Distributions of Residual Strain Components in Welded
Stiffened Ship Hull Plates
S Y Kenno, S Das, M Hamdoon, J B Kennedy, R Rogge and M Gharghouri
Contact: sdas@uwindsor.ca
Abstract: Ship failures are often caused due to several factors,
and one of the prime factors is the presence of high residual stresses
resulting from the welding of stiffeners on the parent plate. A thorough
experimental study using the neutron diffraction method was undertaken to
determine the residual strain distributions associated with the stiffened
plates typically used in ship hulls. The specimens were built of 350WT grade
9.5 mm thick steel plate stiffened by welding 127x76x9.5 angle steel
stiffeners of 300W grade. This paper provides a detailed discussion on the
specimens, test procedure, and the results obtained. Emphasis has been given
on the resulting strain distributions when there is a stop and restart during
the welding process or when a stiffener is terminated before the plate is
terminated. This study shows that for these cases, the change in strain may
not be a matter of concern for the ship building industry.
Laser Cladding - A Coating Process for Marine
Applications
Sanjeet Kanungo
Contact: kanungos@gmail.com
Abstract: This paper highlights on relative advantages seen on
laser as a tool for surface engineering applications vis-à-vis other
conventional methods available such as APS and HVOF techniques. The research
work was carried out on mild steel plates where three different cermets were
used as surface coating materials coated both by Laser cladding and
Atmospheric Plasma Spray Process. The results have been summarized below to
extent possible.
Optimum Conceptual Design of an
Ultra-low Motion Semi-submersible Floating Oil
and Gas Production System
R Sharma, Tae-wan Kim, O P Sha
Contact: rajivatri@yahoo.com
Abstract: Economic and
efficient energy resources are keys to a nation’s development. Because of
their low cost and advancement in drilling and exploration technologies oil
and gas based energy systems are most widely used in practice throughout the
world. The inexpensive oil and gas based energy systems are used for
everything from transportation of goods and people to the harvesting of crops
for food to being able see at night. As the energy demand continues to rise,
this is pushing further the demands for inexpensive energy solutions. Since,
available reservoirs of energy rich fossil fuels at shallow and moderately
deep waters have been exploited already, the fossil fuel exploration and
production is being forced to move into extremely deep waters. At deep water
the expenses associated with fixed production platforms are no longer
feasible, and that makes a floating production platform design a far more
economical choice. This paper presents a critical parameter driven optimum
conceptual design of an ultra-low motion semi-submersible floating oil and gas
production system. The design is carried to satisfy the given parameter of
weights and dimensions of the platform topsides required for production and
drilling, water depth location, and low motion requirements. The proposed
design process is highly iterative process of altering the key dimensions of a
‘-column ring’ pontoon, and it meets applicable regulations and requests of
the order placing agency while minimizing costs and satisfying the chosen
parameters. The chosen parameters are classified into groups depending upon
the scientific and technological requirements, and they are: GAaOHD-general
arrangement and overall hull design, WaCL-wind and current loading, LaGL-local
and global loading, WBS- weight/buoyancy/stability, HMaL–hydrodynamic motion
and loading, SaSD- strength and structural design, M–mooring, and EaC–economics
and cost. Overall, this paper introduces a novel design process for an
ultra-low motion semi-submersible that covers the complete life cycle of the
structure. Finally, we discuss one design example motivated by real world
applications to show the effectiveness, usability and efficiency of our
proposed model.
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