Advanced Structural Safety Studies (eBook)

Preface 6
Contents 9
About the Author 18
Computer Programs Used 22
Abbreviations 24
1 Principles of Structural Safety Studies 26
Abstract 26
1.1 Types of Extreme and Accidental Events 26
1.2 Volatile, Uncertain, Complex, and Ambiguous Environments 28
1.3 Modeling of Random Parameters Affecting Structural Safety 29
1.3.1 Geometric Properties 29
1.3.2 Material Properties 30
1.3.3 Fabrication-Related Initial Imperfections 30
1.3.4 Types of Load 31
1.3.5 Loading Speed 32
1.3.6 Temperature 34
1.3.7 Age-Related Degradation 35
1.3.8 Accident-Induced Damage 36
1.3.9 Human Error 36
1.4 Limit States and Risks 37
1.5 Future Trends Toward Advanced Structural Safety Studies 39
References 41
2 Probabilistic Selection of Event Scenarios 43
Abstract 43
2.1 Introduction 43
2.2 Procedure for Event Scenarios Selection 44
2.3 Random Parameters Affecting an Event 45
2.4 Data Sources 45
2.5 Probability Density Functions 45
2.6 Latin Hypercube Sampling 58
2.7 Exercises to Select Event Scenarios 64
References 68
3 Limit State-Based Safety Studies 69
Abstract 69
3.1 Introduction 69
3.2 Ultimate Limit States 70
3.3 Accidental Limit States 73
3.4 Fatigue Limit States 74
3.5 Serviceability Limit States 76
3.6 Health Condition Monitoring, Assessment, and Prediction 77
3.6.1 Health Condition Monitoring 78
3.6.2 Health Condition Assessment 80
3.6.3 Health Condition Prediction 80
References 80
4 Risk-Based Safety Studies 81
Abstract 81
4.1 Introduction 81
4.2 Types of Risk 82
4.2.1 Risk to Personnel 82
4.2.2 Risk to Assets 84
4.2.3 Risk to the Environment 85
4.3 Main Tasks for Risk-Based Safety Studies 85
4.4 Planning a Risk-Based Safety Study 87
4.5 Defining the Structural System 87
4.6 Identifying Hazards 87
4.7 Selecting Scenarios 89
4.8 Conducting Frequency Analyses 90
4.9 Conducting Consequence Analyses 91
4.10 Calculating Risk 91
4.11 Frequency Exceedance Diagrams 92
4.12 Risk Acceptance Criteria 98
4.13 Defining Risk Mitigation Options 100
References 100
5 Safety Assessment of Damaged Structures 101
Abstract 101
5.1 Introduction 101
5.2 Residual Strength-Damage Index Diagram 102
5.3 Hull Collapse-Based Safety Assessment of Ships Damaged by Grounding 104
5.3.1 Definition of Residual Strength and Grounding Damage Indices 104
5.3.2 Considered Ships 105
5.3.3 Random Parameters Affecting Residual Strength 105
5.3.4 Probability Density Functions of Random Parameters 105
5.3.5 Selection of Grounding Damage Scenarios 108
5.3.6 Residual Ultimate Strength Analysis 110
5.3.7 Residual Ultimate Strength-Grounding Damage Index Diagram 110
5.4 Rapid Planning of Rescue and Salvage Operations 118
References 120
6 Computational Models for Ship Structural Load Analysis in Ocean Waves 122
Abstract 122
6.1 Introduction 122
6.2 Methods for Determining the Structural Loads of Ships in Ocean Waves 124
6.3 Design Wave Loads of a Very Large Crude Oil Carrier 126
6.4 Design Wave Loads of a 9300-TEU Containership 145
6.5 Design Wave Loads of a 22,000-TEU Containership 152
6.6 Design Wave Loads of a 25,000-TEU Containership 155
6.7 Comparison of Design Wave Loads Between Ships of Different Sizes 162
References 167
7 Computational Models for Offshore Structural Load Analysis in Collisions 168
