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BS EN 17149-3:2025 Railway applications. Strength assessment of rail vehicle structures - Fatigue strength assessment based on cumulative damage >
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BS EN 17149-3:2025 Railway applications. Strength assessment of rail vehicle structures - Fatigue strength assessment based on cumulative damage, 2025
- undefined
- European foreword
- Introduction
- 1 Scope
- 2 Normative references
- 3 Terms and definitions
- 4 Stress determination [Go to Page]
- 5 Fatigue strength [Go to Page]
- Table 1 — Anisotropy factor fA for steel and aluminium [Go to Page]
- Table 2 — Factors aRσ and bR for steel and aluminium
- Table 3 — Typical values for RZ, Ra and fSR,edge [Go to Page]
- Table 4 — Fatigue strength factors for direct stresses and shear stresses related to NC = 106 cycles [Go to Page]
- Table 5 — Correction factor for casting fR,C [Go to Page]
- Table 6 — Parameters for S-N curves
- Figure 1 — S-N curves for parent material for direct stresses: a) Miner modified; b) Miner consistent for ferritic steel, steel castings and spheroidal graphite cast iron; c) Miner consistent for austenitic steel and aluminium
- Table 7 — Material-related values for S-N curve parameters [Go to Page]
- Table 8 — Enhancement factor for post-weld improvement fpost [Go to Page]
- Table 9 — Quality level factor fQL [Go to Page]
- Table 10 — Enhancement factor for the weld inspection class fCT [Go to Page]
- Table 11 — Exponent m and number of cycles at knee point ND of the S-N curve for welded joints
- Table 12 — Exponent beyond knee point of S-N curve, cut-off limit and damage sum limit
- Figure 2 — S-N curve for welded joints based on direct stresses: a) Miner modified; b) Miner consistent [Go to Page]
- 6 Partial factors covering uncertainties [Go to Page]
- Table 13 — Partial factor for the fatigue strength γM [Go to Page]
- Table 14 — Partial factor for the consequence of failure γM,S [Go to Page]
- Table 15 — Partial factor for the inspection during maintenance γM,I [Go to Page]
- Table 16 — Partial factor for the degree of the validation process γM,V
- 7 Procedure of the fatigue strength assessment based on cumulative damage calculation [Go to Page]
- Figure 3 — Example of stress spectrum for the assessment of the fatigue strength and S-N curve related to modified version of Miner's rule [Go to Page]
- Figure 4 — Example of original and scaled state of stress spectrum for the assessment of the fatigue strength and S-N curve related to modified version of Miner's rule [Go to Page]
- Annex A (informative) Procedure for determination of mean stress factors for parent material and welded joints
- A.1 General
- A.2 Mean stress sensitivity
- A.2.1 Parent material
- Table A.1 — Mean stress sensitivity parameters am and bm
- A.2.2 Welded joints
- Table A.2 — Mean stress sensitivity for welded joints
- A.3 Determination of mean stress factors
- Figure A.1 — Haigh diagram for direct stresses
- Figure A.2 — Stress plot example for direct stresses
- Figure A.3 — Haigh diagram for shear stresses
- Annex B (informative) Specification example for permissible volumetric defects in steel, iron and aluminium castings
- B.1 General
- Table B.1 — Relevant ASTM documents
- Table B.2 — Definition of quality class levels based on defect categories in accordance with ASTM documents referenced in Table B.1
- Annex C (informative) Material factors for parent material
- Table C.1 —Summary of material factors for parent material
- Annex D (normative) Fatigue classes ΔσC and ΔτC for welded joints based on the nominal stress approach
- D.1 Explanation of the tables for fatigue classes
- D.1.1 General
- D.1.2 Number and marking in accordance with EN 15085-3:2022+A1:2023, Table B.1
- D.1.3 Sketch of the joint
- D.1.4 Joint specific requirements
- D.1.5 Potential crack initiation point
- D.1.6 Feasibility for inspection
- D.1.7 Relevant thickness for the assessment of a welded joint
- D.1.8 Material
- D.1.9 Fatigue classes ΔσC and ΔτC
- D.1.10 Exponent m and number of cycles at the knee point of the S-N curve ND
- D.1.11 Thickness correction exponents nσ,┴, nσ,|| and nτ
- D.1.12 Lower limit of the plate thickness for the thickness correction tmin
- D.1.13 Parameter αbend used for the determination of fbend
- D.2 Tables of fatigue classes for welded joints
- Table D.1 — Overview of joint types and corresponding weld numbers in accordance with EN 15085-3:2022+A1:2023, Table B.1
- Table D.2 — Joint type 11
- Table D.3 — Joint type 12
- Table D.4 — Joint type 13
- Table D.5 — Joint type 14
- Table D.6 — Joint type 15
- Table D.7 — Joint type 17
- Table D.8 — Joint type 18
- Table D.9 — Joint type 21
- Table D.10 — Joint type 24
- Table D.11 — Joint type 25
- Table D.12 — Joint type 26
- Table D.13 — Joint type 28
- Table D.14 — Joint type 29
- Table D.15 — Joint type 31
