Chapter 27 - Fatigue Reliability

Abstract

This chapter discusses fatigue reliability. Proper prediction of the fatigue behavior is of vital importance to maintain a sufficient level of reliability and integrity in structures. A large uncertainty is introduced in fatigue assessment due to various assumptions and hypotheses. The fundamentals of fatigue strength assessment for ships and other marine structures are explained in this book. This chapter discusses the uncertainty in fatigue stress model. The process of computing stresses in a component includes the following steps; defining and modeling the environment, translating the environment into forces on the structure, computing the response of the structure to the environmental loads, computing nominal stresses in the components, and computing the stresses to be used for design. Fatigue reliability models are described in this chapter. Information about the degree of uncertainty of different variables is discussed. The other subdivisions include fatigue reliability—S–N approach, fatigue reliability—fracture mechanics (FM) approach, simplified fatigue reliability model—lognormal format, calibration of FM model by S–N approach, fatigue reliability application—fatigue safety check, target safety index for fatigue, and partial safety factors. This chapter covers many numerical examples, like fatigue reliability based on simple S–N approach and fatigue reliability of large aluminum catamaran.