bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of Structural Service Life of Ships
Authors: AYYUB BILAL M. , WHITE GREGORY J. , PURCELL EDWARD S. 
Published: March 2009

ABSTRACTA methodology for the structural life assessment of a ship's structure is suggested. The methodology is based on probabilistic analysis using reliability concepts and the statistics of extremes. In this approach, the estimation of structural life expectancy is based on selected failure modes. All possible failure modes of the ship must be investigated and the most likely paths to structural failure identified. For the purpose of illustration two failure modes are considered in this study. They are plate plastic deformation and fatigue cracking. Structural life based on these two failure modes is determined for an example vessel.The methodology determines the probability of failure of the ship's structural components according to the identified failure modes as a function of time. The results can be interpreted as the cumulative probability distribution function (CDF) of structural life. Due to the unknown level of statistical correlation between failure modes, limits or bounds on the CDF of the structural life are established. The limits correspond to the extreme cases of fully correlated and independent failure modes. The CDFs of structural life are determined for two inspection strategies; namely, inspection every year and inspection every two years with a warranty inspection at the end of the first year.The meaning of the results for the case investigated in this study is that, for example, given an inspection strategy of two years and a desired life of 15 years, there is a 72% chance that the vessel will not experience enough partial damage‘ in the failure modes identified to constitute reaching the “end of structural life” as defined.
Naval Lithium Battery Safety Program
Authors: SHULER STANLEY C. , MORANSKI JOHN W. 
Published: March 2009

ABSTRACTThe stringent performance requirements of present and future naval battery powered systems necessitate the use of advanced lithium batteries with extended energy and life characteristics. In recent years, battery manufacturers in the United States and various foreign nations have been developing new lithium batteries using lithium metal anodes coupled with either carbon monofluoride (CF)x, sulfur dioxide (SO2), thionyl chloride (SOCI2) or other cathode materials. These batteries represent a major breakthrough as primary power sources and provide certain unique advantages over conventional electrochemical systems. The advantages are: (1) a substantial increase in specific energy, (2) higher operating cell voltage, (3) low temperature operation and (4) projected long shelf life. While lithium batteries in general offer five to ten times the specific energy of conventional systems, each design differs from the other in its level of performance and in its hazards. The Naval Lithium Battery Safety Program addresses these hazards within the areas of acquisition, design, use, packaging, storage, transportation, and disposal.The safety program also establishes minimum safety test requirements for lithium batteries in lithium battery powered equipment when used by the Navy or on Navy facilities.
Toward a Survivable Radio Room
Authors: BRUNINGA R.E. 
Published: March 2009

ABSTRACTSignificant progress has been made in recent years in the survivability of naval systems through the principles of redundancy, separation, hardening and careful consideration of arrangements of equipments. In the area of radio communications, however, these principles are being applied on individual communications subsystems, but not as an overall survivability strategy to the total radio communications suite. Significant advances in automatic control, networking and distributed architectures have not been fully exploited in U.S. Navy communications and ship design to improve user friendliness and survivability under adverse conditions. This paper suggests that automated, remote control of communications equipment through a distributed/redundant networking system could eliminate the centralized radio room concept and allow much greater flexibility in ship design and arrangements to accomplish the objectives of NavSea Survivability Policy.
Flammability and Toxicity of Composite Materials for Marine Vehicles
Authors: SEVART JEFFREY L. , GRIFFIN O. HAYDEN , GÜRDAL ZAFER , WARNER GAIL A. 
Published: March 2009

ABSTRACTCharacteristics of both thermoplastic and thermoset composite materials as they pertain to marine vehicle applications are discussed. Comparison of various material selection factors such as strength, damage and moisture resistance, and flammability and toxicity as well as cost and availability of thermoset and thermoplastic composite materials are presented. Methods for testing and reducing the flammability and toxicity are discussed. Many commercially available composite systems are reported to provide favorable characteristics for marine applications. Although there seems to be a need for improved production technology for thermoplastics, they present potential advantages in physical properties over thermoset composites.
CAD/CAM Manufacturing of Prototype Shipboard Components
Authors: CALVERT T.E. , RODRIGUEZ F.A. , SLEBZAK J.S. 
Published: March 2009

ABSTRACTThe machine shop at the Annapolis Laboratory of the David Taylor Research Center (DTRC) provides model making and prototype support to a large variety of naval ship related engineering projects. In order to meet these challenging requirements, computer aided design/computer aided manufacturing (CAD/CAM) techniques are being used to produce “one of a kind” prototypes or very low volume production parts. The use of computer aides in these cases is to facilitate the accurate manufacture of a difficult part, rather than to improve manufacturing efficiencies. In addition, the approach provides the flexibility required to support research and development projects. Several examples of prototype shipboard components manufactured using CAD/CAM techniques are presented in this paper. The hardware and software that facilitated these projects are discussed. The examples described have met the requirements to produce a wide variety of prototype shipboard machinery components quickly and accurately.
Stability Analysis and Displacement Measurements of Graving Drydock Walls
Authors: WU ARTHUR H. , CECILIO JOHN , BAYLES ROBERT A. 
Published: March 2009

