1. SIM SBO DeMoPreCI-MDT 27/10/2015 Steel degradation in Offshore – from model to prediction 1

2. Que¿ DeDevelopment Mo Monitoring Pre Prediction CICoupled Interactions MDTMaterial Durability Testing 2

3. The concept 3 damage modes – Abrasion – Corrosion (dissolution / H embrittlement) – Fatigue 1 forming process – Welding 3

4. INDUSTRIAL CASES 4

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12. Starting point Do often occur simultaneously offshore All have their ‘state of the art’ But: interaction not well understood  over-estimation in real applications 12

13. ‘Marry’ + further develop understanding Corrosion (H embrittlement) + fatigue Abrasion + corrosion (material dissolution) Fatigue + abrasion First attempt to corrosion + fatigue + abrasion 13

14. For each ‘damage mode’ Generate a numerical model – To understand behavior – To predict behavior Experiments: improve understanding + generate input to build the models 14

15. Industrial parties 15

16. 16 Abrasion - corrosion Impeller Monopile Dredging MaterialHigh Cr IronLC high tensile structural steel Abrasive type (2B/3B)Two-body Dry or wetWet Dominant MechanismErosionAbrasion - corrosion Particle typeDepends on soil conditionsDepends on soil condition Particle size4mm maxTypical sea sand Impact velocity22 – 30 m/s (speed of the impeller)8-20 m/s (Wind speed) Operational hours40 – 60 hours20 – 25 years (design life) SourceLehigh Univeristy/Jan De NulM. Damgard et. al., Engineering Structures, 2014 Offshore wind

17. 17 Design of abrasion tester Configurations realized in this design Single asperity Multiple asperity Abrasion-corrosion Configurations not realized in this design  Impact abrasion/erosion FNFN

18. 18 Resonant Bending Fatigue Test Setup Corrosion – fatigue instrumentation MTS universal test machine

19. 19 Environmental controlled chamber Corrosion – fatigue instrumentation

20. 20 Scripting in ABAQUS with Python Parameterized Model 3D solid single-edge notch in a specimen along an arbitrary path. Fixed load  cyclic load  in environment

21. 21 Cathodic cellAnodic cell Hydrogen diffusion  Hydrogen diffusion coefficient  Hydrogen provided from the cathodic cell  Hydrogen diffusion through the sample  Oxidation H ads at surface in the anodic cell generating an anodic current Permeation cell

22. 22 j/j ∞ Experimental Theoretical Permeation results t

23. 23 H evolution and transport experiments (*Ref 1): A.V. Uluc, F.D. Tichelaar, H. Terryn, A.J. Bottger: Journal of Electroanalytical Chemistry 739 (2015) 130-136

24. 24 H evolution and transport experiments

25. 25 Governing equation for each species: Domain 1: metal Domain 2: interface Na + OH - Fe 2+ H 2 O + e -  H ads + OH - Fe  Fe 2+ + 2e - H ads H diffusion Domain 3: solution H evolution and transport model

26. 26 H evolution and transport model

27. 27 Interaction with heat transfer analysis Production of ferrite at initial transformation temperature Weight percentage: C% -- 0.39 Si% -- 2.05 Ni% -- 4.08 Ae 3 = 660 ͦC T h = 460 ͦC M s = 319 ͦC Test with JMAK model f = 1 - exp( -b·t n ) 660 ͦC SDV1 = volume fraction of ferrite and pearlite SDV2 = volume fraction of Bainite and W-ferrite Temperature distribution where temperature initially falls below 660 ͦC Welds: thermal analysis

28. 28 Heat source heat transfer analysis τ τ Metallurgical analysis f, carbon diffusion HETVAL Output: Moving heat source HETVAL Simulation of heat source of double ellipsoidal distribution Input: Ae 3, T h, M s, τ i USDFLD Chemical composition Grain size Chemical composition Grain size Welds: thermal analysis

29. 29 Questions?: More information: posters 23 – 28 at the poster session