bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trimaran Ships
Authors: Andrews D. J. , Zhang Jun Wu 
Published: March 2009

ABSTRACT  This paper follows on from two previous papers from UCL. The first describes a student ship design for an advanced technology frigate, configured with three hulls, whilst the second, given by the first author's predecessor at UCL and the second author at the RINA in 1994, described the reseach undertaken at University College London into the naval architecture of Trimaran Ships.The paper commences with a resume of the origins of the Trimaran concept, its first power boat example, the Ilan Voyager, and the Advanced Technology Frigate design which adapted the trimaran configuration to a modern warship requirement. The other UCL design studies, ranging from an offshore patrol vessel to a small aircraft carrier, are outlined. The various naval architectural considerations of powering, stability, structures and manoeuvring are then described.Particular attention is focused on the seakeeping analysis which is being undertaken jointly by UCL and DRA Haslar from the autumn of 1994 although the submission date for publication precludes inclusion of model and analytical results. Finally, on work in hand, preliminary results on a spatial analysis of the Trimaran configuration and the advantages this appears to provide in a more spacious upper deck and main deck arrangement in the central portion of the ship is outlined.The paper concludes by postulating that, in respect of the capabilities likely to be most significant in the requirements for frigate designs in the future, the Trimaran would appear to have distinct advantages over the monohull and other unconventioanl hull forms.
Waterjet versus Propeller Engine Matching Characteristics
Authors: Alexander Keith 
Published: March 2009

ABSTRACT  This paper outlines the major differences between waterjets and fixed‐pitch propellers in the way they absorb engine power. Some of these differences are subtle and far reaching, and have only recently come to light. They have consequences for the operator, the engine selection and the engine settings. This paper touches on the following areas:

the rigid relationship between power absorption and rpm, which means the waterjet can be used as an engine dynamometer, and the contrast with propellers where rpm is related to boat speed
the differences in power absorption off the match point, and the fact that the waterjet cannot overload an engine: the consequences for the operator and the engine
comparisons of engine rpm with boat speed, and the propulsion power available against boat speed for waterjets and propellers
the differences in power absorption characteristics with overloaded or light boats
strategies used by engine manufacturers to accommodate waterjet and propeller characteristics

These issues are discussed as factors which are significant in the selection of the propulsor, and are sometimes not appreciated by operators familiar with propeller driven craft.
A Comparison of French and U.S. Amphibious Ships
Authors: Ferreiro Larrie , Autret Gérard 
Published: March 2009

ABSTRACT  Amphibious and littoral operations have become the prime naval focus for many countries, and have elevated the level of interest in the ships and technologies concerned. This paper explores the effects of differing national approaches to amphibious warfare by comparing the capabilities and systems of two amphibious ships, the French TCD (equivalent to LSD in English) Foudre and the U.S. LSD 41 Whidbey Island class. Both classes of ships have broadly similar roles and capabilities, but differing operational doctrines, military requirements and design standards have led to quite different approaches in ship design.The French Navy is similar in function and composition to the U.S. Navy, but about one‐fifth the size. French amphibious assault is carried out by an Army division, while the U.S. assault force is a branch of the Navy, the Marines. The French amphibious fleet is sized to carry a proportionally smaller landing force than that of the U.S.: but the Foudre would be the centerpiece of the French assault group, while the LSD 41 would normally operate with big‐deck ships like LHDs and LHAs. Current French assault doctrine calls for conventional landing craft, while the U.S. uses air‐cushion vehicles. Finally, the ground assault forces differ in size and composition.These operational differences, as well as other technical ones, have led to outwardly similar but in fact rather different ships. This paper describes the technical differences between the ships in the context of differing operational requirements, and illustrates how these larger factors greatly influence the outcome of the design process.
The Solberq Award
Authors: Liu Yuan‐Ning 
Published: March 2009

for his significant engineering research and development contributions to the field of structural acoustics technology as set forth in the followingThe Solberq Award, presented annually since 1967, is given to an individual who has made a significant contribution to naval engineering through personal research during the past three years. Admiral Thorwald A. Solberg's greatest forte was the pursuit of basic and applied research leading to solutions of shipboard problems. His long career as a naval engineer, culminating in his appointment as Chief of Naval Research, inspired the research and development engineering profession and this award.
Computer Assisted Weld Evaluation
Authors: Brown Lawrence M. , DeNale Robert 
Published: March 2009

