REVIEW OF COMPLETED PROJECTS

Projects completed since the 1994 annual report was published are listed in Table 5. Project descriptions follow, with the addition of a brief summary of the final report, which represents the CMS's understanding of the results as reported by the author.

Project reports have been published, are in publication, or will be available from the National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161. The NTIS numbers are given with each project description, along with the SSC report number. NTIS numbers also appear in Table 6.

Many recent reports may be available from the executive director of the SSC. Requests may be mailed to Commander Stephen E. Sharpe, Commandant (G-MI/SSC), 2100 Second Street, SW, Washington, D.C. 20593-0001.

TABLE 5 Completed Projects

Number

Project Title

Page

SR-1338

Uncertainty in Strength Models for Marine Structures . . . . . . . . . .

86

SR-1339

Effect of High-strength Steels on Strength Considerations of Design and Construction Details of Ships . . . . . . . . . . . . . . . . . . . . . . . . .

86

SR-1341

Residual Strength Assessment for Damaged Marine Structures . . . . . .

87

SR-1342

Hydrodynamic Impact on Displacement Ship Hulls . . . . . . . . . . . . .

87

SR-1346

Improved Ship Hull Structural Details Relative to Fatigue . . . . . . . .

88

SR-1348

Measurement of Ice Loads on Ship Structures . . . . . . . . . . . . . . . . . .

88

SR-1350

Reexamination of Design Criteria for Stiffened Plate Panels . . . . . . .

89

SR-1351

Hull Structure Concepts for Improved Producibility . . . . . . . . . . . .

89

SR-1353

The Role of Human Error in the Design, Construction, and Reliability of Marine Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

90



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Marine Structures Research Recommendations: Recommendations for the Interagency Ship Structure Committee's FYs 1996-'97 and Later-Years Research Program REVIEW OF COMPLETED PROJECTS Projects completed since the 1994 annual report was published are listed in Table 5. Project descriptions follow, with the addition of a brief summary of the final report, which represents the CMS's understanding of the results as reported by the author. Project reports have been published, are in publication, or will be available from the National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161. The NTIS numbers are given with each project description, along with the SSC report number. NTIS numbers also appear in Table 6. Many recent reports may be available from the executive director of the SSC. Requests may be mailed to Commander Stephen E. Sharpe, Commandant (G-MI/SSC), 2100 Second Street, SW, Washington, D.C. 20593-0001. TABLE 5 Completed Projects Number Project Title Page SR-1338 Uncertainty in Strength Models for Marine Structures . . . . . . . . . . 86 SR-1339 Effect of High-strength Steels on Strength Considerations of Design and Construction Details of Ships . . . . . . . . . . . . . . . . . . . . . . . . . 86 SR-1341 Residual Strength Assessment for Damaged Marine Structures . . . . . . 87 SR-1342 Hydrodynamic Impact on Displacement Ship Hulls . . . . . . . . . . . . . 87 SR-1346 Improved Ship Hull Structural Details Relative to Fatigue . . . . . . . . 88 SR-1348 Measurement of Ice Loads on Ship Structures . . . . . . . . . . . . . . . . . . 88 SR-1350 Reexamination of Design Criteria for Stiffened Plate Panels . . . . . . . 89 SR-1351 Hull Structure Concepts for Improved Producibility . . . . . . . . . . . . 89 SR-1353 The Role of Human Error in the Design, Construction, and Reliability of Marine Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

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Marine Structures Research Recommendations: Recommendations for the Interagency Ship Structure Committee's FYs 1996-'97 and Later-Years Research Program SR-1338 Uncertainty in Strength Models for Marine Structures (SSC-375) (NTIS PB95-126819) Investigator Owen Hughes Contractor Ross/McNatt Naval Architects, Stevensville, Maryland Objective Quantify bias and uncertainty in structural-strength formulations in order to evaluate safety margins and derive design criteria. Summary The report provides a methodology for the modeling and analysis of uncertainties in strength parameters that are suitable for the development of a reliability-based design method for ship structures. The report identifies the failure modes of principal structural members of ships that involve modeling uncertainty and, based on a review of sufficient test data, demonstrates the methodology. Data were collected about strength parameters for the selected failure mode of panel compressive collapse, and the method was applied to assess uncertainties. The report also identifies further research needs for uncertainty modeling and analysis of strength parameters. Project Chair Rickard Anderson, Military Sealift Command, Washington, D.C. Technical Adviser Paul H. Wirsching, University of Arizona, Tucson SR-1339 Effect of High-strength Steels on Strength Considerations of Design and Construction Details of Ships (SSC-374) (NTIS PB95-100376) Investigator Peter W. Buermann Contractor Gibbs & Cox, Inc., New York, New York Objective Analyze the in-service failures in construction details using high-strength steels, identify problem areas, and recommend design and construction details to reduce problems. Summary The report calls attention to the problem of high-strength-steel structural details and provides a general methodology for assessing their strength using existing technology. Examples using this methodology are presented for existing high-strength-steel structural details that have presented problems in service. Project Chair Philip G. Rynn, American Bureau of Shipping, Houston, Texas Technical Adviser Roger G. Kline, Consultant—Ship Structures, New Berlin, Wisconsin

