09 - DNVs Hull Str for WW - Hull Str - Cargo Area - Tr Bkhd
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Transcript of 09 - DNVs Hull Str for WW - Hull Str - Cargo Area - Tr Bkhd
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DNVs
Hull Structure course for
World Wide Shipping
9 - Hull Structure cargo area
Transverse Bulkhead
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16.03.2004Slide 2
4.Transverse
bulkhead
Hull Structural Breakdown -
Transverse bulkhead
1. Side
Bottom
Deck
Transverse bulkhead
Longitudinal bulkheadWebframes
2.
3.
4.
5.
6.
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16.03.2004Slide 3
4.Transverse
bulkhead
Structural build up of
transverse bulkhead
Stringers
Transverse bulkheadplating w/stiffeners
Buttress
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16.03.2004Slide 4
4.Transverse
bulkheadStructural functions
Watertight integrity
- Resist internal pressure from cargo and ballast
(cargo boundary)
- Safety against collapse if water ingress (boundary for
flooding)
Hull girder stiffness
- Transverse bulkhead is an important contributor to the
hull girder transverse stiffness
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16.03.2004Slide 5
4.Transverse
bulkheadFunctions of transverse bulkhead
The transverse bulkhead must withstand
internal pressure loads from cargo and ballast
The distribution of cargo and ballast introduces
alternate loading on sections of the transverse
bulkheads (single skin tanker)
Typical fully loaded
condition (single skin)Typical ballast condition
(single skin)
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16.03.2004Slide 6
4.Transverse
bulkheadFunction: tank boundary
Stiffener
Stringer
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16.03.2004Slide 7
4.Transverse
bulkheadFunction: tank boundary
One sided loading on the transverse bulkhead
introduces stresses in the transverse bulkhead as a panel
Bulkhead will flex out and high stresses occur at end
connections towards deck and bottom
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16.03.2004Slide 8
4.Transverse
bulkheadFunction: transverse stiffness
Transverse bulkheads are an important contributor
to the hull girder transverse stiffness
Transversestiffness
Sea
pressure
Sea
pressure
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16.03.2004Slide 9
4.Transverse
bulkheadCharacteristic damages
1. Stringer toes cracking
2. Bottom longitudinal bracket connection to
transverse bulkhead - cracks
3. Cracking of transverse bulkhead stiffenersconnection to stringers
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16.03.2004Slide 10
4.Transverse
bulkheadCracking in stringer toe
Cracks in stringer toes and heel
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16.03.2004Slide 11
4.Transverse
bulkheadCause for cracking in stringer toe
Full cargo tank
Full cargo tankSea
pressure
Compression/tension stresses
from one sided loading
Very high alternating bending stresses in stringer toe
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16.03.2004Slide 12
4.Transverse
bulkheadCracks in stringer
May cause contamination of ballast water andsmall oil spills
Stringer flange
Stringer webLongitudinal bulkhead
Crack
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16.03.2004Slide 13
4.Transverse
bulkheadCharacteristic damages
1. Stringer toes cracking
2. Bottom longitudinal bracket connection to
transverse bulkhead - cracks
3. Cracking of transverse bulkhead stiffenersconnection to stringers
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16.03.2004Slide 14
4.Transverse
bulkheadCracks in bottom longitudinals
17.
Cracks in toe of transverse bulkhead
bracket ending at bottom longitudinals
(wing tanks, midship area)
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16.03.2004Slide 15
4.Transverse
bulkheadCause - cracks in bottom brackets
Crack in bracket
toe (hot spot)
One sided loading at the transverse bulkheadinduce high local alternating bending stresses at
the bracket toe
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16.03.2004Slide 16
4.Transverse
bulkheadDouble btm at transverse bulkhead
Similarily, one sided alternate loading at the transverse bulkhead also
induces high stresses for a double bottom structure
Critical areas
Modern designs have nolongitudinal girders in
double bottom giving large
relative deflection
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16.03.2004Slide 17
4.Transverse
bulkheadCharacteristic damages
1. Stringer toes cracking
2. Bottom longitudinal bracket connection to
transverse bulkhead - cracks
3. Cracking of transverse bulkhead stiffenersconnection to stringers
Crack in transverse bulkhead
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16.03.2004Slide 18
4.Transverse
bulkhead
Crack in transverse bulkhead
stiffeners connection to stringers
of stringer to transversewith associated brackets
Connectionbulkhead
C f ki i t
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16.03.2004Slide 19
4.Transverse
bulkhead
Cause for cracking in transverse
bulkhead stiffeners
One sided internal loading from cargo and ballast sets up a
shear stress distribution in the bulkhead stiffener
Highly stressed areas are
created around geometrichard points at stiffener
end connections to the
stringer
-may cause ballast water contamination and possible oil spills
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16.03.2004Slide 20
4.Transverse
bulkhead
Questions ?