Multiaxial fatigue assessment of welded joints – Recommendations for design codes

Experimental and numerical analysis of fillet-welded joints under low-cycle fatigue loading by means of full-field techniques

“…14 The assessment becomes more complex in the presence of a multiaxial stress state. [15][16][17] Some fatigue cracks have been detected in ship structures within a few years of their service life, and this type of fatigue cannot be adequately explained by the high-cycle fatigue (HCF) approaches based on the S-N curve. Most ship structures consist of plate details, connected to longitudinal and transverse members by welded joints, which are the sites of high stress concentrations, and are subject to severe environmental loading from wave pressure, ship motions and loading/unloading operations, which induce significant fatigue loads.…”

The equivalent stress on the critical plane determined by the maximum covariance of normal and shear stresses

“…As it was shown in [6,7], there are intermediate materials, where the critical plane position is not influenced only by normal or shear stress. Aluminium alloys belong to that group of materials.…”

Fatigue analysis of multipass welded joints considering residual stresses

“…There are different approaches to deal the previous problem, which are based on obtaining an equivalent uniaxial stress. Between the different approaches, the following methods can be remarked: (i) the recommendations suggested by the standard codes [11,12,14,29], (ii) the effective equivalent stress hypothesis proposed by Sonsino [30,31], for ductile steels welds under multiaxial non-proportional loadings, (iii) the methods based on critical plane approach [2,32,33]. The main drawback of the previous methods is that they do not consider the real value of RS.…”