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Marine Structures Research Recommendations: Recommendations for the Interagency Ship Structure Committee's FYs 1996-'97 and Later-Years Research Program SR-1341 Residual Strength Assessment for Damaged Marine Structures Investigator Christopher J. Wiernicki Contractor Designers and Planners, Inc., Arlington, Virginia Objective Develop approaches to assess the residual strength and life of marine structures that have sustained damage in service. Summary This report identifies key elements that are required to undertake an analysis to evaluate the residual strength of damaged marine structures. Emphasis is placed on assessing the residual strength of marine structures that have been damaged due to normal operating loads. The report summarizes methods that are available to industry for evaluation of damage such as fracture. An example problem is presented that represents the application of an integrated approach to residual strength assessment to a particular ship type. Project Chair John S. Spencer, American Bureau of Shipping, Houston, Texas Technical Adviser Maria Celia C. Ximenes, Chevron Shipping Company, San Francisco, California SR-1342 Hydrodynamic Impact on Displacement Ship Hulls Investigator John C. Daidola Contractor M. Rosenblatt & Son, New York, New York Objective Assess the state of the art in estimating forebody hydrodynamic impacts on displacement ship hulls, and develop a plan for future research on hydrodynamic impact loadings on marine structures. The plan must address slamming, wave slap, and “frontal” impacts. Summary The report identifies theories of hydrodynamic impact loading that have been developed over the years by many researchers. These theories and prediction methods are evaluated to identify those that are the most accurate, identifying gaps and assumptions that exist in the current technology. These prediction methods are compared by applying them to two vessels. The report also identifies the need for future research to address the gaps and assumptions that are identified. Project Chair Allen H. Engle, Naval Sea Systems Command, Washington, D.C. Technical Adviser Subrata K. Chakrabarti, Chicago Bridge & Iron Co., Plainfield, Illinois

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Marine Structures Research Recommendations: Recommendations for the Interagency Ship Structure Committee's FYs 1996-'97 and Later-Years Research Program SR-1346 Improved Ship Hull Structural Details Relative to Fatigue (SSC-379) Investigator Karl Stambaugh Contractor Consulting Naval Architects, Severna Park, Maryland Objective Develop a series of improved structural details that account for the unique fatigue stress pattern of ship structures. Summary The report presents a fatigue design strategy for welded ship structural details that is based on cumulative damage theory using nominal stress. The approach is modified to account for the complex geometry of welded structural details of ships. Fatigue notch factors and stress concentration factors are derived from experimental data and finite-element analysis. Guidance is provided showing detail designers how to improve the fatigue life of details by using this approach. Project Chair Chao Lin, U.S. Maritime Administration, Washington, D.C. Technical Adviser Robert L. Clark, Clark–Cim, Inc., Reston, Virginia SR-1348 Measurement of Ice Loads on Ship Structures (SSC-376) Investigator James W. St. John Contractor Science Technology Corporation, Columbia, Maryland Objective Develop a database on ice loads that could be used for probability-based design approaches. Assess the effects of ship displacement, impact location, and hull shape on the ice impact loads on icebreakers and other marine structures. Summary Beginning in August 1992, the Nathaniel B. Palmer, a research vessel, operated for 3 weeks in mid-winter ice conditions, including first-year and second-year ice. In addition to an instrumented bow panel, there were instrumented panels on the starboard side, the transom, and on the bottom, so that the relative magnitudes of the impact loads could be compared for similar ice conditions but different hull locations. Data from a total of 800 ice- impact events were obtained using the four instrumented hull panels. This report covers instrumentation and data collection, analysis of the data gathered, and a comparison study between different ice-load measurement programs on different types of icebreakers. Project Chair Rubin Sheinberg, U.S. Coast Guard, Washington, D.C.

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Marine Structures Research Recommendations: Recommendations for the Interagency Ship Structure Committee's FYs 1996-'97 and Later-Years Research Program Technical Adviser none assigned SR-1350 Examination of Design Criteria for Stiffened Plate Panels Investigator Natale S. Nappi, Sr. Contractor Designers and Planners, Inc., Arlington, Virginia Objective Evaluate the effects of loadings such as vertical shear, membrane stress, and torsion in the mathematic model for stress analysis of stiffened plate panels, and propose revised design criteria as warranted. Summary The report presents the results of a study conducted to determine the effect of the stiffness characteristics of the supporting members of a grillage structure on plate panel stress. Grillage scantlings were developed using a first-principles–based approach and then analyzed using finite-element analysis techniques to take into account the flexibility of the grillage stiffeners and to quantify the effects of vertical shear, membrane, and torsional stress components. The results are summarized, indicating that the stress in a plate panel can be 50 percent higher if the stiffeners deflect than if the stiffeners are rigid. Vertical-shear stresses are only 10 percent greater than normal stresses, and initial plate deflection does not significantly affect the behavior of stiffened plate structures. The report also provides recommendations for future research. Project Chair Gary North/Todd Ripley, U.S. Maritime Administration, Washington, D.C. Technical Adviser Hsien Yun Jan, Martech Inc., Neshanic Station, New Jersey SR-1351 Hull Structure Concepts for Improved Producibility (SSC-377) Investigator John C. Daidola Contractor M. Rosenblatt and Son, Inc., New York, New York Objective Develop alternative structural system concepts for selected ship types that decrease labor requirements in design, fabrication, and outfitting phases. The structural systems should also be capable of low-cost maintenance during the life of a vessel. Summary The report establishes foreign ship production baselines that are then used to evaluate alternative structural concepts from a construction time and manpower viewpoint. Project Chair Norman Hammer, U.S. Maritime Administration, Washington, D.C.

