FprEN 17149-3

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

This document describes a procedure for fatigue strength assessment based on cumulative damage of rail vehicle structures that are manufactured, operated and maintained in accordance with standards valid for rail system 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 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; 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

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

General Information

• Status: Not Published
• Publication Date: 20-Nov-2024
• ICS: 45.060.01 - Railway rolling stock in general
• Technical Committee: CEN/TC 256 - Railway applications
• Drafting Committee: CEN/TC 256/WG 2 - Structural requirements
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 11-Mar-2024
• Due Date: 31-Jan-2024
• Completion Date: 11-Mar-2024
• Ref Project: oSIST prEN 17149-3:2023 - Railway applications - Strength assessment of rail vehicle structures - Part 3: Fatigue strength assessment based on cumulative damage

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2023
Železniške naprave - Ocenjevanje odpornosti konstrukcije železniških vozil - 3.
del: Ocena odpornosti proti utrujenosti na podlagi kumulativne škode
Railway applications - Strength assessment of rail 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
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

prEN 17149-3:2023 (E)
Contents Page
European foreword . 6
Introduction . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Stress determination . 9
4.1 General. 9
4.2 Parent material . 9
4.3 Welded joints . 9
4.3.1 Modified nominal stresses . 9
4.3.2 Structural stresses and notch stresses . 9
5 Fatigue strength . 9
5.1 Parent material . 9
5.1.1 General. 9
5.1.2 Component fatigue strength Δσ and Δτ . 10
R R
5.1.3 Material properties . 10
5.1.4 Design Parameters . 11
5.1.5 Fatigue strength factors for direct stresses f and for shear stresses f . 13
R,σ R,τ
5.1.6 Correction factor for casting fR,C . 14
5.1.7 S-N curves and methods of cumulative damage rule . 15
5.2 Welded joints . 16
5.2.1 General. 16
5.2.2 Fatigue classes Δσ and Δτ . 16
C C
5.2.3 Component fatigue strength Δσ and Δτ . 17
R R
5.2.4 Influence of thickness f and bending . 17
thick
5.2.5 Residual stress factors f and f . 18
res,σ res,τ
5.2.6 Enhancement factor for post-weld improvement f . 18
post
5.2.7 Quality level factor f . 19
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 . 20
5.3 Determination of the fatigue strength of parent material and welded joints by
laboratory tests . 22
6 Partial factors covering uncertainties . 23
6.1 General. 23
6.2 Partial factor for loads γ . 23
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 . 24
M,S
6.3.3 Partial factor for the inspection during maintenance γ . 25
M,I
6.3.4 Partial factor for the degree of the validation process γ . 26
M,V
7 Procedure of the fatigue strength assessment based on cumulative damage
calculation . 26
prEN 17149-3:2023 (E)
7.1 General . 26
7.2 Stress determination . 27
7.3 Determination of the design stress spectrum . 27
7.3.1 Conditioning . 27
7.3.2 Stress history adjustment . 27
7.3.3 Counting . 28
7.3.4 Mean stress adjustment . 28
7.3.5 Omission . 29
7.4 Damage calculation for each single stress component . 29
7.4.1 General . 29
7.4.2 Determination of stress spectrum shape factor A . 30
eq
7.4.3 Determination of admissible damage sum D . 30
m
7.4.4 Determination of the utilization for a single stress component U . 31
c
7.5 Assessment of fatigue strength . 32
7.6 Critical plane approach . 33
Annex A (informative) Procedure for determination of mean stress factors for parent
material and welded joints . 35
A.1 General . 35
A.2 Mean stress sensitivity . 35
A.2.1 Parent material . 35
A.2.2 Welded joints . 36
A.3 Determination of mean stress factors . 36
Annex B (informative) Specification example for permissible volumetric defects in steel,
iron and aluminium castings . 40
B.1 General . 40
Annex C (informative) Material factors for parent material . 41
Annex D (normative) Fatigue classes Δσ and Δτ for welded joints based on the nominal
C C
stress approach . 43
D.1 Explanation of the tables for fatigue classes . 43
D.1.1 General . 43
D.1.2 Number in accordance with EN 15085-3:2022, Table B.1 . 43
D.1.3 Sketch of the joint . 43
D.1.4 Joint specific requirements . 44
D.1.5 Potential crack initiation point . 44
D.1.6 Feasibility for inspection . 44
D.1.7 Relevant thickness for the assessment of a welded joint . 44
D.1.8 Material . 44
D.1.9 Fatigue classes Δσ and Δτ . 44
C C
D.1.10 Exponent m and number of cycles at the knee point of the S-N curve N . 45
D
D.1.11 Thickness correction exponents n n and n . 45
σ,┴, σ,|| τ
D.1.12 Lower limit of the plate thickness for the thickness correction t . 45
min
D.1.13 Parameter α used for the determination of f . 45
bend bend
prEN 17149-3:2023 (E)
D.2 Tables of fatigue classes for welded joints . 46
D.3 Determination of fatigue strength based on comparative notch case models . 81
Annex E (informative) Thickness and bending influence on nominal and structural stress
approaches for welded joints . 82
E.1 General. 82
E.2 Influence quantities . 83
E.2.1 Thickness correction factor f . 83
thick
E.2.2 Enhancement factor for bending f . 84
bend
E.3 Methods for application of f in the assessment process . 85
bend
E.3.1 General. 85
E.3.2 General ratio method . 85
E.3.3 Constant ratio method . 86
E.3.4 Comparative notch case model method. 86
Annex F (informative) Stress adjustment due to joint geometry for welded joints for nominal
...