Author: Salina Binti Ramli I/C No: 820610-14-5148 Matric No: MA061181 Year: 2008 Type of Degree: Master of Engineering (Civil-Structure) Supervisor: Dr. Norhazilan Bin Md. Noor Panel of Examiners: 1) Assoc. Prof. Dr. Mohamed Abdelkader El-Gelani Ismail 2) Prof. Ir. Dr. Mohd Warid Bin Hussin 3) Dr. Ahmad Kueh Beng Hong
24
Embed
Author: Salina Binti Ramli 820610-14-5148 MA061181 2008engineering.utm.my/civil/ethesis/wp-content/uploads/sites/47/MASTERS/...Pengaratan merupakan faktor utama kepada masalah kemerosotan
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Author: Salina Binti Ramli
I/C No: 820610-14-5148
Matric No: MA061181
Year: 2008
Type of Degree: Master of Engineering (Civil-Structure)
Supervisor: Dr. Norhazilan Bin Md. Noor
Panel of Examiners: 1) Assoc. Prof. Dr. Mohamed Abdelkader
El-Gelani Ismail
2) Prof. Ir. Dr. Mohd Warid Bin Hussin
3) Dr. Ahmad Kueh Beng Hong
CORROSION GROWTH PREDICTION IN SEAWATER BALLAST TANK OF
BULK CARRIERS USING STATISTICAL MODEL
SALINA BINTI RAMLI
A project report submitted in partial fulfillment of the
requirements for the award of degree of
Master of Engineering (Civil-Structure)
Faculty of Civil Engineering
Universiti Teknologi Malaysia
April 2008
I declare that this project report entitled “Corrosion Growth Prediction In Seawater
Ballast Tank Of Bulk Carriers Using Statistical Model” is the result of my own
research except as cited in references. This project has not been accepted for any
degree and is not concurrently submitted in candidature of any other degree
Teristimewa untuk Ibu dan bapa tersayang; Pn. Aminah Binti Pandak Soud dan En. Ramli Bin
Kassim, tunang yang banyak memberi sokongan; En. Nazrul Aizad Bin Harun serta adik-adik
yang dikasihi; Mohd Shahril, Saliza, Syahirah dan Syafiqa.
APPRECIATION
First of all, grateful to Allah S.W.T , after a year of struggle and hard work,
with His will, this thesis is completed. Thanks to Allah for giving me the strength to
complete this project and the strength to keep on living.
To my supervisor, Dr. Norhazilan Md. Noor, thanks a lot for the guidance
you gave in completing this thesis. All advises and help you gave, academically or
non-academically, are really helpful and will never be forgotten.
To all my friends, thanks a lot for all the helps. Not to forget my partner for
this project, Kak Ros, really appreciate all those moments, having fun when the
pressure of this project is too much for me. Not forgotten, a million of appreciation
to Kak Mazura, Kak Eyza and Kak Shidah with all their helps in completing this
project especially for improving my writting in English.
To my mom, dad and family, thank you for all the support you gave to me.
Your sacrifice is too great to be measured. I will never be here, if you have never
been there for me. You’ll never be forgotten.
Lastly, to my beloved fiancé, Nazrul Aizad Bin Harun, all the support, spirit
and inspiration from you all these years had brought me here to complete my master.
Really appreciate all your patient and consent. Thanks for everything dear…..
ABSTRACT
Corrosion is the major cause of deterioration in marine structures. For the
past few years have seen an increase in the number of reported instances of
accelerated corrosion in ship’s ballast tank. This is why careful attention needs to be
taken to prevent the deterioration due to corrosion of ballast tank. Therefore,
corrosion growth prediction is important in failure analysis. This paper developed a
statistical time dependent model for corrosion depth of seawater ballast tank in bulk
carriers. The model is based on available group of statistical data for corrosion of
existed bulk carriers. The proposed model is benefit for future prediction of
corrosion data by eliminating the dependent factors such as environment factor,
material properties and operational condition. In specific, a simple simulation
procedure is implemented to predict the future distribution of corrosion depth.
Based on the result in simulation stage, the result were synthesized and analyzed for
validity of proposed model by comparing the actual data with predicted data. The
result shows that the model is reliable and practical in predicting the distribution of
corrosion depth. From the study, the proposed model seems to be more flexible
comparing to the available analysis method and hopefully will facilitate the engineer
in the future prediction of ship failure in marine structures.
