Issue 38

X. Yu et alii, Frattura ed Integrità Strutturale, 38 (2016) 148-154; DOI: 10.3221/IGF-ESIS.38.20 153 shear mode FCG was observed for A106-93 mild steel [3]. This result reconfirms an earlier review finding [3] that under cyclic mode II loads, a shear mode FCG is more likely in aluminium alloys than in steels. Figure 4 : Fatigue cracks at the outer surface of tubular specimens at the end of tests. Coplanar FCG was also observed under almost all load cases as summarised in Tab. 1. Nevertheless, for the loading cases where both  and  were cyclically applied, the coplanar growth was a transient behaviour, typically less than 1mm long, after which the FCG turned into the direction as discussed above. θ