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The Australian Maritime College is an institute of the University of TasmaniaCRICOS Provider Code: 00586B

Websites: AMC: www.amc.edu.au, UTAS: www.utas.edu.au

Oasis of the Seas (courtesy of http://www.oasisoftheseas.com)

SHIP VIBRATIONLecture 1 Introduction

By Dr. Hung NguyenNational Centre for Maritime Engineering and Hydrodynamics

Australian Maritime College/University of TasmaniaLaunceston, Tasmania, Australia

Main topics of Lecture 1

Introduction to Syllabus/Unit Outline Chapter 1 Introduction to Ship Vibration

Basic concepts of vibrationI t f ib ti t d Importance of vibration study

Case study: Tacoma Bridge Collapse in 1940 Overview of ship vibration

Classification of vibration Vibration analysis procedure Harmonic motion (a review)

Unit Outline

Description Basic knowledge and understanding of

mechanical vibrations applications of theory of vibration into study ofapplications of theory of vibration into study of

ship hull vibration, prevention and avoindance of vibration in ships

Learning Objectives See handout

Unit Outline Contents

Chapter Contents Duration(hours) References

1, 2, 3 Fundamentals of VibrationIntroduction to Ship VibrationFree Vibration of Single DOF System

[1,2]

Free Vibration of Single DOF SystemForced Vibration of S-DOF SystemsVibration of Two & Multi-DOF Systems

15

4, 5, 6 Torsional VibrationContinuous Vibration

5 [1,2]

7 Ship VibrationHull girder vibration

10 [1,2,3,4,7]

8 Experimental Investigation TBA

Unit Outline

Learning Schedule

Day Date Topic Readings /Problems Assessment

Introduction h1 14/12 (Mon)IntroductionFundamentals of Vibration (free vibration, damped vibration, forced vibration of S-DOF systems)

Chapters 1-3 Homework/Tute

2 15/12 (Tue) Vibration of 2-DOF and MDOF Systems Chapters 4-5 Homework/Tute

3 16/12 (Wed) Continuous Vibration Chapters 6 Class Test

4 17/12 (Thu) Ship Vibration Chapter 7 Homework/Tute

5 18/12 (Fri) Exam

Unit Outline

Assessment information

No Assessment Component Due/Detail

Weighting(%)Component (%)

1 Test Day 3 202 Practical/Lab N/A3 Tutorial/Homework Continuous 20

Assignment N/A4 Final exam TBA 60

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Unit Outline Textbooks and

References Required textbook:

Rao, S.S. (2005). MechanicalMechanical Vibrations, 4th Edition in SI Units. Pearson Education.

Books in Vietnamese

Books in English Ship Vibration (GL)

Unit Outline

E-learning resources Lecturers website:

http://academic.amc.edu.au/~hnguyen/shipvib/shipvib.html

Unit Outline Organisation of Lecture Notes

Chapter 1 Introduction to Ship Vibration (Nhp mn dao ng tu thy)

Chapter 2 Free Vibration (S-DOF Systems) (Dao ng t do H mt bc t do)t do H mt bc t do)

Chapter 3 Forced Vibration (S-DOF Systems) (Dao ng cng bc H mt bc t to)

Chapter 4 Multi DOF Systems (H nhiu bc t do) Chapter 5 Torsional Vibration (Dao ng xon) Chapter 6 Continuous Vibration (Dao ng lin tc) Chapter 7 Ship Vibration (Dao ng tu thy)

Any Questions?

Chapter 1 Introduction

Basic concepts of vibration Vibration Oscillation/oscillatory motion Elementary parts of vibration systems

Example: Simple Pendulum Example: Simple Pendulum Displacement Velocity Acceleration Frequency

Degree of freedom (DOF) Discrete and Continuous Systems

Chapter 1 Introduction

Basic concepts of vibration Degree of Freedom (DOF): minimum number

of independent coordinates

Figure 2 One degree of freedom systems (Rao, 2005)

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Chapter 1 Introduction Degree of

freedom: 2 and M-DOF

Chapter 1 Introduction

Basic concepts of vibration Discrete and continuous systems

Importance of Vibration Study Why do we need to study vibration

for engineering design?

