Project: Analysis of ultimate capacity of the structural elements of single hull VLCC subject to corrosion

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West Pomeranian University of Technology, Szczecin Faculty of Maritime Technology and Transportation Chair of Structure, Mechanics and Ship Fabrication MASTERS THESIS DEFENSE Project: Analysis of

1 West Pomeranian University of Technology, Szczecin Faculty of Maritime Technology and Transportation Chair of Structure, Mechanics and Ship Fabrication MASTERS THESIS DEFENSE Project: Analysis of ultimate capacity of the structural elements of single hull VLCC subject to corrosion Presented by : DAMI RACHID (Emship Student) Advisor: Dr. Maciej Taczala Szczecin, Poland بولندا شتاشين Content of presentation. Introduction 2. The details points will be presented : 2. The new corrosion model comparing with others models and the assumed data to defined the depth the corrosion of the ship structure 2.2 Various Parameters Influence the Ultimate Strength of the plate 2.3 Application : ULS capacity of the tanker ship including effect the corrosion ULS capacity of the plates, and panels The Progressive hull girder collapse analysis 3. Summary and conclusions 2

Introduction Computational comparison between PULS theory and other candidate

corrosion Computational comparison between CSR and other candidate models

Atmospheric corrosion Fe + 2OH Fe(OH) 2 + 2e 2H 2 O + O 2 + 4e 4OH 4Fe(OH) 2 + 2H 2

2 Introduction Computational comparison between PULS theory and other candidate models discussing ULS capacity of the plates and stiffened panels subject to the corrosion Computational comparison between CSR and other candidate models discussing progressive collapse of the hull girder subject to the corrosion 3 Atmospheric corrosion Fe + 2OH Fe(OH) 2 + 2e 2H 2 O + O 2 + 4e 4OH 4Fe(OH) 2 + 2H 2 O + O 2 4Fe(OH) 3 2Fe(OH) 3 Fe 2 O 3 3H 2 O 4 Source: 2

model: If t > Tst If η= by using Taylor series we keep the first term linear we

3 Electrochemical corrosion Pitting corrosion 5 The candidates models The corrosion model is based to this equation : If β= then we get the Guedes Soares and Garbatov model: If t > Tst If η= by using Taylor series we keep the first term linear we get the Paik /al model : Finally if we take β=0.6257, and we get the Melcher model: 6 3

4 Solve basic equation using LSM Using the least squares method we get the Model () : 7 Describe the new model (2) from the assumption of the Paik/al,keep the second order of Taylor series : To make computation we take for : For new model developing as follow Paik/al model : we made analysis of flexibility to the distribution of the rate corrosion to fixe two parameters β and η. 8 4

5 The flexibility of the rate corrosion distribution beta=.5 eta=2 rate corrosion(mm/years) at eta= beta= beta=0. rate the corrosion(mm/years) at beta= eta=5 eta= time(years) time(years) 9 The reference data : ABS ref and the assumed data (ref paper Shengping Qin and Weicheng Cui School of Naval Architecture and Ocean Engineering, Shanghai Jiao Tong University, Shanghai, , China ) 3,26,8 The thickness the corrosion (m m ) 2,76 2,26,76,26 0,76 Cargo deck plating (mm) Ballast deck plating (mm) side shell Cargo (mm) side shell Ballast (mm) Bottom shell Cargo (mm) Bottom shell Ballast (mm) Long Bulkhead Cargo (mm) Long bulkhead plating Ballast (mm) The thicknes the corrosion (mm),6,4,2 0,8 0,6 0,4 0,2 0, Time service (years) ,2 Time service (years) The data ref ABS The assumed data (ref paper Shengping Qin and Weicheng Cui School of Naval Architecture and Ocean Engineering, Shanghai Jiao Tong University, Shanghai, , China) 0 5

6 Parameters β η D inf Run Run For β=[0.62,0.7] we describe the ratio between the parameters β and η equal to : Initial corrosion rate T h e d e p t h t h e c o rro s io n ( m m ) Assumed Data model (2) Paik/al model Guedes Soares/Garbatov Melcher Model Long -term corrosion rate time (years) Coating life 6

