Global and Local
Structural
Analysis and
Design
•
Structural
Modeling
•
Finite
Element Analysis
•
Structural
Evaluation
•
Optimization
•
Detailed
Stress Analysis
Ultimate
Longitudinal
Bending Strength
Overall
Structure
Vibration
•
Lightship
mass
distribution
•
Selfweight,
actual or scaled
•
Distributed
masses (e.g.,
weight curve)
•
Large
selected masses
(e.g., engines)
•
Hydrostatic
loads:
stillwater and
waves
•
Internal tank
fluid mass loads
•
Cargo masses
(containers &
bulk cargo)
•
Accelerations
(6 d.o.f.)
•
Pressure
loads, actual
and design
•
Point loads
(forces and/or
moments)
•
External
bending moment
and shear force
at ends of
partial models
Overall
Failure Modes
OVERALL
STRUCTURE
•
Progressive
collapse
•
Fatigue
•
Bending
deflection limit
•
Bending
stress limit
•
Static
•
Low frequency
•
Waves,
live loads
•
Medium
frequency
• Vibration
•
Slamming
CYLINDER
COLLAPSE
• General
buckling
• Bay
buckling
• Local
buckling
Individual
Member Failure
Modes
PANELS
• Collapse
•
Stiffener
flexure
•
Combined
buckling
•
Membrane
yield
•
Stiffener
buckling
• Stiffener
yield
•
Compression,
plate & flange
•
Tension,
plate & flange
• Plate
unserviceability
•
Yield :
Transverse
bending
Longitudinal
bending
•
Compression,
plate & flange
•
Local
buckling
•
Allowable
permanent set
Pressure loads
Concentrated
loads
GIRDER
• Collapse
•
Torsional
buckling
•
Plastic
buckling, flange
•
Plastic
buckling, plate
• Yield
•
Compression,
plate & flange
•
Tension,
plate & flange
FRAME
• Collapse,
plastic hinge
• Yield
•
Compression,
plate & flange
•
Tension,
plate & flange
![](Mar_Analysis/image001.gif)
![](Mar_Analysis/image003.gif)
Hogging-sagging
conditions of
the FFG frigate
hull (global
model)
![](Mar_Analysis/image005.gif)
Figure:
Structural
idealization as
an assembly of
plate-stiffener
separation
models (left) or
plate-stiffener
combination
models (middle)
or
stiffened panel
models (right)
![](Mar_Analysis/image007.gif)
Axial stress
distributions at
ULS for the
frigate test
hull under
sagging (left)
and hogging
(right)
![](Mar_Analysis/image009.gif)
Von Misses
stress
distributions at
ULS for the
frigate test
hull under
sagging (left)
and hogging
(right)
![](Mar_Analysis/image011.gif)
Axial stress
distributions at
ULS for the uni-directional
double-skin
tanker test hull
under sagging
(left) and
hogging (right)
![](Mar_Analysis/image013.gif)
Axial stress
distributions at
ULS for the uni-directional
double-skin
tanker test hull
under sagging
(left) and
hogging (right)
![](Mar_Analysis/image015.gif)
Von Mises stress
distributions at
ULS for the uni-directional
double-skin
tanker test hull
under sagging
(left) and
hogging (right)
|