Large Surface Effect Ship Size Limits

2013 ◽  
Vol 29 (02) ◽  
pp. 84-91
Author(s):  
Stefanos Koullias ◽  
Santiago Balestrini Robinson ◽  
Dimitri N. Mavris
Keyword(s):  
Historical Data ◽  
Surface Effect ◽  
Advanced Materials ◽  
Complex Structures ◽  
First Principle ◽  
Simplified Models ◽  
Surface Effect Ship ◽  
Size Limits ◽  
Technology Level ◽  
Insight Into

The purpose of this study is to obtain insight into surface effect ship (SES) endurance without reliance on historical data as a function of geometry, displacement, and technology level. First-principle models of the resistance, structures, and propulsion system are developed and integrated to predict large SES endurance and to suggest the directions that future large SESs will take. It is found that large SESs are dominated by structural weight, which indicates the need for advanced materials and complex structures, and that advanced propulsion cycles can increase endurance by up to 33%. SES endurance is shown to be a nonlinear discontinuous function of geometry, displacement, and technology level that cannot be predicted by simplified models or assumptions.

Large Surface Effect Ship Size Limits

2013 ◽  
Vol 29 (2) ◽  
pp. 84-91
Author(s):  
Stefanos Koullias ◽  
Santiago Balestrini Robinson ◽  
Dimitri N. Mavris
Keyword(s):  
Surface Effect ◽  
Surface Effect Ship ◽  
Size Limits

scholarly journals Detecting bursty terms in computer science research

2019 ◽  
Vol 122 (1) ◽  
pp. 681-699 ◽  
Author(s):  
E. Tattershall ◽  
G. Nenadic ◽  
R. D. Stevens
Keyword(s):  
Computer Science ◽  
Historical Data ◽  
Science Research ◽  
Detection Algorithm ◽  
Trend Detection ◽  
Free Text ◽  
Research Topics ◽  
Computer Science Research ◽  
Insight Into ◽  
Over Time

AbstractResearch topics rise and fall in popularity over time, some more swiftly than others. The fastest rising topics are typically called bursts; for example “deep learning”, “internet of things” and “big data”. Being able to automatically detect and track bursty terms in the literature could give insight into how scientific thought evolves over time. In this paper, we take a trend detection algorithm from stock market analysis and apply it to over 30 years of computer science research abstracts, treating the prevalence of each term in the dataset like the price of a stock. Unlike previous work in this domain, we use the free text of abstracts and titles, resulting in a finer-grained analysis. We report a list of bursty terms, and then use historical data to build a classifier to predict whether they will rise or fall in popularity in the future, obtaining accuracy in the region of 80%. The proposed methodology can be applied to any time-ordered collection of text to yield past and present bursty terms and predict their probable fate.

Optimum Structural Design of High-Speed Surface Effect Ships Built of Composite Materials

2003 ◽  
Vol 40 (01) ◽  
pp. 42-48
Author(s):  
Chang Doo Jang ◽  
Ho Kyung Kim ◽  
Ha Cheol Song
Keyword(s):  
Composite Materials ◽  
Computer Program ◽  
Structural Design ◽  
High Speed ◽  
Surface Effect ◽  
Minimum Weight ◽  
Original Design ◽  
Optimum Structural Design ◽  
Surface Effect Ship ◽  
Speed Performance

A surface effect ship is known to be comparable to a high-speed ship. For the structural design of surface effect ships, advanced design methods are needed which can reflect the various loading conditions different from those of conventional ships. Also, minimum weight design is essential because hull weight significantly affects the lift, thrust powering and high-speed performance. This paper presents the procedure of optimum structural design and a computer program to minimize the hull weight of surface effect ships built of composite materials. By using the developed computer program, the optimum structural designs for three types of surface effect ships—built of sandwich plate only, stiffened single skin plate only, and both plates—are carried out and the efficiency of each type is investigated in terms of weight. The computer program, developed herein, successfully reduced the hull weight of surface effect ships by 15–30% compared with the original design. Numerical results of optimum structural designs are presented and discussed.

scholarly journals Characteristic Constraint Modes for Component Mode Synthesis

1999 ◽  
Author(s):  
Matthew P. Castanier ◽  
Yung-Chang Tan ◽  
Christophe Pierre
Keyword(s):  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Component Mode Synthesis ◽  
Complex Structures ◽  
Cantilever Plate ◽  
Vibration Transmission ◽  
Stiffness Matrices ◽  
Physical Insight ◽  
Insight Into

