Marine Structures in Fluids

Learning Outcomes

Knowledge and Understanding

Having successfully completed this module, you will be able to demonstrate knowledge and understanding of:

• Critique concepts of rational structural design procedures
• Assess the importance of safety and sustainability in structural design
• Through analysis and critical assessment, understand the nuances of dynamics in relation to floating vessel design and operation.
• Argue how fatigue, fracture, and fluid structure interactions impact the structural design of floating vessels.
• Quantify the structural effect on floating vessels of fluid-structure interactions through the synthesis of seakeeping and hydroelasticity methods
• Critique fatigue and fracture assessment approaches for floating vessels and formulate a spectral fatigue assessment for the long-term structural performance.
• Qualify the dynamic behaviour of differing floating vessel types through synthesis of concepts into engineering application and design.
• Apply deterministic and statistical measures to assess wave loading and floating vessel behaviour in different sea states

Full CEng Programme Level Learning Outcomes

Having successfully completed this module you will be able to:

• In the fatigue life assessment (Part B) students are expected to understand the link between stakeholders in vessel design through operation to end of life. They are expected to understand socio-economic and environmental sustainability, the impact of human decisions and actions in design and operation and the role of regulation and classification.
• In both Part A (wave induced loads) and Part B (fatigue life assessment) assignments, students will be expected to apply a comprehensive knowledge of mathematics, statistics, natural science and engineering principles to the solution of the complex problems of floating vessel operation in waves, structural response and fatigue life determination.
• In both assignments, students will select and critically evaluate technical literature to underpin their arguments.
• The wave induced loads (Part A) assignment has both group and individual elements, whilst the fatigue life assessment (Part B) is an individual contribution. Students will have feedback on Part A to evaluate their individual and team performance before continuing onto Part B.
• In both assignments, students are asked to demonstrate their understanding of risk: in the wave induced loads assignment (Part A) by comparing floating vessel forms for slamming and deck wetness and the effect of structural design on hydrodynamic performance, and in the fatigue life assessment (Part B) through the discussion of structural design methods and goal-based analyses.
• In both assignments, students will be expected to formulate and analyse the complex problems of floating vessel operation in waves, structural response and fatigue life determination, using statistical methods to underpin engineering judgement.
• In the fatigue life assessment (Part B) students need to demonstrate their understanding of issues related to through life sustainability (socio-economic environmental) and the impact of engineering decisions on the longer term consequences of vessel design and operation.
• In both assignments, students are expected to select and apply appropriate computation and analytical techniques, including FEA and coding to model wave induced load effects and make fatigue life predictions of floating vessels.
• In the fatigue life assessment (Part B) students need to demonstrate their understanding of issues related to through life sustainability (socio-economic environmental) and the impact of engineering decisions on the longer term consequences of vessel design and operation.
• In determining the impact of engineering decisions on floating vessel performance in waves and subsequent load effects in Part A and B assignments, students will demonstrate a systems-based engineering approach.

Part A; lectures on:

Fluid-Structure Interactions

• Introduction to hydroelasticity theory.
• Dynamics of flexible beamlike structure in vacuo.
• Principal modes and natural frequencies.
• Hydroelastic approach to still water problem.
• Hydrodynamics of regular waves
• Strip theory, boundary value problems.
• Fluid actions in equilibrium axes.
• Hydrodynamic coefficients
• Generalized equation of motion in seaway.
• Responses (bodily motions -seakeeping, distortions, bending moments, stresses) in waves.
• Random seas and responses in random seas.
• Criteria for comparing floating vessel forms - slamming, deck wetness, etc..

Part B; lectures on:

Structural Integrity

• The rational structural design of floating vessels:
• Levels of structural design processes
• Limit state design including ultimate and fatigue limits and load effects
• Fatigue of floating vessel structures:
• Basic concepts of fatigue, fatigue damage mechanisms, S-N methodology, local strain methodology
• Life time load determination, wave induced loads, stochastic combination of loads
• Load effect determination, FEA approaches and choices of elements, meshing, structural details
• Fatigue assessments, voyage simulation behaviour, long term fatigue damage
• Fracture modelling in ship and offshore structures:
• Fundamental concepts - energy-based and stress intensity based approaches
• LEFM, modes of crack extension, useful K solutions, fracture testing, life modelling

The integrations of Parts A (worth 65%) and B (worth 35%) will take place through two group assignments.

Wave-induced Loads Assignment (65%);

where the students perform predict wave-induced loads on a real floating vessel using quasi-static and coupled hydroelastic analyses and understand how flexible models can be used for experimentatal validation.

Ship Fatigue Life Assignment (35%);

where the students analyse stress records (measured or predicted) of a real floating vessel in order to predict the fatigue life of a structural detail.

Teaching methods include

• lectures on hydroelasticity and fluid structure interactions
• lectures on fatigue and fracture related to ship structures
• lectures on design methods
• supervised design office sessions focused on the two assignments

Learning activities include

• Directed reading/independent learning
• Example sheets for problem solving exercises
• Report-writing for the 2 group assignments
• Application of structures and fluid-structure interactions related knowledge to real floating vessels through the two assignments
• Use of commercial and academic software to perform the two assignments

Summative

This is how we’ll formally assess what you have learned in this module.

Referral

This is how we’ll assess you if you don’t meet the criteria to pass this module.