US Space Shuttle

SydneyBridges

Tokyo

Queen Mary II

Car: Lexus

Marine engines

Importance of Vibration Study

Case study: Undesired vibration Tacoma Bridge Collapse in 1940 an

example of engineering failure See movie clipSee movie clip

Vibration in ships 5 types of ship

How does vibration affect?

Importance of Vibration Study Overview of ship vibration

Vibration modes (Simulation by ANSYS)

Torsional Vibration of Ship (Clark, 2005)

Vertical Vibration of Ship (Clark, 2005)

Horizontal Vibration of Ship (Clark, 2005)

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Bending and twisting of a catamaran Chapter 1 Introduction

Classification of Vibration Free and forced vibration Undamped and damped vibration

Linear and nonlinear vibration Linear and nonlinear vibration Continuous and discrete vibration Deterministic and random vibration

Chapter 1 Introduction

To analyse a vibration system, it is usually required to study the behaviour of the system to given excitations. The behaviour is referred to as the system response:is referred to as the system response: Displacement Velocity or Acceleration of the system and/or its

components

Chapter 1 Introduction

Vibration analysis procedure Step 1: Mathematical modelling Step 2: Derivation of Governing Equations Step 3: Solution of the Governing

Equations Step 4: Interpretation of the Results

Chapter 1 Introduction

Vibration analysis procedure Example 1: Mass-spring-damper systems

Chapter 1 Introduction

Vibration analysis procedure Example 2: Motorbike

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Chapter 1 Introduction

Basic concepts of vibration Example 3: A car running on a rough road

Chapter 1 Introduction Harmonic motion

Harmonic motion (chuyn ng iu ha)

Chapter 1 Introduction Harmonic motion:

projection of a point moving on a circle

Chapter 1 Introduction

Harmonic motion:

2

x Asin t= f2

T2 ==

x A cos t Asin t2 = = +

( )2 2x Asin t Asin t= = +

Chapter 1 Introduction Harmonic motion

Velocity and acceleration: same frequency, lead /2 and radians

Chapter 1 Introduction

Harmonic motion: Complex representation of harmonic motion

je cos jsin = + jj tz Ae A cos t jA sin t x jy= = + = +

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Chapter 1 Introduction

Harmonic motion: Definitions and terminology

Cycle (chu trnh) Amplitude (bin ) Period (chu k) Frequency (Tn s) Phase angle (Gc pha) Natural frequency (Tn s t nhin) Beat (Nhp p) Decibel ( xi ben)

Chapter 1 Introduction

Vibration computation and simulation tools MathWorks: MATLAB/Simulink & Toolboxes National Instruments: LabVIEW & Modules

ANSYS: www ansys com ANSYS: www.ansys.com Programming languages Numerical methods

Eulers method, Runge-Kutta method, Fourier, etc. Finite Element Methods

Chapter 1 Summary of Chapter 1

Basic concepts of vibration Importance of vibration study

Case study: Tacoma Bridge Collapse in 1940 Overview of ship vibration

Classification of vibration Vibration analysis procedure Harmonic motion (a review)

Displacement, velocity, acceleration, frequency Definitions and terminology

References & Further Reading Hybrid (solar) vessel/ferry:

http://www.solarsailor.com/ Vibration simulation (Flash):

http://www.cfa.harvard.edu/~jbattat/pitf/engin125/ M. Norton and D. Karczub (2003). Fundamentals of Noise and Vibration

Analysis for Engineers. Cambridge University Press. Cambridge. UK. De Silva C W Vibration Fundamentals and Practice Taylor andDe Silva, C.W. Vibration Fundamentals and Practice. Taylor and

Francis. 2007. Thomson, W.T., Theory of Vibration with Applications, 4th Ed, Chapman

& Hall, London, 1993. Rao, S.S., Mechanical Vibration, Addison-Wesley Publishing Co,

Massachusetts, 1985. Fahy, F. and H. Walker. Fundamentals of Noise and Vibration. Spon

Press (Taylor and Francis Group). E-learning source: http://academicearth.org/courses/physics-iii-

vibrations-and-waves

Any Questions? Chapter 1 Introduction

Tutorial 1 Harmonic Motion