A proposed cost effective alternative to current U.S. Navy structurally configured hulls is presented in this paper. This proposed design for producibility concept involves the elimination of structural stanchions and...
A proposed cost effective alternative to current U.S. Navy structurally configured hulls is presented in this paper. This proposed design for producibility concept involves the elimination of structural stanchions and transverse web frames. The potential impact of this “no frame” concept on structural design, weight and construction and material costs for naval surface frigates and destroyers is reflected in 1) reduced costs for the installation of distributive systems and 2) a reduced number and complexity of structural details providing a more reliable and less costly structure. This study was performed in three parts: 1) Determine the most feasible length between bulkheads without frames; 2) Using this length perform detail weight studies and construction and material costs analysis comparison on a 72-foot long hull module, with and without frames, for a FFG-7, and 3) Estimate the saving in man hours of labor on the installation of distributive systems and shipfitting for an FFG-7. For the feasible length studies on the “no frame” structural configuration, thirty-seven strength, weight and vertical center of gravity studies were performed on two ship classes; twenty-two on the FFG-7 class and fifteen on the DD-963 class. The detailed weight studies and construction and material cost analyses were conducted for FFG-7 “no frame” and “as built” modules. Results indicating the “no frame” concept module was 6.8% heavier and 14.8% less costly than the “as built” module. For the impact of an FFG-7 “no frame” structurally configured hull on the cost of labor required for the installation of distributive systems and for other functional work such as ship fitting, welding, and electrical, this study indicated a reduction of 169,206 labor hours per ship, representing 7.12% of the total required man hours to fabricate an FFG-7 class ship. With the employment of the “no frame” concept, certain areas of significant concern and potential risk were addressed. These include: 1) t
The structural design of a ship's section is a complicated, repetitive and time consuming task. With the advent of new technology, high speed computers have enabled the ship designer to accomplish in a matter of s...
The structural design of a ship's section is a complicated, repetitive and time consuming task. With the advent of new technology, high speed computers have enabled the ship designer to accomplish in a matter of seconds what would formerly take days to accomplish by hand. The Structural Synthesis Design program (SSDP) is a N avy developed computer-aided design tool which is used to design (or to analyze) the longitudinal scantlings for a variety of ship cross sections, consisting of any practical combinations of decks, platforms, bulkheads and materials, i.e., various steel and aluminum alloys. The final hull section design will have the lowest practical weight for the chosen geometric configuration, structural arrangements, and imposed loadings. The scantling developed by the program will satisfy all U.S. N avy ship structural design criteria. An explanation of the objective and design elements of N avy ship structures is included. The rationale behind the SSDP design philosophy is developed along with the significant program capabilities. In an attempt to highlight the influence of automated design procedures on the current naval ship design process, the effect of the SSDP on the DDG 51 destroyer structural development is addressed.
作者：
WHITE, GJAYYUB, BMGregory J. White:
LCdr. USNR-R is an assistant professor of naval architecture at the U.S. Naval Academy. He received a B. S. degree in engineering mechanics from Vanderbilt University in 1975 an M. E. degree in naval architecture from the University of California Berkeley in 1981 and a Ph.D. from the University of Maryland in 1986. Dr. White served on active duty with the U.S. Navy from 1975 to 1979 first as the damage control assistant aboard the USS Reasoner (FF-1063) and then as the commissioning CIC officer aboard the USS Merrill (DD-976). After leaving active duty and while attending graduate school he worked at Mare Island Naval Shipyard in the scientific section (Code 250.1). Upon completion of graduate school he then worked for Exxon International Company as a research engineer in the R & D division of the tanker department. A lieutenant commander in the Ready Reserve Dr. White drills with the repair department of a submarine tender reserve unit and recently completed the reserve engineering duty officer qualification program. A member of ASNE since 1983 Dr. White is also a member of SNAME and the U.S. Naval Institute Dr. White received the “Jimmie” Hamilton Award for 1985. Bilal M. Ayyub:is currently an assistant professor of civil engineering at the University of Maryland. He received his B. S. degree in civil engineering from the University of Kuwait in 1980. He completed both his M. S. (1981) and Ph.D. (1983) in civil engineering at the Georgia Institute of Technology. While there he was awarded the Kuwait Foundation for the Advancement of Science Fellowship. Dr. Ayyub has extensive background in risk-based analysis and design
simulation pre-stressed composite steel girders and construction engineering. He is engaged in research work involving structural reliability bridges marine structures mathematical modelling using the theories of probability statistics and fuzzy sets. His research work is sponsored by the National Transportation Safety Board the University of Maryland the Natio
In the continuing effort to apply reliability methods to marine structures, the next logical step is to include these techniques in the design process. The advantage of doing this would be the ability to design more e...
