bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zone-Oriented Drawings for Life-Cycle Management
Authors: Wilkins James R. 
Published: January 2021

ABSTRACT
This paper presents the results of a study conducted to determine whether unit-oriented construction drawings, which are being developed and used by shipbuilders using modern zone-oriented, or modular, construction techniques, will satisfactorily substitute for system-oriented detailed arrangement drawings in the Navy's life-cycle maintenance management process. The study concluded that modular construction drawings will provide the necessary data in a more usable format, and thus are the preferred approach for the Navy's use. However, the study also identified several additionally needed features that are not now being provided in unit-oriented drawings, but which must be included in order to meet the needs of planning and maintenance activities during the operational life of a ship. A number of other observations about drawing use and maintenance are provided.
Improving Overhaul Planning Through Risk Assessment and Risk Management
Authors: Gorgone Robert G. 
Published: January 2021

The execution of the overhaul of U.S. naval vessels at a public shipyard is fraught with risk. Far too often the work authorization process is constrained by a limited budget. This situation can result in two common outcomes:The shipyard delivers a ship to the customer that has significant repair work either deferred or incomplete.The deferred or incomplete work is screened back to the shipyard late in the overhaul, forcing an upheaval in the logical planning and execution of the availability.
Risk affects both the shipyard and ship's force because the completion of the overhaul could be affected by late authorized work resulting in the ship not being able to meet her commitments. As Philadelphia Naval Shipyard (PNSV) is an industry leader in Zone or Group Technology execution methods, it is particularly disruptive to work flow to return to geographic areas and perform work in an area out of phase—or even worse—in an area where similar work is already complete. With the innovation of Zone Technology, it was clear that a consistent and effective risk assessment method must be developed to determine the probability of equipment failure during the testing phase of the overhaul and the impact on cost and schedule to the overhaul. The USS Kidd (DD-963) scheduled availability in 1989 proved to be the ideal opportunity to develop and execute a formal risk assessment and management program. The USS Constellation (CV-64) SLEP availability in 1990 afforded the opportunity to refine and expand the risk assessment methodology.
Concurrent Engineering in Ship Design
Authors: Elvekrok Dag Runar 
Published: January 2021

Concurrent engineering is a systematic approach for integration and concurrent design of products. The systematic approach intends to consider all elements influencing the products and their related processes during the product life-cycle, such as manufacturing, support, costs, quality, user requirements etc. Especially the engineering design phase should be considered for improvements. This paper presents some of the major and most acknowledged concepts, ideas and principles of concurrent engineering. They are among others:trends and demands to product development time and product life-timeintroduction of a concurrent engineering environment, including the forces, dimensions, mechanisms and targets of concurrent engineeringthe design process, including considerations regarding to the quality and extent of iteration loops and construction of improved design processesquality function deployment, a method for identifying and managing requirements which is based on interfunctionality and interdisciplinary project-teams.
The paper also discusses concurrent engineering in proportion to traditional design theories. The human and organization aspects in concurrent engineering are treated superficially. Finally, some applied concepts, principles and methods are briefly presented. This paper gives an overview and introduction to concurrent engineering.
Optimization of a Working Route Using the Genetic Algorithm
Authors: Okumoto Yasuhisa 
Published: January 2021

ABSTRACT
Since the working situation of the Japanese shipbuilding industry is changing due to the decrease of skilled workers, the production management system should be improved as suitable for skill-independent production. Under such conditions, it is important to indicate working details to non-skilled workers, which contain so-called 4W1H - Who, When, Where, What, How - including the working procedure. In this report, a working route simulation to achieve a minimum working period is carried out using the genetic algorithm (GA) for assembly welding or block painting work on a ship hull as an example. This defines the job sequence of each worker in a block. A personal computer based program (C++) was developed and applied. The calculation result of the sample data showed a good result to get optimum working route to have minimum working period.
Elastic-Plastic Analytical Solution for SEMI’s Horizontal Brace with a Circumferential Through Crack under Tension and Bending
Authors: Wang Fei 
Published: January 2021

The elastic-plastic behavior of semi-submersible’s horizontal brace with a circumferential through crack which lies at its boundary was studied. Both tension and bending were considered to investigate the closed-form analytical solution. The results indicate that the tensile plastic zone and crack tip opening displacement (CTOD) on the cracked section increase sharply after a smoothly increment when loads became larger. The cracked horizontal brace with a greater initial circumferential through crack has a larger tensile plastic zone and earlier compressive plastic zone appearance on the cracked section. Compared with the load of tension, the bending load has larger effect on the plastic zones of the cracked section and CTOD of the crack.

