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INTRODUCTION The Committee on Manne Structures (CMS) annual report outlines a coordinated research plan for the interagency Ship Structure Committee (SSC). The SSC is an interagency body through which the U.S. Coast Guard, Naval Sea Systems Command, Mantime Administration, Military Sealift Command, Amencan Bureau of Shipping, Transport Canada, and the Canadian Department of Defence coordinate their research on structural integrity of marine structures. The research program of the SSC is intended to accommodate advanced concepts and long-range planning, as well as research in technology areas of matenais cntena, loads and response, design methods, fabrication and maintenance, and reliability. The SSC, which has Easter for almost 50 years, represents a consensus among government agencies on the importance of maintaining a strong research program in ship structures. The CMS recommendations embody a multlyear research planning program that makes recommendations for the research program of the SSC for fiscal years (FY) 1995 and later and reviews FY 1993 research activities. The projects, though capable of standing alone as specific technology enhancements, are grouped into four thrust areas: reliability, composites, producibility/competitiveness, and inspection/maintenance. In addition, in order to maximize knowledge of potential follow-on projects, Appendix A describes those projects considered for out-year support of specific thrust areas. The report contains five color-coded sections that compose: I. introduction, the SSC strategic plan, recommendations for the research program, and appendices B and C white; 2. FY 1995 project recommendations~reen; 3. active and pending projects yellow; 4. completed projects blue; and 5. potential future-year projects - (Appendix AWbei~e. ~ 1 ~ ~ ~ The CMS provides advice that is independent and objective in accordance with the National Research Council process. However, the CMS does meet regularly with the SSC to ensure that the marine structures research that the SSC considers most important is considered in the recommendations of the CMS. The responsibilities of the CMS and its relationship to the SSC are more fully described in AppendLx B. The CMS keeps abreast of major technical issues of interest to federal agencies and national programs In which marine structures research can have significant positive impacts. Dunng its 1992 meetings, the committee discussed agency research and development programs that were presented at the Ship Structure Subcommittee spring meeting; the areas of national interest that might be affected by CMS research recommendations; and special technical topics concerned with safety, reliability, structural maintenance, industry competitiveness,
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and advanced-matenals technology. In order to provide proper visibility to the recommended projects, they are related as parts of totaI-program thrust areas that support SSC goals. In September 1993, the CMS held its annual joint meeting with the Ship Structure Subcommittee to discuss research areas of most Interest to sponsoring agencies, the strategic plan, and the future financial status of the SSC and its potential effect on CMS efforts. The CMS recognizes that research in ship structures is being sponsored independently by agencies with relatively large funds compared with those available to the SSC. The challenge to the CMS thus becomes one of developing and recommending meaningful and timely research programs that wall dovetail with these funded major . . ~ - ` ~ . ^^ . . ~ .~~ an. . programs. ln ~ ~ ~ and provide initial guidance for' or otherwise enhance, sponsonug agency efforts. Furthermore, the research recommendations represent a basis for establishing agency research programs. For example, the Navy's Reliability-based Structural Design Program stems from, and is supported by, the reliability thrust of the CMS. In order to properly support the SSC, the CMS strives to maintain a balanced composition of expertise on the Design and Matenals work groups. To ensure broad appeal among the sponsoring agencies and secure the benefits of relevant technologies and technology transfer, representation is obtained from al] relevant techrucal disciplines, academia, the research community, and the marine industry. The SSC unanimously endorsed a strategic plan on June 5, 1992, and this approved plan is reproduced in its entirety in Appendix C. The CMS project recommendations are keyed to the national coals and specific strategies adriressed in the 1 11S way, tne _~ .