Page 158 - Marine Structural Design

134 PART I Smctural Design Principles

es for Different Types of Cylinders (NTS, 1998)
Type of Structure Geomc Y
5ng Stiffened
Buckling Mode mngitudinal Mhogonally
unstiffened ;tiffend ;tiffened
ircular)

Shell buckling

Panel stiffener
buckling

Panel ring buckling

General buckling

R
Column buckling

7.3 Fatigue Limit State Design
7.3.1 Introduction
Marine structures are subjected to a wide variety of loads that are cyclic in nature (e.g. storm
winds, waves, and currents). These cyclic loadings develop cyclic strains in these structures.
If the strains are large enough, then the strength, stiffness, and capacity of the structural
elements can be reduced due to fatigue degradation.
Most fatigue problems have been associated with flaws introduced into the structure in the
course of its fabrication and construction (e.g. poor welding, misaligned members), or in the
course of its operation (e.g. corrosion damage, dropped objects damage). Thus, one of the