ABSTRACTMaintenance and safety certification of the Navy's graving drydocks are essential in supporting fleet operation and readiness. Thus, structural analyses of graving drydocks are made regularly by the Naval Facilities Engineering Command using a finite element computer program. An analytical method is implemented to evaluate the structural adequacy of existing drydocks which are subjected to static and earthquake loads. The results of the analyses are used in certifying the safety of drydocks. Due to the complexity of the drydock structure, an analysis is begun by setting up structural models which can accurately include structural and geotechnical parameters for finite element numerical analysis. The accuracy of the results can then be checked through a comparison of the different models used in the analysis, and the comparison of field observations made from carefully monitored instrumentation. For example, in order to evaluate a mathematical analysis of the response of a drydock to static and earthquake loads, measurements of the movement of drydock walls in Charleston Naval Shipyard, South Carolina, were made by flooding and draining the drydock during a docking operation. A dial gauge instrument was used to measure the displacement of a wall and a laser electronic distance measuring instrument (EDM) was used to measure the displacement across the width of the dry‐dock.The purpose of this paper is to present the drydock wall stability analysis method and to compare the analytical results with the observed wall displacement. Conclusions were derived from the results of the finite element analysis and the measured wall displacement. The results were useful in the structural analyses and safety certification of the graving drydocks.
The Determination of Ship Loads and Motions: A Recommended Engineering Approach
Authors: BUCKLEY WILLIAM H. 
Published: March 2009

ABSTRACTThis paper outlines the essential features of a recommended engineering approach to load and motion determination, required developments, progress to date and remaining key developments. An engineering approach is defined as one in which all significant cause and effect relationships have been identified and quantified so that the resulting design criteria and methods can play a deterministic role in the give and take of ship design. In defining the essential features of such an approach consideration is given to (a) the random nature of the seaway, (b) linear and nonlinear characteristics of the seaway and ship responses to it, and (c) the use of resulting loads and stresses in the assessment of as‐built static strength, fatigue and flaw growth degradation of static strength, and energy absorption under seaway impact loadings.Progress to date in these areas is overviewed and recent developments summarized which serve to demonstrate that the rather demanding elements of an engineering approach are attainable. Because of the importance of seaway characteristics, primary attention has been given to providing an effective engineering definition of world wide wave climates. In addition, because of the importance of nonlinear seaways and ship responses, a method of characterizing the nonlinearity of measured random data has been developed.With these advances in hand, remaining critical developments are identified and approaches to their resolution suggested.
Comparative Structural Life Assessment of Patrol Boat Bottom Plating
Authors: AYYUB BILAL M. , WHITE GREGORY J. , BELL‐WRIGHT THOMAS F. , PURCELL EDWARD S. 
Published: March 2009

ABSTRACTThe estimation of an absolute life expectancy of a structure is a complex process and the results are expected to have relatively large levels of uncertainty. In this study, a comparative analysis is undertaken between two different patrol boats. This is an approach which results in a higher confidence level because certain factors common to both boats can be eliminated by assuming them to be at constant normal levels. The study is limited to the critical forward bottom plating and takes into account the differences in material, plate dimensions, operational profile, structure and loading of the two vessels. Two failure modes, plastic plate deformation and fatigue, are considered, and a novel approach to plate wastage is included. Many factors affect the structural life of a vessel. They include structural type, operational profile, structural details, loads, inspection and maintenance, design methods, safety factors, corrosion, and environmental factors. There are three types of uncertainty associated with these factors; namely, physical randomness, statistical uncertainties, and model uncertainties. The method described is designed to address these uncertainties.The objective of the paper is to present the reliability‐based structural life assessment method, and then to use it to evaluate and compare the structural performance of the forward bottom plating of the two patrol boats. The results of the evaluation are presented in the form of graphs and tables in order to facilitate the comparative evaluation. The method is performed within a computer‐based format which allows parametric sensitivity analysis of several variables including the size of the plating panel, thickness, operational profile and loading. The sensitivity of the structural life expectancy of the forward bottom plating to variations in these parameters is evaluated.
Fiber Optic Coupler Sensors
Authors: GERDT DAVID W. 
Published: March 2009