Introduction
Since the first semi-submersible platform (SEMI) named as “Ocean Driller” which was designed for drilling wells in the ocean, the SEMIs have gained popularity in the recent decades with ongoing development in oil and natural gas exploration in deepwater. Because of the high risk of environment pollution and casualties of operators which a destruction accident of SEMI might bring, making sure the structure is safe during its service life has become the most important task of SEMI designers and operators. Although the safety design standards for SEMI structures are quite strict, cracks inescapably are initiated during their service life. According to the destruction accidents happened before, Moan (2009) and Zaron et al. (2015) found that the cracks often occur at the horizontal braces which function as the supporting structures in SEMIs and bear complex loads. The presence of such cracks at critical locations can compromise the safety of the braces and then can cause serious disaster eventually. Because of the initial fracture of a horizontal brace, e.g., the accident of Alexander Kielland platform, the loads were transferred to the other braces and led them break because of the overload (see Colin et al. [2014]).
A Framework for Integrating Human Factors in the Early Stages of Ship Design: Application to the Mess Halls of a Surface Combatant
Authors: González-Cela Gerardo , Bellas Roberto , Carreño Rafael , Martínez Javier , Touza Ramón , González-Gil Arturo , Gómez Miguel , González Diego 
Published: January 2021

The new F-110 frigates project is currently in the conceptual design and definition phase. General arrangement has to be defined; there are many demands and proposals of changes. One of them is the design of the most crowded areas, the mess halls. The aim of this article is to provide the Spanish Navy Staff with a decision tool that helps in determining the optimal distribution of the future F-110 mess halls. For this purpose, a new "analytical decision maker" model was designed providing advanced statistical methods and computer pedestrian simulations within multicriteria decision-making framework that allows optimizing conceptual designs. To reduce subjectivity, crew movement simulations and statistical methods were added to the multicriteria decision model, thus creating a less-subjective decision tool. A sensitivity analysis was conducted to check the robustness of results. An integrative decision and design approach are necessary for broad acceptance of human factors adoption within naval architecture design.

1. Introduction

1.1. Ship design and human factors
Ship design is a complex challenging process that requires the successful coordination of many different disciplines and that necessarily involves trade-offs between competing interests to achieve a balanced result. Hence, ship designers need to understand the complex interaction between different design drivers and their influence on the final solution, always being aware that the cost of rework may become drastically high if errors are found in the later stages of the design.
Preliminary Stability and Resistance Analysis of the Cheops Boat
Authors: Morabito Michael G. , Brier Bob , Greene Stuart 
Published: January 2021

The Cheops Boat is the most complete, largest, and one of the oldest boats ever excavated, but it has received surprisingly little study by Naval Architects. The 43-m boat was constructed around 2500 BC and placed, disassembled, in a pit next to the Great Pyramid at Giza in Egypt. Since its discovery in 1954, there has been speculation about its original design, means of propulsion, and purpose. This article presents previously unpublished results of the first tank testing of a model of the Cheops Boat and some preliminary conclusions about the design, propulsion, and function of the original. It is shown that the stability characteristics of the boat make it suited for carrying lightweight cargo and people in the protected waters of the Nile. Towing tests have shown that the boat can be safely rowed in a variety of wind and current conditions. Windward sailing calculations have shown that, if fitted with sail, then boats such as the Cheops Boat perform well downwind, but sail no closer than a beam reach.
During the 1954 clearing of debris from the Giza Plateau, it was noticed that the Great Pyramid's north and west enclosure walls were 23.6m from the base of pyramid, but the south wall was 5mcloser to the base. Careful inspection revealed that the south wall had been built in an asymmetrical location to conceal two boat pits beneath it. The two pits were end to end, one covered by 41 massive limestone blocks and the other by 40. When the eastern pit was opened, the remains of the disassembled boat were revealed. Figure 1 shows photographs of some of the pieces as they were removed from the pit. Remarkably, the 4500-year-old cedar had been so well preserved that it was possible to reassemble this boat like a kit. Even the rope was preserved, and looked like what could be bought today.
Interactive Creation of Fair Ship Lines
Authors: Reed Arthur M. , Nowacki Horst 
Published: January 2021

A procedure for the initial design of ship lines by means of interactive computer graphics from a display terminal is formulated and illustrated by a fairly elaborate pilot study. The emphasis of the paper lies on two essential aspects of the problem:The formulation of a systematic stepwise procedure for lines creation in the interactive graphics medium, andthe generation of underwater sections from given shape parameters by means of conformal mapping representation. Other features of the hull shape such as sectional area curve, design waterline, and deck contours are generated from polynomial influence functions.
The result of the interactive lines creation process is a mathematical definition of a fair ship hull closely approximating the hull form parameters specified by the designer.
Polynomial Approximations to Mooring Forces in Equations of Low-Frequency Vessel Motions
Authors: Oppenheim B. W. , Wilson P. A. 
Published: January 2021

