽNP - Reilway applications
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 01-Jul-2021
• Due Date: 18-Nov-2021
• Completion Date: 16-Sep-2021
• Ref Project: prEN 17149-3 - Railway applications - Strength assessment of railway vehicle structures - Part 3: Fatigue strength assessment based on cumulative damage

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN 17149-3:2021
01-september-2021
Železniške naprave - Ocenjevanje odpornosti konstrukcije železniških vozil - 3.
del: Ocena odpornosti proti utrujenosti na podlagi kumulativne škode
Railway applications - Strength assessment of railway vehicle structures - Part 3: Fatigue
strength assessment based on cumulative damage
Bahnanwendungen - Festigkeitsnachweis von Schienenfahrzeugstrukturen - Teil 3:
Betriebsfestigkeitsnachweis
Applications ferroviaires - Évaluation de la résistance des structures de véhicule
ferroviaire - Partie 3 : Évaluation de la résistance à la fatigue basée sur la méthode des
dommages cumulés
Ta slovenski standard je istoveten z: prEN 17149-3
ICS:
45.060.01 Železniška vozila na splošno Railway rolling stock in
general
oSIST prEN 17149-3:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 17149-3:2021

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oSIST prEN 17149-3:2021


DRAFT
EUROPEAN STANDARD
prEN 17149-3
NORME EUROPÉENNE

EUROPÄISCHE NORM

June 2021
ICS 45.060.01
English Version

Railway applications - Strength assessment of railway
vehicle structures - Part 3: Fatigue strength assessment
based on cumulative damage
Applications ferroviaires - Évaluation de la résistance Bahnanwendungen - Festigkeitsnachweis von
des structures de véhicule ferroviaire - Partie 3 : Schienenfahrzeugstrukturen - Teil 3:
Évaluation de la résistance à la fatigue basée sur la Betriebsfestigkeitsnachweis
méthode des dommages cumulés
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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17149-3:2021 E
worldwide for CEN national Members.

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oSIST prEN 17149-3:2021
prEN 17149-3:2021 (E)
Contents Page
European foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Stress determination . 8
4.1 General. 8
4.2 Parent material . 8
4.3 Welded joints . 8
4.3.1 Modified nominal stresses . 8
4.3.2 Structural stresses and notch stresses . 8
5 Fatigue strength . 8
5.1 Parent material . 8
5.1.1 General. 8
5.1.2 Component fatigue strength Δσ and Δτ . 9
R R
5.1.3 Material properties . 9
5.1.4 Design Parameters . 11
5.1.5 Fatigue strength factors for normal and shear stresses f and f . 13
R,σ R,τ
5.1.6 Fatigue strength factor for castings f . 13
R,C
5.1.7 S-N curves and methods of cumulative damage rule . 15
5.2 Welded joints . 17
5.2.1 General. 17
5.2.2 Reference values of the fatigue strength Δσ and Δτ . 17
C C
5.2.3 Component fatigue strength Δσ and Δτ . 18
R R
5.2.4 Influence of thickness f and bending . 18
thick
5.2.5 Residual stress factor f and f . 19
res,σ res,τ
5.2.6 Enhancement factor for post-weld improvement f . 19
post
5.2.7 Quality level factor f . 20
QL
5.2.8 Enhancement factor for the weld inspection class f . 20
CT
5.2.9 S-N curves and methods of cumulative damage rule . 21
5.3 Determination of the fatigue strength of parent material and welded joints by
laboratory tests . 23
6 Partial factors for covering uncertainties . 23
6.1 General. 23
6.2 Partial factor for loads γ . 24
L
6.3 Partial factor for the component fatigue strength γ . 24
M
6.3.1 General. 24
6.3.2 Partial factor for the consequence of failure γ . 25
M,S
6.3.3 Partial factor for the inspection during maintenance γ . 26
M,I
6.3.4 Partial factor for the degree of the validation process γ . 26
M,V
2

