Ultimate Limit State Assessment of Ships and Ship-shaped Offshore Structures
Jeom Kee Paik, Bong Ju Kim, Jung Kwan Seo, Jae Hyung Park, Sung Yong Han, Yong Suk Suh and Beom Seon Jang

Development of Autonomous Underwater Vehicle for Defence Applications
Commodore N Banerjee

Manoeuvring Trials of Underwater Vehicles
LtCdr Amit Ray

Concept and Early Preliminary Design Methodologies for High-Speed Vessels
Donald Jacobson and John Almeter

Experimental Method and Fundamental Studies of Splash Phenomena
Kazuo Suzuki, Hisashi Kai, Go Oishi, Kenichi Tachihara, Taro Horiuchi

Hydrodynamic Stability of Fluid Flow through a Flexible Pipe with Outer Rigid Shroud by the Energy Method Part - I: Non-Axisymmetric Disturbances
Munendra Kumar, P.K. Sen and A.K. Raghav

BACK COVER, Vol. 3, No. 2, Jul 2007

Ultimate Limit State Assessment of Ships and Ship-shaped Offshore Structures
Jeom Kee Paik, Bong Ju Kim, Jung Kwan Seo, Jae Hyung Park, Sung Yong Han, Yong Suk Suh and Beom Seon Jang

ABSTRACT
It is now well recognized that the ultimate limit state approach is a much better basis for design and strength assessment of ships and offshore structures because it is difficult to determine the true margin of safety using the conventional allowable working stress approach that is based on linear elastic method solutions alone. ALPS is a computer software which stands for nonlinear Analysis of Large Plated Structures. This paper outlines ALPS theory for ultimate limit state assessment of ships and ship-shaped offshore structures. Application examples of ALPS programs to ultimate limit state assessment of plates, stiffened panels and hull girders are presented. A benchmark study is made by a comparison of the ALPS solutions with other methods including class rule formulae, nonlinear finite element methods and experimental results. It is concluded that the recent technologies are mature enough to enter in the day-to-day approach for ultimate limit state design and strength assessment of ships and offshore structures.

Keywords: Ultimate limit state analysis, ship structural strength, stiffened panels, ship hull girder, idealized structural unit method, progressive collapse, ALPS software.

Development of Autonomous Underwater Vehicle for

Commodore N Banerjee

ABSTRACT
The Autonomous Underwater Vehicle (AUV) will set a new paradigm in multi-dimensional naval operations for domination of the littoral battle-space. Its capability to operate independently in remote areas for extended periods and undertake potentially dangerous covert missions makes AUV a force multiplier allowing the costly manned systems to be spared for more complex duties. This paper provides an overview of the AUV development for defence applications giving an insight to its role, operational requirement, application and technologies involved. A brief account of the
development of AUV at Naval Science & Technological Laboratory (NSTL), Visakhapatnam, India, is provided. At the end a list of the internationally renowned AUVs under operation is included.
Keywords : AUV, Autonomous Underwater Vehicle, submarine, submersible, design and
development, defence technology, UUV, undersea vehicle.

Manoeuvring Trials of Underwater Vehicles
LtCdr Amit Ray

ABSTRACT
The manoeuvring characteristics of any underwater vehicle are the subject of detailed calculations and extensive model testing during design. This paper examines the requirement for undertaking full-scale manoeuvring trials on underwater vehicles and the possible applications of the data generated. The experience of carrying out full-scale manoeuvring trials on two classes of vessels at sea is described. More than 80 variants of four basic types of definitive manoeuvres were carried out during each of the
trials, spread over four days at sea for each of two different designs. The trials were carried out for various speeds, in the vertical as well as horizontal plane, in submerged as well as surface conditions. Qualitative and non-dimensional results from the trials are presented and compared to previous published data. Physical explanations are offered for observed characteristics. Future work and proposed
applications of the database generated are outlined.
Keywords: Manoeuvring, Manoeuvrability, Sea trials, Full scale trials, Underwater Vehicle, Submarine, Submersible

Concept and Early Preliminary Design Methodologies for High-Speed Vessels
Donald Jacobson and John Almeter

ABSTRACT
In order to support United States Department of Defense investigations into the utility of Highspeed Vessels (HSVs) in various roles, Naval Architects and Marine Engineers at government laboratories have reviewed hundreds of technical papers, experimentation reports and regulatory documents, have conducted full and model scale testing of HSVs and investigated the capabilities and efficacy of existing and developed software programs. This paper aims to lend the reader the benefit of thousands of man hours of experience by recommending useful sources and outlining design methods proven suitable for concept and initial design of fast ferries and
other HSVs.
Keywords : High-Speed Vessels, preliminary design, concept design, review, HSVs

Experimental Method and Fundamental Studies of Splash Phenomena

ABSTRACT
In the first part of this paper, an experimental method on splash phenomena is proposed with special reference to surface tension effect for small-scale models. In this paper, two dimensional water entry splash problems of high-speed bodies are discussed. According to the experimental result, the surface tension effect on the law of similarity of splash phenomena are clarified. In the latter part, trial experiments using the present experimental technique are carried out to investigate the effect of side shape of floating structure to reduce its splash.
Keywords:

Hydrodynamic Stability of Fluid Flow through a Flexible Pipe with Outer Rigid Shroud by the Energy Method Part - I: Non-Axisymmetric Disturbances
Munendra Kumar,  P.K. Sen and A.K. Raghav

ABSTRACT
In this paper we study the hydrodynamic stability of compliant pipe flow, considering a viscoelastic pipe, with an outer rigid shroud, and with Hagen-Poiseuille flow through the pipe. Only non-axisymmetric disturbances have been considered. The coupled fluid-solid equations have been solved numerically by the Sen and Arora [1] method. Stability of surface flow of a ship can be used to set up criteria for drag reduction on such bodies, requiring special surface materials. Energy methods have been rigorously developed, both for the fluid-side and for the solid-side, for the non-axisymmetric disturbances. The importance of the various terms in the energy equation are examined.
Keywords: Stability, flexible pipe, visco-elastic material, drag reduction, normal + tangential (N+ T) compliance.

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