- Table D.16 — Joint type 34
- Table D.17 — Joint type 35
- Table D.18 — Joint type 36
- Table D.19 — Joint type 38
- Table D.20 — Joint type 39
- Table D.21 — Joint type 41
- Table D.22 — Joint type 46
- Table D.23 — Joint type 47
- Table D.24 — Joint type 48
- Table D.25 — Joint type 51
- Table D.26 — Joint type 56
- Table D.27 — Joint type 57
- Table D.28 — Joint type 61
- Table D.29 — Joint type 62
- Table D.30 — Joint type 63
- Table D.31 — Joint type 64
- Table D.32 — Joint type 65
- Table D.33 — Joint type 71
- Table D.34 — Joint type 72
- D.3 Determination of fatigue strength based on comparative notch case models
- Annex E (informative) Thickness and bending influence on nominal and structural stress approaches for welded joints
- E.1 General
- E.2 Influence quantities
- E.2.1 Thickness correction factor fthick
- Figure E.1 — Thickness correction factor with respect to t for steel
- Figure E.2 — Thickness correction factor with respect to t for aluminium
- E.2.2 Enhancement factor for bending fbend
- E.3 Methods for application of fbend in the assessment process
- E.3.1 General
- E.3.2 General ratio method
- E.3.3 Constant ratio method
- E.3.4 Comparative notch case model method
- Annex F (informative) Stress adjustment due to joint geometry for welded joints for nominal stress approach
- F.1 General
- F.2 Methods for stress adjustment
- F.2.1 General
- Figure F.1 — Options of modelling techniques for welded joints
- F.2.2 Modelling techniques for welded joints
- F.2.2.1 Option A – No Adjustment in the calculation model
- F.2.2.2 Option B – Adjustment of throat thickness implemented in the calculation model
- F.2.2.3 Option C – Adjustment of throat thickness and eccentricity implemented in the calculation model
- F.2.3 Adjustment in the stress evaluation
- F.2.3.1 General
- Table F.1 — Values for eccentricity effect factor for membrane stresses fe
- F.2.3.2 General ratio method
- F.2.3.3 Constant ratio method
- F.2.3.4 Parameters
- Table F.2 — Parameters for the assessment of option A
- Table F.3 — Parameters for the assessment of option B
- Annex G (informative) Application of structural stress approach for welded joints of steel and aluminium
- G.1 General for fatigue stress determination on weld toe
- Figure G.1 — Definition of structural stresses for T-joint
- Figure G.2 — Position of the evaluation point for butt joints
- Figure G.3 — Position of the evaluation point for T- or cruciform joints
- G.2 Fatigue stress determination with Finite Element method
- G.2.1 Fatigue stress determination at the weld toe
- Figure G.4 — Stress distribution on surface plate and over the plate thickness at weld toe
- G.2.2 Fatigue stress determination at the root
- Figure G.5 — Stress distribution in weld leg section and internal force and moment in weld joints
- G.3 Fatigue strength assessment with structural stresses
- Annex H (informative) Application of notch stress approach for welded joints of steel and aluminium
- H.1 General
- Figure H.1 — Fictitious rounding of weld toes and roots
- H.2 Calculation of notch stresses
- H.2.1 General
- H.2.2 Reference notch radius rref for modelling of weld notches
- Figure H.2 — Recommendations for reference radii for the fictitious rounding of notches for notch stress calculation
- H.2.3 Modelling of nominal weld cross-sections
- Figure H.3 — Cross-section examples
- Figure H.4 — Idealization of welded joints
- Figure H.5 — Rounding of roots
- H.2.4 Methods for notch stress calculation
- H.2.4.1 2D or 3D FEA analysis
- H.2.4.2 Mesh refinement
- Table H.1 — Recommended element lengths (along and normal to notch surface)
- H.2.4.3 Spot welds
- H.2.4.4 Weld notch factor Kw
- H.3 S-N curves
- H.3.1 Direct stress transverse to the weld
- Table H.2 — Fatigue class ΔσC,e and ΔτC,e for steel - related to stress ratio R = 0,5
- Table H.3 — Fatigue class ΔσC,e and ΔτC,e for aluminium - related to stress ratio R = 0,5
- H.3.2 Direct stress longitudinal to the weld
- H.3.3 Shear stress
- H.3.4 Characteristic values dependent on thickness effect
- Annex I (informative) Example for fatigue strength assessment
- I.1 Description
- Table I.1 — Parameters
- Table I.2 — Stress spectrum
- I.2 Task
- I.3 Assessment
- Table I.3 — Mean stress adjustment
- Table I.4 — Stress spectrum for the damage accumulation
- Table I.5 — Cumulative damage sum calculation with xit = 1,0
- Table I.6 — Cumulative damage sum calculation with xit = xDm = 2,129
- Annex J (informative) Flow chart diagrams of the fatigue strength assessment procedure
- Figure J.1 — Legend of the flow chart boxes
- Figure J.2 — Overview of fatigue strength assessment
- Figure J.3 — Fatigue strength assessment of one stress component
- Figure J.4 — Determination of the component fatigue strength
- Figure J.5 — Data pre-processing
- Figure J.6 — Damage and utilization calculation
- Bibliography [Go to Page]