7 The flexibility of the rate corrosion distribution 3 The flexibility of the rate corrosion distribution model (2) The rate function basic equation The rate corrosion (mm/years) time(years) 4 7

8 Ref. experimental data: Book Metal corrosion in the atmosphere (968 library of congress catalog card Numb: ) Depth of c orroson(m m ) Numerical model (2)AL2024-T8 Alloy Experimental data ref : Book Metal corrosion in the atmosphere (Americain society for material, 968 library of congress catalog card Numb: Time (years) Depth of corrosion versus time for Al2024-T-8 Alloy 5 Ref. experimental data: Book Metal corrosion in the atmosphere (968 library of congress catalog card Numb: ) model(2) for Aloy 62- ICU Zinc Data experimental Depth of the c orros ion (m m ) Time(years) Depth of corrosion versus time for Aloy 62-ICU Zinc 6 8

9 Effect of the corrosion to reduce the section modulus and the section area for cargo deck of SHVLCC RSM ratiosm(time) = 2E-05t t t t t t model Ship age (years) We lost 9,3% the mean section area during 25 years the service Data corrrosion model Poly. (Data corrrosion ) The mean section area (mm2) We lost 5% the section modulus during 5 years the service section arae(time) = t t t t t2-4665t ship age (years) model (2) Assumed Data Poly. (Assumed Data ) 7 Effect of the corrosion to reduce the section modulus and the section area for cargo deck of SHVLCC.005 y = - 7.6e-006*x *x 2-0.0*x + model (2) cubic 0.99 y = -.2e-005*x *x *x +. model (2) cubic the ratio the section modulus (Z/Z0) the ratio the section area (A/A0) time ship service (years) time ship service (years) 8 The fit of the curve section modulus versus ship age, subject to the uniform corrosion The fit of the curve section area versus ship age, subject to the uniform corrosion 9

10 Effect of the corrosion to reduce the section modulus using the aluminium and zinc material RSM aluminum(t) = -4E-05t 3 + 0,0006t 2-0,0029t + 0,9999 RSM zinc(t) = -0,003t + The ratio of the section modulus Time(years) Alloy62-ICU Zinc AL2024-T8ALLOY Linéaire (Alloy62-ICU Zinc) Poly. (AL2024-T8ALLOY) 9 The fit curve section modulus versus ship age, subject to the uniform corrosion Correlation between weight and ratio of the section modulus of the cargo deck SHVLCC 2.06E E E E+03.98E+03.96E+03.94E+03.92E+03.90E+03 Weight (tonne) Weight(tonne) = 540.9*ratiosectionmodlus R² =.88E Section modulus the full deck /section built model (2) Assumed Data cargo deck Linéaire (Assumed Data cargo deck) 20 0

11 The ULS computation of the plate subject to the corrosion.00 Cui/Mansour DNV PULS with lateral pressure a/b=6,23 DNV PULS without pressure a/b=6,23 Φup β 2 The ULS computation of the plate subject to the corrosion.25 σ u,y /σ Y p=2 mm pressure=0mpa indef=2,7mm p2=4 mm pressure =0 MPa indef=2,22mm p3=9,5 mm pressure =0 Mpa indef=,59mm p=8mm/b=500mm indef=0,6mm p=8mm/b2=850mm indef=,72 mm p=8mm/b=950mm indef=2,5mm σ u,x /σ Y 22

12 The ULS computation of the plate subject to the corrosion Reduction the ultimate strength the plate Hogging Bottom 8.0% Bottom2 8.54% lower longitudinal bulkhead 7.9% Lower side 8.98% Sagging Deck 8.90% Deck2 8.48% upper longitudinal bulkhead 9.35% Upper side 7.97% 23 The ULS computation of the stiffened panel subject to the corrosion The dimension of the stiffened panel bottom Element ei(breath) mm bi(height) mm Effective plating 870,00 22 Web Flange The neutrale axis:zg 8,64 mm λ 0,25 β,38 be (effectif width) 0,804 m 24 2

