ssc-367 - Ship Structure Committee

imperfections, fabrication defects, improper inspection or
maintenance, unpredicted loads or, more likely, a combination of
these interactingvariables. As the complexityof marinestructures
increases,betterunderstandingof the variablescontributingto the
integrity of structure components and the global response of the
structure becomes very important. Although several excellent
documents on fatigue are available, most address fatigue design of
either ship or offshore platform structures (References1.1 through
1.8). Thus the engineer may have difficulty in assessing the
significance of fatigue within the context of overall design of
marine structures. It is also difficult to evaluatethe sensitivity
and interactionof variables affecting fatigue life or the relative
uncertaintiesthat are built in. The UEGReconnnendations(Reference
1.8), although applicable to only tubular joints, provides a
detailed discussion of various design requirements and code
recommendations.
Fatigue analysis and design must be carried out while the structure
is being designed and revised to satisfy numerous other pre-service
and in-service loading conditions. Thus, to achieve an effective
design the overall design strategy should incorporatefatigue as an
integral part of design, with primary impact on design details,
redundancy, material and fabrication specifications, operational
performance, inspection program and cost. Because structures’
susceptibility to fatigue and the severity of fatigue environment
varies, the chosen fatigue design and analysis methodology, the
sequence, and the extent of the fatigue design effort should be
compatible with the overall design program and should be carefully
planned and monitored to prevent construction delays or costly
modifications during construction.
1.2
OBJECTIVES
This document was prepared to provide the engineer with an up-todate
assessment of fatigue analysis and design. It may be used
either as a comprehensive guideline or a quick reference source.
The first four sections of the report provide an overview and
1-2