OVERVIEW

The course deals with the application of the finite element method in ship structural analysis and design. It includes first engineering principles of the method as well as hints for practical applications.

AIMS AND CONTENT

LEARNING OUTCOMES

The course aims at illustrating to the students criteria and methods for limit state checks of ship and offshore structures, carried out according to shipbuilding fundamental principles and to the recently issued classification societies rules. Typical case studies about ship and offshore structures are solved either applying analytical and finite element methods, presenting loading actions on structures as well as global and local checks generally adopted in design common practice.

AIMS AND LEARNING OUTCOMES

Students will be able to apply the finite element method for ship structural design and analysis. A well-rounded knowledge, ranging from theoretical basis and lasting with application cases is provided. Moreover, the concept of limit state design, implying different scantling checks, is illustrated encompassing not only typical strength checks but also verifications related to service of merchant and navy ships as well as offshore structures.

PREREQUISITES

Knowledge of main theories of structural mechanics (advanced course), with emphasis on beam theory and shell theory.

TEACHING METHODS

Lectures and guided exercises in IT class. Totally, 60 hours of lectures, almost equally divided.

SYLLABUS/CONTENT

Introduction: structural mechanics models (beam, shell theory), finite element method. Limit state checks and application of structural models to ship and offshore structures

Modern rule checks: IMO Goal Based Standards, rule scantling checks, general principles and idealization of structural components, models selection depending on check types, definition of actions and application to structural models, relevant implications and approximations.

Structural modeling: analytical and numerical models, 2D and 3D models (frames, grillages, plates, orthotropic plates, stiffened panels, complex models). Finite element modeling strategies. Local and global models, primary, secondary and tertiary strength, interaction of structural models.

Analysis types: static linear, collapse (nonlinear), buckling and modal (Eigenvalues), dynamic in time domain (hints). Post-processing, critical analysis and presentation of results.

• Planned exercises (to be discussed during the examination):

a) Introduction to FEM software (Kirsch problem, frames, grillages, etc.)

b) Scantling checks on a typical stiffened panel (e.g. deck panel with boundary conditions on bulkheads and side shell)

c) Scantling check of a ship transverse section (e.g. web frame of a longitudinally framed ship)

d) Three holds/tanks model according to classification societies rules (e.g. according to IACS H-CSR, Ch.7)

e) Scantling checks of stress concentration factors and fatigue assessment of typical structural details

f) Application example of a dynamic analysis (voluntary and variable each academic year)

RECOMMENDED READING/BIBLIOGRAPHY

1. Rules for ship construction of the main classification societies (www.iacs.org.uk), particularly the Harmonized Common Structural Rules (IACS)
2. Hughes OF, Paik JK (2010): Ship structural analysis and design, SNAME (ISBN No. 978-0-939773-78-3)
3. Lamb T. Editor (2004): Ship Design and Construction, SNAME (ISBN 0-939773-41-4)
4. Lewis EV Editor (1988): Principles of Naval Architecture, SNAME (ISBN-13: 978-0939773008)
5. Mansour A, Liu D (2008): Strength of Ships and Ocean Structures, SNAME (ISBN No. 0-939773-66-X)
6. Okumoto Y, Takeda Y,· Mano M, Okada T (2009): Design of Ship Hull Structures, Springer (ISBN: 978-3-540-88444-6)

Other books and publications will be suggested during lectures

TEACHERS AND EXAM BOARD

Exam Board

CESARE MARIO RIZZO (President)

MARTINA AGUIARI

DARIO BOOTE

TOMASO GAGGERO

TATIANA PAIS (President Substitute)

LESSONS

LESSONS START

As per Polytechnic School calendar

Class schedule

SHIP STRUCTURE

EXAMS

EXAM DESCRIPTION

Oral exam (including discussion of exercises carried out during the course). Further details will be given during lectures.

ASSESSMENT METHODS

Exercises will be discussed and checked considering structural idealization issues, input for modeling and analysis of results. A short technical report is required and it will be checked for completeness and clarity. Oral examination will start discussing the exercises and will continue to ascertain comprehension of theoretical content of the course.

Exam schedule

FURTHER INFORMATION

Knowledge of structural mechanics (advanced course Scienza delle Costruzioni 2); in parallel it is suggested to follow the Machine Construction course (Costruzioni di Macchine)