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Marine Structures Research Recommendations: Recommendations for the Interagency Ship Structure Committee's FYs 1996-'97 and Later-Years Research Program Technical Adviser James R. Wilkins, Jr., Wilkins Enterprise, Inc., Riva, Maryland SR-1353 The Role of Human Error in the Design, Construction, and Reliability of Marine Structures (SSC-378) (NTIS PB95-126827) Investigator Robert G. Bea Contractor Ocean Engineering Services, Moraga, California Objective Perform a state-of-the-art assessment of the impact of human error (nonphysical factors) on the safety of marine structures. It would be a first step toward reducing the risk of failures due to human error and establishing procedures and guidelines to consider the effects of human error in design and the formulation of structural design criteria. Summary The report presents an assessment of the influences of human error on the design, construction, and reliability of marine structures. The report categorizes human factors, considers relevant case studies, identifies qualitative and quantitative processes for evaluating the incidence and effects of human error, studies the impacts of human error on design guidelines, and evaluates how marine critical structural components and systems should be designed to accommodate human and organizational errors. The report also recommends fundamental approaches to improve the management of human and organizational errors in design and construction. Project Chair John S. Spencer, American Bureau of Shipping, Houston, Texas Technical Adviser Paul Fischbeck, Carnegie Mellon University, Pittsburgh, Pennsylvania; Marc Wilson, Dowling College, Long Island, New York.

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Marine Structures Research Recommendations: Recommendations for the Interagency Ship Structure Committee's FYs 1996-'97 and Later-Years Research Program TABLE 6 Cross-Reference of Ship Structure Committee Project Numbers and Report Numbers BY SSC REPORT NUMBER BY SSC PROJECT NUMBER SSC Report Number SSC Project Number   NTIS Accession Number SSC Project Number SSC Report Number 338 1297   PB91-152330 1297 338 339 1308   PB91-152759 1298 346 340 1308   PB91-146191 1300 349 341 1313   PB91-153635 1301 358 342 1313   PB91-146209 1303 344 343 1320   PB91-152124 1304 347 344 1303   PB91-153262 1305 334 345 1321 Part 1 PB91-149476 1306 348 345 1321 Part 2 PB91-146043 1307 359 346 1298   PB91-146043 1308 339 347 1304   PB91-173070 1308 340 348 1306   PB91-169748 1309 353 349 1300   PB91-160325 1310 351 350 1312   ADA-232630 1311 352 351 1310   PB91-153304 1312 350 352 1311 Abridged version PB92-163294 1313 341         1313 342 352 1311 4-volume set PB92-176296 1314 362         1315 357 353 1309   PB91-173328 1316 354 354 1316   ADA-247671 1317 355 355 1317   PB91-153270 1319 366 356 1323   PB91-153288 1320 343 357 1315   PB91-169730 1321 345 358 1301   PB91-146035 1322 364 359 1307   PB91-193458 1323 356 360 1328   PB91-129270 1324 367 361 1327   PB91-133421 1326 363 362 1314   PB91-170241 1327 361 363 1326   PB91-193441 1328 360 364 1322   PB91-201343 1330 368 365 1332   PB92-163286 1331 ** 366 1319   ADA-258160 1332 365 367 1324   ADA-268409 1333 370 367 1324 Appendix PB94-102225 1334 371 368 1330   PB94-109675 1336 369 369 1336   PB94-121928 1337 373 370 1333   PB94-121936 1338 375 371 1334   PB94-121944 1339 374 372 1347   PB94-121951 1341 * 373 1337   PB94-188208 1342 * 374 1339   PB95-100376 1346 379 375 1338   PB95-126819 1347 372 376 1348   PB95- 1348 376 377 1351   PB95- 1350 * 378 1353   PB95-126827 1351 377 379 1346   PB95- 1353 378 * To be assigned. Report numbers for all projects have not been assigned. ** Proceedings and Summary of National Conference on Use of Composite Materials in Load-bearing Marine Structures. 1990. Washington, D.C.: National Academy Press.

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