unified IACS rules for double hull tankers
unified IACS rules for double hull tankers
unified IACS rules for double hull tankers
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25.05.20052003-12-10
What do we face in the design?<br />
25.05.20052003-12-10
Existing Tanker Fleet<br />
25.05.20052003-12-10
World Oil Movements<br />
25.05.20052003-12-10
Oil Tanker Categories<br />
25.05.20052003-12-10
Principal Dimensions of Tankers I<br />
25.05.20052003-12-10
Principal Dimensions of Tankers II<br />
25.05.20052003-12-10
Principal Dimension Considerations<br />
• Breadth Limitations (Panama Canal)<br />
• Draft Limitations (Trade Route)<br />
Suez Canal<br />
Malacca Straits<br />
25.05.20052003-12-10
A new type of VLCC is Born<br />
MALACCA-MAX<br />
T=20.5m Cargo same as a large VLCC<br />
25.05.20052003-12-10
Double vs Single Hull Tankers<br />
• We have come a long way !<br />
25.05.20052003-12-10
Double vs Single Hull Tankers<br />
• Increased Strength Requirements<br />
• Increased Stability Requirements<br />
• Increased Cargo Temperature<br />
• Increased Ballast Surface<br />
25.05.20052003-12-10
Structural Design Considerations<br />
25.05.20052003-12-10
Structural Design Considerations<br />
• Longitudinal Strength (Global Bending/Shear)<br />
• Transverse Strength (Primary Support<br />
Members)<br />
• Buckling (In combination with above)<br />
• Fatigue (Long Term Effect)<br />
• Ultimate Strength (Extreme Load/Plasticity)<br />
25.05.20052003-12-10
Longitudinal Strength (Beam Model)<br />
• Minimum Section Modulus (<strong>IACS</strong><br />
Requirement)<br />
• Static and Wave induced Bending and Shear<br />
• Sagging and Hogging<br />
• Sagging dominates in Full Load<br />
• Hogging dominates in Ballast Load<br />
25.05.20052003-12-10
Transverse Strength (Local Loads)<br />
25.05.20052003-12-10
Typical Midship Section of a VLCC<br />
25.05.20052003-12-10
More Mid-ship Sections<br />
25.05.20052003-12-10
How to do it? Cavalry To the Rescue!<br />
25.05.20052003-12-10
POSEIDON ND<br />
Computer Supported Tanker Scantling<br />
Assessment<br />
• Rule Based Structural Design<br />
• First Principle Structural Design<br />
• Support of Plan Approval Procedure<br />
• Condition Assessment<br />
25.05.20052003-12-10
Midship Section of a Suezmax Tanker Created by<br />
POSEIDON-Plating<br />
25.05.20052003-12-10
It is not over yet!<br />
2 nd Stage of Analysis FEA<br />
25.05.20052003-12-10
Model of a Suezmax Tanker without<br />
Deck and Shell Plating<br />
25.05.20052003-12-10
FE Model 319,000 dwt VLCC<br />
25.05.20052003-12-10
The bad and the ugly:<br />
Sloshing and Slamming<br />
25.05.20052003-12-10
Sloshing<br />
Critical <strong>for</strong>:<br />
L tank >0.1L and/or B tank >0.5B<br />
25.05.20052003-12-10
Slamming<br />
Critical at Low Draft Fwd-High Speed<br />
25.05.20052003-12-10
Fatigue Assessment<br />
Critical Areas<br />
25.05.20052003-12-10
Fatigue Input (In addition to Stresses)<br />
Wave Scatter<br />
25.05.20052003-12-10
Material Tolerance (S-N curves)<br />
25.05.20052003-12-10
Detailed Stress Analysis (Zooming)<br />
25.05.20052003-12-10
In Conclusion of Fatigue 101<br />
• Miner Damage Accumulation Model<br />
• North Atlantic Wave Input<br />
• Weibull Stress Distribution<br />
• Proper S-N curves (depend on approach)<br />
• Satisfy Target Life (>20 years)<br />
BUT…………<br />
25.05.20052003-12-10
The Fatigue Doctor: Good Details<br />
25.05.20052003-12-10
Design Proper Structural Details !<br />
Quiz:Find what is missing below<br />
25.05.20052003-12-10
LAST BUT NOT LEAST<br />
Operational Considerations in Design<br />
25.05.20052003-12-10
• Noise prediction<br />
Ship Acoustics<br />
• Optimisation of engine foundations<br />
• Optimisation of structure-borne<br />
noise<br />
insulation index<br />
• Noise measurements<br />
25.05.20052003-12-10
Vibrations<br />
• Local Vibration Analysis<br />
• Mast Vibration Analysis<br />
• Shaft Vibration Analysis<br />
• Vibration Level Prediction<br />
• Analysis of coupled<br />
machinery/foundation<br />
vibrations<br />
• Vibration measurement<br />
Overall frequencyweighted<br />
r.m.s.-<br />
values<br />
from 1 to 80 Hz<br />
A<br />
Passenger Cabins <strong>for</strong><br />
instance<br />
Area Classification<br />
B<br />
Crew Accommo<br />
dation <strong>for</strong> instance<br />
C<br />
Working Areas<br />
<strong>for</strong> instance<br />
mm/s 2 mm/s mm/s 2 mm/s mm/s 2 mm/s<br />
Values above which<br />
adverse comments<br />
are possible<br />
143 4 214 6 286 8<br />
Values below which<br />
adverse comments<br />
are not probable<br />
71.5 2 107 3 143 4<br />
Note: The zone between upper and lower values reflect the shipboard vibration environment<br />
commonly experienced and accepted<br />
25.05.20052003-12-10
The Big Enemy: Corrosion!<br />
25.05.20052003-12-10
Coatings do not last <strong>for</strong>ever!<br />
25.05.20052003-12-10
Protection of Cargo Oil Tanks<br />
• Pitting corrosion caused by<br />
sulphur components in<br />
combination with water<br />
• Formation of hydrochloric acid<br />
• Sulphur reducing bacteria<br />
• Susceptible areas to be<br />
protected by coatings<br />
25.05.20052003-12-10
Where to Protect?<br />
25.05.20052003-12-10
Do not Forget : Eco-friendliness<br />
25.05.20052003-12-10
THANK YOU FOR YOUR<br />
ATTENTION!<br />
25.05.20052003-12-10
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