ABSTRACT:
Multivariate polynomial approximations are considered to the coupled nonlinear mooring forces acting on a vessel moored with multileg moorings. The objective is to yield explicit forms of equations of the low-frequency vessel motions, since the exact mooring forces are known numerically only. Such forms could then be used for analytical solutions of the equations of motion. It is shown that the polynomials lack sufficient generality and accuracy for this purpose, and hence solution of the problem can be considered only by the exact method.
Reliability and Uncertainty Evaluation for Longitudinal Bending of Hull Girders of Surface Ships
Authors: Chao Ru-Jen , Ayyub Bilal M. 
Published: January 2021

Structural reliability and uncertainty assessment of hull-girder bending of surface ships requires the consideration of the following three aspects:structural strength,loads, andmethods of reliability analysis.
A methodology was developed to assess the reliability of hull girders subjected to extreme bending moments. The methodology is based on ultimate strength assessment of hull-girder bending using an incremental strain compatibility method. Two reliability assessment methods—(1) advanced second moment (ASM) method, and (2) Monte Carlo simulation (MCS) method with variance reduction techniques—were employed for structural reliability assessment of hull-girder bending of surface ships. This study demonstrates the structural reliability evaluation of hull-girder bending of ships (1) by considering its strength parameters as random variables, and (2) by considering a non-closed performance function using both reliability methods. This technique can also be applied to a closed-form expression of the performance function. Utilizing such a methodology, ultimate strength and loads for hull-girder bending can be developed individually as modules, and then combined into a non-closed form in a performance function. Simulation methods are also used to assess the uncertainty in hull girder strength due to uncertainties in basic random variables. Examples using the ASM and MCS methods for reliability assessment are also presented.
SWATH Ship Motion Simulation Based on a Self-Tuning Fuzzy Control
Authors: Chiou Shan-Chin , Fang Ming-Chung 
Published: January 2021

A time simulation technique using the self-tuning fuzzy control algorithm is applied to control stabilizing fins to reduce the pitch motion of the SWATH ship in longitudinal regular waves. A back-propagation-based fuzzy controller using the gradient descent method is presented and incorporated with the previous mathematical model to simulate the SWATH ship motion. The effects of surge force and viscous force are included. Basically the fuzzy controller consists of five parts:fuzzifier,rule base,database,inference engine, anddefuzzifier.
The calculations of the corresponding hydrodynamic coefficients at each time step follow the simplified technique developed before, which needs only one set of initial input data of the ship configuration. After comparing with the results using the static fuzzy controller, we find that the self-tuning fuzzy controller appears to be more practical and more efficient for operating stabilizing fins while the ship speed is high. Therefore, the fuzzy control with self-tuning algorithm developed here may offer a more efficient way to control fins of the SWATH ship and can also be regarded as a good basis for future studies in irregular waves.
The Generation and Propagation of Ship Internal Waves in a Generally Stratified Ocean at High Densimetric Froude Numbers, Including Nonlinear Effects
Authors: Tulin Marshall P. , Yao Yitao , Wang Pei 
Published: January 2021

A nonlinear theory for internal wave generation and propagation is derived here for slender ships traveling at high densimetric Froude number (Fh &gt;&gt; 1) in water of small density variation. It is based on an asymptotic equation for the evolution of the internal wave vorticity generated under the ship by a known inviscid ship flow and then self-propagating in the wake. In its numerical implementation, arbitrary pycnoclines and slender ship hulls may be used, and boundary conditions on the ship hull are satisfied; the free surface is treated here as rigid, although this may be relaxed. The theory has been implemented by a suitable numerical method and numerous simulations have been carried out. The results have been compared with earlier OEL experiments. In the near field, emphasis is given to a triple-lobe pattern in the pycnocline, an upwelling along the centerline of motion with a trough on either side, forming close behind the ship. Two distinct types of triple lobes are identified:dominant central lobe and very weak troughs, and;weak central lobe and dominant troughs.
The former (a) is shown to result in linear propagation into the far field. The latter (b) results in far-field patterns preceded by a deep trough whose propagation is nonlinear. The comparisons of both simulated trends and actual amplitudes with measurements are good, surprisingly so considering the small scale of the experiment and the asymptotic nature of the theory. The effect of the turbulent wake on the internal waves in the experiments is restricted to a very narrow region behind the ship; the bulk of the wave pattern including the leading waves seem unaffected. Simulations show that under certain conditions of stratification, triple-lobe patterns with abnormally large troughs are generated and lead to strong nonlinear effects; these deep troughs propagate sidewards to large distances aft (over 40 ship lengths) with slow decay, and result in much larger surface currents and strain rates than in the normal case. Correspondingly, fast waves of depression, which decay slowly, were discovered through the simulation of two-dimensional initial value problems, where the initial area of depression was significantly less than required of a true soliton; these "quasi-solitons" are briefly studied here.
Ship Drag Reduction by Microalgal Biopolymers: A Feasibility Analysis
Authors: Gasljevic K. , Matthys E. F. 
Published: January 2021