ABSTRAK
Pengaratan merupakan faktor utama kepada masalah kemerosotan kualiti
sesebuah stuktur laut. Jumlah pengaratan tangki balas kapal dilaporkan mengalami
peningkatan yang drastic beberapa tahun kebelakangan ini. Ini adalah salah satu
sebab mengapa perhatian perlu di titikberatkan dalam pengawalan pengaratan
sesebuah tangki balas. Oleh sebab itu, ramalan pertumbuhan karat adalah penting
dalam menganalisis kegagalan sesebuah struktur. Kajian ini dijalankan bagi
menghasilkan sebuah model pertumbuhan karat di dalam tangki balas sesebuah
kapal penumpang yang mana berkadaran dengan masa. Model ini dilaksanakan
berdasarkan sekumpulan data kapal penumpang yang sedia ada. Model yang
dicadangkan ini berguna dan dijangkakan dapat digunakan dalam membuat ramalan
pertumbuhan karat bagi masa akan datang. Perlaksanaan model ini adalah
berdasarkan faktor bilangan dan umur kapal dengan mengabaikan faktor-faktor lain
seperti persekitaran, bahan dan keadaan operasi kapal. Seterusnya, sebuah prosedur
penyerupaan yang mudah dijalankan ke atas model yang telah dibangunkan untuk
meramal taburan pertumbuhan karat pada masa akan datang. Daripada proses
penyerupaan yang dijalankan, kesahihan model yang dibangunkan dapat dibuktikan
setelah keputusan yang diperolehi di sintesis dan dianalisis dengan membuat
perbandingan secara grafik di antara data sebenar dengan data yang diramalkan.
Hasil akhir menunjukkan model yang dicadangkan adalah sesuai dan praktikal
dalam ramalan taburan kedalaman pengaratan . Melalui kajian ini, model yang
dicadangkan diharap dapat memudahkan jurutera dalam ramalan kegagalan
sesebuah struktur kapal pada masa akan datang.
TABLE OF CONTENT
CHAPTER TITLE PAGE
PROJECT STATUS APPROVAL
SUPERVISOR APPROVAL
TITLE i
DECLARATION ii
DEDICATION iii
APPRECIATION iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENT vii
LIST OF TABLE xi
LIST OF FIGURE xiii
LIST OF SYMBOL xvi
LIST OF APPENDIX xvii
1 INTRODUCTION
1.1 Corrosion of Marine Structures 1
1.2 Problem Statement 2
1.3 Objectives and Aim of Research 3
1.4 Scope of Study 4
1.5 Expected Findings and Importance of Research 4
1.6 Conclusion 5
2 LITERATURE REVIEW
2.1 Corrosion 7
2.1.1 Definition 8
2.1.2 Corrosion Mechanism 8
2.2 Corrosion in Marine Structure 9
2.2.1 Corrosion by sea water 10
2.2.2 Marine Corrosion Mechanism 12
2.2.3 Corrosion Failure 14
2.2.3.1 Corrosion Failure Analysis 15
2.2.4 Form of Corrosion 16
2.2.4.1 Uniform Corrosion 17
2.2.4.2 Localized corrosion 18
2.2.4.3 Galvanic Corrosion 22
2.2.4.4 Environmental Cracking 25
2.2.5 Factor Cause Corrosion 28
2.2.6 Metal Use in Marine Engineering 29
2.2.7 Corrosion Prevention 30
2.2.7.1 Painting 30
2.2.7.2 Cathodic and Anodic Protection 31
2.2.7.3 Metal Coating for Corrosion Protection 33
2.2.8 Material and Design to Avoid Corrosion 33
2.3 Seawater Ballast Tank 34
2.3.1 Introduction 34
2.3.2 Corrosion in Ballast Tank 36
2.3.3 Coating Breakdown Mechanism in Ballast Tank 38
2.3.4 Tank Inspection 41
2.4 Marine Corrosion Model 43
2.5 Literature Review of Previous Research Papers 43
2.5.1 Empirical Model 43
2.5.1.1 Kelly, Et. All. (2007) 43
2.5.2 Mathematical Model 45
2.5.2.1 Paik, Et. All (2003) 45
2.5.2.2 Paik, Kim and Lee (1997) 51
2.5.2.3 Shengping Q, Et. All (2002) 51
3 METHODOLOGY
3.1 Introduction 53
3.2 Research Activities 55
3.2.1 Literature Review 56
3.2.2 Data Analysis 56
3.2.2.1 Data Collection 56
3.2.2.2 Analysis and Interpretation of Data 58
3.2.2.3 Histogram Development 58
3.2.2.4 Model Verification using Chi Square Test 65
3.2.2.5 Statistical modeling of corrosion models 66
3.2.3 Simulation and Prediction 66
3.2.3.1 Corrosion Depth Prediction Using Inverse 66
Transformation Method
3.2.3.2 Verifying the Validity of Proposed Model 67
Based on Simulation Results.