ABSTRACTA new fiber optic sensor, based on sensitive single mode fused couplers, which has wide applicability to shipboard use, is introduced. Recent tests have shown that these sensors may be used as all optical hydrophones. Other tests have demonstrated that these sensors are useful as very sensitive accele‐rometers such as might be used for active machinery monitoring. Fiber optic coupler sensors can be used as all optical strain gauges as well. These sensors are composed of a potted single mode fused directional coupler which changes its coupling ratio in response to applied stress. The sensor may be designed into many configurations, including devices for monitoring seismic activity, magnetic field, temperature, pressure and other activities. Since the manufacturing technology involved in these sensors is rather simple, straightforward applications allow very inexpensive devices. A unique multiplexing scheme allows single source/single receiver operation of a string of all optical sensors.
Underwater Application of Adhesives in Ship Husbandry
Authors: KEENAN PATRICK J. 
Published: March 2009

ABSTRACTWet adhesive technology is currently employed in specific applications of underwater ship husbandry (UWSH). The success and scope of underwater adhesive technology is limited by material and procedural considerations. One class of ad‐hesives, epoxy resins, possesses chemical and physical properties suitable for use in the UWSH environment. Improvements in material capabilities (i.e., biocide impregnation of epoxy resins) are ongoing. Bond formation at the adhesive‐surface interface is the primary factor in producing successful adhesion. The intrinsic difficulty of forming adhesive bonds to a wet surface may be overcome by improvements in application procedures (i.e., pretreatment) and through enhancement of the chemical bonding capabilities of adhesives. Incorporating technological and procedural improvements in underwater adhesive technology into standardized application processes could greatly increase the capability and scope of UWSH.
Smaller Wars: Prospects for Surface Warfare
Authors: Mahncke Frank C. 
Published: March 2009

ABSTRACTEngineering requirements for naval surface warfare weapons systems are partially driven by the geopolitical world to which the Navy must address itself. That situation is changing rapidly; it appears likely that an increasing emphasis will be placed on the Navy's ability to deal with smaller wars, wars of less than global scope. Driven by different rules of engagement and scope, these wars will impose unique weapon systems requirements, particularly in the areas of intelligence and surveillance, command and control, offensive weapons and defensive systems. This paper addresses the increasing likelihood of smaller wars, the special characteristics of such wars, and outlines some of the naval weapons systems requirements that may result.
Artificial Neural Networks and Their Application to Weapons
Authors: WEBSTER WILLARD P. 
Published: March 2009

ABSTRACTComplex processing algorithms associated with requirements for real‐time target detection, acquisition and recognition have far outdistanced our ability to package the necessary processing power into real‐time weapon‐sized hardware. Weapon developers need new, radically different, approaches to solve these difficult weapon signal processing problems. Artificial neural networks (ANN) is one of the new, radically different, signal processing approaches that is currently receiving much attention for weapon applications. The human brain is a powerful image and pattern recognition processor whose basic processing element is the neuron. Synapses are the weighted interconnections between neurons that permit learning and communication between the neurons. Artificial neural network technology attempts to mathematically and/or electrically model neurons and synapses and then interconnect these models in architectures suitable for signal processing tasks.ANN technology is particularly applicable to pattern recognition, speech recognition, machine vision, robotics, and optimization signal processing tasks. Specific military applications include missile seekers, missile fuzing, sonar target discrimination, automatic target recognition, and autopilots. Two unique characteristics of ANN processors are that they are non‐linear processors and that they are trained, not programmed, to accomplish processing tasks in a manner analogous to the way the human brain learns. Learning is achieved by modifying the synaptic weights of each artificial neuron until the final desired system processing response is achieved.Several years ago the Naval Weapons Center (NavWpnCen) identified ANN technology as a high risk‐high payoff approach to missile signal processing requirements and initiated several research and development efforts in this area. One result of this work is the new 80170NW ANN analog VLSI chip produced by Intel Inc. Another is the current Missileborne Integrated Neural Network Demonstration (MINND) Advanced Technology Demonstration (ATD) project to develop a hybrid analog/digital artificial neural computer for real‐time processing of data from imaging missile seekers. The neural computer will use several Intel chips interconnected in a flexible architecture, which is loosely based on the operation of the human retina, to demonstrate desired target/background discrimination and target detection and tracking processing capabilities. This paper provides an introduction to artificial neural network technology and discusses some of the results that have been achieved by applying ANN technology to weapon system problems at the Naval Weapons Center.
Fouling Control of Navy Surface Ships — 1990
Authors: COLOGER CHRIS P. 
Published: March 2009