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prEN 17149:2021 (E)
7 Procedure of the fatigue strength assessment based on cumulative damage
calculation . 27
7.1 General . 27
7.2 Stress determination . 28
7.3 Determination of the stress spectrum . 28
7.3.1 Conditioning . 28
7.3.2 Stress history adjustment . 28
7.3.3 Counting . 28
7.3.4 Mean stress adjustment . 29
7.3.5 Omission . 29
7.4 Damage calculation for each single stress component . 30
7.4.1 General . 30
7.4.2 Determination of stress spectrum shape factor A . 31
eq
7.4.3 Determination of admissible damage sum D . 31
m
7.4.4 Determination of cumulative damage sum D and scaling factor x to reach the
it it
admissible damage sum . 31
7.5 Assessment of fatigue strength . 33
Annex A (informative) Procedure for determination of mean stress factors for parent
material and welded joints . 34
A.1 General . 34
A.2 Mean stress sensitivity . 34
A.2.1 Parent material . 34
A.2.2 Welded joints . 35
A.3 Determination of mean stress factors . 35
Annex B (informative) Specification example for permissible volumetric defects in castings
of steel, iron and aluminium . 39
B.1 General . 39
Annex C (informative) Material factors for parent material . 41
Annex D (normative) Reference values of the fatigue strength Δσ and Δτ for welded
C C
joints based on the nominal stress approach . 42
D.1 Explanation of the tables for reference values of the fatigue strength . 42
D.1.1 General . 42
D.1.2 Weld seam type according to EN 15085-3, Table B.1 . 42
D.1.3 Sketch of the joint . 42
D.1.4 Joint specific requirements . 43
D.1.5 Potential crack initiation point . 43
D.1.6 Feasibility for inspection . 43
D.1.7 Relevant thickness for the assessment of a welded joint . 43
D.1.8 Material . 43
D.1.9 Reference values of the fatigue strength Δσ and Δτ . 43
C C
D.1.10 Exponent m and number of cycles at the knee point of the S-N curve N . 43
D
D.1.11 Thickness correction exponents n n and n . 43
σ,┴, σ,|| τ
D.1.12 Fatigue strength factor for structural stresses f (Ω =0) . 44
struc
D.1.13 Lower limit of the plate thickness for the thickness correction t . 44
min
D.1.14 Parameter α used for the determination of f . 44
bend bend
D.2 Tables of reference values of the fatigue strength for welded joints . 45
D.3 Determination of fatigue strength based on comparative notch case models . 80
Annex E (informative) Thickness influence and consideration of bending for welded joints
for nominal and structural stress approach . 81
3

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oSIST prEN 17149-3:2021
prEN 17149-3:2021 (E)
E.1 General. 81
E.2 Influence quantities . 81
E.2.1 Effective plate thickness t . 81
eff
E.2.2 Thickness correction factor f . 82
thick
E.2.3 Enhancement factor for bending f . 83
bend
E.3 Consideration methods. 84
Annex F (informative) Stress adjustment due to joint geometry for welded joints for
nominal stress approach . 86
F.1 General. 86
F.2 Methods for stress adjustment . 86
F.2.1 Adjustment implemented in the calculation model . 86
F.2.2 Adjustment in the stress evaluation . 86
Annex G (informative) Enhancement of reference value of the fatigue strength Δσ for load
C
carrying T- and cruciform joints with double fillet weld . 90
G.1 General. 90
G.2 Examples for the determination of the enhancement factor for cruciform joints . 90
Annex H (informative) Application of structural stress approach for welded joints of steel
and aluminium . 94
H.1 General for fatigue stress determination on weld toe . 94
H.2 Fatigue stress determination with Finite Element method . 95
H.2.1 Fatigue stress determination at the weld toe . 95
H.2.2 Fatigue stress determination at the root . 96
H.3 Fatigue strength assessment with structural stresses . 96
Annex I (informative) Application of notch stress approach for welded joints of steel and
aluminium . 98
I.1 General. 98
I.2 Calculation of notch stresses . 98
I.2.1 General. 98
I.2.2 Reference notch radius r for modelling of weld notches . 99
ref
I.2.3 Modelling of nominal weld cross sections . 99
I.2.4 Methods for notch stress calculation . 102
I.2.4.1 2D or 3D FEA analysis. 102
I.2.4.2 Mesh refinement . 102
I.2.4.3 Spot welds . 103
I.2.4.4 Weld notch factor K . 103
w
I.3 S-N curves . 103
I.3.1 Direct stress transverse to the weld . 103
I.3.2 Direct stress longitudinal to the weld . 104
I.3.3 Shear stress . 104
I.3.4 Characteristic values dependent on thickness effect . 105
Annex J (informative) Example for fatigue strength assessment . 106
J.1 Description . 106
J.2 Task . 107
J.3 Assessment . 107
Annex K (informative) Flow chart diagrams of fatigue strength assessment procedures . 113
Bibliography . 120

