ssc-367 - Ship Structure Committee

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An indirect fatigue design where the design for extreme
Ioadingandexperience-based detailingare intendedto provide
ample fatigue resistance. This approach may be valid for
structures subjected to negligible cyclic loadings.
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Simplified allowable stress methods based on in-servicedata
and valid theoreticaldevelopments. This approach isvalid as
a design tool to size structure components.
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Comprehensive fatigue analyses and design methods with
appropriatefatigue strength and stress history models. This
approach, including finite element analyses to accurately
determine the stress distributions, should be used in the
design of all structures susceptible to fatigue failure.
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Comprehensivefatigue analyses and design methods, taking the
lifetime inspection and maintenance strategies into account.
This is the valid approach to implement a cost-effective
fatigue avoidance strategy.
Design, inspection and maintenance are thus logically treated as
interdependent parts of an overall process contributing to the
quality of a structure.
The other basic premises affecting fatigue avoidance strategies can
be summarized as follows:
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The fatigue life is usually taken as twice the design life.
The target fatigue lives can be chosen tobe about fiveto ten
times the design life with very little increase in steel.
The additional expenditures caused by the slight increase in
steel cost can be offset many times over by savings in
operating expendituresassociatedwith inspection,repair and
maintenance.
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Service experience is of utmost importance in the design of
marine structures. The designer should have an access to
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