13 The ULS computation of the stiffened panel subject to the corrosion The reduction the ULS of the stiffened panel (effect the uniform corrosion) in hogging 6.00% 4.00% 2.00% DNV PULS Paik Model 0.00% 8.00% 9.25% 6.00% 5.39% 5.33% 6.6% Rahman model Hughes model 4.00% 2.00% Average 0.00% Bottom Bottom2 lower longitudinal bulkhead LOWER SIDE 25 The ULS computation of the stiffened panel subject to the corrosion The reduction the ULS of the stiffened panels (effect the uniform corrosion) in sagging 4.00% 2.00% 0.00% 0.49% DNV PULS Paik model 8.00% 7.86% Rahman model Hughes model 6.00% 6.7% 5.9% average 4.00% 2.00% % Deck Deck2 upper longitudinal bulkhead upperside 3

14 The ULS computation of the hull girder subject to the corrosion SHIP MAIN PARTICULARS Length O.A of the tanker ship L 3 m Breadth of the tanker ship B 57.2 m Bloc coefficient C B 0.84 Design speed V 5.4 Kn Depth of ship D 30.4 m Dead-weight DWT The general arrangement of the upper deck and the tank plan The 3D views of the tanker ship single hull VLCC 28 4

15 The ULS computation of the hull girder subject to the corrosion Ultimate Bending moment (GN.m) Ship age (years) MU Hogging with uniforme corrosion (GN.m) MU Sagging with uniforme corrosion (GN.m) 3 x 04 The reduction the MU hogging with uniform corrosion = 7 %. The reduction the MU sagging with uniform corrosion = 5%. 2.5 The reduction the N.Axis position in hogging with uniform corrosion = 26 % The reduction the N.Axis position in sagging with uniform corrosion = 4 % T h e p o s itio n o f th e N e u tral a x is ( m m ) 2.5 YNAXIS=5.9 m Y NAXIS=7.4 m Y Naxis=23.48 m The neutral axis position in hogging ignoring corroion The neutral axis position in sagging ignoring corroion The neutral axis position in hogging with uniforme corroion Y NAXIS=6.09 m The neutral axis position in sagging with uniforme corroion Y Naxis=4.4 m Y Naxis=.2 m 0.5 Y Naxis=4.2 m Y Naxis= 0.76 m X: 2.53e-007 Y: The curvature (/mm) x 0-7 The ULS computation of the hull girder subject to the corrosion Sagging Hogging 35% Average Sag Average Hog 20% The reduce the ultimate bending moment (%) 30% 25% 20% 5% 0% 5% 5.75% 7.76% 4.87% 7.05% 7.0% 6.08% 6.30% 8.86% 6.92% 7.72% 7.2% 29.98% 5.62% 5.70% 7% 0% 5% Paik/Mansour Modiefed Caldwell Vinner Faulkner/Sadden Valsgaad/steen Rahman CSR Tanker 9% 9% 8% 8% 7% 6% 6% 5% The average the reduce the ultimate bending moment in hogging and sagging The candidates model 30 5

16 Summary and conclusions keep the model (2) : Reduce 5% the section modulus during 5 years the service subject to the uniform corrosion. Reduce 9,3% the mean section area during 25 years the service subject to the uniform corrosion. Reduce 8% the ultimate strength capacity of the plate. Reduce 5-9% the ultimate strength capacity of the stiffened panels. The reduction the MU hogging with uniform corrosion = 8.86 %. The reduction the MU sagging with uniform corrosion = 6%. The reduction the N.Axis position hogging with uniform corrosion = 26 %. The reduction the N.Axis position sagging with uniform corrosion = 4 %. 3 ﲆ اﻫ"ﻣﲂ % ﺷﻜﺮﰼ 32 Merci pour votre attention 6

NEW CORROSION MODEL TO PREDICT STEEL STRENGTH

NEW CORROSION MODEL TO PREDICT STEEL STRENGTH Proceedings of the 7th International Conference on Mechanics and Materials in Design Albufeira/Portugal 11-15 June 217. Editors J.F. Silva Gomes and S.A. Meguid. Publ. INEGI/FEUP (217) PAPER REF: 6415