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oSIST prEN 17149-3:2021
prEN 17149:2021 (E)
European foreword
This document (prEN 17149-3:2021) 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 3: Fatigue strength assessment based on cumulative damage
The following part is under preparation:
 Part 2: Static strength assessment
5

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oSIST prEN 17149-3:2021
prEN 17149-3:2021 (E)
Introduction
If a fatigue strength assessment is necessary for railway vehicle structures, this assessment may be
made with an endurance limit approach or a cumulative damage approach.
An endurance limit approach is based on the assessment of the stress amplitudes (e.g. derived from the
design load cases or from measurements) against the applicable endurance limit. Such an approach is
established in combination with the normative loads such as those defined in EN 12663 series or
EN 13749.
A fatigue strength assessment based on cumulative damage takes into consideration stress spectra with
varying amplitudes and numbers of cycles or stress time histories. This document provides the basic
procedure and criteria for a pragmatic method to be applied for fatigue strength assessments based on
the cumulative damage approach.
The main body of the document is based on the nominal stress approach, but the consideration of
variable amplitudes and cycles counts according to methods described in this standard may equally be
applied with the structural stress and the notch stress approach (additional information is included as
informative annexes).
Within this document the term fatigue strength assessment is always related to the cumulative damage
approach unless otherwise noted.
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oSIST prEN 17149-3:2021
prEN 17149:2021 (E)
1 Scope
This document specifies a procedure for fatigue strength assessment of rail vehicle structures based on
cumulative damage.
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 variable amplitude load data with total number of cycles higher than
10 000 cycles.
An endurance limit approach is outside the scope of this document.
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 a fatigue strength assessment using cumulative damage 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.
1)
EN 15085-3:2007 , Railway applications — Welding of railway vehicles and components — Part 3:
Design requirements
2)
prEN 17149-1:202X , Railway applications — Strength assessment of railway vehicle structures — Part
1: General
ISO/TR 25901-1:2016, Welding and allied processes — Vocabulary — Part 1: General terms
3 Terms and definitions
For the purposes of this document, the terms and definitions, symbols and abbreviations given in
ISO/TR 25901-1:2016 and prEN 17149-1:202X 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

1)
document impacted by AC:2009.
2)
under development.
7

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prEN 17149-3:2021 (E)
4 Stress determination
4.1 General
The stress spectrum used to perform the fatigue strength assessment based on cumulative damage
approach shall be expressed in terms of stress amplitudes, mean stresses and number of cycles to
represent the design life.
The design stress spectrum shall incorporate any necessary allowance to account for uncertainties in
their values. If relevant, this may be achieved by application of a partial factor γ on the representative
L
stress spectrum as specified in the application code. In 6.2 recommendations and requirements for the
partial factor γL are given.
NOTE EN 12663 series, EN 15827 and EN 13749 contain information on how to determine design loads for
cumulative damage assessment of railway vehicles.
The combination of the individual stress components direct and shear is considered in 7.5.
4.2 Parent material
The stresses for the parent material shall be determined by the nominal stress approach as described in
prEN 17149-1:202X.
4.3 Welded joints
4.3.1 Modified nominal stresses
The modified nominal stresses for welded joints shall be determined according to prEN 17149-1:202X,
5.3.
4.3.2 Structural stresses and notch stresses
For the fatigue strength assessment of welded joints, the structural stress approaches and the notch
stress approach may be applied. For the application of these approaches, the requirements for the
calculation of the relevant stresses and fatigue strength is described in the following informative
annexes:
 Annex H for the structural stress approach and
 Annex I for the notch stress approach.
5 Fatigue strength
5.1 Parent material
5.1.1 General
This clause describes the method for a derivation of the fatigue strength of parent material under the
following conditions:
 materials used such as construction steel, weldable cast steel, cast iron (GJS and ADI), wroug
...