Abstract 168
7.1 Introduction 168
7.2 Methods for Determining the Structural Loads of Offshore Platforms in Collisions 170
7.3 Structural Collision Loads of a Fixed Type Offshore Platform 172
7.3.1 Target Structures—Supply Vessel and Offshore Platform 172
7.3.2 Parameters Affecting Collisions 173
7.3.3 Selection of Collision Scenarios 179
7.3.4 Computational Fluid Dynamics Simulations 180
7.3.5 Collision Load Characteristics 182
7.3.6 Analysis of Collision Frequency 186
7.3.7 Probability Exceedance Diagrams 189
7.3.8 Design Collision Loads 199
References 209
8 Computational Models for Gas Cloud Temperature Analysis in Fires 211
Abstract 211
8.1 Introduction 211
8.2 Industry Fire Curves 212
8.3 Gas Cloud Temperatures of Steel and Concrete Tubular Members in Jet Fire 213
8.3.1 Experimental Study 214
8.3.2 Computational Fluid Dynamics Simulations 216
8.3.2.1 CFX Simulations 217
8.3.2.2 KFX Simulations 218
8.3.3 Comparison of Experimental Results and Computational Fluid Dynamics Simulations 218
8.4 Gas Cloud Temperatures in Jet Fire Caused by the Combustion of Propane Gases 219
8.4.1 Experimental Study 221
8.4.2 Computational Fluid Dynamics Simulations 222
8.4.2.1 CFX Simulations 222
8.4.2.2 KFX Simulations 232
8.5 Convergence Study in Fire Computational Fluid Dynamics Modeling Techniques 234
References 237
9 Computational Models for Blast Pressure Load Analysis in Explosions 239
Abstract 239
9.1 Introduction 239
9.2 Industry Practices of Blast Pressure Loads 242
9.3 Analysis of Gas Dispersion 244
9.4 Analysis of Gas Explosions 248
9.4.1 Experimental Study 248
9.4.2 Computational Fluid Dynamics Simulations 250
9.5 Effects of Structural Congestion and Surrounding Obstacles 252
9.5.1 Experimental Study 253
9.5.2 Computational Fluid Dynamics Simulations 262
References 271
10 Computational Models for Nonlinear Structural Response Analysis in Extreme Loads 273
Abstract 273
10.1 Introduction 273
10.2 Incremental Galerkin Method 274
10.2.1 Unstiffened Plates Under Uniaxial Compressive Loads 274
10.2.2 Stiffened Plate Structure Under Uniaxial Compressive Loads 278
10.3 Intelligent Supersize Finite Element Method 282
10.3.1 Dow’s Frigate Test Hull Under Vertical Bending Moments 282
10.3.2 13,000-TEU Containership Hull Under Combined Vertical Bending and Torsional Moments 284
10.3.3 Very Large Floating Structure (Runway of Airplanes at Sea) 289
10.4 Nonlinear Finite Element Method 291
10.4.1 Stiffened Plate Structure Under Axial Compressive Loads 294
10.4.2 Stiffened Plate Structure Under Lateral Patch Loads 296
References 298
11 Computational Models for Structural Crashworthiness Analysis in Collisions and Grounding 300
Abstract 300
11.1 Introduction 300
11.2 Material Property Modeling 301
11.3 Type of Finite Elements 302
11.4 Size of Finite Elements 302
11.5 Strain-Rate Effect Modeling 305
11.6 Contact Problem Modeling 308
11.7 Friction Effect Modeling 311
11.8 Surrounding Water Effect Modeling 311
11.9 Modeling the Interaction Effects Between Striking and Struck Bodies 312
11.10 Impact Response Modeling at Low Temperatures 313
11.10.1 Experimental Study 314
11.10.2 Computational Models 322
11.10.3 Effects of Low Temperature 329
11.10.4 Effects of Brittle Fracture 330
