Abstract:
High frequency mechanical impact (HFMI) is widely used in the field as a reliable and efficient repost-weld treatment. In order to evaluate the fatigue life of steel welded joints treated by HFMI under different stress ratio
R and material yield strength
fy, extensive fatigue test data were re-analyzed using the notch stress approach combined with SWT (smith-watson-topper) and Walker models. The results reveal that the relationship between the fatigue grades FAT,
R and
fy of the joints under nominal stress system can be expressed by FAT = 0.1
fy + M(
R). Under the notched stress system, for joints made of the same material loaded under different
R values, both models can be used to predict fatigue life, but the Walker model has higher accuracy. For joints of various materials with different
R values, SWT model has a fixed form and can comprehensively consider the influence of
R and
fy. Based on this, the survival rate
PS = 97.7% of the
S-N curve with FAT = 325 MPa and slope
m = 6.5 is obtained. The research will directly support the fatigue assessment and anti-fatigue design of engineering structures.