1The Author The Author received a B.S. degree from the New York State College of Forestry, Syracuse University. He joined the staff of the Material Laboratory at the New York Naval Shipyard in 1951 and carried out applied research as a wood technologist in the foreign wood program for all wood minesweepers. In 1962, at the Naval Applied Science Laboratory, he was engaged as a rubber technologist in the development of elastomeric vibration damping materials and the Laboratory's research studies on marine fouling. Since 1970, at the David W. Taylor Naval Ship Research and Development Center, he has been a materials engineer involved with the Center's programs on deck coverings, corrosion and conservation of energy. He is a member of ASNE.ABSTRACTOngoing investigations on three test ships covering a period of five years have identified the performance characteristics of an antifouling (AF) paint for long‐term service. This paint ablates by the sequential hydrolysis of the surface and shearing action of the ship's passage through the water to remove the persistent settlement of microorganisms while continuously releasing an environmentally acceptable component to control calcareous fouling. During the past decade a variety of toxicants have been investigated and formulated into a number of AF paints that can be grouped on the basis of how the toxicant is combined and released from the paint matrix. Observations relative to color change, fouling and paint deterioration, define the qualitative criteria for evaluation. Quantitative data obtained with improved instruments for taking dry film thickness measurements and roughness determinations both in drydock and underwater accurately track these parameters during long‐term service. Field studies have shown that ablation of the AF paint is an effective mechanism to limit the formation of microbial biofilms on AF paint surfaces. Field studies have also revealed that reliance on toxics will not control the accretion of microorganisms on a ship's hull. The ablative AF paint has been found to be superior to all non‐ablative AF paints evaluated by the Navy to date.
Ship Electromagnetic Pulse Survivability Trials
Authors: JUMP MICHAEL E. , EMBERSON WILLIAM C. 
Published: March 2009

ABSTRACTThe Navy conducted an EMP (Electromagnetic Pulse) trial on a Spruance class destroyer (USS Deyo; DD‐989) during July 1990 using the Electromagnetic Pulse Radio Frequency Environment Simulator for Ships (EMPRESS II).The Navy has selected a layered hardening approach consisting of platform level hardening and system level hardening to provide EMP survivability for the mission critical systems of surface ships. One key question is how much of the hardening can be allocated to and achieved by platform hardening? The other key questions are which systems will also require system level hardening and can system level hardening be effectively achieved?Prior to the trial, a platform level EMP hardening package was installed to evaluate the effectiveness of platform hardening techniques. Electromagnetic interference (EMI) fixes were installed when the EMI fixes were determined to provide system level hardening to emissions similar in frequency content to EMP. Temporary system level EMP hardening measures were also installed on selected combat systems and extensive pretrial EMP susceptibility assessments were performed on many of the ship systems.During the trial period, USS Deyo was subjected to over 700 sub‐threat level pulses at increasing power levels. The highest test level during this trial was approximately 10dB below the EMP threat level. The induced transient currents exterior and interior to the ship and on a variety of systems were measured and used to evaluate the effectiveness of the platform hardening and system hardening. During the trial, a number of combat system operability tests were also conducted to help identify potential problem areas and evaluate system performance.This paper describes some of the events prior to and during the USS Deyo trial and the lessons learned as a result of the trial. The lessens learned from this trial will have a positive impact on future ship hardening efforts and EMP trials.
Magnetohydrodynamic Submarine Propulsion Systems
Authors: SWALLOM DANIEL W. , SADOVNIK ISAAC , GIBBS JUDY S. , GUROL HUSAM , NGUYEN LONG V. , VAN DEN BERGH HUGO H. 
Published: March 2009

ABSTRACTMagnetohydrodynamic propulsion systems for submarines offer several significant advantages over conventional propeller propulsion systems. These advantages include the potential for greater stealth characteristics, increased maneuverability, enhanced survivability, elimination of cavitation limits, greater payload capability, and the addition of a significant emergency propulsion system. These advantages can be obtained with a magnetohydrodynamic propulsion system that is neutrally buoyant and can operate with the existing submarine propulsion system power plant.A thorough investigation of magnetohydrodynamic propulsion systems for submarine applications has been completed. During the investigation, a number of geometric configurations were examined. Each of these configurations and mounting concepts was optimized for maximum performance for a generic attack class submarine. The optimization considered each thruster individually by determining the optimum operating characteristics for each one and accepting only those thrusters that result in a neutrally buoyant propulsion system.The results of this detailed optimization study show that the segmented, annular thruster is the concept with the highest performance levels and greatest efficiency and offers the greatest potential for a practical magnetohydrodynamic propulsion system for attack class submarines. The optimization study results were used to develop a specific point design for a segmented, annular magnetohydrodynamic thruster for an attack class submarine. The design point case has shown that this thruster may be able to provide the necessary thrust to propel an attack class submarine at the required velocity with the potential for a substantial acoustic signature reduction within the constraints of the existing submarine power plant and the maintenance of neutral buoyancy. This innovative magnetohydrodynamic propulsion system offers an approach for submarine propulsion that can be an important contribution to the development of the submarine force of the next century.