1. Introduction - TSCF 4.4 MHI DILAM, the most... · 9MHI has developed State-of-the-art structural analysis with Direct Loading Analysis Method ... Overview of MHI DILAM: ... FPSO

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TANKER STRUCTURE CO-OPERATIVE FORUM 2010SHIPBUILDERS MEETING 27-28 October 2010

Mitsubishi Heavy Industries, Ltd.Ship & Ocean Engineering DepartmentShipbuilding & Ocean Development HQ

—— Application of MHI DILAM to the latest design of a Application of MHI DILAM to the latest design of a MalaccamaxMalaccamax VLCC VLCC ——

“MHI DILAM”, the most sophisticated Fatigue Design methodology developed by MHI

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1. IntroductionMHI has developed State-of-the-art structural analysis with Direct Loading Analysis Method (DILAM) on purpose to assess fatigue strength of the ships with novel design or offshore structure.

This presentation shows the result of fatigue study by DILAM for the latest Mallaccamax VLCC, which conforms to the CSRs, is currently under construction.

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1. Introduction

2. Overview of MHI DILAM: Latest fatigue analysis method by direct wave load

3. Application of DILAM to primary member of Mallaccamax VLCC

4. Conclusion

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2. MHI-DILAM: Latest fatigue analysis method by direct wave load

2.1 History of MHI’s development of fatigue analysis method

MHI DISAM MHI DILAM1980 1990 2000 20202010

Discrete analysis Direct loading analysis

Fatigue assessment

Yield and Buckling assessment

Short/Long term prediction

Design wave approach

FEM RUN: 3,000 CasesOutput data: Several Gbyte

FEM RUN: 400 CasesOutput data: Several hundred Mbyte

patched load

Improvement of CPU

Accuracy of analysis

Harmonization with design wave approach

Fatigue damage of side longitudinals

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2.1 History / Application

SAYAENDO

LNG Carrier

Enhanced fatigue life

New structural concept

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LPG Carrier

Mega Container Ship

Independent tank

Non-linier: Contact, Friction

Exceeds conventional sizeComparison with full scale measurement

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FPSO (FLNG)

Independent tank type B

Non-linier: Contact, Friction

Exceeds the scope of conventional service

conditionBearing reaction force

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2.2 Concept of MHI-DILAMSimplified “design wave loads”

(Conventional structural analysis method)

Wave crest Wave trough

Relativecomparison with existing structures

Development of a new type of structure

Analysis which can faithfully simulate the complexity of the loads

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2.2 Concept of MHI-DILAMMHI-DILAM

Long term stress distributionare obtained stochasticallyIrregular wave

12 wave directions 20 wavelengths

Represented by set of regular waves

Long wavelength

Short wavelength

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Generate numerous load data automatically

Hull girder bending moment, wave pressure and tank pressure simultaneously


2.3 System configuration

Feature of MHI-DILAMAutomatic load-generation moduleAutomatically generates load data for NASTRANGlobal load-check moduleAutomatically sums up local loads and checks load and moment balancePost-processing moduleAutomatically generate the stress Response Amplitude Operator (RAO)

Summarize FEM out put about 3,000 cases

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Loading calculation

Wave load analysis

Load transfer toFE model

Structural analysis

Ncondition*Nheading*Nwaveperiod

Ncondition*Nheading*Nwaveperiod*NtimestepNcondition*Nheading*Nwaveperiod*Ntimestep


2.3 System configuration

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Comulative damage factor　（North Atrantic 25 years)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

S-O S-I S4 S5 S6 S7 S8

Damage Factor

Stress RAO

Stress Short term prediction

Stress Long term prediction

Fatigue assessment

Hot spot stress Range

Wave scatter diagram

Stress RAO

0 .00000

0 .05000

0 .10000

0 .15000

0 .20000

0 .25000

0 .30000

0 .00 0.50 1.00 1.50 2.00 2 .50 3.00

ω

S(ω)/H2

Tv=4

Tv=5

Tv=6

Tv=7

Tv=8

Tv=9

Tv=10

Tv=11

Tv=12

Tv=13

Tv=14

Tv=15

Wave spectrum

Damage factor

ISSCJONSWAP

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2.3 System configurationLoad transfer

Stress RAO

Stress short-term and long-term prediction

Integrated user interface

Structural analysis

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1. Introduction

2. MHI DILAM: Latest fatigue analysis method by direct wave load


4. Conclusion

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The main particulars of the VLCC LxBxD: 324.0 x 60.0 x 29.1ddes./dscant. 20.5 / 20.8

15.5 ktSpeed27,020 kWMain engine output

Mitsubishi UE 7UEC85LS IIMain engine160,300 tGross tonnage355,000 m3Cargo tank capacity

298,500 t (ddes.)304,000 t (dscant.)