详细信息
In the continuing effort to apply reliability methods to marine structures, the next logical step is to include these techniques in the design process. The advantage of doing this would be the ability to design more efficient structures with some measure of certainty of the reliability level involved. The particular application in ship structural design which would benefit the most from using reliability methods is the design against fatigue failure. In this paper, some of the reliability-based methods currently being used (or proposed for use) in the design of structures against fatigue are examined. Each is evaluated as to its suitability for use in the structural design of ships. In addition, the authors propose a new reliability-based fatigue design format which is based on their recently introduced Reliability-Conditioned (RC) design method and the Load and Resistance Factor Design (LRFD) code format. This approach is hoped to provide the design engineer with an easy to understand and use tool based on the LRFD format. The RC method will enable him to quickly and accurately design the components of a ship's structure such that a desired level of safety against fatigue is achieved. Each of the methods discussed is used to solve a practical example. The results of that example and several others are used to discuss the relative merits of each method.
作者：
SEJD, JJWATKINSON, KWHILL, WFMr. James J. Sejd received his B.S. degree in Civil Engineering from Case
Western Reserve University and has since undergone considerable graduate study at both The George Washington and American Universities. He served almost four years in the U.S. Navy as a Naval Aviator and enjoys the unique distinction of being qualified in both Heavier- and Lighter-than-Air aircraft. Early in his career he was employed at the Navy's Bureau of Ships in the capacity of a Structural Designer and Structural Research Monitor. In 1966 he joined the Staff of the Center for Naval Analyses where he was involved in the mathematical modeling of ships and aircraft and in economic “trade-off‘ analysis. In 1970. he went to the Naval Ship Engineering Center as an Operations Research Analyst in the Ship Design and Development Division. At the present time he is employed as a Program Manager for the Naval Sea Systems Command Ship Design Research and Development Office. A member of ASNE since 1973 he also is a member of the Association of Scientists and Engineers at NAVSEA the Operations Research Society of America and the Lighter-Than-Air Society. Mr. Kenneth W. Watkinson received both is B.S. and M.S. degrees in Engineering Science from Florida State University in 1970 and 1971 respectively. Since graduation
he has been employed at the Naval Coastal Systems Center (NCSC). Panama City. Fla. where he is primarily involved in the investigation of the stability and control of underwater vehicles. For the past four years he has been the Task Leader and Principal Investigator for the NCSC portion of the Advanced Submarine Control Program involved in developing control design methods and the instrumentation system for the Submarine Control System Test Vehicle. Mr.
William F. Hill is currently the ASCOP Program Manager at Lockheed Missiles & Space Company (LMSC) Inc. where he has the overall responsibility for design and construction of the Control System Test Vehicle (CSTV). He entered the aircraft industry in England as an Apprentice w
As part of the Advanced Submarine Control program (ASCOP), the Naval Sea Systems Command has developed an open water Submarine Control System Test Vehicle (CSTV). This vehicle is a 1/12 scale model of an SSN 688 Class...
As part of the Advanced Submarine Control program (ASCOP), the Naval Sea Systems Command has developed an open water Submarine Control System Test Vehicle (CSTV). This vehicle is a 1/12 scale model of an SSN 688 Class Submarine, with provisions for easy geometric changes. Such changes include alternate Sail size and location, the addition of parallel middle-bodies, alternative tail sections, and alternative control configurations. A self-contained instrumentation and control system provides the capability for “on-board” recording of all relevant Submarine-state variables, over the entire speed and depth range, to a degree of data accuracy exceeding any known system. With the means thus available to correlate measured vehicle hydrodynamics with selected maneuvers, conditions, and changes in hull geometry and control surface configuration, modern mathematical techniques for improving submarine equations of motion can be employed to permit dramatic design enhancements in both safety and performance. This paper provides the rationale and history of the development of this vehicle, a description of the instrumentation and control package, and a description of the vehicle itself.
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