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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
d—~ 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.
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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.
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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:
ssc strategic