References 331
12 Computational Models for Structural Crashworthiness Analysis in Fires 333
Abstract 333
12.1 Introduction 333
12.2 Nonlinear Finite Element Method Modeling 335
12.2.1 Beam Element Models Versus Plate-Shell Element Models 335
12.2.2 Thermal Properties of Materials 336
12.2.3 Mechanical Properties of Materials 337
12.2.4 Constitutive Equations of Materials 338
12.3 Automated Export of Computational Fluid Dynamics Simulations to Heat Transfer Analysis 338
12.4 Heat Transfer Analysis Models Without Passive Fire Protection 339
12.4.1 Thermal Analysis Method 340
12.4.2 EN 1993-1-2 Method 340
12.4.3 Validation of the Computational Models 342
12.5 Heat Transfer Analysis Models with Passive Fire Protection 343
12.5.1 Thermal Analysis Method 343
12.5.2 Modified EN 1993-1-2 Method 343
12.5.3 Validation of the Computational Models 345
12.6 Combined Thermal and Structural Response Analysis Models 349
12.6.1 I-Section Steel Beam Under Constant Uniform Loads 349
12.6.2 I-Section Steel Beam Under Varying Uniform Loads 350
12.6.3 I-Section Steel Beam Under Constant Concentrated Loads 357
12.6.4 Corrugated Fire Wall Under Varying Uniform Lateral Pressure Loads 361
12.6.5 Topside Module of Offshore Oil and Gas Production Installations 364
12.7 Effects of Heating Rate 376
12.8 Effects of Fire Loading Path 386
12.9 Effects of the Interaction Between Heat Transfer and Structural Response 391
12.9.1 I-Section Steel Beam 391
12.9.2 Topside Module of Offshore Oil and Gas Production Installations 395
References 403
13 Computational Models for Structural Crashworthiness Analysis in Explosions 404
Abstract 404
13.1 Introduction 404
13.2 Nonlinear Finite Element Method Modeling 408
13.3 Topside Module of a Floating, Production, Storage, and Offloading Unit 411
13.4 Further Considerations 428
References 435
14 Quantitative Collision Risk Assessment and Management 436
Abstract 436
14.1 Introduction 436
14.2 Procedure for Assessing Collision Risk 437
14.3 Selection of Collision Scenarios 438
14.3.1 Hazard Identification 439
14.3.2 Parameters Affecting Collisions 441
14.3.3 Probability Density Functions of Collision Parameters 443
14.3.4 Collision Scenario Selection 443
14.4 Analysis of Collision Frequency 448
14.5 Analysis of Collision Consequence 455
14.5.1 Volume of Structural Damage 458
14.5.2 Amount of Oil Spill 458
14.5.3 Damage Repair Costs 461
14.5.4 Oil Spill Recovery Cost 462
14.6 Calculation of Collision Risk 464
14.6.1 Risk to Assets 464
14.6.2 Risk to the Environment 468
14.7 Collision Risk Exceedance Diagrams 471
14.8 Risk of Hull Collapse Followed by Total Loss 474
14.8.1 Definition of the Residual Strength Index 475
14.8.2 Residual Hull Collapse Strength Analysis 476
14.8.3 Residual Strength Index-Loading Ratio Diagrams 478
14.8.4 Hull Collapse Risk Exceedance Diagrams 479
14.9 Collision Risk Management 484
References 492
15 Quantitative Grounding Risk Assessment and Management 494
Abstract 494
15.1 Introduction 494
15.2 Procedure for Assessing Grounding Risk 496
15.3 Methods for Assessing Ship Grounding Risk 497
15.3.1 Hazard Identification 497
15.3.2 Parameters Affecting Ship Grounding 502
15.3.3 Probability Density Functions of Grounding Parameters 505
15.3.4 Selection of Grounding Scenarios 506