3.2.4 Analysis of Model Using Root Mean Square Error 67
Method (RMSE)
4 ANALYSIS AND RESULT
4.1 Introduction 68
4.2 Linear Regression Model 70
4.3 Probability Time-Dependent Model 72
4.4 Chi-Square Test 78
4.5 Simulation 80
4.5.1 Inverse Transformation Method 80
4.6 Result Analysis 81
4.6.1 Graphical Comparison 82
4.7 Root Mean Square Error Method (RMSE) 92
5 DISCUSSION AND RECOMMENDATION
5.1 Overview 95
5.2 Data Collection 97
5.3 Data Analysis 99
5.4 Simulation and Prediction 103
5.5 Recommendation 106
6 CONCLUSION 107
REFERENCES 109
APPENDIX 112
LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 Galvanic series of in flowing seawater 23
2.2 Gathered number of measured data set of thickness loss 48
due to corrosion in seawater ballast tank of bulk carriers
(Paik and Thayambali, 2003).
2.3 Summary of computed results for mean and the COV of 49
Annualized corrosion rate of bulk carrier’s seawater ballast
Tank (Paik and Thayambali, 2003)
3.1 Gathered number of measured data set of thickness loss due 57
to corrosion in seawater ballast tank of bulk carriers.
4.1 Corrosion distribution data in seawater ballast tank of bulk 69
Carriers
4.2 Chi square test (average depth = 0.6443) 79
4.3 Chi square test (average depth = 0.9883) 79
4.4 Chi square test (average depth = 0.7555) 79
4.5 Comparison for group of vessel’s age 18 – 18.5 (1st trial) 82
4.6 Comparison for group of vessel’s age 18 – 18.5 (2nd trial) 83
4.7 Comparison for group of vessel’s age 18 – 18.5 (3rd trial) 84
4.8 Comparison for group of vessel’s age 20 – 20.5 (1st trial) 84
4.9 Comparison for group of vessel’s age 20 – 20.5 (2nd trial) 85
4.10 Comparison for group of vessel’s age 20 – 20.5 (3rd trial) 86
4.11 Comparison for group of vessel’s age 21 – 21.5 (1st trial) 86
4.12 Comparison for group of vessel’s age 21 – 21.5 (2nd trial) 87
4.13 Comparison for group of vessel’s age 21 – 21.5 (3rd trial) 88
4.14 Comparison for group of vessel’s age 23 – 23.5 (1st trial) 88
4.15 Comparison for group of vessel’s age 23 – 23.5 (2nd trial) 89
4.16 Comparison for group of vessel’s age 23 – 23.5 (3rd trial) 90
4.17 Comparison for group of vessel’s age 25 – 25.5 (1st trial) 90
4.18 Comparison for group of vessel’s age 25 – 25.5 (2nd trial) 91
4.19 Comparison for group of vessel’s age 25 – 25.5 (3rd trial) 92
4.20 RMSE value for each class of vessel’s age 93
4.21 The best simulation result based on RMSE 94
5.1 Collected data 98
5.2 Mean depth and standard deviation for each vessel’s age 100
LIST OF FIGURES
FIGURE NO. TITLE PAGE
1.1 Organization of study 6
2.1 Schematic representation of current flow in simple 9
Corrosion cell
2.2 Regions where the metal will freely corrode 11
2.3 Crevice corrosion mechanism 12
2.4 Corrosion of metal in marine environment 15
2.5 Electrochemical cell 17
2.6 Uniform corrosion 18
2.7 Pitting corrosion 19
2.8 Crevice corrosion 20
2.9 Filiform corrosion on welded tank 22
2.10 “Worm-like” filiform corrosion 22
2.11 Galvanic corrosion 24
2.12 Effect of cathode-to-anode (C/A) ratio on galvanic 25