Proceedings of the 20th International Ship and Offshore Structures Congress (ISSC 2018) Volume II – M.L. Kaminski and P. Rigo (Eds.) © 2018 The authors and IOS Press. This article is published online with Open Access by IOS Press and distributed under the terms of the Creative Commons Attribution Non- Commercial License 4.0 (CC BY-NC 4.0). doi:10.3233/978-1-61499-864-8-391 COMMITTEE V.7 STRUCTURAL LONGEVITY COMMITTEE MANDATE Concern for the structural longevity of ship, offshore and other marine structures. This shall include diagnosis and prognosis of structural health, prevention of structural failures such as corrosion and fatigue, and structural rehabilitation. The focus shall be on methodologies translating monitoring data into operational and life-cycle management advice. The research and development in passive, latent and active systems including their sensors and actuators shall be addressed. AUTHORS/COMMITTEE MEMBERS Chairman: P. Hess S. Aksu M. Vaz G. Feng L. Li P. Jurisic M. R. Andersen P. Caridis D. Boote H. Murayama N. Amila B. Leira M. Tammer J. Blake N. Chen A. Egorov KEYWORDS Ship structures, fatigue, service life, corrosion, structural health monitoring, digital twin, structural longevity, structural inspection, structural repair, structural maintenance, structural damage detection, fatigue life, crack detection, structural life-cycle assessment, structural life- cycle management, structural sensing, acoustic emission 392 ISSC 2018 committee V.7: STRUCTURAL LONGEVITY CONTENTS 1. INTRODUCTION ............................................................................................................... 394 1.1 Background & Mandate ............................................................................................ 394 1.2 STRUCTURAL LONGEVITY CONSIDERATIONS ...................................................... 394 1.3 Report Content .......................................................................................................... 395 2. LIFE-CYCLE ASSESSMENT & MANAGEMENT FOR STRUCTURAL LONGEVITY .............................................................................................................................. 395 2.1 Introduction ............................................................................................................... 395 2.2 Life-cycle Assessment & Integrity Management .................................................... 396 2.2.1 Classification Societies ................................................................................ 396 2.2.2 Offshore platform - API and ISO Rules ..................................................... 397 2.3 Lifetime Extension .................................................................................................... 399 2.4 Challenges and Opportunities ................................................................................... 399 2.5 Conclusions ............................................................................................................... 402 3. INSPECTION AND MONITORING ................................................................................. 402 3.1 Introduction ............................................................................................................... 402 3.2 Inspection .................................................................................................................. 402 3.3 Monitoring techniques .............................................................................................. 405 3.4 Hull monitoring systems ........................................................................................... 406 3.5 Data acquisitions, transfer, processing, and management ....................................... 410 3.6 Conclusions ............................................................................................................... 413 3.7 Recommendations ..................................................................................................... 413 4. OFFSHORE STRUCTURAL LONGEVITY METHODS AND EXAMPLES ............... 414 4.1 Introduction ............................................................................................................... 414 4.2 Prediction of Longevity ............................................................................................ 414 4.3 Main factors influencing longevity .......................................................................... 415 4.3.1 Corrosion ...................................................................................................... 416 4.3.2 CP/Anode depletion / Coating deterioration ............................................... 416 4.3.3 Wear & tear .................................................................................................. 417 4.3.4 Fatigue .......................................................................................................... 417 4.3.5 Buckling ....................................................................................................... 419 4.4 Methods ensuring safe operation .............................................................................. 420 4.4.1 General ......................................................................................................... 420 4.4.2 Structural Integrity Management (SIM) ..................................................... 420 4.4.3 Codes and guidelines covering structural integrity management .............. 421 4.4.4 Survey and inspection methods ................................................................... 422 4.4.5 Repair/mitigation ......................................................................................... 423 4.4.6 Lifetime extension ....................................................................................... 424 4.5 Special items ............................................................................................................. 425 4.5.1 Risers / pipelines .......................................................................................... 425 4.5.2 Mooring lines ............................................................................................... 425 4.5.3 Caisson ......................................................................................................... 426 4.5.4 Conductors ................................................................................................... 426 4.5.5 Wind turbines ............................................................................................... 427 4.6 Offshore Platform Longevity Processes ................................................................... 428 4.7 Conclusions and Recommendations......................................................................... 429 5. SHIP STRUCTURAL LONGEVITY METHODS AND EXAMPLES ........................... 429 ISSC 2018 committee V.7: STRUCTURAL LONGEVITY 393 5.1 Introduction ............................................................................................................... 429 5.2 Prediction of longevity.............................................................................................. 429 5.2.1 Models for prediction of longevity ............................................................. 429 5.2.2 Failure Modes Contributing to Longevity Assessment .............................. 431 5.3 Main factors influencing longevity .......................................................................... 436 5.3.1 Role of Life Extension Programs ................................................................ 438 5.4 Methods for ensuring safe operation ........................................................................ 440 5.4.1 Current practice and future directions ......................................................... 440 5.4.2 Structure Monitoring, Inspection, Maintenance, and Repairs .................... 440 5.4.3 At-sea damage response: measurement, analysis, repair, and/or change in operation .................................................................................................................... 441 5.4.4 Remaining Service Life ............................................................................... 442 5.5 Notional Examples of Longevity and Life Extension Decisions ............................ 442 5.5.1 Naval Ship .................................................................................................... 442 5.5.2 Bulk carrier / Tanker/Container .................................................................. 443 5.5.3 Inland Vessels .............................................................................................. 444 5.6 Discussion and Conclusions ..................................................................................... 446 6. CONCLUSIONS & RECOMMENDATIONS .................................................................. 447 6.1 Conclusions ............................................................................................................... 447 6.2 Recommendations ..................................................................................................... 448 REFERENCES ............................................................................................................................ 449 394 ISSC 2018 committee V.7: STRUCTURAL LONGEVITY 1. INTRODUCTION 1.1 Background & Mandate The structural longevity of ships, offshore, and other marine platform structures is a function of design, operation, and life-cycle management. Each of these aspects together determines