15.4 Analysis of Grounding Frequency 512
15.5 Analysis of Grounding Consequence 518
15.6 Calculation of Grounding Risk 520
15.7 Grounding Risk Exceedance Diagrams 522
15.8 Risk to Hull Collapse Followed by Total Loss 522
15.9 Grounding Risk Management 522
References 522
16 Quantitative Fire Risk Assessment and Management 526
Abstract 526
16.1 Introduction 526
16.2 Fundamentals of Fire Safety Engineering 527
16.3 Procedure for Assessing Fire Risk 530
16.4 Selection of Fire Scenarios 532
16.4.1 Hazard Identification 532
16.4.2 Parameters Affecting Fire 537
16.4.3 Probability Density Functions of Fire Parameters 538
16.4.4 Fire Scenario Selection 539
16.5 Analysis of Fire Frequency 541
16.6 Analysis of Fire Loads 543
16.7 Analysis of Fire Consequences 548
16.8 Calculation of Fire Risk 549
16.9 Fire Risk Exceedance Diagrams 551
16.10 Fire Risk Management 555
References 562
17 Quantitative Explosion Risk Assessment and Management 564
Abstract 564
17.1 Introduction 564
17.2 Procedure for Assessing Explosion Risk 565
17.3 Selection of Gas Dispersion Scenarios 566
17.3.1 Hazard Identification 566
17.3.2 Parameters Affecting Gas Dispersion 567
17.3.3 Probability Density Functions of Gas Dispersion Parameters 568
17.3.4 Gas Dispersion Scenario Selection 577
17.4 Analysis of Gas Dispersion 577
17.5 Selection of Explosion Scenarios 581
17.5.1 Parameters Affecting Explosions 581
17.5.2 Probability Density Functions of Explosion Parameters 592
17.5.3 Explosion Scenario Selection 598
17.6 Analysis of Explosion Frequency 601
17.7 Analysis of Explosion Loads 608
17.8 Analysis of Explosion Consequences 623
17.9 Calculation of Explosion Risk 627
17.10 Explosion Risk Management 627
References 627
18 Facilities for Physical Model Testing 628
Abstract 628
18.1 Introduction 628
18.2 Similarity Laws for Structural Mechanics Model Testing 629
18.3 Scaling Laws for Hydrodynamic Model Testing 630
18.3.1 Froude Law for the Flow Speed Effect 630
18.3.2 Reynolds Law for the Viscosity Effect 631
18.3.3 Strouhal Law for the Vortex Shedding Effect 632
18.3.4 Scaling Law for the Water Surface Tension Effect 632
18.3.5 Scaling Law for the Water Compressibility Effect 633
18.4 Experimental Definition of Material Properties 633
18.4.1 Chemical Composition Testing 633
18.4.2 Tensile Coupon Testing 635
18.4.3 Effect of Low Temperature 639
18.4.4 Effect of Elevated Temperatures 640
18.4.5 Effect of Loading Speed 641
18.4.6 Compression Testing for Brittle Materials 645
18.4.7 Fatigue Testing 645
18.4.8 Hardness Testing 646
18.4.9 Material Database Software 646
18.5 Measurements of Fabrication-Related Initial Imperfections 648
18.5.1 Initial Deformation Measurements 648
18.5.2 Welding Residual Stress Measurements 650
18.5.3 Softening of Welded Zone 651
18.6 Structural Failure Tests 651
18.7 Dropped Object Testing 654
18.8 Furnace Fire Tests 656
18.9 Fire Collapse Tests 658
18.10 Indoor Fire Tests 658
18.11 Outdoor Fire/Explosion Tests 660
18.12 Blast Wall Tests 662
18.13 Hyperbaric Pressure Tests 662
References 664
Appendix A: Latin Hypercube Sampling Program 666
Appendix B: Passive Fire Protection Materials 670
Appendix C: SI Units 674
C.1—SI Unit Prefixes 674
Conversion Factors 674
Index 677