STANDARD

DNVGL-ST-0361 Edition September 2016

Machinery for wind turbines

DNV GL AS

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FOREWORD

DNV GL standards contain requirements, principles and acceptance criteria for objects, personnel,organisations and/or operations.

DNV GL AS September 2016

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Contents

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Sec.1 Introduction.................................................................................................. 91.1 Objectives ..............................................................................................91.2 Scope and application ............................................................................91.3 References ...........................................................................................101.4 Informative references.........................................................................141.5 Definitions............................................................................................14

1.5.1 Terminology and definitions...........................................................141.5.2 Acronyms and abbreviations..........................................................141.5.3 Symbols .....................................................................................15

Sec.2 Materials ..................................................................................................... 192.1 General requirements...........................................................................19

2.1.1 General ......................................................................................192.1.2 Categories of structural members...................................................192.1.3 Material tests ..............................................................................19

2.2 Metallic materials ................................................................................202.2.1 General ......................................................................................202.2.2 Selection criteria of steelsfor welded structures ..............................212.2.3 Requirements for steels for welded structures..................................212.2.4 Requirements for cast steels..........................................................242.2.5 Stainless steels............................................................................252.2.6 Forging steels..............................................................................252.2.7 Cast iron.....................................................................................292.2.8 Aluminium alloys .........................................................................312.2.9 Wrought alloys ............................................................................312.2.10 Cast alloys ..................................................................................31

Sec.3 Corrosion protection ................................................................................... 323.1 Machinery for wind turbines.................................................................32

3.1.1 General ......................................................................................323.1.2 Coatings .....................................................................................333.1.3 Metallic coatings and platings ........................................................333.1.4 Corrosion protection of bolts..........................................................33

3.2 Offshore application .............................................................................343.2.1 General ......................................................................................343.2.2 Atmosphere ................................................................................343.2.3 Corrosion protection.....................................................................343.2.4 Surface preparation for protective coatings......................................35

Sec.4 Machinery structures .................................................................................. 364.1 General ................................................................................................36

4.1.1 General requirements ...................................................................364.1.2 Limit states .................................................................................37

4.2 Determination of stresses ....................................................................394.2.1 General notes on the loading of the structure ..................................394.2.2 Methods of analysis......................................................................394.2.3 Dynamic calculation .....................................................................41

4.3 Static strength analysis........................................................................414.3.1 General ......................................................................................414.3.2 Method for static strength analysis .................................................42

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4.4 Fatigue strength analysis .....................................................................42

4.4.1 General ......................................................................................424.4.2 Methods for fatigue strength analysis..............................................434.4.3 Damage calculation ......................................................................444.4.4 Superposition of multi-axial stress conditions...................................444.4.5 Equivalent stress hypotheses.........................................................454.4.6 Mean stress correction..................................................................46

4.5 S/N curves for metallic materials.........................................................474.5.1 S/N curves for welded steel structures ............................................474.5.2 S/N curves for cast steel, cast, forged and rolled parts .....................484.5.3 S/N curves for the design of aluminium parts...................................50

4.6 Calculation of synthetic S/N curves......................................................504.6.1 General ......................................................................................504.6.2 Non-welded forged and rolled parts ................................................514.6.3 Cast steel and spheroidal graphite cast iron.....................................524.6.4 Documentation of input parameters................................................534.6.5 Documentation of result parameters...............................................53

4.7 Partial safety factors ............................................................................544.7.1 Ultimate limit state ......................................................................544.7.2 Fatigue limit state ........................................................................544.7.3 Serviceability limit state................................................................54

Sec.5 Bolted connections...................................................................................... 555.1 Assessment documents ........................................................................555.2 Tensioning of bolted joints ...................................................................55

5.2.1 General ......................................................................................555.2.2 Yielding ......................................................................................55

5.3 Strength analysis of preloaded bolted joints ........................................565.3.1 Analytical strength assessment of preloaded bolted joints..................565.3.2 Numerical strength assessment of bolted joints................................57

5.4 Requirements on materials and corrosion protection of bolting elements ..............................................................................................575.4.1 Fatigue strength of bolts ...............................................................575.4.2 Corrosion protection.....................................................................585.4.3 Inspection of bolted connections ....................................................58

Sec.6 Bearings...................................................................................................... 596.1 General.................................................................................................596.2 Assessment documents ........................................................................596.3 Materials ..............................................................................................59

6.3.1 Approved materials ......................................................................5