Deadweight tonnage


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Basic conditionsNorth Atlantic wave25 years design life Net thickness approach

Requirement of Fatigue Design Methodology by CSR

Load for fatigue assessmentvertical wave bending momenthorizontal wave bending momentdynamic wave pressuredynamic tank pressure

Provability of dynamic loadQ=10-4 probability level

Long.bhd 2

Deck trans web 4.0Face plate 4.0

Long bhd 4.0Long bhd stiff

4.0

Long stiff 4.0

Long bhd 2.5

Internals inupper portion

of WBT 4.0

Faceplate 3.5

Web 2.5

Long stiff. 3.0Inner bottom4.0

Hopper3.0

Long stiff3.0

Innerskin 3.0

Long bhd stiff2.5


IACS CSR-T RULE

IACS CSR-T RULE

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Example of standard design of primary member by CSR


IACS CSR-T RULE

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Whole ship model

Number of Element: 400,000

FEM cases;Ncondition*Nheading*Nwaveperiod*Ntimestep = 2(full,ball) *

12(each 30deg.)*20(wave)*12(step) = 5,760

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Whole ship model

0deg

30deg

60deg90deg

120deg

150deg

180deg

χ

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3. Application of DILAM to primary member of Mallaccamax VLCC1. Bilge hopper knuckle

connection

2. End of deck trans.

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4.1 Bilge Hopper Structure

Cross bending

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0 2 4 6 8 10

Web2

Web1

Web3

Web4

TC2

TC1

TC3

TC4

CB2

HP2

CB4

HP4

SG1

CB1

HP1

CB3

HP3

Hot

Spo

t Stre

ss

Time step

χ = 120 CB1

CB2HP1

HP2

Web1

Web2Web3

Web4

Mises Stress (Hopper plate)

Mises Stress (Trans. web plate)

λ = 1.1

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Oblique sea (120 degree)



0 2 4 6 8 10

120deg

90deg

180deg

Dominant phenomena can be confirmed with stress history and structural deformation.

Dominant phenomena can be confirmed with stress history and structural deformation.

+ Beam sea (90degree)+ Heading sea (180 degree)H

ot S

pot S

tress

Time step

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0

1

CB1CB2

CB3CB4

HP1HP2

HP3HP4

WEB2

WEB3

TC2TC3

WEB1

WEB4

TC1TC4

SG1

CB1CB2CB3CB4HP1HP2HP3HP4WEB2WEB3TC2TC3WEB1WEB4TC1TC4SG1


3.1 Bilge Hopper StructureAssessed hot spot:

17 points

Fatig

ue d

amag

e

Assessed Location

North Atlantic25 years

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3.2 End connection of Deck Trans.

Toe of Snake head BKT

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Mises Stress

Mises Stress(Trans. web)

Mises Stress(Inner L.BHD. plate)

Stress contour and deformation

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Extrapolation of Hot Spot stress

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θ

0.000

1.000

-90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90

Fracture angle θ (deg)

Dam

age

Fact

or

DFi (Full)

DFi (Ballast)

DF (Total)

Results of fatigue assessment (DF)

North Atlantic25 years

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4. Conclusion1. The technical overview of state-of-the-art direct loading analysis,

DILAM is presented.

2. Fatigue assessment with DILAM is applied to primary member ofthe latest Malaccamax VLCC which is designed with CSR.

It is confirmed that fatigue damage is enough less than the criteria of CSR. (North Atlantic, 25 years fatigue life)

Another feature of MHI-DILAM is...・Technical maturity through down-to-earth efforts ・Continuous comparative study with actual service experience From a historical angle in shipbuilding industries, we believe that simultaneous blending among experience, rules and new technology is the very nature of an advancement of the reliability and safety of ship structure.

Another feature of MHI-DILAM is...・Technical maturity through down-to-earth efforts ・Continuous comparative study with actual service experience From a historical angle in shipbuilding industries, we believe that simultaneous blending among experience, rules and new technology is the very nature of an advancement of the reliability and safety of ship structure.

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Thank you for your attention!

Documents

1. Introduction - TSCF 4.4 MHI DILAM, the most... · 9MHI has developed State-of-the-art structural analysis with Direct Loading Analysis Method ... Overview of MHI DILAM: ... FPSO