Prenorme Europeenne Europische Vornorm

May 1998

ICS 91.010.30; 91.080.10

Descriptors: civil engineering, steel construction, aluminium, design, building codes, computation, mechanical strength

This European Prestandard (ENV) was approved by CEN on 26 October 1997 as a prospective standard for provisional application.

The period of validity of this ENV is limited initially to three years. After two years the members of CEN will be requested to submit their comments, particularly on the question whether the ENV can be converted into a European Standard.

CEN members are required to announce the existence of this ENV in the same way as for an EN and to make the ENV available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the ENV) until the final decision about the possible conversion of the ENV into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.

English version

Eurocode 9: Design of aluminium structures - Part 2: Structures susceptible to fatigue

Eurocode 9: Conception et dimensionnement des structures en aliminium - Partie 2: Structures sensibles à la fatigue

Eurocode 9: Bemessung und Konstruktion von Aluminiumbauten - Teil 2: Ermüdungsanfällige Tragwerke

EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG

Central Secretariat: rue de Stassart, 36 B-1050 Brussels

© 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.

Contents

0 Foreword

1 General

1.1 Scope of Eurocode 9 Part 2

1.1.1 Application

1.1.2 Structural forms

1.1.3 Basic products

1.1.4 Member forms

1.1.5 Materials

1.1.6 Joining methods 9

1.1.7 Environmental conditions 9

1.2 Normative references 9

1.3 Distinction between Principles and Application Rules 9

1.4 Assumptions 10

1.5 Definitions 10

1.5.1 Terms common to all Eurocodes 10

1.5.2 Special terms used in this Part 2 of Eurocode 9 10

1.6 Symbols 13

1.7 Design Documents 14

1.7.1 Drawings 14

1.7.2 Manufacturing specification 14

1.7.3 Operation manual 14

1.7.4 Maintenance manual 14

2 Basis of design 15

2.1 General 15

2.1.1 Design objective 15

2.1.2 Influence of fatigue on design 15

2.1.3 Mechanism of failure 15

2.1.4 Potential sites for fatigue cracking 16

2.1.5 Conditions for fatigue susceptibility 16

2.1.6 Methods of fatigue design 17

2.2 Safe life design 17

2.2.1 Prerequisites for safe life design 17

2.2.2 Calculation procedure for safe life design 17

2.3 Damage tolerant design 17

2.3.1 Prerequisites for damage tolerant design 17

2.3.2 Determination of inspection strategy for damage tolerant design 19

2.4 Design by assisted testing 20

3 Loading 21

3.1 Sources of fatigue loading 21

3.2 Derivation of fatigue loading 21

3.3 Equivalent fatigue loading 22

3.4 Partial safety factors for fatigue loading 22

4 Stress Analysis 23

4.1 Global stress analysis 23

4.1.2 Use of beam elements 23

4.1.3 Use of membrane and shell elements 24

4.2 Applicability of nominal, modified nominal and hot spot stresses 24

4.2.1 Nominal stresses 24

4.2.2 Modified nominal stresses 25

4.2.3 Hot spot stresses 25

4.3 Derivation of stresses 25

4.3.1 Derivation of nominal stresses 25

4.3.2 Derivation of modified nominal stresses 27

4.3.3 Derivation of hot spot stresses 27

4.3.4 Stress orientation 27

4.4 Stress range parameters for specific initiation sites 28

4.4.1 Parent material, full penetration welds and mechanically fastened joints 28

4.4.2 Fillet and partial penetration butt welds 28

4.4.3 Adhesive bonds 28

4.4.4 Castings 29

4.5 Stress spectra 29

4.5.1 Cycle counting 29

4.5.2 Derivation of stress spectrum 29

5 Fatigue strength 31

5.1 Detail categories 31

5.1.1 Factors affecting detail category 31

5.1.2 Detail category tables 31

5.2 Fatigue strength data 32

5.2.1 Classified details 32

5.2.2 Unclassified details 33

5.2.3 Adhesively bonded joints 33

5.2.4 Hot spot stress 46

5.3 Effect of mean stress 46

5.3.1 General 46

5.3.2 Plain material and mechanically fastened joints 46

5.3.3 Welded joints 46

5.3.4 Adhesive joints 46

5.3.5 Low endurance range 46

5.3.6 Cycle counting for R-ratio calculation 47

5.4 Effect of environment 47

5.5 Improvement techniques 47

6 Quality requirements 48

6.1 Determination of required quality level 48

6.2 Designation of quality levels on drawings 48

6.3 Fitness-for-purpose assessment 49

Annex A: (Informative) Stress analysis 50

Annex B: (Informative) Guidance on assessment by fracture mechanics 54

Annex C: (Informative) Testing for fatigue design 72

Annex D: (Normative) Inspection and workmanship acceptance levels 77

Annex E: (Informative) Fatigue strength improvement of welds 85

Annex F: (Informative) Low cycle fatigue 87

Annex G: (Informative) Influence of R-ratio 89

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