ABSTRACT  The Naval Surface Warfare Center has developed a knowledge‐based nondestructive evaluation (KBNDE) system to automate the interpretation of ultrasonic weld inspections. The designed software prototype, KBNDE Version 1.0, operates on IBM®, PS/2® or AT compatible computers operating under Microsoft® Windows™ 3.1. The system automates the following functions: 1) examination of the recorded UT data to determine the location of potential discontinuities in the material, 2) 3‐dimensional sizing and classification of the disclosed discontinuities, and 3) application of an acceptance criteria to the discontinuities.The KBNDE system employs time‐of‐flight‐diffraction ultrasonics to locate and size the discontinuities in the weld metal, and a 3‐layer back‐propagation artificial neural network to classify the discontinuities as being planar or volumetric. In addition, advanced algorithms are used to determine whether the discontinuities in the weld material are acceptable or rejectable, based on an automated implementation of NAVSEA 0900‐LP‐006–3010. The system has been demonstrated on flush ground welds and on various laboratory specimens.
Problem Resolution During Life Cycle Maintenance: A Case Study
Authors: Kerchner R. J. , Bailey J. , McCarthy M. , Seegal R. H. , Warpinski J. , Wilson J. 
Published: March 2009

ABSTRACTThis paper is a case study of how problem resolution can operate in the life cycle maintenance stage of a large tactical sonar system. Here, the system design agent is not the original designer, so the principles of operation, hardware and software architecture, and test tools need to be learned. To deal with this challenge, the system design agent evolved a team approach that integrates the talents of a program manager, a system engineer, a test engineer, and a software engineer to analyze fleet problems. This team has proven effective at localizing problems for repair. Lessons are drawn to further improve maintenance efficiency.
Standards‐Based IETMs: The Key to Integrated Weapon System Support
Authors: Patton Thomas , Quallen John R. 
Published: March 2009

ABSTRACTThis paper describes the role of the DOD Interactive Electronic Technical Manual (IETM) standards in the application of electronic documentation to the TRIDENT II Strategic Weapon System (SWS) Program. The SWS Program integrates IETMs with SWS data providing automated operational and maintenance procedures and reference documentation at the SWS operator consoles. Integrated ship's logistics, administration, and onboard training can also be supported.An operational environment is provided that supports multiple “views” of a MIL‐D‐87269 compliant database, including a legacy view of the database used to minimize the operator impacts of the transition from paper to electronic documentation.An IETM database development process is described that includes: Establishing the Baseline, the one‐time low cost legacy technical manual conversion; Exploiting the Media, the incorporation of Class 4 IETM capabilities; and Maintaining the Baseline, an integrated IETM maintenance environment used for recurring maintenance of the IETM database. Authoring capabilities of the IETM Maintenance System are discussed as are other capabilities supporting workflow management, configuration control, electronic review and approval, and IETM database verification and validation.Finally, programmatic experience is described including Navy/contractor coordination, adoption of standards, and suitability of the standards to the SWS application.
Affordability, Logistics R&D and Fleet Systems
Authors: Schulte Donald P. , Skolnick Alfred 
Published: March 2009

ABSTRACTThe Fleet continues to require high performance systems that can operate with dependability in the seas' unforgiving environments and under hostile action. Those demands are not new. What has changed is the urgent priority formerly assigned to national defense issues. The arguments for continued superpower military strength are now roiled in politics along with unsettled budgets and uncertain force level projections. Current expectations revolve about indefinite fiscal and operational issues (difficult funding constraints and broadband threats). In the actual event of “doing more with less,” a practical response is to apply the creative power available from sound engineering judgement and the crucible of experience to the immediate needs of the Fleet. The attempt to shorten the path between advanced development effort and Fleet use has been tried occasionally in the past, often, without exemplary results. The Sustainable Hardware and Affordable Readiness Practices (SHARP) program, is a generic R&D effort under OpNav sponsorship that has been working steadily on sensible solutions to product engineering problems. Armed today with fast‐time, large‐scale computation abilities and modern tools for technical problem solving coupled with specialized engineering knowledge, it has been refreshed and is underway satisfying existing Fleet needs. The relationship between fully responsive engineering services and current operational needs is always demanding. The connection between advanced engineering development (6.3 category funds) and immediate Fleet usage brings added complexity and challenge, both technical and organizational. Illustrative examples of affordable engineering solutions to “retain, revise, replace or retire” questions are presented within the context of both Fleet realities and budgetary limitations. The discussion covers legacy system support, civil/military considerations and Fleet maintenance issues. It describes the substantial and critical payoffs in cost, schedule and performance that are possible when product engineering professionals can concentrate their diverse talents upon operational urgencies.
Feasibility Study of a Novel Integrated Electric Motor/Pump for Underwater Applications
Authors: Cho C. Peter , Krol William P. 
Published: March 2009

