| Popis: |
The design of fixed platform structures for deeper water and more hostile environments places increased emphasis on the consideration of long-life (> 10 6 cycles) corrosion-fatigue behavior of low- and medium-strength structural steels in seawater. An interpretive review of available information on this technical area has been conducted, with separate consideration given to both fatigue-crack initiation and propagation. Emphasis is placed upon weldments because welded tubular joints are the areas of main concern in the fatigue evaluation of conventional offshore platform-type structures. Effects of strain range or range of stress intensity, stress ratio, cycling frequency, and type of loading spectrum are addressed. Also, environmental effects of oxygen level, temperature, pH, cathodic polarization, and high hydrostatic pressure are covered. The merits of cathodic protection in mitigating corrosion-fatigue damage are discussed in detail. Finally, results of this review are used to develop recommendations of the variables to be included in future experimental studies of long-life corrosion-fatigue resistance of such steels in seawater. |