Abstract In this paper, a technique is presented for improving the efficiency of the Craig-Bampton method of Component Mode Synthesis (CMS). An eigenanalysis is performed on the partitions of the CMS mass and stiffness matrices that correspond to the so-called constraint modes. The resultant eigenvectors are referred to as “characteristic constraint modes,” since they represent the characteristic motion of the interface between the component structures. By truncating the characteristic constraint modes, a CMS model with a highly-reduced number of degrees of freedom may be obtained. An example of a cantilever plate is considered. It is shown that relatively few characteristic constraint modes are needed to yield accurate approximations of the lower natural frequencies. This method also provides physical insight into the mechanisms of vibration transmission in complex structures.

scholarly journals Seasonal dynamics of a generalist and a specialist predator on a single prey

2021 ◽  
pp. 1-20
Author(s):  
Noah Bolohan ◽  
Victor LeBlanc ◽  
Frithjof Lutscher
Keyword(s):  
Seasonal Variation ◽  
Community Dynamics ◽  
Alternative Prey ◽  
Ecological Communities ◽  
Season Length ◽  
Simplified Models ◽  
Hunting Behaviour ◽  
Temporal Averaging ◽  
Invasion Analysis ◽  
Insight Into

In ecological communities, the behaviour of individuals and the interaction between species may change between seasons, yet this seasonal variation is often not represented explicitly in mathematical models. As global change is predicted to alter season length and other climatic aspects, such seasonal variation needs to be included in models in order to make reasonable predictions for community dynamics. The resulting mathematical descriptions are nonautonomous models with a large number of parameters, and are therefore challenging to analyze. We present a model for two predators and one prey, whereby one predator switches hunting behaviour to seasonally include alternative prey when available. We use a combination of temporal averaging and invasion analysis to derive simplified models and determine the behaviour of the system, in particular to gain insight into conditions under which the two predators can coexist in a changing climate. We compare our results with numerical simulations of the temporally varying model.

Analysis of Complex Structures Coupling Variable Kinematics One-Dimensional Models

2014 ◽  
Author(s):  
Erasmo Carrera ◽  
Enrico Zappino
Keyword(s):  
Mechanical Design ◽  
Computational Cost ◽  
Advanced Materials ◽  
Complex Structures ◽  
Displacement Fields ◽  
One Dimensional ◽  
Classical Models ◽  
Kinematic Models ◽  
Carrera Unified Formulation ◽  
Dimensional Models

One-dimensional models are widely used in mechanical design. Classical models, Euler-Bernoulli or Timoshenko, ensure a low computational cost but are limited by their assumptions, many refined models were proposed to overcome these limitations and extend one-dimensional models at the analysis of complex geometries or advanced materials. In this work a new approach is proposed to couple different kinematic models. A new finite element is introduced in order to connect one-dimensional elements with different displacement fields. The model is derived in the frameworks of the Carrera Unified Formulation (CUF), therefore the formulation can be written in terms of fundamental nuclei. The results show that the use variable kinematic models allows the computational costs to be reduced without reduce the accuracy, moreover, refined-one dimensional models can be used in the analysis of complex structures.

Wing in surface effect ship with canard configuration

2010 ◽  
Vol 1 (1) ◽  
pp. 3 ◽  
Author(s):  
Hiromichi Akimoto ◽  
Syozo Kubo ◽  
Makoto Kanehira
Keyword(s):  
Surface Effect ◽  
Surface Effect Ship

Flexibility of Seakeeping Simulation Tools for Landing Craft Hullforms

2017 ◽  
Author(s):  
Kevin Silva ◽  
Andrew Silver ◽  
Kenneth Weems ◽  
David Wundrow ◽  
Sheguang Zhang
Keyword(s):  
Surface Effect ◽  
Water Jet ◽  
Operating Conditions ◽  
Physical Models ◽  
Simulation Tools ◽  
Test Conditions ◽  
Seakeeping Performance ◽  
Surface Effect Ship ◽  
Analytical Tools ◽  
Large Amplitude Motion

As the operational requirements of landing craft expand to faster speeds and higher sea states, more complex hullforms are being proposed to meet these requirements. The seakeeping performance of such vessels can become difficult to predict. Analytical tools must be flexible in order to handle the variety of operating conditions, hull geometries, loading conditions, and other attributes. The analytical seakeeping models should be based on the physical models of the hydrodynamic phenomena rather than case-specific empirical tuning. This paper describes a study that evaluated the ability of the Large Amplitude Motion Program (LAMP) to simulate traditional and non-traditional landing craft hullforms in varying operating conditions. The hullforms include a traditional semi-planing monohull, a semi-planing water jet propelled “W” shaped hull, a water jet propelled catamaran, and a catamaran Surface Effect Ship (SES) style hull. The measures taken to model each hullform and test conditions in LAMP are discussed and the correlation between experimental data and LAMP predictions are presented through comparisons of motions and accelerations.

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