ABSTRACTThis paper presents the results of a feasibility study of a novel electric motor/pump system that combines an axial field, permanent magnet motor with a centrifugal pump. This system, unique because the motor permanent magnet (PM) rotor and pump impeller vanes are a single unit, provides a compact, reliable, low‐noise, and high‐power‐density electrically driven centrifugal pump suitable for underwater applications in which minimizing noise, vibration, and volume are major design objectives. Performance tradeoffs for the electromagnetic analysis were made by two‐ and three‐dimensional finite element analysis (FEA) models in conjunction with a lumped parameter magnetic circuit model. The study results reveal that theoretically the new integrated electric motor/pump concept (1) provides up to seventy‐three percent electromagnetic efficiency with a significantly reduced volume and weight and (2) substantially increases the power density and reliability with the potential for quiet and high performance. This study is also evidence that new concepts can be explored with expanded computer modeling and simulation techniques.
Simulation Modeling of LHA 1 Class Cargo Handling System
Authors: Sumera Paavo , Feeney Daniel , Grzelka Andrew , Royle Michael 
Published: March 2009

ABSTRACTMovement of cargo from the holds of LHA 1 Class ships to landing craft in the ship's wet well involves the simultaneous use of a number of interdependent cargo handling systems. These systems include forklift trucks in the ship's holds, transfer tables at each deck serviced by the elevators, five cargo elevators that run from either the inner bottom or the second platform to the third deck or the hangar deck, a longitudinal conveyor and eight cargo monorail trains in the overhead of the wet well. In support of the LHA Mid‐Life Upgrade, NAVSEA PMS 335 tasked Westinghouse Machinery Technology Division to develop a cargo flow simulation model for these ships in an effort to reduce the number of trains and the complexity of the cargo handling systems needed to support amphibious assault operations. This paper discusses the development of the simulation model and the potential system simplifications derived through the use of the model. Future application of the model as a training or shipboard management tool is also evaluated.
Waterjet to Hull Load Transfer
Authors: Alexander Keith 
Published: March 2009

ABSTRACTThe propulsion and control loads from a waterjet must be transmitted to the craft hull. The philosophy in many waterjet installations is to carry the loads from the waterjet through the transom and into the hull. For this purpose the transom is required to be stiffened by the boat designer and builder.Recent analysis by boat builders and waterjet manufacturers has highlighted the fact that while the transom is stiff laterally so that it easily carries steering loads, it is difficult to stiffen in a fore and aft direction. By contrast the inlet ducting is stiff in the fore and aft direction. Consequently it frequently carries the major thrust loads. The problem is that the inlet ducting, in many cases, is only designed to deliver the water to the jet pump and is not intended to carry these loads. Because of this, failures can occur in the ducting and its support structure.An alternative approach is to design the ducting specifically to carry these major thrust loads. This leads to heavier ducting but lighter transom structures. In this case the loads are transferred directly to the hull bottom which is more readily stiffened to take these loads in the fore and aft direction.This paper identifies waterjet loads and moments for normal running, steering and reverse. It specifies where they act and discusses the implications with respect to the two philosophies for transmitting these loads to the boat hull.Finite element analyses for the two approaches are compared, and the critical issues identified. Conclusions are drawn from the point of view of safety, ease of duct manufacture and jet installation.
Uncertainty Analysis of Structural Strength of Stiffened Panels
Authors: Muhanna Rafi L. , Ayyub Bilal M. , Bruchman Daniel D. 
Published: March 2009

ABSTRACTA prototype computational methodology for reliability assessment of continuum structures using finite element analysis with instability failure modes is described in this paper. Examples were used to illustrate and test the methodology. Geometric and material uncertainties are considered in the finite element model. A Computer program was developed to implement this methodology by integrating uncertainty formulations to create a finite element input file, and to conduct the reliability assessment on a machine level. A commercial finite element package was used as a basis for the strength assessment in the presented procedure. A parametric study for a stiffened panel strength was also carried out.The finite element model for the stiffened panel is based on the 8‐node doubly curved shell element, which can provide the non‐linear behavior prediction of the stiffened panel. The mesh is designed to ensure the convergence of eigenvalue estimates. Failure modes are predicted on the basis of elastic non‐linear analysis using the finite element model.Reliability assessment is performed using Monte Carlo simulation with variance reduction techniques that consisted of the conditional expectation method. Conditional expectation estimates the failure probability in each simulation cycle, then the average failure probability and its statistical error are computed. The developed method is expected to have significant impact on the reliability assessment of structural components and systems. This impact can extend beyond structural reliability into the generalized field of engineering mechanics.
Modeling and Simulation in the Sealift Program
Authors: Edinberg D. , Back K. , McVeigh J. 
Published: March 2009

