Experiment and simulation investigation of multiple cracks evolution at the weld toe

Local weld geometry-based characterization of fatigue strength in laser-MAG hybrid welded joints

“…5 demonstrates a significant difference in fatigue performance as a result of a difference of a factor of three in the average notch depth. Indeed, this finding is in line with previous research showing that the undercut depth has a deleterious effect on fatigue performance [20,21,23,25,34,35,37,47].…”

“…In a later publication, a statistical analysis of weld notch parameters was performed on marginally smoothed scanned geometry, showing that the weld transition radius and undercut depth follow a lognormal distribution, while the flank angle follows a normal distribution [40]. Wei et al studied the evolution of fatigue cracks, focusing on the weld geometry, indicating that the early crack initiation is composed of small cracks and the initiation behavior is strongly related to the weld transition radius [47]. The paper shows a sharp increase in the fatigue crack propagation rate in the crack coalescence region with increasing crack depth and the coalescence of irregular crack shapes into semi-elliptical shapes.…”

Fatigue Crack Propagation Behavior of the 2195-T8 Aluminum-Lithium Alloy with a Precorroded Hole

“…Paris law can reflect crack stable growth rates which was confirmed in [43]. However, for considering the effects of multiparameters, NASGRO formula, evolved from the Paris law, has been used to simulate the crack growth [43,44]: Step 25…”

“…To improve calculation efficiency, the FEM model has been divided into submodels. A no-crack region was set to signify the barrier, as shown in the yellow region [42].…”

“…The crack front propagation length Δa i can be calculated by specifying the load cycles step ΔN [42] that can be expressed as…”