We have investigated the feasibility of using high-molecular-weight polysaccharides produced by marine microalgae to reduce the drag on ships and therefore to be able to reduce the needed propulsion power and fuel costs or, alternatively, to increase the ship speed. Experimental and analytical studies were used to answer four critical questions:How suitable are the biopolymers for drag reduction on ships?What is the needed polymer consumption rate at a given level of drag reduction?What is the achievable polymer production rate that can be achieved by the microalgae?What are possible modes of implementation of the proposed technology?
It is seen that in situ production of biopolymers by microalgae growing on the hull may be a possible approach to polymeric ship drag reduction. Production of biopolysaccharide off the ship and even harvesting it from the ocean are other possibilities. The use of biopolymers is naturally advantageous from an environmental point of view as well. Some comparison of biopolymers and synthetic polymers is also presented. Several technical issues remain to be investigated, but the information available suggests that biopolymers may be the best additives for drag reduction on ships.
Reducing Undesired Wave Reflection at Domain Boundaries in 3D Finite Volume-Based Flow Simulations via Forcing Zones
Authors: Peric Robinson , Abdel-Maksoud Moustafa 
Published: January 2021

This article reviews different types of forcing zones (sponge layers, damping zones, relaxation zones, etc.) as used in finite volume-based flow simulations to reduce undesired wave reflections at domain boundaries, with special focus on the case of strongly reflecting bodies subjected to long-crested incidence waves. Limitations and possible sources of errors are discussed. A novel forcing-zone arrangement is presented and validated via three-dimensional (3D) flow simulations. Furthermore, a recently published theory for predicting the forcing-zone behavior was investigated with regard to its relevance for practical 3D hydrodynamics problems. It was found that the theory can be used to optimally tune the case-dependent parameters of the forcing zones before running the simulations.

1. Introduction
Wave reflections at the boundaries of the computational domain can cause significant errors in flow simulations, and must therefore be reduced. In contrast to boundary element codes, where much progress in this respect has been made decades ago (see e.g., Clement 1996; Grilli &Horillo 1997), for finite volume-based flow solvers, there are many unresolved questions, especially:How to reliably reduce reflections and disturbances from the domain boundaries?How to predict the amount of undesired wave reflection before running the simulation?
This work aims to provide further insight to these questions for flow simulations based on Navier-Stokes-type equations (Reynolds-averaged Navier-Stokes, Euler equations, Large Eddy Simulations, etc.), when using forcing zones to reduce undesired reflections. The term "forcing zones" is used here to describe approaches that gradually force the solution in the vicinity of the boundary towards some reference solution, as described in Section 2; some examples are absorbing layers, sponge layers, damping zones, relaxation zones, or the Euler overlay method (Mayer et al. 1998; Park et al. 1999; Chen et al. 2006; Choi &Yoon 2009; Jacobsen et al. 2012; Kimet al. 2012; Schmitt & Elsaesser 2015; Perić & Abdel-Maksoud 2016a; Vukčević et al. 2016).
A Method for the Prediction of Extreme Ship Responses Using Design-Event Theory and Computational Fluid Dynamics
Authors: Xu Wenzhe , Filip Grzegorz , Maki Kevin J. 
Published: January 2021

The design of a naval vessel requires accurate estimation of the extreme loads and motions that it will experience during its lifetime. Operation in large seaways in which the ship-wave interaction is highly nonlinear and transient leads to design events such as maximum internal loads due to global wave bending, local slamming loads, extreme roll, combinations of the global wave bending and local slamming, and many others. In this article, a method is presented that allows for nonlinear analysis to be used to predict events with user-specified rareness. The core of the method combines probability, frequency, and time-domain analyses to generate short time-window sea environments that lead to extreme dynamical events. The Office of Naval Research Tumblehome geometry is analyzed for the extreme roll angle when advancing in stern quartering irregular seas.

1. Introduction
The design of a naval vessel requires accurate estimation of extreme loads and motions that it will experience during its lifetime. Specific quantities of interest are the maximum slamming load during wet-deck impact, maximum acceleration at different locations on the vessel, maximum green-water load on the bow structure or helicopter deck, maximum roll angle, or frequency of occurrence of capsize, to name a few. It is important to recognize that a ship lifetime is decades long, and the exposure time in different severe storms over the lifetime is of the order of weeks, if not months. Furthermore, because of the random nature of the sea and, hence, the dynamical response of the ship, the extreme response is also random and should be characterized statistically. This means that a single lifetime realization in a given seaway by either model tests or numerical simulation only gives one sample of the extreme response, and multiple lifetime realizations are required to characterize the extreme response.