ABSTRACTThe Navy's Sealift Program had several unique problems associated with it which have been addressed using innovative modeling and simulation techniques. These techniques fall under two categories: visualization and dynamic analysis. This paper will discuss the employment of these techniques and the impact their application has had in the program. Also examined will be various difficulties that were encountered in the application of these techniques.Commercial‐off‐the‐shelf (COTS) visualization tools were used to model the interior Ro/Ro spaces on the four classes of new construction and conversion ships now being procured. These models were employed for vehicle maneuvering simulations, operator familiarization and visualization of the results of an analysis of the loading and unloading of Ro/Ro vehicles.A COTS dynamic analysis system was used to simulate dynamic behavior during the assembly/deployment and retrieval/disassembly of the side port ramp using the ships' cranes. These analyses supported reviews of design configurations, proposed handling procedures, and in conjunction with extensive post‐processing, operability assessments for system operation. In a parallel effort, an interactive crane simulator was developed to support on‐going engineering studies, indoctrination, and test and evaluation purposes.Lessons learned have been applied to other activities at the Naval Sea Systems Command. Critical areas were the validation and maintenance of up‐to‐date configuration data for the visual models, adaptive levels of detail to meet the requirements of each study objective, and the need to provide comprehensive documentation of models.
Low Observable Technology for Future Surface Combatants
Authors: Nicholas John , Strattan Robert D. 
Published: March 2009

ABSTRACTThe naval shipbuilding community is in the initial steps of the widespread application of low observable technology. The aerospace community has several decades of experience with the research, development, design integration and production of low observable technologies into aircraft and other platforms. This paper will address the basics of radar cross section (RCS) reduction with an emphasis on their applications to surface ships. The possibility for affordable and timely adaptations of the aerospace experience to naval shipbuilding challenges will be addressed.The basic definition and characteristics of radar scattering will be described along with a discussion of the benefits of reduced radar cross section. Methods for reducing RCS and budgeting for reduction goals will be discussed. These methods include shaping and the use of radar absorbing materials. The properties of absorbing materials and their integration in composite structures will be discussed, along with issues of performance evaluation and design integration.
Maintenance Avoidance and Maintenance Reduction
Authors: Jacobs K. S. , McComas J. P. 
Published: March 2009

ABSTRACT  Maintenance is performed to restore a system's inherent reliability. However, reliability is not enough: a maintenance task must “pay for itself‘ in dollars or readiness. This applies to all types of maintenance: corrective, preventive, and alterative. We can reduce corrective maintenance costs through preventive and alterative maintenance. We can reduce preventive maintenance costs by eliminating inapplicable and ineffecitve tasks. We must weigh alterative maintenance costs against the value of improved readiness and cost‐avoidance of future corrective maintenance.The U. S. Navy is improving alterative maintenance by engineering for reduced maintenance (ERM). This process corrects the root cause of some high‐cost items by replacing the system, component, or coating with an improved design or material. It overcomes the limit of preventive maintenance: higher levels of inherent reliability require design improvement.The U. S. Navy is improving preventive maintenance through condition‐based maintenance (CBM). The Navy's CBM initiative encompasses three parallel efforts: rules (improving maintenance requirements and plans), tools (using computer and diagnostic technology to facilitate maintenance decision‐making), and schools (educating all levels of maintenance decision‐makers in reliability and condition‐based maintenance engineering principles).This paper addresses how the U. S. Navy surface ship community plans to avoid inapplicable and ineffective maintenance and reduce maintenance costs without sacrificing reliability.
ISO Certification and the Department of Defense
Authors: Scott H. , Kuehn R. G. 
Published: March 2009

ABSTRACT  The leaders of the United States Government are advocating a new way of doing business, because the Department of Defense (DoD) budget has been declining since the Reagan administration. With this decline comes the realization that private industry and the government can no longer afford the detailed government funded standards and related management bureaucracy. The value added by these standards is not visible to the higher levels of the DoD. In an economy that is turning global, an international (non‐governmental sponsored) standard such as ISO 9000 (ISO) has high appeal.ISO does not do away with standards, it is one. ISO provides uniformity and standardization via training of registrars, certification of processes, and periodic audits. A more consistent set of audit findings allows managers to focus on product and functional issues.The Coast Guard Yard at Baltimore, Maryland and the Naval Surface Warfare Center Carderock Division are already certified and the Naval Surface Warfare Center Crane Division is now joining them. The lessons learned are: know the registrar, plan, work the plan, and learn from others. Most of all, get management support at all levels.