Fatigue Damage Initiation in Oil and Gas Steel Pipes Assessment

7 Fatigue Damage Initiation in Oil and Gas Steel Pipes Assessment 

In order to assure structural integrity of oil and gas steel pipes and forewarn a fatigue-related failme, it is very important to adopt a consistent fatigue criterion. Nonetheless, the fatigue-related damage may be divided into the following two main phases [14]  

Incubation phase During this phase, only microstructural changes, microcracks nucleation, and microcracking can be observed. It is to be noted that the study of this phase is more cumbersome to perform since microstructural changes and fatigue damage cannot be easily separated. 

Propagation phase During this phase, macroscopic cracking and macrocrack propagation result in fatigue failure, and the physical data that may quantify the material s damage state can be more easily obtained. 

It is to be noted that among the nondestructive methods for fatigue damage imitation assessments, x-ray diffraction method is considered to be one of the most suitable analysis methods [14]. Additional information on this method is available in Reference 14. 

---

Discuss fatigue damage initiation in oil and gas steel pipes assessment ... 

---