ssc-367 - Ship Structure Committee

period, are also designed tomeet the rules and other fatigue design
procedures. However, such vessels also require spectral fatigue
analysisto define the loadings,response and stress distributions.
Often, model basin tests are also carried out to validate the
applied loadings and motions.
Stationary marine structures are generally unique and have
specialized functions. Since the design criteria and functional
requirements dictate the general configuration of such structures,
each structuremust be analyzedthoroughlyto generate the loads,to
determine the response to these loads, and to determine its
susceptibility to.fatigue. Most specialized structures require
spectral fatigue analysis.
4.4
SENSITIVITY OF FATIGUE PARAMETERS
Fatiguedesign and analysis parametersdiscussed in Sections 3.1 and
3.2 i11ustrate the general interaction of these parameters. The
specific interactions and the actual sensitivities of these
parameters depend largely on the structure’s global configuration,
joint configuration and details, material characteristics,
fabrication quality and the design requirements other than fatigue.
Therefore, fatigue analysis and design efforts often incorporate
flexibilityto carry out parallel studies to assess the sensitivity
of major parameters that affect fatigue life.
Although the parametersillustratedon Figure3-l are all important,
some of the more important parameters for fatigue life improvement
are:
●
Enhance fabrication quality and minimize defects
●
Minimize applied loads and motions to minimize nominal cyclic
stress ranges
●
Optimize the design for uniform load distributions
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