Notched fatigue life curves of welded joints were established and compared with International Institute of Welding (IIW) standards to verify the metal fatigue performance of welded joints treated with pneumatic impact (PIT).
This paper was based on the notched stress method, and this approach not only allows for the assessment of fatigue failure of welded structures with toes and roots but also for the assessment of fatigue strength of joints with localized post-treatments. The paper summarizes the nominal stress data of weld and pneumatic impact treated (PIT) steel joints of different strengths, fits the nominal stress curves of the joints without the use of strength and obtains the stress concentration factor of the joints through the establishment of the finite element (FE) method. Notched fatigue life curves for welded joints were established and compared with IIW standards.
Notched stress concentration data obtained by the FE method was more reliable. The slope of the fatigue life curve of welded joints treated with pneumatic impact (PIT) increases by at least 2.5%, and the stress concentration factor decreases by 20%.
In the fatigue study of notched systems, there were fewer studies on fatigue life assessment of joints processed by high frequency mechanical impact. The purpose of this paper was to analyze the fatigue test data of typical strength steel welded joints and fit fatigue life curves, and the research content provides an important reference for improving the safety and fatigue failure assessment of heavy steel structures.
