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From a local stress approach to fracture mechanics: a comprehensive evaluation of the fatigue strength of welded joints
Author(s) -
Atzori B.,
Lazzarin P.,
Tovo R.
Publication year - 1999
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1046/j.1460-2695.1999.00179.x
Subject(s) - welding , structural engineering , fatigue limit , residual stress , fillet weld , stress intensity factor , materials science , fracture mechanics , stress concentration , fillet (mechanics) , stress (linguistics) , fracture (geology) , transverse plane , vibration fatigue , mechanics , fatigue testing , engineering , composite material , physics , linguistics , philosophy
This paper investigates the possibility of unifying different criteria concerned with the fatigue strength of welded joints. In particular, it compares estimates based on local stress fields due to geometry (evaluated without any crack‐like defect) and residual life predictions in the presence of a crack, according to LEFM. Fatigue strength results already reported in the literature for transverse non‐load‐carrying fillet welds are used as an experimental database. Nominal stress ranges were largely scattered, due to large variations of joint geometrical parameters. The scatter band greatly reduces as soon as a 0.3‐mm virtual crack is introduced at the weld toe, and the behaviour of the joints is given in terms of Δ K I versus total life fatigue. Such calculations, not different from residual life predictions, are easily performed by using the local stress distributions determined near the weld toes in the absence of crack‐like defects. More precisely, the analytical expressions for K I are based on a simple combination of the notch stress intensity factors K 1 N and K 2 N for opening and sliding modes. Then, fatigue strength predictions, as accurate as those based on fracture mechanics, are performed by the local stress analysis in a simpler way.