~ recommenc s como. ementaw enorts teat Ale all in gaps dó~ c_ ~ Ad, , e ~~ ~ ~ , it, , ~ , , ~ ~ , ~ ~ ~ b5c Strategic Plan. Flowever, penod~c review and revision of the strategic plan by the SSC wall keep the plan abreast of changing circumstances. In November 1993, the SSC approved publishing a biennial, rather than an annual, report of research recommendations. This step had two potential benefits: first, encouragement of multiyear contracts, thus streamlining the contracting process, and second, a potential for more cost-effective advice. The first biennial report is planned for the FY 1996 - 1997 recommendations. For the research program for the SSC for FY 1995, the current report recommends 16 research Droiects that film SUDDort the strategic nian and its stated coals and strategies. Also incIudec] in (Appendix A) are 26 potential follow-on projects for later years for the 4 specific thrust areas. In the following sections, projects designated with an "SSC" prefix are published SSC reports, those designated with an "SR-" prefix are currently being funded, .. ... .. . .. ~ 1 J J ~ ~ - =- rid o- those warn a Ye- pretrx are recommended for FY 1995, and those with a "95D-" or "95M-" prefix are out-year potential projects. Many of these proposed projects are recommendations from the CMS report for FY 1994 that have been reviewed and either were found to be relevant as written, or were rewritten to resect changes In the technology. These continued projects have their previous number appended to their titles. The designation 'TIC" refers to projects recommended by Transport Canada rather than by the work groups. Discussions of the projects for later years that are contained in this report are a first step toward the development of a biennial report. 2
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CMS Recommendations for Implementing the SSC Strategic Plan The approved SSC Strategic Plan is reproduced in its entirety in Appendix C. This section of the report presents the considerations of the CMS In focusing on the national goals as defined In the strategic plan and in supporting the strategies for the 199Os as defined In the plan. As mentioned earlier, each project recommended herein is related to at least one specific goal and strategy. But more significantly, rather than present a group of isolated projects, the CMS has grouped the recommended projects into specific thrust areas that support of the overall strategic plan, thus providing a framework to consolidate and focus the efforts. The Thrust Areas were developed to support the three SSC national goals: repair. Goal I. improve the safety and integrity of marine structures; Goal 2. reduce marine environmental risks; and Goal 3. support the U.S. maritime industry in shipbuilding, maintenance, and As expressed in the strategic plan, the SSC is interested in leveraging its limited funds by means of joint-industry projects and by independent support. Indllstnes, agencies, and research committees should contact the executive director of the SSC if they are interested in projects listed in this report and are welling to sponsor and fund a project, or cosponsor and share costs. 3
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Thrust Areas Al] thrust areas in the recommended research plan support at least two national goals of the SSC Strategic Plan, and one supports al] three goals. The specific thrust areas and the goals they support are as follows: ∑ Reliability Shoals ~ and 2) ∑ Composites (goals ~ and 3) ∑ Producibility/Competitiveness (goals ~ and 3) ∑ Inspection/Maintenance (goals I, 2, and 3~. Reliability On June 17, 1987, the CMS convened an ad hoc committee with experts in the subject areas of marine structures and structural reliability. The consensus of that group was that the SSC should have a long-range program in reliability to develop a probability- based design approach for ship structures. Following that meeting, the CMS formulates! a four-phase program, which began in FY 1989. This program has been modified since that time to reflect the results of the first phases, and to add a fifth phase, but it remains the principal thrust area of the CMS. The SSC also is committed to supporting the reliability thrust. The goad is development of technology to support preparation of a probability-based design code for ships. The program is described later in the section on reliability in the chapter on research program development. Because reliability-based design criteria promise to improve structural efficiency, a U.S. Navy pane] is studying this approach. Reliability projects proposed for SSC funding provide a sound basis for a much larger, three-pronged effort that would include computer simulation, tow~ng-tank tests, ant] fulI-scale teals. Predicting environmental loads and the responses of complex marine structures is extremely difficult. Because assumptions and simplifications are frequently introduced, uncertainty and risk can follow. A research program initiated by the SSC to develop design criteria for marine structures is addressing uncertainties in loads. Many other research projects in structural reliability supported by the SSC either have been or are being completed. At this time, it would be advantageous to provide a synthesis of the projects in the reliability thrust area, as we]] as in other related SSC projects, and the most recent developments in structural-reliability technology that are likely to impact analysis and design of marine structures. Therefore, a document summarizing the state of the an In marine structural reliability was proposed by the CMS and selected for funding by the SSC In 1994 as Project SR-1362. This document could be the fundamental reference for (~) the development of a probability-based ship-structure design code, (2) the definition of procedures for performing failure analysis, and (3) reliability analysis for e~st~ng ships. In order to ascertain the large uncertainties associated with the visual inspection of data, a probabilistic mode} will be developed. This will improve the use of fatigue 4
Representative terms from entire chapter: